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general description the max148/max149 10-bit data-acquisition systems combine an 8-channel multiplexer, high-bandwidth track/hold, and serial interface with high conversion speed and low power consumption. they operate from a single +2.7v to +5.25v supply, and sample to 133ksps. both devices?analog inputs are software configurable for unipolar/bipolar and single-ended/differential operation. the 4-wire serial interface connects directly to spi/ qspi and microwire devices without external logic. a serial-strobe output allows direct connection to tms320-family digital signal processors. the max148/ max149 use either the internal clock or an external serial- interface clock to perform successive-approximation analog-to-digital conversions. the max149 has an internal 2.5v reference, while the max148 requires an external reference. both parts have a reference-buffer amplifier with a ?.5% voltage- adjustment range. these devices provide a hard-wired shdn pin and a software-selectable power-down, and can be pro- grammed to automatically shut down at the end of a con- version. accessing the serial interface automatically powers up the max148/max149, and the quick turn-on time allows them to be shut down between all conver- sions. this technique can cut supply current to under 60? at reduced sampling rates. the max148/max149 are available in a 20-pin dip and a 20-pin ssop. for 4-channel versions of these devices, see the max1248/max1249 data sheet. ________________________applications portable data logging data acquisition medical instruments battery-powered instruments pen digitizers process control ____________________________features ? 8-channel single-ended or 4-channel differential inputs ? single-supply operation: +2.7v to +5.25v ? internal 2.5v reference (max149) ? low power: 1.2ma (133ksps, 3v supply) 54? (1ksps, 3v supply) 1? (power-down mode) ? spi/qspi/microwire/tms320-compatible 4-wire serial interface ? software-configurable unipolar or bipolar inputs ? 20-pin dip/ssop packages max148/max149 +2.7v to +5.25v, low-power, 8-channel, serial 10-bit adcs ________________________________________________________________ maxim integrated products 1 v dd i/o sck (sk) mosi (so) miso (si) v ss shdn sstrb dout din sclk cs com agnd dgnd v dd ch7 4.7 m f 0.1 m f ch0 0v to +2.5v analog inputs max149 cpu +3v vref 0.01 m f refadj __________typical operating circuit 19-0464; rev 2; 5/98 part ? max148 acpp max148bcpp max148acap 0? to +70? 0? to +70? 0? to +70? temp. range pin-package 20 plastic dip 20 plastic dip 20 ssop evaluation kit available ordering information ordering information continued at end of data sheet. ? contact factory for availability of alternate surface-mount packages. max148bcap 0? to +70? 20 ssop inl (lsb) ?/2 ? ?/2 ? spi and qspi are trademarks of motorola, inc. microwire is a trademark of national semiconductor corp. pin configuration appears at end of data sheet. for free samples & the latest literature: http://www.maxim-ic.com, or phone 1-800-998-8800. for small orders, phone 408-737-7600 ext. 3468.
max148/max149 +2.7v to +5.25v , low-power , 8-channel, serial 10-bit adcs 2 _______________________________________________________________________________________ absolute maximum ratings electrical characteristics v dd = +2.7v to +5.25v; com = 0v; f sclk = 2.0mhz; external clock (50% duty cycle); 15 clocks/conversion cycle (133ksps); max149?.7 f capacitor at vref pin; max148?xternal reference, vref = 2.50 0 v applied to vref pin; t a = t min to t max ; unless otherwise noted.) stresses beyond those listed under ?bsolute maximum ratings?may cause permanent damage to the device. these are stress rating s only, and functional operation of the device at these or any other conditions beyond those indicated in the operational sections of the specificatio ns is not implied. exposure to absolute maximum rating conditions for extended periods may affect device reliability. v dd to agnd, dgnd ................................................. -0.3v to 6v agnd to dgnd ...................................................... -0.3v to 0.3v ch0?h7, com to agnd, dgnd ............ -0.3v to (v dd + 0.3v) vref, refadj to agnd ........................... -0.3v to (v dd + 0.3v) digital inputs to dgnd .............................................. -0.3v to 6v digital outputs to dgnd ........................... -0.3v to (v dd + 0.3v) digital output sink current ................................................. 25ma continuous power dissipation (t a = +70 c) plastic dip (derate 11.11mw/ c above +70 c) ......... 889mw ssop (derate 8.00mw/ c above +70 c) ................... 640mw cerdip (derate 11.11mw/ c above +70 c) .............. 889mw operating temperature ranges max148_c_p/max149_c_p .............................. 0 c to +70 c max148_e_p/max149_e_p ............................ -40 c to +85 c max148_mjp/max149_mjp ........................ -55 c to +125 c storage temperature range ............................ -60 c to +150 c lead temperature (soldering, 10sec) ............................ +300 c s 1.5 t acq differential nonlinearity track/hold acquisition time ns 30 aperture delay 6 s 35 65 t conv conversion time (note 5) 5.5 7.5 ps mhz 1.0 full-power bandwidth mhz 2.25 small-signal bandwidth db -75 channel-to-channel crosstalk db 70 sfdr spurious-free dynamic range db -70 thd total harmonic distortion db 66 sinad signal-to-noise + distortion ratio lsb 0.05 channel-to-channel offset matching ppm/ c 0.25 gain temperature coefficient 0.5 <50 bits 10 resolution gain error (note 3) 1 aperture jitter offset error lsb 1.0 inl relative accuracy (note 2) lsb 1 dnl 0.15 1 lsb 0.15 2 units min typ max symbol parameter external clock = 2mhz, 12 clocks/conversion internal clock, shdn = v dd internal clock, shdn = float max14_a -3db rolloff 65khz, 2.500v p-p (note 4) up to the 5th harmonic max14_a max14_b no missing codes over temperature max14_a max14_b conditions lsb 2 max14_b dc accuracy (note 1) dynamic specifications (10khz sine-wave input, 0v to 2.500vp-p, 133ksps, 2.0mhz external clock, bipolar input mode) conversion rate
max148/max149 +2.7v to +5.25v , low-power , 8-channel, serial 10-bit adcs _______________________________________________________________________________________ 3 multiplexer leakage current a 0.01 10 shutdown vref input current k 18 25 vref input resistance a 100 150 vref input current v 1.0 v dd + 50mv vref input voltage range (note 9) pf 16 input capacitance 1.8 mhz 0.225 internal clock frequency a 0.01 1 units min typ max symbol parameter shdn = float vref = 2.500v shdn = v dd on/off leakage current, v ch_ = 0v or v dd conditions electrical characteristics (continued) v dd = +2.7v to +5.25v; com = 0v; f sclk = 2.0mhz; external clock (50% duty cycle); 15 clocks/conversion cycle (133ksps); max149?.7 f capacitor at vref pin; max148?xternal reference, vref = 2.50 0 v applied to vref pin; t a = t min to t max ; unless otherwise noted.) v 2.470 2.500 2.530 vref output voltage t a = +25 c (note 7) ma 30 vref short-circuit current 30 max149 mv 0.35 load regulation (note 8) 0ma to 0.2ma output load 0 internal compensation mode f 4.7 capacitive bypass at vref external compensation mode f 0.01 capacitive bypass at refadj % 1.5 refadj adjustment range v v dd - 0.5 refadj buffer-disable threshold f 0 capacitive bypass at vref internal compensation mode 2.00 v/v 2.06 reference buffer gain 4.7 max148 max149 external compensation mode 10 a 50 refadj input current max148 max149 ppm/ c vref temperature coefficient 0 to vref v vref / 2 input voltage range, single- ended and differential (note 6) unipolar, com = 0v bipolar, com = vref / 2 0.1 2.0 mhz 0 2.0 external clock frequency data transfer only conversion rate (continued) analog/com inputs internal reference (max149 only, reference buffer enabled) external reference at vref (buffer disabled) external reference at refadj
i dd max148/max149 +2.7v to +5.25v , low-power , 8-channel, serial 10-bit adcs 4 _______________________________________________________________________________________ electrical characteristics (continued) v dd = +2.7v to +5.25v; com = 0v; f sclk = 2.0mhz; external clock (50% duty cycle); 15 clocks/conversion cycle (133ksps); max149?.7 f capacitor at vref pin; max148?xternal reference, vref = 2.50 0 v applied to vref pin; t a = t min to t max ; unless otherwise noted.) v 3.0 v ih din, sclk, cs input high voltage v dd > 3.6v mv 0.3 psr supply rejection (note 12) full-scale input, external reference = 2.500v, v dd = 2.7v to 5.25v pf 15 c in din, sclk, cs input capacitance a 0.01 1 i in din, sclk, cs input leakage v 0.2 v hyst din, sclk, cs input hysteresis v 0.8 v il din, sclk, cs input low voltage 2.0 a 4.0 i s shdn input current v 0.4 v sl shdn input low voltage v v dd - 0.4 v sh shdn input high voltage shdn = 0v or v dd na 100 shdn maximum allowed leakage, mid input v v dd / 2 v flt shdn voltage, floating shdn = float shdn = float units min typ max symbol parameter (note 10) v in = 0v or v dd v dd 3.6v conditions a 0.01 10 i l three-state leakage current v v dd - 0.5 v oh output voltage high v 0.8 v ol output voltage low 0.4 pf 15 c out three-state output capacitance cs = v dd (note 10) cs = v dd i source = 0.5ma i sink = 16ma i sink = 5ma 2.70 5.25 1.2 2.0 operating mode, full-scale input (note 11) 3.5 15 full power-down 1.2 10 ma 1.6 3.0 v 1.1 v dd - 1.1 v sm shdn input mid voltage positive supply current v dd positive supply voltage v i dd a 30 70 digital inputs (din, sclk, cs , shdn ) digital outputs (dout, sstrb) power requirements fast power-down (max149) i dd v dd = 5.25v v dd = 3.6v v dd = 5.25v v dd = 3.6v
max148/max149 +2.7v to +5.25v , low-power , 8-channel, serial 10-bit adcs _______________________________________________________________________________________ 5 figure 1 __________________________________________ t ypical operating characteristics (v dd = 3.0v, vref = 2.500v, f sclk = 2.0mhz, c load = 20pf, t a = +25 c, unless otherwise noted.) 0 256 512 768 1024 integral nonlinearity vs. code 0.10 0.05 -0.10 -0.05 0 max148/9-01 code inl (lsb) 0.125 0 2.25 2.75 4.25 integral nonlinearity vs. supply voltage 0.100 0.075 0.050 0.025 supply voltage (v) inl (lsb) 3.75 5.25 3.25 4.75 max148/9-02 max149 max148 0 0.025 0.050 0.075 0.100 0.125 -60 -20 20 60 100 140 integral nonlinearity vs. temperature temperature (?) inl (lsb) max148/9-03 max148 max149 v dd = 2.7v timing characteristics (v dd = +2.7v to +5.25v, t a = t min to t max , unless otherwise noted.) note 1: tested at v dd = 2.7v; com = 0v; unipolar single-ended input mode. note 2: relative accuracy is the deviation of the analog value at any code from its theoretical value after the full-scale range has been calibrated. note 3: max149?nternal reference, offset nulled; max148?xternal reference (vref = +2.500v), offset nulled. note 4: ground ?n?channel; sine wave applied to all ?ff?channels. note 5: conversion time defined as the number of clock cycles multiplied by the clock period; clock has 50% duty cycle. note 6: the common-mode range for the analog inputs is from agnd to v dd . note 7: sample tested to 0.1% aql. note 8: external load should not change during conversion for specified accuracy. note 9: adc performance is limited by the converter? noise floor, typically 300 vp-p. note 10 : guaranteed by design. not subject to production testing. note 11 : the max148 typically draws 400 a less than the values shown. note 12 : measured as | v fs (2.7v) - v fs (5.25v) | . internal clock mode only (note 7) external clock mode only, figure 2 external clock mode only, figure 1 din to sclk setup figure 1 figure 2 figure 1 max14_ _c/e conditions max14_ _m ns 20 240 figure 1 ns t csh ns 240 t str cs rise to sstrb output disable ns 240 t sdv cs fall to sstrb output enable 240 t sstrb sclk fall to sstrb ns 200 t cl sclk pulse width low ns 200 sclk pulse width high ns 0 cs to sclk rise hold ns 100 t css cs to sclk rise setup ns 240 t tr cs rise to output disable ns 240 t dv cs fall to output enable t ch 20 200 t do sclk fall to output data valid ns 0 t dh din to sclk hold ns s 1.5 t acq acquisition time 0 t sck sstrb rise to sclk rise ns 100 t ds units min typ max symbol parameter
max148/max149 +2.7v to +5.25v , low-power , 8-channel, serial 10-bit adcs 6 _______________________________________________________________________________________ 2.00 0.50 2.25 2.75 supply current vs. supply voltage 1.75 1.25 1.50 1.00 0.75 supply voltage (v) supply current (ma) 3.75 5.25 3.25 4.25 4.75 max148/9-04 r l = code = 1010101000 c load = 50pf max148 max149 c load = 20pf 0 2.25 2.75 shutdown supply current vs. supply voltage 3.0 2.5 1.5 2.0 1.0 0.5 supply voltage (v) shutdown supply current ( m a) 3.75 5.25 3.25 4.25 4.75 max148/9-05 full power-down 2.5020 2.4990 2.25 2.75 max149 internal reference voltage vs. supply voltage 2.5015 2.5005 2.5010 2.5000 2.4995 supply voltage (v) internal reference voltage (v) 3.75 5.25 3.25 4.25 4.75 max148/9-06 0.8 0.9 1.0 1.1 1.2 1.3 -60 -20 20 60 100 140 supply current vs. temperature temperature (?) supply current (ma) max148/9-07 max148 max149 r load = code = 1010101000 0 0.4 0.8 1.2 1.6 2.0 -60 -20 20 60 100 140 shutdown current vs. temperature temperature (?) shutdown current ( m a) max148/9-08 2.494 2.495 2.496 2.497 2.498 2.499 2.500 2.501 -60 -20 20 60 100 140 max149 internal reference voltage vs. temperature temperature (?) internal reference voltage (v) max148/9-09 v dd = 2.7v v dd = 3.6v v dd = 5.25v ____________________________ t ypical operating characteristics (continued) (v dd = 3.0v, vref = 2.500v, f sclk = 2.0mhz, c load = 20pf, t a = +25 c, unless otherwise noted.)
max148/max149 +2.7v to +5.25v , low-power , 8-channel, serial 10-bit adcs _______________________________________________________________________________________ 7 ______________________________________________________________ pin description v dd 6k dgnd dout c load 50pf c load 50pf dgnd 6k dout a) high-z to v oh and v ol to v oh b) high-z to v ol and v oh to v ol v dd 6k dgnd dout c load 50pf c load 50pf dgnd 6k dout a) v oh to high-z b) v ol to high-z figure 1. load circuits for enable time figure 2. load circuits for disable time input to the reference-buffer amplifier. to disable the reference-buffer amplifier, tie refadj to v dd . refadj 12 serial-strobe output. in internal clock mode, sstrb goes low when the max148/max149 begin the a/d conversion, and goes high when the conversion is finished. in external clock mode, sstrb pulses high for one clock period before the msb decision. high impedance when cs is high (external clock mode). sstrb 16 serial-data input. data is clocked in at sclk? rising edge. din 17 active-low chip select. data will not be clocked into din unless cs is low. when cs is high, dout is high impedance. cs 18 serial-clock input. clocks data in and out of serial interface. in external clock mode, sclk also sets the conversion speed. (duty cycle must be 40% to 60%.) sclk 19 reference-buffer output/adc reference input. reference voltage for analog-to-digital conversion. in internal reference mode (max149 only), the reference buffer provides a 2.500v nominal output, externally adjustable at refadj. in external reference mode, disable the internal buffer by pulling refadj to v dd . vref 11 analog ground agnd 13 digital ground dgnd 14 serial-data output. data is clocked out at sclk? falling edge. high impedance when cs is high. dout 15 three-level shutdown input. pulling shdn low shuts the max148/max149 down; otherwise, they are fully operational. pulling shdn high puts the reference-buffer amplifier in internal compensation mode. letting shdn float puts the reference-buffer amplifier in external compensation mode. shdn 10 ground reference for analog inputs. com sets zero-code voltage in single-ended mode. must be stable to 0.5lsb. com 9 pin sampling analog inputs ch0?h7 1? function name positive supply voltage v dd 20
max148/max149 +2.7v to +5.25v , low-power , 8-channel, serial 10-bit adcs 8 _______________________________________________________________________________________ _______________ detailed description the max148/max149 analog-to-digital converters (adcs) use a successive - approximation conversion technique and input track/hold (t/h) circuitry to convert an analog signal to a 10-bit digital output. a flexible seri - al interface provides easy interface to microprocessors ( ps). figure 3 is a block diagram of the max148/ max149. pseudo - differential input the sampling architecture of the adc? analog com - parator is illustrated in the equivalent input circuit (figure 4). in single - ended mode, in+ is internally switched to ch0?h7, and in - is switched to com. in differential mode, in+ and in - are selected from the fol - lowing pairs: ch0/ch1, ch2/ch3, ch4/ch5, and ch6/ch7. configure the channels with tables 2 and 3. in differential mode, in - and in+ are internally switched to either of the analog inputs. this configuration is pseudo - differential to the effect that only the signal at in+ is sampled. the return side (in - ) must remain stable within 0.5lsb ( 0.1lsb for best results) with respect to agnd during a conversion. to accomplish this, connect a 0.1 f capacitor from in - (the selected analog input) to agnd. during the acquisition interval, the channel selected as the positive input (in+) charges capacitor c hold . the acquisition interval spans three sclk cycles and ends on the falling sclk edge after the last bit of the input control word has been entered. at the end of the acquisition interval, the t/h switch opens, retaining charge on c hold as a sample of the signal at in+. the conversion interval begins with the input multiplexer switching c hold from the positive input (in+) to the negative input (in - ). in single - ended mode, in - is simply com. this unbalances node zero at the comparator? input. the capacitive dac adjusts during the remainder of the conversion cycle to restore node zero to 0v within the limits of 10-bit resolution. this action is equiv - alent to transferring a 16pf x [(v in + ) - (v in - )] charge from c hold to the binary - weighted capacitive dac, which in turn forms a digital representation of the analog input signal. track/hold the t/h enters its tracking mode on the falling clock edge after the fifth bit of the 8 - bit control word has been shifted in. it enters its hold mode on the falling clock edge after the eighth bit of the control word has been shifted in. if the converter is set up for single - ended inputs, in - is connected to com, and the converter samples the ??input. if the converter is set up for dif - ferential inputs, in - connects to the - ?input, and the difference of | in+ - in - | is sampled. at the end of the conversion, the positive input connects back to in+, and c hold charges to the input signal. the time required for the t/h to acquire an input signal is a function of how quickly its input capacitance is charged. if the input signal? source impedance is high, the acquisition time lengthens, and more time must be input shift register control logic int clock output shift register +1.21v reference (max149) t/h analog input mux 10+2-bit sar adc in dout sstrb v dd dgnd agnd sclk din com refadj vref out ref clock +2.500v 20k *a ? 2.00 (max148) 10 11 12 9 15 16 17 18 19 ch6 7 ch4 5 ch2 3 ch0 1 ch7 8 ch5 6 ch3 4 ch1 2 max148 max149 cs shdn 20 14 13 ? 2.06* a figure 3. block diagram ch0 ch2 ch4 ch6 ch1 ch3 ch5 ch7 com c switch track t/h switch r in 9k c hold hold capacitive dac vref zero comparator + 16pf single-ended mode: in+ = ch0?h7, in- = com. differential mode: in+ and in- selected from pairs of ch0/ch1, ch2/ch3, ch4/ch5, and ch6/ch7. at the sampling instant, the mux input switches from the selected in+ channel to the selected in- channel. input mux figure 4. equivalent input circuit
max148/max149 +2.7v to +5.25v , low-power , 8-channel, serial 10-bit adcs _______________________________________________________________________________________ 9 allowed between conversions. the acquisition time, t acq , is the maximum time the device takes to acquire the signal, and is also the minimum time needed for the signal to be acquired. it is calculated by the following equation: t acq = 7 x (r s + r in ) x 16pf where r in = 9k , r s = the source impedance of the input signal, and t acq is never less than 1.5 s. note that source impedances below 4k do not significantly affect the adc? ac performance. higher source impedances can be used if a 0.01 f capacitor is connected to the individual analog inputs. note that the input capacitor forms an rc filter with the input source impedance, limiting the adc? signal bandwidth. input bandwidth the adc? input tracking circuitry has a 2.25mhz small - signal bandwidth, so it is possible to digitize high - speed transient events and measure periodic sig - nals with bandwidths exceeding the adc? sampling rate by using undersampling techniques. to avoid high - frequency signals being aliased into the frequency band of interest, anti - alias filtering is recommended. analog input protection internal protection diodes, which clamp the analog input to v dd and agnd, allow the channel input pins to swing from agnd - 0.3v to v dd + 0.3v without damage. however, for accurate conversions near full scale, the inputs must not exceed v dd by more than 50mv or be lower than agnd by 50mv. if the analog input exceeds 50mv beyond the sup - plies, do not forward bias the protection diodes of off channels over 2ma. quick look to quickly evaluate the max148/max149? analog perfor - mance, use the circuit of figure 5. the max148/max149 require a control byte to be written to din before each conversion. tying din to +3v feeds in control bytes of $ff (hex), which trigger single - ended unipolar conver - sions on ch7 in external clock mode without powering down between conversions. in external clock mode, the sstrb output pulses high for one clock period before the most significant bit of the conversion result is shift - ed out of dout. varying the analog input to ch7 will alter the sequence of bits from dout. a total of 15 clock cycles is required per conversion. all transitions of the sstrb and dout outputs occur on the falling edge of sclk. 0.1? v dd dgnd agnd com cs sclk din dout sstrb shdn +3v n.c. 0.01? ch7 +3v refadj vref c1 0.1 f 0v to +2.500v analog input oscilloscope ch1 ch2 ch3 ch4 * full-scale analog input, conversion result = $fff (hex) optional for max149, required for max148 max148 max149 +3v 2mhz oscillator sclk sstrb dout* 2.5v 1000pf comp v out +3v max872 figure 5. quick-look circuit
max148/max149 +2.7v to +5.25v , low-power , 8-channel, serial 10-bit adcs 10 ______________________________________________________________________________________ how to start a conversion start a conversion by clocking a control byte into din. with cs low, each rising edge on sclk clocks a bit from din into the max148/max149? internal shift register. after cs falls, the first arriving logic ??bit defines the control byte? msb. until this first ?tart?bit arrives, any number of logic ??bits can be clocked into din with no effect. table 1 shows the control - byte format. the max148/max149 are compatible with spi/ qspi and microwire devices. for spi, select the cor - rect clock polarity and sampling edge in the spi control registers: set cpol = 0 and cpha = 0. microwire , spi, and qspi all transmit a byte and receive a byte at the same time. using the typical operating circuit, the simplest software interface requires only three 8 - bit transfers to perform a conversion (one 8 - bit transfer to configure the adc, and two more 8 - bit transfers to clock out the conversion result). see figure 20 for max148/ max149 qspi connections. bit name description 7(msb) start the first logic ??bit after cs goes low defines the beginning of the control byte. 6 sel2 these three bits select which of the eight channels are used for the conversion (tables 2 and 3). 5 sel1 4 sel0 3 uni/ bip 1 = unipolar, 0 = bipolar. selects unipolar or bipolar conversion mode. in unipolar mode, an analog input signal from 0v to vref can be converted; in bipolar mode, the signal can range from - vref/2 to +vref/2. 2 sgl/ dif 1 = single ended, 0 = differential. selects single - ended or differential conversions. in single - ended mode, input signal voltages are referred to com. in differential mode, the voltage difference between two channels is measured (tables 2 and 3). 1 pd1 selects clock and power - down modes. 0(lsb) pd0 pd1 pd0 mode 0 0 full power - down 0 1 fast power-down (max149 only) 1 0 internal clock mode 1 1 external clock mode table 1. control-byte format bit 7 bit 6 bit 5 bit 4 bit 3 bit 2 bit 1 bit 0 (msb) (lsb) start sel2 sel1 sel0 uni/ bip sgl/ dif pd1 pd0 sel2 sel1 sel0 ch0 ch1 ch2 ch3 ch4 ch5 ch6 ch7 com 0 0 0 + 1 0 0 + 0 0 1 + 1 0 1 + 0 1 0 + 1 1 0 + 0 1 1 + 1 1 1 + table 2. channel selection in single - ended mode (sgl/ d d i i f f = 1)
max148/max149 +2.7v to +5.25v , low-power , 8-channel, serial 10-bit adcs ______________________________________________________________________________________ 11 simple software interface make sure the cpu? serial interface runs in master mode so the cpu generates the serial clock. choose a clock frequency from 100khz to 2mhz. 1) set up the control byte for external clock mode and call it tb1. tb1 should be of the format: 1xxxxx11 binary, where the xs denote the particular channel and conversion mode selected. 2) use a general - purpose i/o line on the cpu to pull cs low. 3) transmit tb1 and, simultaneously, receive a byte and call it rb1. ignore rb1. 4) transmit a byte of all zeros ($00 hex) and, simulta - neously, receive byte rb2. 5) transmit a byte of all zeros ($00 hex) and, simulta - neously, receive byte rb3. 6) pull cs high. figure 6 shows the timing for this sequence. bytes rb2 and rb3 contain the result of the conversion, padded with one leading zero, two sub-lsb bits, and three trail - ing zeros. the total conversion time is a function of the serial-clock frequency and the amount of idle time between 8 - bit transfers. to avoid excessive t/h droop, make sure the total conversion time does not exceed 120 s. digital output in unipolar input mode, the output is straight binary (figure 17). for bipolar input mode, the output is twos complement (figure 18). data is clocked out at the falling edge of sclk in msb - first format. clock modes the max148/max149 may use either an external serial clock or the internal clock to perform the succes - sive - approximation conversion. in both clock modes, the external clock shifts data in and out of the sstrb cs sclk din dout 1 4 8 12 16 20 24 start sel2 sel1 sel0 uni/ bip sgl/ dif pd1 pd0 b9 msb b8 b7 b6 b5 b4 b3 b2 b1 s0 s1 b0 lsb acquisition (f sclk = 2mhz) idle filled with zeros idle conversion t acq a/d state rb1 rb2 rb3 1.5 m s figure 6. 24-clock external clock mode conversion timing ( microwire and spi-compatible, qspi-compatible with f sclk 2mhz) sel2 sel1 sel0 ch0 ch1 ch2 ch3 ch4 ch5 ch6 ch7 0 0 0 + 0 0 1 + 0 1 0 + 0 1 1 + 1 0 0 + 1 0 1 + 1 1 0 + 1 1 1 + table 3. channel selection in differential mode (sgl/ d d i i f f = 0)
max148/max149 +2.7v to +5.25v , low-power , 8-channel, serial 10-bit adcs 12 ______________________________________________________________________________________ max148/max149. the t/h acquires the input signal as the last three bits of the control byte are clocked into din. bits pd1 and pd0 of the control byte program the clock mode. figures 7?0 show the timing characteris - tics common to both modes. external clock in external clock mode, the external clock not only shifts data in and out, but it also drives the analog - to - digital conversion steps. sstrb pulses high for one clock period after the last bit of the control byte. succes- sive - approximation bit decisions are made and appear at dout on each of the next 12 sclk falling edges (figure 6). sstrb and dout go into a high - impedance state when cs goes high; after the next cs falling edge, sstrb outputs a logic low. figure 8 shows the sstrb timing in external clock mode. the conversion must complete in some minimum time, or droop on the sample - and - hold capacitors may degrade conversion results. use internal clock mode if the serial-clock frequency is less than 100khz, or if serial-clock interruptions could cause the conversion interval to exceed 120 s. internal clock in internal clock mode, the max148/max149 generate their own conversion clocks internally. this frees the p t sdv t sstrb pd0 clocked in t str sstrb sclk cs t sstrb figure 8. external clock mode sstrb detailed timing cs sclk din dout t csh t css t cl t ds t dh t dv t ch t do t tr t csh figure 7. detailed serial-interface timing
max148/max149 +2.7v to +5.25v , low-power , 8-channel, serial 10-bit adcs ______________________________________________________________________________________ 13 from the burden of running the sar conversion clock and allows the conversion results to be read back at the processor? convenience, at any clock rate from 0mhz to 2mhz. sstrb goes low at the start of the conversion and then goes high when the conversion is complete. sstrb is low for a maximum of 7.5 s ( shdn = float), during which time sclk should remain low for best noise performance. an internal register stores data when the conversion is in progress. sclk clocks the data out of this register at any time after the conversion is complete. after sstrb goes high, the next falling clock edge produces the msb of the conversion at dout, followed by the remaining bits in msb - first format (figure 9). cs does not need to be held low once a conversion is started. pulling cs high prevents data from being clocked into the max148/max149 and three - states dout, but it does not adversely affect an internal clock mode con - version already in progress. when internal clock mode is selected, sstrb does not go into a high - impedance state when cs goes high. figure 10 shows the sstrb timing in internal clock mode. in this mode, data can be shifted in and out of the max148/max149 at clock rates exceeding 2.0mhz if the minimum acquisition time (t acq ) is kept above 1.5 s. data framing the falling edge of cs does not start a conversion. the first logic high clocked into din is interpreted as a start bit and defines the first bit of the control byte. a conversion starts on sclk? falling edge, after the eighth sstrb cs sclk din dout 1 4 8 12 18 20 24 start sel2 sel1 sel0 uni/ bip sgl/ dif pd1 pd0 b9 msb b8 b7 s0 s1 b0 lsb filled with zeros idle conversion 7.5 m s max (shdn = float) 2 3 5 6 7 9 10 11 19 21 22 23 t conv acquisition (f sclk = 2mhz) idle a/d state 1.5 m s figure 9. internal clock mode timing pd0 clock in t sstrb t csh t conv t sck sstrb sclk dout t css t do note: for best noise performance, keep sclk low during conversion. cs figure 10. internal clock mode sstrb detailed timing
max148/max149 +2.7v to +5.25v , low-power , 8-channel, serial 10-bit adcs 14 ______________________________________________________________________________________ bit of the control byte (the pd0 bit) is clocked into din. the start bit is defined as follows: the first high bit clocked into din with cs low any time the converter is idle; e.g., after v dd is applied. or the first high bit clocked into din after bit 3 of a con - version in progress is clocked onto the dout pin. if cs is toggled before the current conversion is com - plete, the next high bit clocked into din is recognized as a start bit; the current conversion is terminated, and a new one is started. the fastest the max148/max149 can run with cs held low between conversions is 15 clocks per conversion. figure 11a shows the serial-interface timing necessary to perform a conversion every 15 sclk cycles in external clock mode. if cs is tied low and sclk is continuous, guarantee a start bit by first clocking in 16 zeros. most microcontrollers ( cs) require that conversions occur in multiples of 8 sclk clocks; 16 clocks per con - version is typically the fastest that a c can drive the max148/max149 . figure 11b shows the serial - interface timing necessary to perform a conversion every 16 sclk cycles in external clock mode. __________ applications infor mation power - on reset when power is first applied, and if shdn is not pulled low, internal power - on reset circuitry activates the max148/max149 in internal clock mode, ready to con - vert with sstrb = high. after the power supplies stabi - lize, the internal reset time is 10 s, and no conversions should be performed during this phase. sstrb is high on power - up and, if cs is low, the first logical 1 on din is interpreted as a start bit. until a conversion takes place, dout shifts out zeros. (also see table 4.) reference-buffer compensation in addition to its shutdown function, shdn selects inter - nal or external compensation. the compensation affects both power-up time and maximum conversion speed. the100khz minimum clock rate is limited by droop on the sample-and-hold and is independent of the compensation used. float shdn to select external compensation. the typical operating circuit uses a 4.7 f capacitor at vref. a 4.7 f value ensures reference-buffer stability and allows converter operation at the 2mhz full clock speed. external compensation increases power-up time (see the choosing power-down mode section and table 4). pull shdn high to select internal compensation. internal compensation requires no external capacitor at vref and allows for the shortest power-up times. the maximum clock rate is 2mhz in internal clock mode and 400khz in external clock mode. choosing power-down mode you can save power by placing the converter in a low- current shutdown state between conversions. select full power-down mode or fast power-down mode via bits 1 and 0 of the din control byte with shdn high or floating (tables 1 and 5). in both software power-down modes, the serial interface remains operational, but the adc does not convert. pull shdn low at any time to shut down the converter completely. shdn overrides bits 1 and 0 of the control byte. full power-down mode turns off all chip functions that draw quiescent current, reducing supply current to 2 a (typ). fast power-down mode turns off all circuitry except the bandgap reference. with fast power-down mode, the supply current is 30 a. power-up time can be shortened to 5 s in internal compensation mode. table 4 shows how the choice of reference-buffer com - pensation and power-down mode affects both power-up reference buffer reference- buffer compensation mode vref capacitor ( f) power-down mode power-up delay ( s) maximum sampling rate (ksps) enabled internal fast 5 26 enabled internal full 300 26 enabled external 4.7 fast see figure 14c 133 enabled external 4.7 full see figure 14c 133 disabled fast 2 133 disabled full 2 133 table 4. typical power-up delay times
max148/max149 +2.7v to +5.25v , low-power , 8-channel, serial 10-bit adcs ______________________________________________________________________________________ 15 delay and maximum sample rate. in external compensa - tion mode, power-up time is 20ms with a 4.7 f compen - sation capacitor when the capacitor is initially fully discharged. from fast power-down, start-up time can be eliminated by using low-leakage capacitors that do not discharge more than 1/2lsb while shut down. in power- down, leakage currents at vref cause droop on the ref - erence bypass capacitor. figures 12a and 12b show the various power-down sequences in both external and internal clock modes. sclk din dout cs s control byte 0 control byte 1 s conversion result 0 b9 b8 b7 b6 b5 b4 b3 b2 b1 b0 s1 s0 conversion result 1 sstrb b9 b8 b7 b6 b5 b4 b3 b2 b1 b0 s1 s0 control byte 2 s 1 8 1 15 15 8 1 figure 11a. external clock mode, 15 clocks/conversion timing cs sclk din dout s 1 8 16 1 8 16 control byte 0 control byte 1 s conversion result 0 b9 b8 b7 b6 b5 b4 b3 b2 b1 b0 s1 s0 b9 b8 b7 b6 conversion result 1 figure 11b. external clock mode, 16 clocks/conversion timing powered up hardware power- down powered up powered up 10 + 2 data bits 10 + 2 data bits invalid data valid data external external s x x x x x 1 1 s 0 0 x x x x x x x x x x s 1 1 software power-down mode dout din clock mode shdn sets external clock mode sets external clock mode sets software power-down figure 12a. timing diagram power-down modes, external clock
max148/max149 +2.7v to +5.25v , low-power , 8-channel, serial 10-bit adcs 16 ______________________________________________________________________________________ table 6. hard - wired power-down and internal clock frequency pd1 pd0 device mode 0 0 full power-down 0 1 fast power-down 1 0 internal clock 1 1 external clock table 5. software power-down and clock mode figure 13. average supply current vs. conversion rate with external reference 1000 10,000 0.1 0.1 average supply current vs. conversion rate with external reference 100 10 1 conversion rate (hz) average supply current (?) 1 100 10 1k 10k 1m 100k max148/9-13 v ref = v dd = 3.0v r load = code = 1010101000 1 channel 8 channels figure 14a. max149 supply current vs. conversion rate, fullpd 100 1 0.01 0.1 1 average supply current vs. conversion rate (using fullpd) 10 conversion rate (hz) average supply current ( m a) 100 10 1k max148/9-f14a r load = code = 1010101000 8 channels 1 channel power-down powered up powered up data valid data valid internal s x x x x x 1 0 s 0 0 x x x x x s mode dout din clock mode sets internal clock mode sets power-down conversion conversion sstrb figure 12b. timing diagram power-down modes, internal clock n/a n/a power-down 0 1.8mhz external enabled floating 225khz internal enabled 1 internal clock frequency reference- buffer compensation device mode shdn state
max148/max149 +2.7v to +5.25v , low-power , 8-channel, serial 10-bit adcs ______________________________________________________________________________________ 17 software power - down software power - down is activated using bits pd1 and pd0 of the control byte. as shown in table 5, pd1 and pd0 also specify the clock mode. when software shutdown is asserted, the adc operates in the last specified clock mode until the conversion is complete. then the adc powers down into a low quiescent - current state. in internal clock mode, the interface remains active and conversion results may be clocked out after the max148/max149 enter a software power - down. the first logical 1 on din is interpreted as a start bit and powers up the max148/max149 . following the start bit, the data input word or control byte also determines clock mode and power - down states. for example, if the din word contains pd1 = 1, then the chip remains powered up. if pd0 = pd1 = 0, a power - down resumes after one conversion. hardware power - down pulling shdn low places the converter in hardware power-down (table 6). unlike software power-down mode, the conversion is not completed; it stops coin- cidentally with shdn being brought low. shdn also controls the clock frequency in internal clock mode. letting shdn float sets the internal clock frequency to 1.8mhz. when returning to normal operation with shdn floating, there is a t rc delay of approximately 2m x c l , where c l is the capacitive loading on the shdn pin. pulling shdn high sets internal clock frequency to 225khz. this feature eases the settling-time requirement for the reference voltage. with an external reference, the max148/max149 can be considered fully powered up within 2 s of actively pulling shdn high. power-down sequencing the max148/max149 auto power-down modes can save considerable power when operating at less than maximum sample rates. figures 13, 14a, and 14b show the average supply current as a function of the sam - pling rate. the following discussion illustrates the vari - ous power-down sequences. lowest power at up to 500 conversions/channel/second the following examples show two different power-down sequences. other combinations of clock rates, compen - sation modes, and power-down modes may give lowest power consumption in other applications. figure 14a depicts the max149 power consumption for one or eight channel conversions utilizing full power- down mode and internal-reference compensation. a 0.01 f bypass capacitor at refadj forms an rc filter with the internal 20k reference resistor with a 0.2ms time constant. to achieve full 10-bit accuracy, 8 time constants or 1.6ms are required after power-up. waiting this 1.6ms in fastpd mode instead of in full power-up can reduce power consumption by a factor of 10 or more. this is achieved by using the sequence shown in figure 15. 10,000 1 0.1 1 average supply current vs. conversion rate (using fastpd) 1000 100 10 conversion rate (hz) average supply current ( m a) 100 1m 10 1k 10k 100k max148/9-f14b r load = code = 1010101000 8 channels 1 channel figure 14c. typical reference-buffer power-up delay vs. time in shutdown 2.0 0 0.001 0.01 0.1 1 10 typical reference-buffer power-up delay vs. time in shutdown 1.5 1.0 0.5 time in shutdown (sec) power-up delay (ms) max148/9-f14c figure 14b. max149 supply current vs. conversion rate, fastpd
max148/max149 +2.7v to +5.25v , low-power , 8-channel, serial 10-bit adcs 18 ______________________________________________________________________________________ lowest power at higher throughputs figure 14b shows the power consumption with external - reference compensation in fast power - down, with one and eight channels converted. the external 4.7 f compensation requires a 75 s wait after power - up with one dummy conversion. this graph shows fast multi - channel conversion with the lowest power consumption possible. full power - down mode may provide increased power savings in applications where the max148/max149 are inactive for long peri - ods of time, but where intermittent bursts of high - speed conversions are required. internal and external references the max149 can be used with an internal or external reference voltage, whereas an external reference is required for the max148. an external reference can be connected directly at vref or at the refadj pin. an internal buffer is designed to provide 2.5v at vref for both the max149 and the max148. the max149? internally trimmed 1.21v reference is buf- fered with a 2.06 gain. the max148? refadj pin is also buffered with a 2.00 gain to scale an external 1.25v reference at refadj to 2.5v at vref. internal reference (max149) the max149? full-scale range with the internal refer - ence is 2.5v with unipolar inputs and 1.25v with bipo - lar inputs. the internal reference voltage is adjustable to 1.5% with the circuit in figure 16. external reference with both the max149 and max148, an external refer - ence can be placed at either the input (refadj) or the output (vref) of the internal reference-buffer amplifier. the refadj input impedance is typically 20k for the max149, and higher than 100k for the max148. at output code full-scale transition 11 . . . 111 11 . . . 110 11 . . . 101 00 . . . 011 00 . . . 010 00 . . . 001 00 . . . 000 1 2 3 0 (com) fs fs - 3/2lsb fs = vref + com zs = com input voltage (lsb) 1lsb = vref 1024 figure 17. unipolar transfer function, full scale (fs) = vref + com, zero scale (zs) = com +3.3v 510k 24k 100k 0.01? 12 refadj max149 figure 16. max149 reference-adjust circuit 1 0 0 din refadj vref 1.21v 0v 2.50v 0v 1 0 1 1 1 1 1 0 0 1 0 1 fullpd fastpd nopd fullpd fastpd 1.6ms wait complete conversion sequence t buffen ? 75 m s t = rc = 20k w x c refadj (zeros) ch1 ch7 (zeros) figure 15. max149 fullpd/fastpd power-up sequence
max148/max149 +2.7v to +5.25v , low-power , 8-channel, serial 10-bit adcs ______________________________________________________________________________________ 19 vref, the dc input resistance is a minimum of 18k . during conversion, an external reference at vref must deliver up to 350 a dc load current and have 10 or less output impedance. if the reference has a higher output impedance or is noisy, bypass it close to the vref pin with a 4.7 f capacitor. using the refadj input makes buffering the external reference unnecessary. to use the direct vref input, disable the internal buffer by tying refadj to v dd . in power-down, the input bias current to refadj is typi - cally 25 a (max149) with refadj tied to v dd . pull refadj to agnd to minimize the input bias current in power-down. transfer function table 7 shows the full-scale voltage ranges for unipolar and bipolar modes. the external reference must have a temperature coeffi - cient of 20ppm/ c or less to achieve accuracy to within 1lsb over the 0 c to +70 c commercial temperature range. figure 17 depicts the nominal, unipolar input/output (i/o) transfer function, and figure 18 shows the bipolar input/output transfer function. code transitions occur halfway between successive-integer lsb values. output coding is binary, with 1lsb = 2.44mv (2.500v / 1024) for unipolar operation, and 1lsb = 2.44mv [(2.500v / 2 - - 2.500v / 2) / 1024] for bipolar operation. 011 . . . 111 011 . . . 110 000 . . . 010 000 . . . 001 000 . . . 000 111 . . . 111 111 . . . 110 111 . . . 101 100 . . . 001 100 . . . 000 - fs com* input voltage (lsb) output code zs = com +fs - 1lsb *com vref / 2 + com fs = vref 2 -fs = + com -vref 2 1lsb = vref 1024 figure 18. bipolar transfer function, full scale (fs) = vref / 2 + com, zero scale (zs) = com +3v +3v gnd supplies dgnd +3v dgnd com agnd v dd digital circuitry max148 max149 r* = 10 w *optional figure 19. power-supply grounding connection unipolar mode bipolar mode full scale zero scale positive zero negative full scale scale full scale vref + com com vref / 2 com -vref / 2 + com + com table 7. full scale and zero scale
max148/max149 +2.7v to +5.25v , low-power , 8-channel, serial 10-bit adcs 20 ______________________________________________________________________________________ layout, grounding, and bypassing for best performance, use printed circuit boards. wire - wrap boards are not recommended. board layout should ensure that digital and analog signal lines are separated from each other. do not run analog and digi - tal (especially clock) lines parallel to one another, or digital lines underneath the adc package. figure 19 shows the recommended system ground connections. establish a single - point analog ground (star ground point) at agnd, separate from the logic ground. connect all other analog grounds and dgnd to the star ground. no other digital system ground should be connected to this ground. for lowest-noise operation, the ground return to the star ground? power supply should be low impedance and as short as possible. high - frequency noise in the v dd power supply may affect the high - speed comparator in the adc. bypass the supply to the star ground with 0.1 f and 1 f capacitors close to pin 20 of the max148/max149. minimize capacitor lead lengths for best supply - noise rejection. if the power supply is very noisy, a 10 resis - tor can be connected as a lowpass filter (figure 19). 20 19 18 17 16 15 14 13 12 11 1 2 3 4 5 6 7 8 9 10 max148 max149 mc683xx ch0 ch1 ch2 ch3 ch4 ch5 ch6 ch7 com shdn v dd sclk cs din sstrb dout dgnd agnd refadj vref (power supplies) sck pcs0 mosi miso 0.1 m f 1 m f (gnd) 0.1 m f analog inputs +3v +3v +2.5v figure 20. max148/max149 qspi connections, external reference xf clkx clkr dx dr fsr cs sclk din dout sstrb tms320lc3x max148 max149 figure 21. max148/max149-to-tms320 serial interface
high - speed digital interfacing with qspi the max148/max149 can interface with qspi using the circuit in figure 20 (f sclk = 2.0mhz, cpol = 0, cpha = 0). this qspi circuit can be programmed to do a conversion on each of the eight channels. the result is stored in memory without taxing the cpu, since qspi incorporates its own microsequencer. the max148/max149 are qspi compatible up to the maximum external clock frequency of 2mhz. tms320lc3x interface figure 21 shows an application circuit to interface the max148/max149 to the tms320 in external clock mode. the timing diagram for this interface circuit is shown in figure 22. use the following steps to initiate a conversion in the max148/max149 and to read the results: 1) the tms320 should be configured with clkx (transmit clock) as an active - high output clock and clkr (tms320 receive clock) as an active - high input clock. clkx and clkr on the tms320 are tied together with the max148/max149? sclk input. 2) the max148/max149 ? cs pin is driven low by the tms320? xf_ i/o port to enable data to be clocked into the max148/max149? din. 3) an 8 - bit word (1xxxxx11) should be written to the max148/max149 to initiate a conversion and place the device into external clock mode. refer to table 1 to select the proper xxxxx bit values for your specific application. 4) the max148/max149 ? sstrb output is monitored via the tms320? fsr input. a falling edge on the sstrb output indicates that the conversion is in progress and data is ready to be received from the max148/max149 . 5) the tms320 reads in one data bit on each of the next 16 rising edges of sclk. these data bits rep - resent the 10 + 2-bit conversion result followed by 4 trailing bits, which should be ignored. 6) pull cs high to disable the max148/max149 until the next conversion is initiated. max148/max149 +2.7v to +5.25v , low-power , 8-channel, serial 10-bit adcs ______________________________________________________________________________________ 21 cs sclk din sstrb dout start sel2 sel1 sel0 uni/bip sgl/dif pd1 pd0 msb b8 s1 s0 high impedance high impedance figure 22. tms320 serial-interface timing diagram
max148/max149 +2.7v to +5.25v , low-power , 8-channel, serial 10-bit adcs 22 ______________________________________________________________________________________ 20 19 18 17 16 15 14 13 12 11 1 2 3 4 5 6 7 8 9 10 top view dip/ssop v dd sclk cs din sstrb dout dgnd agnd refadj vref shdn com ch7 ch6 ch5 ch4 ch3 ch2 ch1 ch0 max148 max149 __________________ pin configuration ___________________ chip infor mation transistor count: 2554 ? contact factory for availability of alternate surface-mount packages. * contact factory for availability of cerdip package, and for processing to mil-std-883b. or dering infor mation (continued) 1 1/2 20 cerdip* -55 c to +125 c max149bmjp 1 20 cerdip* -55 c to +125 c 1/2 20 ssop -40 c to +85 c max149amjp max149beap 20 ssop -40 c to +85 c max149aeap 1 1/2 20 plastic dip -40 c to +85 c max149bepp 1 20 plastic dip -40 c to +85 c 1/2 20 ssop 0 c to +70 c 1 1/2 max149aepp max149bcap 20 ssop 20 plastic dip 20 plastic dip 0 c to +70 c 0 c to +70 c 0 c to +70 c max149acap max149bcpp max149 acpp 1 1/2 20 cerdip* -55 c to +125 c max148bmjp 20 cerdip* -55 c to +125 c max148amjp 1 1/2 20 ssop -40 c to +85 c 1 1/2 inl (lsb) max148beap 20 ssop 20 plastic dip 20 plastic dip pin-package temp. range -40 c to +85 c -40 c to +85 c -40 c to +85 c max148aeap max148bepp max148aepp part ?
max148/max149 +2.7v to +5.25v , low-power , 8-channel, serial 10-bit adcs ______________________________________________________________________________________ 23 ________________________________________________________ package infor mation ssop.eps
maxim cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a maxim product. no circu it patent licenses are implied. maxim reserves the right to change the circuitry and specifications without notice at any time. 24 ____________________ maxim integrated products, 120 san gabriel drive, sunnyvale, ca 94086 408-737-7600 1998 maxim integrated products printed usa is a registered trademark of maxim integrated products. max148/max149 +2.7v to +5.25v , low-power , 8-channel, serial 10-bit adcs pdipn.eps ___________________________________________ package infor mation (continued)
e nglish ? ???? ? ??? ? ??? what's ne w p roducts solutions de sign ap p note s sup p ort buy comp any me mbe rs m axim > p roduc ts > a nalog-to-digital c onverters max148, max149 +2.7v to +5.25v low-power 8-c hannel serial 10-bit adc s quickview technical documents ordering info more information all ordering information notes: other options and links for purchasing parts are listed at: http://www.maxim-ic.com/sales . 1. didn't find what you need? ask our applications engineers. expert assistance in finding parts, usually within one business day. 2. part number suffixes: t or t&r = tape and reel; + = rohs/lead-free; # = rohs/lead-exempt. more: see full data sheet or part naming c onventions . 3. * some packages have variations, listed on the drawing. "pkgc ode/variation" tells which variation the product uses. 4. devices: 1-53 of 53 m ax148 fre e sam ple buy pack age : type pins footprint drawing code/var * te m p rohs/le ad-fre e ? m ate rials analys is max148amjp c eramic dip;20 pin;219 mm dwg: 21-0045a (pdf) use pkgcode/variation: j20-2 * -55c to +125c rohs/lead-free: no materials analysis max148bmjp c eramic dip;20 pin;219 mm dwg: 21-0045a (pdf) use pkgcode/variation: j20-2 * -55c to +125c rohs/lead-free: no materials analysis max148bc /d rohs/lead-free: see data sheet max148bc pp pdip;20 pin;219 mm dwg: 21-0043d (pdf) use pkgcode/variation: p20-4 * 0c to +70c rohs/lead-free: no materials analysis max148bc pp+ pdip;20 pin;219 mm dwg: 21-0043d (pdf) use pkgcode/variation: p20+4 * 0c to +70c rohs/lead-free: lead free materials analysis max148ac pp+ pdip;20 pin;219 mm dwg: 21-0043d (pdf) use pkgcode/variation: p20+4 * 0c to +70c rohs/lead-free: lead free materials analysis max148ac pp pdip;20 pin;219 mm dwg: 21-0043d (pdf) use pkgcode/variation: p20-4 * 0c to +70c rohs/lead-free: no materials analysis max148aepp pdip;20 pin;219 mm dwg: 21-0043d (pdf) use pkgcode/variation: p20-4 * -40c to +85c rohs/lead-free: no materials analysis max148aepp+ pdip;20 pin;219 mm dwg: 21-0043d (pdf) use pkgcode/variation: p20+4 * -40c to +85c rohs/lead-free: lead free materials analysis max148bepp+ pdip;20 pin;219 mm dwg: 21-0043d (pdf) use pkgcode/variation: p20+4 * -40c to +85c rohs/lead-free: lead free materials analysis max148bepp pdip;20 pin;219 mm dwg: 21-0043d (pdf) use pkgcode/variation: p20-4 * -40c to +85c rohs/lead-free: no materials analysis max148ac ap+t ssop;20 pin;58 mm dwg: 21-0056c (pdf) use pkgcode/variation: a20+1 * 0c to +70c rohs/lead-free: lead free materials analysis max148ac ap+ ssop;20 pin;58 mm dwg: 21-0056c (pdf) use pkgcode/variation: a20+1 * 0c to +70c rohs/lead-free: lead free materials analysis
max148ac ap ssop;20 pin;58 mm dwg: 21-0056c (pdf) use pkgcode/variation: a20-1 * 0c to +70c rohs/lead-free: no materials analysis max148bc ap+ ssop;20 pin;58 mm dwg: 21-0056c (pdf) use pkgcode/variation: a20+1 * 0c to +70c rohs/lead-free: lead free materials analysis max148ac ap-t ssop;20 pin;58 mm dwg: 21-0056c (pdf) use pkgcode/variation: a20-1 * 0c to +70c rohs/lead-free: no materials analysis max148bc ap-t ssop;20 pin;58 mm dwg: 21-0056c (pdf) use pkgcode/variation: a20-1 * 0c to +70c rohs/lead-free: no materials analysis max148bc ap ssop;20 pin;58 mm dwg: 21-0056c (pdf) use pkgcode/variation: a20-1 * 0c to +70c rohs/lead-free: no materials analysis max148bc ap+t ssop;20 pin;58 mm dwg: 21-0056c (pdf) use pkgcode/variation: a20+1 * 0c to +70c rohs/lead-free: lead free materials analysis max148beap+ ssop;20 pin;58 mm dwg: 21-0056c (pdf) use pkgcode/variation: a20+1 * -40c to +85c rohs/lead-free: lead free materials analysis max148aeap+t ssop;20 pin;58 mm dwg: 21-0056c (pdf) use pkgcode/variation: a20+1 * -40c to +85c rohs/lead-free: lead free materials analysis max148aeap+ ssop;20 pin;58 mm dwg: 21-0056c (pdf) use pkgcode/variation: a20+1 * -40c to +85c rohs/lead-free: lead free materials analysis max148beap+t ssop;20 pin;58 mm dwg: 21-0056c (pdf) use pkgcode/variation: a20+1 * -40c to +85c rohs/lead-free: lead free materials analysis max148aeap ssop;20 pin;58 mm dwg: 21-0056c (pdf) use pkgcode/variation: a20-1 * -40c to +85c rohs/lead-free: no materials analysis max148aeap-t ssop;20 pin;58 mm dwg: 21-0056c (pdf) use pkgcode/variation: a20-1 * -40c to +85c rohs/lead-free: no materials analysis max148beap-t ssop;20 pin;58 mm dwg: 21-0056c (pdf) use pkgcode/variation: a20-1 * -40c to +85c rohs/lead-free: no materials analysis max148beap ssop;20 pin;58 mm dwg: 21-0056c (pdf) use pkgcode/variation: a20-1 * -40c to +85c rohs/lead-free: no materials analysis m ax149 fre e sam ple buy pack age : type pins footprint drawing code/var * te m p rohs/le ad-fre e ? m ate rials analys is max149ac pp+ 0c to +70c rohs/lead-free: see data sheet max149bepp+ -40c to +85c rohs/lead-free: see data sheet max149aepp+ -40c to +85c rohs/lead-free: see data sheet max149bmjp c eramic dip;20 pin;219 mm dwg: 21-0045a (pdf) use pkgcode/variation: j20-2 * -55c to +125c rohs/lead-free: no materials analysis max149amjp c eramic dip;20 pin;219 mm dwg: 21-0045a (pdf) use pkgcode/variation: j20-2 * -55c to +125c rohs/lead-free: no materials analysis max149bc pp+ pdip;20 pin;219 mm dwg: 21-0043d (pdf) use pkgcode/variation: p20+4 * 0c to +70c rohs/lead-free: lead free materials analysis max149ac pp pdip;20 pin;219 mm dwg: 21-0043d (pdf) use pkgcode/variation: p20-4 * 0c to +70c rohs/lead-free: no materials analysis max149bc pp pdip;20 pin;219 mm dwg: 21-0043d (pdf) use pkgcode/variation: p20-4 * 0c to +70c rohs/lead-free: no materials analysis
max149bepp pdip;20 pin;219 mm dwg: 21-0043d (pdf) use pkgcode/variation: p20-4 * -40c to +85c rohs/lead-free: no materials analysis max149aepp pdip;20 pin;219 mm dwg: 21-0043d (pdf) use pkgcode/variation: p20-4 * -40c to +85c rohs/lead-free: no materials analysis max149ac ap ssop;20 pin;58 mm dwg: 21-0056c (pdf) use pkgcode/variation: a20-1 * 0c to +70c rohs/lead-free: no materials analysis max149ac ap-t ssop;20 pin;58 mm dwg: 21-0056c (pdf) use pkgcode/variation: a20-1 * 0c to +70c rohs/lead-free: no materials analysis max149bc ap+ ssop;20 pin;58 mm dwg: 21-0056c (pdf) use pkgcode/variation: a20+1 * 0c to +70c rohs/lead-free: lead free materials analysis max149bc ap+t ssop;20 pin;58 mm dwg: 21-0056c (pdf) use pkgcode/variation: a20+1 * 0c to +70c rohs/lead-free: lead free materials analysis max149bc ap ssop;20 pin;58 mm dwg: 21-0056c (pdf) use pkgcode/variation: a20-1 * 0c to +70c rohs/lead-free: no materials analysis max149bc ap-t ssop;20 pin;58 mm dwg: 21-0056c (pdf) use pkgcode/variation: a20-1 * 0c to +70c rohs/lead-free: no materials analysis max149ac ap+ ssop;20 pin;58 mm dwg: 21-0056c (pdf) use pkgcode/variation: a20+1 * 0c to +70c rohs/lead-free: lead free materials analysis max149ac ap+t ssop;20 pin;58 mm dwg: 21-0056c (pdf) use pkgcode/variation: a20+1 * 0c to +70c rohs/lead-free: lead free materials analysis max149beap ssop;20 pin;58 mm dwg: 21-0056c (pdf) use pkgcode/variation: a20-1 * -40c to +85c rohs/lead-free: no materials analysis max149aeap+ ssop;20 pin;58 mm dwg: 21-0056c (pdf) use pkgcode/variation: a20+1 * -40c to +85c rohs/lead-free: lead free materials analysis max149beap-t ssop;20 pin;58 mm dwg: 21-0056c (pdf) use pkgcode/variation: a20-1 * -40c to +85c rohs/lead-free: no materials analysis max149beap+ ssop;20 pin;58 mm dwg: 21-0056c (pdf) use pkgcode/variation: a20+1 * -40c to +85c rohs/lead-free: lead free materials analysis max149beap+t ssop;20 pin;58 mm dwg: 21-0056c (pdf) use pkgcode/variation: a20+1 * -40c to +85c rohs/lead-free: lead free materials analysis max149aeap+t ssop;20 pin;58 mm dwg: 21-0056c (pdf) use pkgcode/variation: a20+1 * -40c to +85c rohs/lead-free: lead free materials analysis max149aeap ssop;20 pin;58 mm dwg: 21-0056c (pdf) use pkgcode/variation: a20-1 * -40c to +85c rohs/lead-free: no materials analysis max149aeap-t ssop;20 pin;58 mm dwg: 21-0056c (pdf) use pkgcode/variation: a20-1 * -40c to +85c rohs/lead-free: no materials analysis didn't find what you need? next day product selection assistance from applications engineers parametric search applications help quickview technical documents ordering info more information des c ription key features a pplic ations /u s es key spec ific ations diagram data sheet a pplic ation n otes des ign guides e ngineering journals reliability reports software/m odels e valuation kits p ric e and a vailability samples buy o nline p ac kage i nformation lead-free i nformation related p roduc ts n otes and c omments e valuation kits
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