figure 1. functional block diagram 13 no connection 20 no connection 14 bit 1 (msb) 15 bit 2 16 bit 3 17 bit 4 21 bit 5 22 bit 6 23 bit 7 24 bit 8 (lsb) 3 +5v ref. out tri-state buffer 8-bit 20mhz flash converter linearization & temperature compensation network input buffer cs1 11 cs2 12 no connection 8 no connection 9 clock 18 analog input 5 +15v supply 19 ground 4 ground 7 ground 6 C15v supply 10 +5v supply 1 voltage reference network ground 2 features 8-bit ? ash a/d converter 20mhz sampling rate complete support circuitry low power, 900mw sample-hold not required three-state outputs mil-std-883 versions product overview the adc-228a combines analog front-end circuitry and a ? ash a/d converter to digitize high-speed analog signals at a rate of 20 million samples per second. the adc-228a contains an 8-bit, 20mhz, ? ash a/d, a wideband analog input buffer, a precision voltage reference, temperature compensation circuitry, reference trims, and a three-state output buffer in a 24-pin package. the adc-228a offers signi? cant savings by combining all of the circuitry in a single package. valuable board real estate is saved, and design time and manufacturing costs are reduced. the adc-228a is housed in a 24-pin ceramic ddip package and is available in the commercial, 0 to +70c, or military, C55 to +125c, tem- perature ranges. a mil-std-883 version is also available. operation is from 15v and +5v power supplies. input/output connections pin function pin function 1 +5v supply 24 bit 8 (lsb) 2 ground 23 bit 7 3 +5v reference out 22 bit 6 4 ground 21 bit 5 5 analog input 20 no connection 6 ground 19 +15v supply 7 ground 18 clock input 8 no connection 17 bit 4 9 no connection 16 bit 3 10 C15v supply 15 bit 2 11 cs1 14 bit 1 (msb) 12 cs2 13 no connection adc-228a 8-bit, 20mhz, complete flash a/d converter ?? datel ? 11 cabot boulevard, mans? eld, ma 02048-1151 usa ? tel: (508) 339-3000 ? www.datel.com ? e-mail: help@datel.com 31 mar 2011 adc-228a.b02 page 1 of 4
absolute maximum ratings parameter limits power supply voltage, pin 1 C0.3 to +7v pin 19 C0.3 to +18v pin 10 +0.3 to C18v digital inputs, pins 8,9,11,12,18 C0.5 to +5.5v analog input, pin 5 C3.8 to +6.6v digital outputs C0.5 to +5.5v (short circuit protected to ground) lead temp. (10 seconds) +300c functional specifications (apply over the operating temperature range with 20mhz clock and 15v and +5v power supply voltages, unless otherwise speci? ed.) analog inputs min. typ. max. units single-ended, non-isolated input range, dc-20mhz 0 +5.0 volts input resistance 1.95 2 k input capacitance 5 10 pf digital inputs logic levels logic 1 +2.0 volts logic 0 +0.8 volts logic loading logic 1 +160 a logic 0 C0.5 ma clock pulse widths "high" 20 ns "low" 20 ns digital outputs coding resolution logic levels logic 1 +2.4 volts logic 0 +0.4 volts logic loading logic 1 C1 ma logic 0 +1 ma output data valid delay from rising edge 40 ns output hold time 6 ns performance sampling rate ? 20 mhz differential linearity code transitions, +25c 0.5 0.75 lsb 0 to +70c 0.5 0.75 lsb C55 to +125c 0.5 0.85 lsb integral linearity, +25c end-point 0.5 1 lsb best-? t line 0.35 0.75 lsb over temperature end-point 1.75 lsb best-? t line 1 lsb zero-scale offset code "0" to "1" transition +25c 0.5 1 lsb C55 to +125c 0.5 1.5 lsb performance min. typ. max. units gain error 0.5 1.5 lsb full scale absolute accuracy 0.5 1.5 lsb differential gain ? 2 % differential phase ? 1 deg. aperture delay 8 ns aperture jitter 50 ps no missing codes power supply rejection dynamic performance total harm. distortion, C0.5db dc to 2.5 mhz C55 C53 db 2.5 mhz to 5 mhz C49 C44 db 5 mhz to 10 mhz C39 C36 db signal-to-noise ratio and distortion, C0.5db dc to 2.5 mhz 44 49 db 2.5 mhz to 5 mhz 41 46 db 5 mhz to 10 mhz 35 38 db signal-to-noise ratio w/o distortion, C0.5 db dc to 2.5 mhz 45 48 db 2.5 mhz to 5 mhz 44 49 db 5 mhz to 10 mhz 42 45 db effective bits, C0.5db dc to 2.5 mhz 7.1 7.75 bits 2.5 mhz to 5 mhz 6.8 7.4 bits 5 mhz to 10 mhz 5.6 6.1 bits input bandwidth large signal (C3db) 15 mhz small signal (C20db) 40 mhz power supply power supply range +15v supply +11 +15 +15.75 volts C15v supply C11 C15 C15.75 volts +5v supply +4.75 +5 +5.25 volts power supply current +15v supply +12 +20 ma C15v supply C13 C20 ma +5v supply +70 +80 ma power dissipation 15v, +5v nominal 0.7 0.9 watts physical/environmental operating temp. range, case adc-228amc 0 to +70c adc-228amm, adc-228a/883 C55 to +125c storage temp. range C65 to +150c package type 24-pin, ceramic ddip weight 0.3 ounces (8.5 grams) footnotes: ? at full power input and chip selects enabled. ? for 10-step, 40 ire ntsc ramp test. over the operating temperature range 0.02% fsr/%v s maximum straight binary 8 bits adc-228a 8-bit, 20mhz, complete flash a/d converter ?? datel ? 11 cabot boulevard, mans? eld, ma 02048-1151 usa ? tel: (508) 339-3000 ? www.datel.com ? e-mail: help@datel.com 31 mar 2011 adc-228a.b02 page 2 of 4
technical notes 1. rated performance requires using good high-frequency techniques. the analog and digital ground pins are connected to each other internally. avoid ground related problems by connecting the grounds to one point, the ground plane beneath the converter. due to the inductance and resistance of the power supply return paths, return the analog and digital ground separately to the power supplies. 2. bypass all the analog and digital supplies and the +5v reference (pin 3) to ground with a 4.7f, 25v tantalum electrolytic capacitor in parallel with a 0.1f ceramic capacitor. analog input code straight bin. +4.96v +fs C 1 lsb 1111 1110 +3.75v + 3/4 fs 1100 0000 +2.50v + 1/2 fs 1000 0000 +1.25v + 1/4 fs 0100 0000 +0.02v + 1 lsb 0000 0001 0.00v zero 0000 0000 table 1. adc-228a unipolar output coding table 2. chip select truth table cs2 pin 12 cs1 pin 11 bits 1-8 0 0 three state mode 0 1 three state mode 1 0 data outputted 1 1 three state mode figure 2. adc-228a timing diagram sample n + 2 sample n + 1 sample n output hold time data n data n + 1 data n + 2 clock digital output output delay fiure 3. adc-228a typial connetions 24 23 b8 (lsb) b7 9k 51 19 v in 5 +15v *optional + 2, 4, 6, 7 +5v reference out no connection 3 8, 9, 13, 20 22 b6 21 b5 17 b4 16 b3 cs1 12 clock 18 analog input 15 b2 14 + + b1 (msb) 4.7f 0.1f 10 1 C15v +5v cs1 11 * use optional resistor only if amp is not used to drive input. adc-228a + 0.1f 0.1f 0.1f 4.7f 4.7f 4.7f ee r = v /1.667ma adc-228a 8-bit, 20mhz, complete flash a/d converter ?? datel ? 11 cabot boulevard, mans? eld, ma 02048-1151 usa ? tel: (508) 339-3000 ? www.datel.com ? e-mail: help@datel.com 31 mar 2011 adc-228a.b02 page 3 of 4
0.200 max. (5.080) 0.235 max. (5.969) 0.600 0.010 (15.240) 0.80 max. (20.32) 0.100 typ. (2.540) 0.100 (2.540) 0.018 0.002 (0.457) 0.100 (2.540) 0.040 (1.016) 1.31 max. (33.27) 112 13 24 1.100 (27.940) 0.190 max. (4.826) 0.010 (0.254) +0.002 C0.001 seating plane 0.025 ( 0.635 )
(unless otherwise indicated): 2 place decimal (.xx) 0.010 (0.254) 3 place decimal (.xxx) 0.005 (0.127)
kovar alloy
50 microinches (minimum) gold plating over 100 microinches (nominal) nickel plating ordering information model temperature range sampling rate adc-228amc 0 to +70c 20msps adc-228amm C55 to +125c 20msps adc-228a/883 * C55 to +105c 15msps receptacle for pc board mounting can be ordered through amp inc., part # 3-331272-8 (component lead socket), 24 required. contact datel for 883 product speci? cations datel's initial quali? cation was done at 15msps and as a mil-std-883 class g product per customer request. mil-std-883 class g allows for a reduced temperature range (C55c to +105c) that applies to this device. contact datel if a 20msps rate or a mil-std-883 class h (C55c to +125c) temperature range is desired. * adc-228a 8-bit, 20mhz, complete flash a/d converter . makes no representation that the use of its products in the circuits described herein, or the use of other technical information contained herein, will not infringe upon existing or future patent rights. the descriptions contained her ein do not imply the granting of licenses to make, use, or sell equipment constructed in accordance therewith. speci? cations are subject to change without notice. www.datel.com ? e-mail: help@datel.com ?? datel 11 cabot boulevard, mans? eld, ma 02048-1151 usa itar and iso 9001/14001 registered 31 mar 2011 adc-228a.b02 page 4 of 4
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