general description the max3806 is a high-gain linear preamplifier for dis - tance measurement applications using a laser beam. the device operates from a single +5.0v supply and converts current from an ac-coupled photodiode into a single-ended voltage signal. the input accepts single pulses or bursts of pulses with widths down to 30ns. the amplifier remains linear with input amplitudes from 42na p (snr = 3) to 40a p . it can also withstand overload sig - nals as large as 2ma p . the output stage is designed to drive a high-impedance load to deliver the output-voltage swing at the lowest possible power dissipation. the gain of the preamplifier stage is selected using the gain pin to be 60k or 30k. there is also an internal 14db attenu - ator that is selected using the att pin. the output stage can be disabled (high impedance). the device is available in a 3mm x 3mm, 12-pin tqfn package and operates over the -40c to +105c tem - perature range. applications laser sensors for portable distance measurement laser sensors for industrial applications beneits and features +5v supply voltage linearity range up to 40a p overload current up to 2ma p 50mw power dissipation at +5.0v 1.5pa/ hz noise density at 60k gain 14na rms input-referred noise at 60k gain selectable gains (60k, 30k) selectable 14db attenuation typical application circuits continued at end of data sheet. pin configuration appears at end of data sheet. + denotes a lead(pb)-free/rohs-compliant package. * ep = exposed pad. part temp range pin- package top mark max3806gtc+ -40c to +105c 12 tqfn-ep* abn in pin +5v single-channel receiver * l and c set the low-frequency cutoff required for the application. +5v out buff gain v cc 0.01f c* l* 0.01f 0.01f max3806 linear lidar rx max1446 adc supply filter gnd att dis +5v to +12v supply filter max3806 receiver for optical distance measurement 19-4700; rev 1; 6/14 typical application circuits ordering information evaluation kit available downloaded from: http:///
supply voltage range, v cc ...................................-0.5v to +6.0v voltage range at att, dis, gain...............-0.5v to (v cc + 0.5v) current range at in, out.......................................-4ma to +4ma continuous power dissipation (t a = +70c) 12-pin tqfn-ep (derate 16.7mw/c above +70c)...1333mw storage temperature range .............................-55c to +150c lead temperature (soldering, 10s) .................................+300c (v cc = +4.5v to +5.5v, ac-coupled (c = 0.01f) output load 2k, t a = -40c to +105c. typical values are at v cc = +5v, t a = +25c, unless otherwise noted.) (note 1) parameter symbol conditions min typ max units power-supply current i cc (note 2) 10 15 ma input specifications input-referred noise output noise up to 100mhz/(gain at 5mhz) c in = 5pf, gain = 1 14 20 na rms c in = 5pf, gain = 0 21 27 input-referred noise density output noise centered at 5mhz over 100hz band/(gain at 5mhz) c in = 5pf, gain = 1 1.5 1.8 pa/ hz c in = 5pf, gain = 0 1.7 2.3 input impedance at 1mhz, gain = 1 800 ? at 1mhz, gain = 0 300 cmos/ttl input specifications input high voltage v ih 2 v cc v input low voltage v il 0 0.8 v input current i ih , i il dis input 150 a i ih gain and att inputs -180 input impedance r pullup dis input 60 k? r pulldown gain and att inputs 40 general specifications small-signal transimpedance i in 15ap, gain = 1 44 60 77 k? iin 50ap, gain = 0 23 30 37 small-signal bandwidth f 3db c in = 5pf gain = 1, att = 0 25 49 mhz gain = 0, att = 0 55 98 gain peaking 5pf c in 15pf 1 db attenuation stability att = 1; 20log(v out_att_on /v out_att_off ) -13 -14 -15 db output specifications total harmonic distortion thd frequency = 1mhz, v out = 0.5v p gain = 1 -54 db gain = 0 -53 frequency = 10mhz, v out = 0.5v p gain = 1 -38 gain = 0 -47 power-supply noise rejection gain = 1 -16 (note 3) psnr noise frequency < 1mhz gain = 1 -16 db gain = 0 -23 max3806 receiver for optical distance measurement www.maximintegrated.com maxim integrated 2 absolute maximum ratings stresses beyond those listed under absolute maximum ratings may cause permanent damage to the device. these are stress ratings only, and functional operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. exposure to absolute maximum rating conditions for extended periods may affect device reliability. electrical characteristics downloaded from: http:///
(v cc = +4.5v to +5.5v, ac-coupled (c = 0.01f) output load 2k, t a = -40c to +105c. typical values are at v cc = +5v, t a = +25c, unless otherwise noted.) (note 1) note 1: ac specifications are guaranteed by design and characterization. note 2: supply current is measured with out unterminated or ac-coupled. note 3: measured by applying 100mv p-p sinusoidal noise to the supply voltage. psnr is defined as 20log(v out_noise /v cc_noise ). (typical values are at v cc = +5v, t a = +25c, c in = 5pf, att = 0, unless otherwise noted.) parameter symbol conditions min typ max units attenuation in disable mode frequency < 5mhz,20log(v out_disabled / v out_enabled ) att = 0 -71 db att = 1 -57 output impedance at 1mhz, dis = 0, att = 0, gain = 0 or 1 51 ? at 1mhz, dis = 0, att = 1, gain = 0 or 1 114 at 1mhz, dis = 1, att = 0 or 1, gain = 0 or 1 9 k? output voltage vs. input current max3806 toc02 input current (a p ) output voltage (v p ) 100 10 1 0.01 0.1 1 10 0.001 0.1 1000 gain = 0, att = 0 gain = 1, att = 1 gain = 0, att = 1 gain = 1, att = 0 frequency response max3806 toc03 frequency (mhz) transimpedance (db ? ) 10 1 65 70 75 80 85 90 95 100 105 60 0.1 100 gain = 1, att = 0 gain = 0, att = 0 gain = 1, att = 1 gain = 0, att = 1 supply current vs. temperature max3806 toc01 temperature (c) supply current (ma) 85 60 -15 10 35 2 4 6 8 10 12 14 16 0 -40 110 dis = 0 dis = 1 max3806 receiver for optical distance measurement www.maximintegrated.com maxim integrated 3 electrical characteristics (continued) typical operating characteristics downloaded from: http:///
(typical values are at v cc = +5v, t a = +25c, c in = 5pf, att = 0, unless otherwise noted.) bandwidth vs. input capacitance (gain = 1) max3806 toc05 input capacitance (pf) bandwidth (mhz) 13 11 9 7 10 20 30 40 50 60 0 5 15 v cc = +5.5v v cc = +5.0v v cc = +4.5v t a = +25c gain peaking vs. input capacitance max3806 toc06 input capacitance (pf) gain peaking (db) 13 11 9 7 0.2 0.4 0.6 0.8 1.0 0 5 15 gain = 0 gain = 1 bandwidth vs. input capacitance (gain = 0) max3806 toc07 input capacitance (pf) bandwidth (mhz) 13 11 9 7 20 40 60 80 100 120 0 5 15 v cc = +5v t a = -40c t a = +25c t a = +105c bandwidth vs. input capacitance (gain = 0) max3806 toc08 input capacitance (pf) bandwidth (mhz) 13 11 9 7 20 40 60 80 100 120 0 5 15 v cc = +5.5v v cc = +5.0v t a = +25c v cc = +4.5v power-supply noise rejection (supply noise = 100mv p-p ) max3806 toc09 frequency (hz) psnr (db) 1m 100k -50 -40 -30 -20 -10 0 10 -60 10k 10m gain = 1, att = 0 gain = 0, att = 0 gain = 1, att = 1 gain = 0, att = 1 input-referred noise vs. input capacitance max3806 toc10 input capacitance (pf) input-referred noise (na rms ) 13 11 9 7 11 12 13 14 15 1610 5 15 t a = +105c t a = +25c t a = -40c v cc = +5v gain = 1bw = 100mhz bandwidth vs. input capacitance (gain = 1) max3806 toc04 input capacitance (pf) bandwidth (mhz) 13 11 9 7 10 20 30 40 50 60 0 5 15 t a = -40 nc t a = +25 nc t a = +105 nc v cc = +5.0v input-referred noise vs. input capacitance max3806 toc11 input capacitance (pf) input-referred noise (na rms ) 13 11 9 7 11 12 13 14 15 1610 5 15 t a = +25c gain = 1bw = 100mhz v cc = +5.5v v cc = +5.0v v cc = +4.5v max3806 toc12 output-referred noise vs. input capacitance input capacitance (pf) output-referred noise (v rms ) 13 11 9 7 5 600 650 750700 800 850 900 950 1000 15 t a = +25c gain = 1bw = 100mhz v cc = +5.5v v cc = +5.0v v cc = +4.5v max3806 receiver for optical distance measurement maxim integrated 4 www.maximintegrated.com typical operating characteristics (continued) downloaded from: http:///
(typical values are at v cc = +5v, t a = +25c, c in = 5pf, att = 0, unless otherwise noted.) max3806 toc13 input-referred noise vs. input capacitance input capacitance (pf) input-referred noise (na rms ) 13 11 9 7 5 15 t a = +105c t a = -40c t a = +25c v cc = +5v gain = 0bw = 100mhz 18 19 2120 22 23 24 25 26 max3806 toc14 input-referred noise vs. input capacitance input capacitance (pf) input-referred noise (na rms ) 13 11 9 7 5 15 v cc = +5.5v v cc = +4.5v v cc = +5.0v t a = +25c gain = 0bw = 100mhz 18 19 2120 22 23 24 25 26 output-referred noise vs. input capacitance max3806 toc15 input capacitance (pf) output-referred noise (v rms ) 13 11 9 7 500 550 600 650 700450 5 15 t a = +25c gain = 0bw = 100mhz v cc = +5.5v v cc = +5.0v v cc = +4.5v total harmonic distortion vs. frequency max3806 toc16 frequency (mhz) thd (db) 10 1 -50 -40 -30 -20 -10 0 -60 0.1 100 v out = 0.5v p gain = 1 gain = 0 max3806 toc17 out (200mv/div) 100ns/div disable switch (dc-block = 0.01 f, load = 2k ? ) dis (5v/div) max3806 toc18 out (200mv/div) 40s/div gain switch (dc-block = 0.01 f, load = 2k ? ) gain (5v/div) max3806 toc19 out (500mv/div) 40s/div att switch (dc-block = 0.01 f, load = 2k ? ) att (5v/div) max3806 receiver for optical distance measurement maxim integrated 5 www.maximintegrated.com typical operating characteristics (continued) downloaded from: http:///
(typical values are at v cc = +5v, t a = +25c, c in = 5pf, att = 0, unless otherwise noted.) max3806 toc21 out 100ns/div transient response (overload region, gain = 1) in 20mhz bw limit zoom in 2ma p 1.4v p max3806 toc22 out 10s/div transient response (overload region, gain = 1) in 0.01f dc-block2ki load 60s settling time zoom out 2ma p 1.4v p max3806 toc20 out 20ns/div transient response (linear region, gain = 1) in 20mhz bw limit 60mv p 1a p functional diagram max3806 attenuator in out gain att dis switchable impedance 60k or 30k 40k ? 40k ? 60k ? v cc max3806 receiver for optical distance measurement www.maximintegrated.com maxim integrated 6 typical operating characteristics (continued) downloaded from: http:///
detailed description the max3806 preamplifier consists of a selectable-gain transimpedance amplifier, a selectable 14db attenu - ator, and an output-driver block. the selectable-gain transimpedance amplifier linearly boosts the signal from the photodiode. this block is followed by an attenuator block that allows the user to attenuate the signal by 14db selected by the att pin. the final block is the output driver that can be disabled by asserting the dis pin. transimpedance ampliier the selectable-gain transimpedance amplifier is con - trolled by the gain pin. see table 1 for gain settings. attenuator the attenuator block can be set to pass the signal through to the output stage with 0db of attenuation (att forced low) or with 14db of attenuation (att forced high). output driver the output driver is designed to drive an ac-coupled load with an impedance of 2k or greater. the output can be disabled by asserting the dis pin high. when the output is disabled, the out pin goes to a high-impedance state. see figure 1 for the equivalent output circuit. warning: the output is designed to be ac-coupled to a high-impedance load. operating the part with its output dc-coupled to gnd through a 2k or less load may dam - age the output. applications information settling time settling time is the required time for the output to achieve the final steady-state or ac amplitude swing after a set - ting has been changed on the max3806. the output common-mode voltage shifts when a change is made table 1. transimpedance gain settings pin name function 1, 12 v cc 5v power-supply connection 2 in ampliier input. accepts ac-coupled photodiode input current. 3, 4 gnd supply ground 5 att cmos/ttl input. assert this pin high to enable a 14db attenuator in the ampliier. force this pin low to disable the attenuator. contains internal 40k? pulldown resistor. connect to gnd if not used. 6, 8, 11 n.c. not connected. this pin is not internally connected. 7 gain cmos/ttl input. selects ampliier gain setting. force high for 60k?. force low for 30k?. contains internal 40k? pulldown resistor. 9 out ampliier output. an increase in current into the in pin causes the voltage at the out pin to decrease. out must be ac-coupled to a load of 2k? or greater. 10 dis cmos/ttl input. force high to disable the output of the max3806. force low to enable the output. contains internal 60k? pullup resistor. ep exposed pad. the exposed pad must be soldered to circuit board ground for proper thermal and electrical performance. gain transimpedance (k?) linear range (a p ) bandwidth (mhz) 0 30 i in 40 98 1 60 i in 20 49 max3806 receiver for optical distance measurement www.maximintegrated.com maxim integrated 7 pin description downloaded from: http:///
to either the gain or att setting. table 2 provides typi - cal output common-mode voltages for the combination of settings. settling time is proportional to the rc time constant set by the output dc-blocking capacitor, load, and max3806 output impedance. for example, a 0.01f dc-blocking capacitor, 2k load, and 51 output imped - ance provide an rc time constant of approximately 20s. after changing the gain or att setting, the system should wait at least three to four time constants before analyzing received signals. settling time is also required when changing the dis set - ting. when dis is asserted high, the output disables to high impedance and typically settles to steady state within 200ns. when dis is deasserted, the output enables and typically settles to steady state within 50ns. overload recovery time transistors saturate when the amplifier is overloaded, resulting in output distortion. overload typically occurs with signals greater than 20a p (gain = 1) or 40a p (gain = 0). it can withstand overload signals as large as 2ma p . recovery time depends on the amplitude and duration of the overload pulse. layout considerations noise performance and bandwidth are adversely affected by capacitance at the in pad. minimize capacitance on this pad and select a low-capacitance photodiode. reducing pcb capacitance can be accomplished by removing the ground plane underneath the connection from the photodiode to the in pin and by keeping the pho - todiode as close as possible to the max3806. use broadband power-supply filtering techniques to achieve the best sensitivity and noise performance. exposed-pad package and thermal considerations the exposed pad on the 12-pin tqfn provides a very low thermal resistance path for heat removal from the ic. the pad is also electrical ground on the max3806 and must be soldered to the circuit board ground for proper thermal and electrical performance. refer to application note 862: hfan-08.1: thermal considerations of qfn and other exposed-paddle packages for additional information. figure 1. equivalent output circuit table 2. output common-mode voltages gain att output common-mode voltage (v) 0 0 1.65 0 1 0.33 1 0 1.82 1 1 0.36 package type package code outline no. land pattern no. 12 tqfn-ep t1233+3 21-0136 90-0018 v cc 400 out 100 200 v cc max3806 gnd gain 3 7 in n.c. 2 8 v cc out 1 9 12 4 v cc gnd 11 5 n.c. att 10 6 n.c. dis thin qfn (3mm 3mm) top view + *ep *exposed pad max3806 receiver for optical distance measurement www.maximintegrated.com maxim integrated 8 pin coniguration package information for the latest package outline information and land patterns (footprints), go to www.maximintegrated.com/packages . note that a +, #, or - in the package code indicates rohs status only. package drawings may show a different suffix character, but the drawing pertains to the package regardless of rohs status. downloaded from: http:///
max3806 receiver for optical distance measurement www.maximintegrated.com maxim integrated 9 * l and c set the low-frequency cutoff required for the application. multiple-channel receiver buff 0.01f 0.01f 0.01f max1446 adc max4311 4:1 mux/amp in pin +5v +5v dis3 out gain v cc 0.01f 7k?3k? c* l* max3806 linear lidar rx supply filter gnd att dis +5v +5v +5v to +12v supply filter in pin +5v +5v dis2 out gain v cc 0.01f 7k?3k? c* l* max3806 linear lidar rx supply filter gnd att dis +5v +5v to +12v supply filter dis0 dis1 in pin +5v +5v dis1 out gain v cc 0.01f 7k?3k? c* l* max3806 linear lidar rx supply filter gnd att dis +5v +5v to +12v supply filter in pin +5v +5v dis0 out gain v cc 0.01f 7k ? 3k? c* l* max3806 linear lidar rx supply filter gnd att dis +5v +5v to +12v supply filter in0in1 in2 in3 a1 a0 dis2 dis3 microcontroller/dsp typical application circuits (continued) downloaded from: http:///
maxim integrated cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a maxim integrated product. no circuit patent licenses are implied. maxim integrated reserves the right to change the circuitry and speciications without n otice at any time. the parametric values (min and max limits) shown in the electrical characteristics table are guaranteed. other parametric values quoted in this data sheet are provided for guidance. maxim integrated and the maxim integrated logo are trademarks of maxim integrated products, inc. max3806 receiver for optical distance measurement ? 2014 maxim integrated products, inc. 10 revision history revision number revision date description pages changed 0 7/09 initial release 1 6/14 removed automotive reference from applications section and corrected page code 1, 8 for pricing, delivery, and ordering information, please contact maxim direct at 1-888-629-4642, or visit maxim integrateds website at www.maximintegrated.com. downloaded from: http:///
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