a ssm2019 information furnished by analog devices is believed to be accurate and reliable. however, no responsibility is assumed by analog devices for its use, nor for any infringements of patents or other rights of third parties that may result from its use. no license is granted by implication or otherwise under any patent or patent rights of analog devices. trademarks and registered trademarks are the property of their respective companies. one technology way, p.o. box 9106, norwood, ma 02062-9106, u.s.a. tel: 781/329-4700 www.analog.com fax: 781/326-8703 ?2003 analog devices, inc. all rights reserved. rev. 0 self-contained audio preamplifier functional block diagram rg 1 rg 2 5k 5k 1 5k 5k v 5k out 5k 1 reference v +in v+ ?n general description the ssm2019 is a latest generation audio preamplifier, combin- ing ssm preamplifier design expertise with advanced processing. the result is excellent audio performance from a monolithic device, requiring only one external gain set resistor or potentiom- eter. the ssm2019 is further enhanced by its unity gain stability. key specifications include ultra-low noise (1.5 db noise figure) and thd (<0.01% at g = 100), complemented by wide bandwidth and high slew rate. applications for this low cost device include microphone pream- plifiers and bus summing amplifiers in professional and consumer audio equipment, sonar, and other applications requiring a low noise instrumentation amplifier with high gain capability. features excellent noise performance: 1.0 nv/ hz or 1.5 db noise figure ultra-low thd: < 0.01% @ g = 100 over the full audio band wide bandwidth: 1 mhz @ g = 100 high slew rate: 16 v/ s @ g = 10 10 v rms full-scale input, g = 1, v s = 18 v unity gain stable true differential inputs subaudio 1/f noise corner 8-lead pdip or 16-lead soic only one external component required very low cost extended temperature range: ?0 c to +85 c applications audio mix consoles intercom/paging systems 2-way radio sonar digital audio systems pin connections 8-lead pdip (n suffix) 8-lead narrow body soic (rn suffix) * top view (not to scale) 8 7 6 5 1 2 3 4 rg 1 ?n +in rg 2 v+ out reference v ssm2019 16-lead wide body soic (rw suffix) top view (not to scale) 16 15 14 13 12 11 10 9 1 2 3 4 5 6 7 8 nc = no connect nc rg 1 nc ?n +in nc v nc nc rg 2 nc v+ nc out reference nc ssm2019 * consult factory for availability.
rev. 0 e2e ssm2019especifications (v s = 15 v and e40 c t a +85 c, unless otherwise noted. typical specifications apply at t a = 25 c.) parameter symbol conditions min typ max unit distortion performance v o = 7 v rms r l = 2 k w total harmonic distortion plus noise thd + n f = 1 khz, g = 1000 0.017 % f = 1 khz, g = 100 0.0085 % f = 1 khz, g = 10 0.0035 % f = 1 khz, g = 1 0.005 % bw = 80 khz noise performance input referred voltage noise density e n f = 1 khz, g = 1000 1.0 nv/ hz hz hz hz hz hz hz hz hz hz hz hz hz k w t a = 25 g e 1 r g = 10 w , g = 1000 0.5 0.1 db r g = 101 w , g = 100 0.5 0.2 db r g = 1.1 k w , g = 10 0.5 0.2 db r g = , g = 1 0.1 0.2 db maximum gain g 70 db reference input input resistance 10 k w voltage range 12 v gain to output 1 v/v power supply supply voltage range v s 5 18 v supply current i sy v cm = 0 v, r l = 4.6 7.5 ma v cm = 0 v, v s = 18 v, r l = 4.7 8.5 ma specifications subject to change without notice.
rev. 0 ssm2019 ? absolute maximum ratings 1 supply voltage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19 v input voltage . . . . . . . . . . . . . . . . . . . . . . . . . . supply voltage output short circuit duration . . . . . . . . . . . . . . . . . . . 10 sec storage temperature range . . . . . . . . . . . . ?5 c to +150 c junction temperature (t j ) . . . . . . . . . . . . . 65 c to +150 c lead temperature range (soldering, 60 sec) . . . . . . . . 300 c operating temperature range . . . . . . . . . . . ?0 c to +85 c thermal resistance 2 8-lead pdip (n) . . . . . . . . . . . . . . . . . . . . . . . ja = 96 c/w . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . jc = 37 c/w 16-lead soic (rw) . . . . . . . . . . . . . . . . . . . . ja = 92 c/w . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . jc = 27 c/w notes 1 stresses above those listed under absolute maximum ratings may cause perma- nent damage to the device. this is a stress rating only; functional operation of the device at these or any other conditions above those indicated in the operational section of this specification is not implied. exposure to absolute maximum rating conditions for extended periods may affect device reliability. 2 q ja is specified for worst-case mounting conditions, i.e., q ja is specified for device in socket for pdip; q ja is specified for device soldered to printed circuit board for soic package. frequency ?hz thd + n ?% 0.0001 10 0.001 0.01 0.1 20 100 1k 10k 20k 15v v s 18v 7vrms v o 10vrms r l 600 bw = 80khz g = 10 g = 1000 g = 100 g = 1 tpc 1. typical thd + noise vs. gain frequency ?hz rti, voltage noise density ?nv/ hz 0.1 110 100 1k 10k 1 10 100 t a = 25 c v s = 15v g = 1000 tpc 2. voltage noise density vs. frequency warning! esd sensitive device caution esd (electrostatic discharge) sensitive device. electrostatic charges as high as 4000 v readily accumulate on the human body and test equipment and can discharge without detection. although the ssm2019 features proprietary esd protection circuitry, permanent damage may occur on devices subjected to high energy electrostatic discharges. therefore, proper esd precautions are recommended to avoid performance degradation or loss of functionality. t ypical performance characteristics ordering guide temperature package package model range description option ssm2019bn 40 c to +85 c8-l ead pdip n-8 ssm2019brw ?0 c to +85 c 16-lead soic rw-16 ssm2019brwrl ?0 c to +85 c 16-lead soic, reel rw-16 ssm2019brn * ?0 c to +85 c8 -lead soic rn-8 ssm2019brnrl * ?0 c to +85 c8 -lead soic, reel rn-8 * consult factory for availability.
rev. 0 ssm2019 e4e gain 1 1 10 10 100 100 1k rti voltage noise density e nv/ hz hzhz hz hz hz hz hz hz
rev. 0 e5e ssm2019 temperature e c 0 v ios e mv e50 v+/ve = 15v 0.005 0.010 0.015 0.020 0.025 0.030 0.035 0.040 e25 0 25 50 75 100 tpc 12. v ios vs. temperature supply voltage (v cc e v ee ) e v v oos e mv 0 510 2 0303 540 e20 20 30 e30 e10 0 10 15 25 t a = 25 c tpc 15. v oos vs. supply voltage temperature e c supply current e ma e50 2 6 8 e2 e4 e6 e8 0 4 e25 0 25 50 75 100 ie @ v+/ve = 15v ie @ v+/ve = 18v i+ @ v+/ve = 18v i+ @ v+/ve = 15v tpc 18. supply current vs. temperature supply voltage (v cc e v ee ) e v v ios e mv e0.06 0 10 20 25 30 35 40 515 e0.05 e0.04 e0.03 e0.02 e0.01 0 0.01 0.02 t a = 25 c tpc 13. v ios vs. supply voltage temperature e c i b e a e50 4 5 3 2 1 0 e25 0 25 50 75 100 v+/ve = 15v i b+ or i be tpc 16. i b vs. temperature supply voltage (v cc e v ee ) e v supply current e ma 0510 20 30 35 40 e6 6 8 e8 e4 e2 0 2 4 15 25 i+ ie t a = 25 c tpc 19. supply current vs. supply voltage temperature e c v oos e mv e8 e25 e50 25 75 100 v+/ve = 15v 050 e7 e6 e5 e4 e3 e2 e1 0 tpc 14. v oos vs. temperature supply voltage (v cc e v ee ) e v i b e a 0 0 3 6 5 1 10 20 30 40 2 4 t a = 25 c tpc 17. i b vs. supply voltage supply voltage e v supply current e ma 5 0 8 10 12 10 15 20 6 4 2 0 t a = 25 c 14 16 tpc 20. i sy vs. supply voltage
rev. 0 ssm2019 ? v+ v out r g +in ?n r g1 r g2 ssm2019 reference g = v out (+in) ?( in) = 10k r g + 1 figure 1. basic circuit connections gain the ssm2019 only requires a single external resistor to set the voltage gain. the voltage gain, g , is: g k r g =+ 10 1 w and the external gain resistor, r g , is: r k g g = 10 1 w ? for convenience, table i lists various values of r g for common gain levels. table i. values of r g for various gain levels r g ( )a v db nc 1 0 4.7 k 3.2 10 1.1 k 10 20 330 31.3 30 100 100 40 32 314 50 10 1000 60 the voltage gain can range from 1 to 3500. a gain set resistor is not required for unity gain applications. metal film or wire-wound resistors are recommended for best results. the total gain accuracy of the ssm2019 is determined by the tolerance of the external gain set resistor, r g , combined with the gain equation accuracy of the ssm2019. total gain drift combines the mismatch of the external gain set resistor drift with that of the internal resistors (20 ppm/ c typ). bandwidth of the ssm2019 is relatively independent of gain, as shown in figure 2. for a voltage gain of 1000, the ssm2019 has a small-signal bandwidth of 200 khz. at unity gain, the bandwidth of the ssm2019 exceeds 4 mhz. 1k 10m vo lta ge gain ?db 60 10k 100k 1m 40 20 0 v s = 15v t a = 25 c figure 2. bandwidth for various values of gain noise performance the ssm2019 is a very low noise audio preamplifier exhibiting a typical voltage noise density of only 1 nv/ hz at 1 khz. the exceptionally low noise characteristics of the ssm2019 are in part achieved by operating the input transistors at high collector currents since the voltage noise is inversely proportional to the square root of the collector current. current noise, however, is directly proportional to the square root of the collector current. as a result, the outstanding voltage noise performance of the ssm2019 is obtained at the expense of current noise perform ance. at low preamplifier gains, the effect of the ssm2019 voltage and current noise is insignificant. the total noise of an audio preamplifier channel can be calculated by: eeire nnnst =+ + 2 2 2 () where: e n = total input referred noise e n = amplifier voltage noise i n = amplifier current noise r s = source resistance e t = source resistance thermal noise for a microphone preamplifier, using a typical microphone impedance of 150 w , the total input referred noise is: envhzpahz nvhz nv hz khz n =++ = ()(/ )(./) ./@ 12 150 1 6 193 1 2 22 w where: e n = 1 nv/ hz @ 1 khz, ssm2019 e n i n = 2 pa/ hz @ 1 khz, ssm2019 i n r s = 150 w , microphone source impedance e t = 1.6 nv / hz @ 1 khz, microphone thermal noise this total noise is extremely low and makes the ssm2019 virtually transparent to the user.
rev. 0 ssm2019 e7e r g c4 200pf z1 z2 z3 z4 r1 10k r2 10k r3 6.8k 1% r4 6.8k 1% +in ein r5 100 c3 47 f c1 c2 v out +18v e18v c1, c2: 22 f to 47 f, 63v, tantalum or electrolytic z1ez4: 12v, 1/2w r g1 r g2 ssm2019 +48v figure 4. ssm2019 in phantom powered microphone circuit inputs the ssm2019 has protection diodes across the base emitter junctions of the input transistors. these prevent accidental avalanche breakdown, which could seriously degrade noise performance. additional clamp diodes are also provided to prevent the inputs from being forced too far beyond the supplies. (inverting) ( noninverting) t ransducer ssm2019 a. single-ended r t ransducer ssm2019 r b. pseudo-differential t ransducer ssm2019 c. true differential figure 3. three ways of interfacing transducers for high noise immunity although the ssm2019 inputs are fully floating, care must be exercised to ensure that both inputs have a dc bias connection capable of maintaining them within the input common-mode range. the usual method of achieving this is to ground one side of the transducer as in figure 3a. an alternative way is to float the transducer and use two resistors to set the bias point as in figure 3b. the value of these resistors can be up to 10 k w , but they should be kept as small as possible to limit common-mode pickup. noise contribution by resistors is negligible since it is attenuated by the transducer?s impedance. balanced transducers give the best noise immunity and interface directly as in figure 3c. for stability, it is required to put an rf bypass capacitor directly across the inputs, as shown in figures 3 and 4. this capacitor should be placed as close as possible to the input terminals. good rf practice should also be followed in layout and power supply bypassing, since the ssm2019 uses very high bandwidth devices. reference terminal the output signal is specified with respect to the reference terminal, which is normally connected to analog ground. the reference may also be used for offset correction or level shifting. a refer- ence source resistance will reduce the common-mode rejection by the ratio of 5 k w /r ref . if the reference source resistance is 1 w , then the cmr will be reduced to 74 db (5 k w /1 w = 74 db). common-mode rejection ideally, a microphone preamplifier responds to only the difference between the two input signals and rejects common-mode voltages and noise. in practice, there is a small change in output voltage when both inputs experience the same common-mode voltage change; the ratio of these voltages is called the common-mode gain. common-mode rejection (cmr) is the logarithm of the ratio of differential-mode gain to common-mode gain, expressed in db. phantom powering a typical phantom microphone powering circuit is shown in figure 4. z1 to z4 provide transient overvoltage protection for t he ssm2019 whenever microphones are plugged in or unplugged.
rev. 0 e8e c02718e0e2/03(0) printed in u.s.a. ssm2019 outline dimensions 8-lead plastic dual in-line package [pdip] (n-8) dimensions shown in inches and (millimeters) seating plane 0.180 (4.57) max 0.150 (3.81) 0.130 (3.30) 0.110 (2.79) 0.060 (1.52) 0.050 (1.27) 0.045 (1.14) 8 1 4 5 0.295 (7.49) 0.285 (7.24) 0.275 (6.98) 0.100 (2.54) bsc 0.375 (9.53) 0.365 (9.27) 0.355 (9.02) 0.150 (3.81) 0.135 (3.43) 0.120 (3.05) 0.015 (0.38) 0.010 (0.25) 0.008 (0.20) 0.325 (8.26) 0.310 (7.87) 0.300 (7.62) 0.022 (0.56) 0.018 (0.46) 0.014 (0.36) controlling dimensions are in inches; millimeter dimensions (in parentheses) are rounded-off inch equivalents for reference only and are not appropriate for use in design compliant to jedec standards mo-095aa 0.015 (0.38) min 16-lead standard small outline package [soic] wide body (rw-16) dimensions shown in millimeters and (inches) controlling dimensions are in millimeters; inch dimensions (in parentheses) are rounded-off millimeter equivalents for reference only and are not appropriate for use in design compliant to jedec standards ms-013aa seating plane 0.30 (0.0118) 0.10 (0.0039) 0.51 (0.0201) 0.33 (0.0130) 2.65 (0.1043) 2.35 (0.0925) 1.27 (0.0500) bsc 16 9 8 1 10.65 (0.4193) 10.00 (0.3937) 7.60 (0.2992) 7.40 (0.2913) 10.50 (0.4134) 10.10 (0.3976) 0.32 (0.0126) 0.23 (0.0091) 8 0 0.75 (0.0295) 0.25 (0.0098) 45 1.27 (0.0500) 0.40 (0.0157) coplanarity 0.10 8-lead standard small outline package [soic] * narrow body (rn-8) dimensions shown in millimeters and (inches) 0.25 (0.0098) 0.19 (0.0075) 1.27 (0.0500) 0.41 (0.0160) 0.50 (0.0196) 0.25 (0.0099) 45 8 0 1.75 (0.0688) 1.35 (0.0532) seating plane 0.25 (0.0098) 0.10 (0.0040) 85 4 1 5.00 (0.1968) 4.80 (0.1890) 4.00 (0.1574) 3.80 (0.1497) 1.27 (0.0500) bsc 6.20 (0.2440) 5.80 (0.2284) 0.51 (0.0201) 0.33 (0.0130) coplanarity 0.10 controlling dimensions are in millimeters; inch dimensions (in parentheses) are rounded-off millimeter equivalents for reference only and are not appropriate for use in design compliant to jedec standards ms-012aa * consult factory for availability. bus summing amplifier in addition to its use as a microphone preamplifier, the ssm2019 can be used as a very low noise summing amplifier. such a circuit is particularly useful when many medium impedance outputs are summed together to produce a high effective noise gain. the principle of the summing amplifier is to ground the ssm2019 inputs. under these conditions, pins 1 and 8 are ac virtual grounds sitting about 0.55 v below ground. to remove the 0.55 v offset, the circuit of f igure 5 is recomm ended. a2 forms a servo amplifier feeding the ssm2019 inputs. this places pins l and 8 at a true dc virtual ground. r4 in conjunction with c2 removes the voltage noise of a2, and in fact just about any operational amplifier will work well here since it is removed from the signal path. if the dc offset at pins l and 8 is not too critical, then the servo loop can be replaced by the diode biasing scheme of figure 5. if ac coupling is used throughout, then pins 2 and 3 may be directly grounded. e in v out ssm2019 r4 5.1k r3 33k c1 0.33 f r2 6.2k c2 200 f + in a2 r5 10k v in4148 to pins 2 and 3 figure 5. bus summing amplifier
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