features ? current mode class h output stage ? current drive power amp ? low distortion / low noise ? low amplifier current 190 m a typical standard packaging ? chip (84 x 112 mils) description the GC590 is a linear amplifier system containing three amplifier stages. this product incorporates a current mode class h power amplifier. by adapting the bias of the output stage to the requirements of the signal being processed, significant current savings can be realised compared to traditional class a amplifiers. the adaptive action does not compromise the characteristics of a current drive output stage. in addition to the output stage, two additional stages of preamplification are provided to allow filtering and gain adjustment to be easily accomplished. document no. 521 - 31 - 01 GC590 - data sheet linear class h amplifier gnd b out - a 10 170 7 b in 24k 12k 4 6 12 11 13 5 - GC590 a out a in v reg rec 9 3 2 1 14 8 control v b 125 12k v reg b + - + - c out r e r e1 v b c sa in b inr v b all resistors in ohms, all capacitors in farads unless otherwise stated. functional block diagram revision date: may 1998. gennum corporation p.o. box 489, stn. a, burlington, ontario, canada l7r 3y3 tel. +1 (905) 632-2996 web site: www.gennum.com e-mail: hipinfo@gennum.com
2 521 - 31 - 01 v b c out r ec gnd r e1 a out chip pin connection caution class 1 esd sensitivity absolute maximum ratings parameter value / units supply voltage 5 vdc power dissipation 25 mw operating temperature range -10 c to 40 c storage temperature range -20 c to 70 c conditions: frequency = 1 khz, temperature 25 c, voltage supply = 1.3 vdc electrical characteristics notes: 1. headroom = 20 log (v re dc / v reacrms ) [v in = -70 dbv] a in v reg c sa r ec b in b out b inr in 1 2 3 4 5 6 14 13 12 11 10 9 7 8 parameter symbol conditions min typ max units overall amplifier current i amp 80 190 300 m a minimum operating voltage v b - - 1.1 v overall gain a v 51 54 57 db distortion thd v in = -40 dbv - 0.2 1 % r trim = r vc = 10 k w input referred noise irn a weighted filter - - 2.5 m v rms voltage regulator regulator voltage v reg i load = 30 m a 870 920 970 mvdc output noise a weighted - 2.9 - m v rms stage a and stage b input bias current i bias -25 0 25 na dc voltage gain stage a a ol -a -52 -db stage b a ol -b -42 -db current source capabilities i source 15 30 - m a output voltage swing - low v sink 260 315 - mv stage c and control circuit maximum current sinking i sink r e grounded, v p4 = 1.3 v 3 6 - ma output impedance r out -24 -k w minimum emitter voltage v re-min 25 9mv maximum emitter voltage v re-max 62 66 74 mv minimum transducer current i t-min r e, r e1 shorted 26 71 126 m a maximum transducer current i t-max r e, r e1 shorted 750 930 1100 m a maximum/minimum transducer i range 16 20 28 db current ratio dynamic headroom headroom note 1 14 17 22 db time constant t c - 100 - ms all parameters and switches remain as shown in the test circuit unless otherwise stated in conditions column.
3 521 - 31 - 01 13 12k 12k 12k 24k 14 50k w 10 12 4 3 2 7 1 8 9 6 5 11 bias control circuitry all resistors in ohms, all capacitors in farads unless otherwise stated. all resistors in ohms, all capacitors in farads unless otherwise stated. fig. 1 test circuit fig. 2 functional schematic diagram 1.3v 1k 2.6v 0 1 100k r vc - a 220n 10 170 7 24k 12k 4 6 12 11 13 5 - GC590 9 3 82n 2 2 2 1 14 8 control v b 125 82n 12k v reg b + - + - c v i 100k r trim 3k9 v b
4 521 - 31 - 01 100k r vc 100k r trim 0 1 - a 220n 10 170 7 24k 12k 4 6 12 11 13 5 - GC590 9 3 82n 2 2 2 1 14 8 control v b 125 82n 12k v reg b + - + - c 1.3v v b all resistors in ohms, all capacitors in farads unless otherwise stated. fig. 3 typical hearing instrument application all resistors in ohms, all capacitors in farads unless otherwise stated. fig. 4 characterization circuit v b =1.3v r l 1k3 v l =2xv b =2.6v 0 1 r vc 10k v reg in - a 220n 10 170 7 24k 12k 4 6 12 11 13 5 - GC590 9 3 82n 2 2 2 1 14 8 control v b 125 82n 12k v reg b + - + - c r gt 100k 3k9 v i v b
5 521 - 31 - 01 10 1 0.1 thd & noise (%) v in =-40dbv 100 1k 10k frequency (hz) thd (%) fig. 9 thd & noise vs input level ? = 1khz transducer current (ma) 1.0 0.4 0.2 0.1 fig. 7 transducer current characteristics v l =v b r l =0 relative gain (db) 1.0 0.5 0 -0.5 -1 1.0 1.2 1.4 1.6 1.8 2.0 supply voltage (v) fig. 8 system gain vs supply 60 50 40 30 20 10 0 gain (db) output level (dbv) 20 0 -20 -40 -60 -80 -120 -100 -80 -60 -40 -20 input level (dbv) fig. 5 input vs output transfer function for the different values of the r vc resistor r vc =100k w r vc =10k w r vc =100 w r vc =1k w 20 100 1k 10k 20k frequency (hz) fig. 6 frequency response for different r vc values v in =80dbv (pink noise generator) r vc =10k w r vc =100k w r vc =1k w 0.06 -80 -70 -60 -50 -40 -30 -20 v re level (dbv) -60 -50 -40 -30 -20 input level (dbv) 10 1 0.1 fig. 10 thd & noise vs frequency
6 521 - 31 - 01 -20 -10 0 10 20 30 40 50 -3 -2 -1 0 1 2 3 rgt=10k 1.3v preamp 10 10 v ac 2.2k 1m 1m v out phase gain 50 40 30 20 10 20 100 1k 10k 20k frequency (hz) gain (db) fig. 12 stage b open loop gain & phase vs frequency 180 90 0 -90 -180 phase (deg) 60 50 40 30 20 1.3v preamp 10 10 v ac 2.2k 1m 1m v out 20 100 1k 10k 20k frequency (hz) fig. 11 stage a open loop gain & phase vs frequency gain (db) gain phase 180 90 0 -90 -180 phase (deg) fig. 13 output noise vs frequency 20 100 1k 10k 20k frequency (hz) noise ( m v/ ? hz) fig. 14 relative gain vs temperature relative gain (db) temperature ( c) 10 1 r gt =10k 1.3v preamp 10 10 v ac 2.2k 1m 1m v out 1.3v preamp 10 10 v ac 2.2k 1m 1m v out document identification: data sheet the product is in production. gennum reserves the right to make changes at any time to improve reliability, function or design, in order to provide the best product possible. gennum corporation assumes no responsibility for the use of any circuits described herein and makes no representations that the y are free from patent infringement. ? copyright march 1995 gennum corporation. all rights reserved. printed in canada. revision notes: updated to data sheet
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