? 8 pin plid ? 8 pin slt (LD512) ? chip (61 x 61 mils) au bump description the gb512 and LD512 are 8 pin stand-alone input compression amplifiers requiring minimal external parts. each consists of a voltage regulator for the electret microphone providing a high power supply rejection ratio (psrr), a compression stage which has a 2:1 compression ratio, and an auto-biasing, class a, voltage drive output stage. the auto-bias output stage can drive a variety of impedances ranging from 500 w to 5 k w without adding any external resistors to set the bias. the gb512 and LD512 are recommended for low to medium gain/output ite and itc type hearing aids. the gb512 is tested to tighter test limits. gb512/LD512 data sheet low parts compression amplifier features ? 44 db typical preamplifier gain ? 14 db typical output stage gain ? compression function ratio 1:1 to 2:1 to :1 ? automatic setting of transducer current ? operation down to 1.1 vdc ? greater than 40 db volume control range standard packaging document no. 500 - 75 - 08 200 mv ref v reg 7 a in v reg c agc 3 8 4 5 6 1 c + _ b - - a gnd b out c in c out 28 db 16 db v b control 2 block diagram revision date: january 2001 gennum corporation p.o. box 489, stn a, burlington, ontario, canada l7r 3y3 tel. (905) 632-2996 fax: (905) 632-5946 japan branch: a-302, miyamae village, 2-10-42, miyamae, suginami-ku, tokyo 168, japan tel. (03) 3334-7700 fax (03) 3247-8839
2 500 - 75 - 08 1 4 5 8 a in v b gnd c out c in pin connection absolute maximum ratings parameter value/units supply voltage 5 v dc power dissipation 25mw operating temperature range -10 c to 40 c storage temperature range -20?c to 70?c v reg c agc b out v o 4 v o 3 v o 2 v o 1 -40 dbv in -54 dbv in -74 dbv in -88 dbv in o/p level (dbv) at pin 1 notes: 1. v o and distortion measurements are taken at pin 1. 2. output stage gain = 20 log (r f / r s ). a gain of 14 db is recommended for optimal stability. stability is dependent upon the ratio of the receiver impedance (z l ) and the battery impedance to r f & r s . (r f / r s ) < (z l / r b ) 3. v bias = v p5 - v p7 4. measured at pin 7 caution class 1 esd sensitivity 290 0.98 -41 v o1 + 11 v o2 +12 -18 3 4 300 - - - 110 0.88 -48 - v o2 + 7 -23.5 - - 160 3 - - 200 0.93 -44 - v o2 +10 -20 1 2 200 8 100 5 290 0.98 -40 - v o2 +13 -17.5 3 4 240 - - - m a v dc dbv db db dbv m v rms % mvdc ma ms/ m f ms/ m f electrical characteristics conditions : temperature 25?c, frequency 1 khz, supply voltage 1.3 vdc. parameter symbol conditions min typ max min t yp max units amplifier current i amp regulator voltage v reg output level v o1 v in = -88 dbv output level v o2 v in = -74 dbv output level v o3 v in = -54 dbv output level v o4 v in = -40 dbv input referred noise irn nfb 0.2-10khz at 12db/oct total harmonic distortion thd v in = -54 dbv receiver bias voltage v bias note 3 current sinking capability i sink note 4 release time factor t rel attack time factor t att 200 0.93 -44 v o1 + 9 v o2 +10 -20 1 2 200 8 100 5 110 0.88 -47 v o1 + 7 v o2 + 8 -23 - - 100 3 - - gb512 LD512 all parameters and switches remain as shown in the test circuit unless stated in conditions column. v px - actual voltage measured on the pin at given condition (x is pin number).
3 500 - 75 - 08 fig. 2 functional schematic regulator control _ _ 5 7 6 8 1 2 3 4 base current compensation 120k 1k fig. 1 test circuit i amp v o 22k 1? v in 200 mv ref v reg 7 2 3k9 0? 3 8 4 5 6 1 b - - a 100k 0? r f 2k2 c + _ 28 db 16 db control r b 4 w 7 v b = 1.3 v dc 1? all resistors in ohms, all capacitors in farads unless otherwise stated
4 500 - 75 - 08 v b =1.3 v dc 1? 0? ed1913 100k r vc 20k 1? 200 mv ref v reg 7 3 8 4 5 6 1 c + _ b - - a 28 db 16 db control 2 r s 3k9 0? c s 4 2 0 -2 -4 -6 -8 -10 -12 -14 -16 -18 -20 -100 -90 -80 -70 -60 -50 -40 -100 -90 -80 -70 -60 -50 -40 20 200 2k 20k 5 0 -5 -10 -15 -20 -25 -30 0.7 0.8 0.9 1.0 1.1 1.2 1.3 1.4 input (dbv) input (dbv) supply voltage (v dc ) relative gain (db) output (dbv) output (dbv) fig. 4 i/o characteristics at various r vc values (pin 7) fig. 5 i/o characteristics at pin 1 fig. 7 gain vs supply voltage fig. 6 closed loop frequency response at various c s values frequency c s = 0.22 m f c s = 0.1 m f c s = 0.033 m f c s = 0.047 m f r vc = 100k r vc = 47k r vc = 22k r vc = 3.3k r vc = 10k relative output (db) all resistors in ohms, all capacitors in farads unless otherwise stated fig. 3 typical hearing aid application 0 -10 -20 -30 -40 -50 -60 -70 -80 0 -10 -20 -30 -40 -50 -60 -70 -80
5 500 - 75 - 08 document identification product proposal this data has been compiled for market investigation purposes only, and does not constitute an offer for sale. advance information note this product is in development phase and specifications are subject to change without notice. gennum reserves the right to remove the product at any time. listing the product does not constitute an offer for sale. preliminary data sheet the product is in a preproduction phase and specifications are subject to change without notice. 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 sept. 1982 gennum corporation. all rights reserved. printed in canada. 1.4 1.2 1.0 0.8 0.6 0.4 0.2 0.0 -0.2 -0.4 -0.6 -0.8 -1.0 30 20 10 0 -10 -20 -30 -40 -50 -20 -10 0 10 20 30 40 50 -20 -10 0 10 20 30 40 50 temperature (?c) temperature (?c) fig. 9 receiver bias voltage vs temperature fig. 8 gain vs temperature relative reference voltage (mv dc ) relative gain (db) -20 -10 0 10 20 30 40 50 50 40 30 20 10 0 -10 -20 -30 -40 -50 -60 -70 temperature (?c) relative amplifier current ( m a) fig. 10 amplifier current vs temperature revision notes changes to standard packaging information.
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