description the GR581 is a level-sensitive, adaptive highpass filter comprised of a current controlled highpass filter, a half- wave rectifier, a voltage regulator for microphone bias and a separate preamplifier. the internal rectifier senses the long term average signal level and controls the filter response by setting the control current of the filter. the rectifier sensitivity, with respect to the input signal, can be increased by placing the internal preamplifier (a) before the filter section of the GR581. the preamplifier has an internal 265 k w feedback resistor from its input to output, to facilitate in setting the gain. an increase of 20 db above the rectifier threshold will automatically increase the corner frequency one decade above the initial corner frequency. the filter will only allow an increase in corner frequency of one decade, regardless of further increases in the input signal level. it is recommended that the attack and release times be set to 30 ms and 90 ms respectively. the average time period of a speech frame is about 15 ms which is not long enough to activate the filter, however long term average noise, which can have time periods greater than 30 ms, will activate the filter (providing that the amplitude is above the rectifier threshold). the GR581 is an improved version of the ls581adaptive high pass filter and has an identical pinout. GR581 data sheet all resistors in ohms, all capacitors in farads unless otherwise stated. 5 98374 rectifier vreg 10 2 1 6 265k -a + - b v reg a in b out 10k v b a out c a c b rect in rect cap gnd adaptive highpass filter with independent gain block features ? unity gain 12 db/oct. highpass butterworth filter ? adaptive frequency range from 200 hz to 2 khz ? rectifier threshold set to 82 dbspl (adjustable) ? low noise, typically 2.6 m v ? 300 m a typical current drain ? operates from 1.1 to 3 vdc ? preamplifier with 56 db open loop gain packaging ? 10 pin micropac ? 10 pin plid ? ? chip (73 x 59 mils) functional block diagram document no. 520 - 60 - 05 revision date: january 2001 gennum corporation p.o. box 489, stn a, burlington, ontario, canada l7r 3y3 tel. (905) 632-2996 fax: (905) 632-2814 gennum japan corporation: c-101, miyamae village, 2-10-42 miyamae, suginami-ku, tokyo 168-0081, japan tel. (03) 3334-7700 fax :(03) 3247-8839
520 - 60 - 05 2 parameter value supply voltage 3 vdc power dissipation 25 mw operating temperature range -10 c to 40 c storage temperature range -20 c to 70 c a out rect cap rect in v b v reg a in gnd c b b out c a caution class 1 esd sensitivity absolute maximum ratings pin connections parameter symbol conditions min typ max units total current i t 165 300 450 m a voltage regulator (pin 1) v reg 0.87 0.93 0.99 v dc nfb 0.2 - 10khz filter f c set to 0.2khz - 2.6 - at 12db/oct filter f c set to 2khz - 5.6 - attack time t att -30 -ms release time t re l -90 -ms stage a quiescent voltage on pin 5 v q5 0.49 - 0.67 v dc open loop gain a ol 45 56 - db feedback resistor r f 175 265 355 k w current sourcing capacity i source 15 30 - m a current sinking capacity i sink 15 30 - m a filter section quiescent voltage on pin 3 v q3 0.49 0.58 0.67 v dc quiescent voltage on pin 4 v q4 0.49 0.58 0.67 v dc quiescent voltage on pin 8 v q8 0.55 - 0.78 v dc quiescent voltage on pin 9 v q9 0.55 - 0.78 v dc filter insertion loss fil v out = 850mv rms f=2khz (s1 closed) -0.5 0.1 1.3 db distortion thd v out = 850mv rms f=1khz (s1 closed) - 2 3 % v ac 2 = 2.5mv rms (s2 closed) 5 7 9 f = 100hz (note 1) rectifier bandwidth b r v ac2 = 20mv rms (s2 closed) - 4 - khz pin 9 nominal current i p9 vp9 = 0v 0.70 1.00 1.30 m a current range i range (note 2, 3) 8 10 12 slope (note 2, 4) 0.75 1 1.25 rectifier threshold v th f = 100hz (note 2, 5) 1.7 2.5 2.8 mv dc corner frequency f c (note 2, 6) 140 200 260 hz m v rms input referred noise rectifier gain a rec irn all conditions and parameters remain as show in test circuit unless otherwise specified in conditions column. v qx - quiescent (unbias) voltage measured on the pin, (nothing connected to the pin). v px - actual voltage measured on the pin at given condition ( x is pin number). notes: 1. a rec = 1.9375 x (v p4 / v p3 ) [v in = 10mv rms ] - 0.9375 x (v p4 / v p3 ) [v in = 18mv rms ] 2. i d0 = i p9 [v p9 = 0] ; i d1 = i p9 [ v p4 = v q4 + 35mv ; v p9 = 0] i d2 = i p9 [v p4 = v q4 + 85mv ; v p9 = 0]; i d3 = i p9 [v p4 = v q4 + 180mv ; v p9 = 0] 3. i range = i d3 / i d0 4. slope = ( (i d2 - i d1 ) / 50mv ) x 14k w 5. v al = 85mv - (( i d2 - i d0 ) / slope) x 14k w : v ah = 85mv + ( 50mv x ( i d3 - i d2 ) / ( i d2 - i d1 )); v p4 v al [v in = 1.7mv rms ] and v p4 3 v al [v in = 2.8mv rms ] 6. ? c = 1 / ( 2 x p x 1.41 x 10nf x r ); r = 26mv x (( 1 / i d0 ) + ( 1 / ( i2 - i d0 ))) i2 = ((3 x ( i d0 + i p9 [v p9 = v q9 + 18mv] )) / ( 4 - (( i d0 + i p9 [v p9 = v q9 + 18mv] ) / ( i d0 + i p9 [v p9 = v q9 - 18mv] ))) electrical characteristics conditions: supply voltage v cc = 1.3 v, temperature 25 o c
520 - 60 - 05 3 5 98374 rectifier 10 2 1 6 265k -a + - b v in 10k v reg 0 m 1 8k4 83k5 ltc1001 + - 82k 2 m 2 2 m 2 s2 ac2 ac1 s1 10n 10n 0 m 1 0 m 1 v out v b fig. 1 test circuit all resistors in ohms, all capacitors in farads unless otherwise stated. regulator base current comp. virtual ground 2 265k 6 7 3 10k 13k5 56k 4 _ control 10 1 180 9 8 5 i _ all resistors in ohms, all capacitors in farads unless otherwise stated. fig. 2 functional schematic 5 98374 rectifier vreg 10 2 1 6 265k -a + - b 10k 0 m 1 0 m 1 45k 10n 10n 0 m 1 2 m 2 0 m 1 10k 100k 18 3 4 r mic -a -b 5 21k r e 2 gp509 6 7 87 v b GR581 fig. 3 typical hearing instrument application all resistors in ohms, all capacitors in farads unless otherwise stated.
520 - 60 - 05 4 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 august 1992 gennum corporation. all rights reserved. printed in canada. 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 a 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. 5 98374 rectifier vreg 10 2 1 6 265k -a + - b 10k 0 m 1 2 m 2 45k 10n 10n 2 m 2 2 m 2 0 m 1 10k GR581 in 3k9 v b out all resistors in ohms, all capacitors in farads unless otherwise stated. fig. 4 characterisation circuit (used to generate typical curves) -20 -30 -40 -50 -60 -70 output level (dbv) 100 1000 10000 frequency (hz) fig. 5 frequency response revision notes changes to standard packaging information. -43dbv -48dbv -53dbv -58dbv -63dbv -68dbv -73dbv
|
