Low Distortion AGC Compression Amplifier LD502 DATA SHEET FEATURES DESCRIPTION • adjustable gain from 0 to 60 dB The LD502 is a compression (AGC) preamplifier that consists of a single ended input inverting amplifier, with an internal current controlled resistance connected between input and output. • 0.94 V DC voltage regulator on-chip • attack time fixed at less than 1 ms • release time adjustable from 40 to 500 ms By using RGT (see test circuit) to vary the value of this current controlled resistance, the amplifier gain and compression threshold can be controlled over a range of 60 dB. • low input referred noise 1.2 µV • <1 % distortion at 10 mVRMS output • operates from 1.05 to 3 VDC The AGC current is derived from a full wave rectifier driven by a differential amplifier. The attack time of the AGC circuit is fixed at less than 1 ms. The release time is adjustable from 40 to 500 ms by selecting the value of an external capacitor (C3). STANDARD PACKAGING • 8 pin MICROpac • 8 pin MINIpac Internally, a series shunt voltage regulator produces a 0.94 V DC regulated output voltage. This provides a bias for electret microphones and permits circuit operations over a wide range of supply voltages, 1.05 to 3 VDC for LD502 without any degradation of electrical performances. • 8 pin PLID ® • 8 pin SLT • Chip (64 x 62 mils) Au Bump VB GAIN SET 7 2 VREG 4 VOLTAGE REGULATOR 1 A OUT AMPLIFIER A IN 3 FULL WAVE RECTIFIER 8 AGC IN 6 5 AGC FILTER GND BLOCK DIAGRAM Patented 1985 Canada 1183580 Patent Pending Europe 83.300836.0 USA 4506169 Japan 58-06886 Revision Date: March 1994 GENNUM CORPORATION P.O. Box 489, Stn A, Burlington, Ontario, Canada L7R 3Y3 Japan Branch: A-302, M i yamae Vi l l age, 2–10–42 M i yamae, Suginami–ku, Tokyo 168, Japan Document No. 500 - 43 - 18 tel. (905) 632-2996 fax: (905) 632-5946 tel. (03) 3334-7700 fax (03) 3247-8839 ABSOLUTE MAXIMUM RATINGS PIN CONNECTION PARAMETER VALUE/UNITS Supply Voltage 3 V DC Power Dissipation 25 mW A OUT Operating Temperature Range -10°C to 50° C VREG Storage Temperature Range -20°C to 70° C A IN GAIN SET 5 4 AGC FILTER AGC IN VB 1 8 GND CAUTION CLASS 1 ESD SENSITIVITY ELECTRICAL CHARACTERISTICS Conditions: Frequency = 1 kHz, Temperature = 25°C, Supply Voltage V B = 1.3 VDC PARAMETER SYMBOL Gain CONDITIONS VOUT = 11.0 mV, AV 20 Log ( V OUT ) MIN TYP MAX UNITS 38 41 46 dB 7.5 12 15.5 mV V IN Output Level VOHIGH VIN = 6.32 mV, S1 closed Distortion -Linear THD VOUT = 11.0 mV - 1 2.9 % VIN = 6.32mV, S1 closed - 1 2.2 % S2 closed,NFB 0.2 to 10 kHz at 12 dB/Oct - 1.2 2.2 µV VIN = 0.1 to 6.32 mV, S1 closed 2 5 8 dB µA - AGC Input Referred Noise IRN Compression Function Ratio Total Amplifier Current I AMP 160 310 380 Regulated Voltage VREG 0.890 0.940 0.990 Supply Rejection PSRR 51 60 - All parameters and switches remain as shown in Test Circuit unless otherwise stated in "Conditions" column ITOT RGT 130k VB= 1.3 VDC 7 2 C1 0.47 4 VOLTAGE REGULATOR C5 1.0 3 1 AMP VOUT RTH 0Ω RS= 3.5k S1 FULL WAVE RECTIFIER S2 C4 0.1 RM 33K C2 1.0 8 5 VIN C3 1.0 All resistors in ohms, all capacitors in microfarads unless otherwise stated Fig. 1 Test Circuit 500 - 43 - 18 6 2 RL 10K VDC dB GAIN TRIM VB=1.3 VDC 4.7 4.7 500k 7 2 4.7 4 LD502 LC549 6 VC =10k 5 0.1 0.1 AMP 1 4 1 VOLTAGE REGULATOR 2 RL=400 TYP 3 RS 3.9k 0.1 8 FULL WAVE RECTIFIER 6 5 8 3 7 NC 0.1-1.0 0.047 All resistors in ohms, all capacitors in microfarads unless otherwise stated Fig. 2 LD502/LC549Hearing Instrument Application GAIN TRIM VB=1.3 VDC 500k 7 2 4.7 4 LD502 VOLTAGE REGULATOR 25k 2 0.1 0.1 AMP 33k 3 1 RS 3.9k 18k 1 BK1606 7 Z=1k 13.5k 2k 5 0.1 8 8 4 LE507 FULL WAVE RECTIFIER 6 5 0.1 VC 10k 3 0.47 6 RE=33 All resistors in ohms, all capacitors in microfarads unless otherwise stated Fig. 3 LD502/LE507 Hearing Instrument Application 3 500 - 43 - 18 100 100 10 OUTPUT (mV) OUTPUT (mV) RTH =50k RTH=22k RTH=10k 10 RTH=0k 1 0.01 0.1 1.0 RGT=130k RGT=82k RGT=68k RGT=47k 1 0.1 0.01 10 0.1 INPUT (mV) Fig. 4 I/O Characteristics at Various RTH Values 10 Fig. 5 I/O Characteristics at Various RGT Values 4 100 2 RELATIVE OUTPUT (dB) 0 RTH =0 OUTPUT (mV) 1.0 INPUT (mV) VB=3 VDC 10 VB=1.3 VDC -2 CS=0.22 µ CS =0.1 µ -4 -6 -8 CS=0.047 µ -10 -12 CS =0.033 µ -14 -16 -18 0.1 0.01 0.1 1.0 -20 20 10 200 2K 20000 FREQUENCY (Hz) INPUT (mV) Fig. 6 Effects of Supply Voltage Variation Fig. 7 Frequency Response at Various CS Values 4.0 REVISION NOTES 3.0 THD (%) Changes to Fig.1, test conditions, Pb/Sn bump removed. 2.0 DOCUMENT IDENTIFICATION PRODUCT PROPOSAL This data has been compiled for market investigation purposes only, and does not constitute an offer for sale. 1.0 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. 0.0 0.0 5.0 10.0 15.0 20.0 25.0 OUTPUT (mV) Fig. 8 Total Harmonic Distortion vs Output Level 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 they are free from patent infringement. © Copyright January 1982 Gennum Corporation. All rights reserved. Printed in Canada. 500 - 43 - 18 4