Medium Power Class B Amplifier LC550 DATA SHEET FEATURES DESCRIPTION • 23 dB class A preamp & 40 dB class B output stage The LC550 is a low voltage linear monolithic integrated circuit amplifier. It is comprised of two separate amplifiers on a single chip. The first is a 23 dB Class A preamp followed by a 40 dB Class B output stage. • 1.0 V DC to 1.7 V DC operating range • 2.2 kΩ on chip microphone decoupling resistor • 350 µA typical quiescent current Both stages incorporate negative feedback to control gain, minimize distortion and stabilize operation at very low quiescent currents. • 400 Hz to 20 kHz frequency response The preamp and output stage have their inputs and outputs separately pinned out. This is an advantage as it allows access to both stages, providing the designer with flexibility and a full range volume control. STANDARD PACKAGING • 10 pin MICROpac • 10 pin MINIpac • 10 pin SLT • 10 pin PLID The combination of low quiescent current and a medium power push-pull output makes the LC550 suitable for medium power BTE hearing aids and for high power ITE aids where efficiency and battery life are a premium consideration. ® • Chip (57 x 47 mils) Au Bump VB V MIC 6 9 2.2k 5 OUT B2 8 IN A 40 dB 23 dB 1 OUT B1 10 GND 7 OUT A 3 IN B 2 DEC B1 4 DEC B2 All resistors in ohms, all capacitors in µF unless otherwise stated. U.S. Patent No. 4,085,382, patented in other countries. BLOCK DIAGRAM Revision Date: December 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 - 37 - 8 tel. (905) 632-2996 fax: (905) 632-5946 tel. (03) 3334-7700 fax (03) 3247-8839 ABSOLUTE MAXIMUM RATINGS PIN CONNECTION PARAMETER TOP VIEW VALUE/UNITS 3V OUT B2 60 mW DEC B2 -10° C to 60° C IN B Supply Voltage Power Dissipation Operating Temperature Range Storage Temperature Range 5 V 6 MIC OUT A IN A VB DEC B1 -20° C to 70° C OUT B1 1 GND 10 CAUTION CLASS 1 ESD SENSITIVITY ELECTRICAL CHARACTERISTICS All switches remain as shown in Test Circuit Conditions: Supply voltage VB= 1.3 V DC, Temperature ambient = 25°C, Ground line resistance 0.03 Ωmax., Volume control setting max. gain PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS Gain AV Output Level 0.707 VRMS 59 63 67 dB Total Current (including I MIC) I TOT S1 - open - 350 475 µA Input Referred Noise IRN NFB 0.2 to 10kHz at 12dB/Oct - 1.5 3 µV Total Harmonic Distortion THD Output Level 0.707 VRMS - 3.5 7.5 % - 1.4 - VRMS - - 60 Ω Preamp O/P Impedance - 1.1 - kΩ Preamp I/P Impedance - 30 - kΩ O/P Stage O/P Impedance - 110 - Ω 18 27 34 kΩ - - 3 sec O/P Swing at 7% Distortion Stable with Battery Resistance to: S4 - open O/P Stage I/P Impedance Start-Up Time Refer to start up test sequence START-UP TEST SEQUENCE SEQUENCE CONDITIONS Power Supply Off S1 Open S2 / S3 Closed S1 Closed S2 / S3 Open Power Supply On COMMENT Removes VIN Discharges C2 & C3 Applies V IN (VIN level is determined from Gain Test) Removes Short from C2 and C3 Gain must be within specification, within 3 seconds after Power Supply is turned on 500 - 37 - 8 2 S4 4.7Ω ITOT + + 10 BATTERY SIMULATOR 9 6 4.7 820 RB + 1.3 V DC 5 2.2kΩ 0.022 S1 V11 3.3k 33K I MIC VB MIC SUPPLY VO 40dB 23dB 1kΩ 0.047 8 1 22k 220 V1 7 2 3 4 10 10k 1kHz RG* 0.047 C2 2.2 0.01 C3 2.2 S2 S3 MICROPHONE SIMULATOR NOTES: 1. 42.13 dB of attenuation from V1 to V11 2 *RG (equivalent gnd resistance) should not exceed 30 mΩ (increasing RG increases distortion) All resistors in ohms, all capacitors in µF unless otherwise stated. Fig. 1 Test Circuit + 4.7NOTE1 + 6 9 0.022 8 VB 1.3 V DC 2.2 10k 7 5 2 23dB 0.047 3 40dB 2k TYP 0.047 4 0.01 1 + 10 2.2 NOTE: 1. 2.2 µF when receiver is ≥ 3kΩ All resistors in ohms, all capacitors in µF unless otherwise stated. Fig. 2 Typical Hearing Aid Application 3 2 9 1 2.2k 6 27k 33k 8 5 10 7 4 All resistors in ohms, all capacitors in µF unless otherwise stated. U.S. Patent No. 4,085,382, patented in other countries. Fig.3 Functional Schematic 3 500 - 37 - 8 35 0.1 30 0.2 25 DISTORTION ( % ) RELATIVE VOLTAGE GAIN (dB) 0 0.3 0.4 0.5 20 15 10 5 0.6 0 0.7 0 20 40 60 80 0 100 20 825 600 725 TOTAL CURRENT (µA) TOTAL CURRENT (µA) (with S1 open) 700 500 400 300 200 100 80 100 625 525 425 325 225 0 125 0.6 0.8 1.0 1.2 1.4 1.6 -40 -20 SUPPLY VOLTAGE (V) 60 68 50 66 40 64 GAIN (dB) 70 30 60 10 58 0 1.0 1.2 40 60 62 20 0.8 20 Fig. 7 Total Current vs Temperature 70 0.6 0 TEMPERATURE ( oC) Fig. 6 Total Current vs Supply Voltage GAIN (dB) 60 Fig. 5 Distortion vs Ground Line Resistance Fig. 4 Gain vs Battery Resistance 1.4 56 -40 1.6 -20 0 20 40 TEMPERATURE ( oC) SUPPLY VOLTAGE (V) Fig. 8 Gain vs Supply Voltage 500 - 37 - 8 40 GROUND RESISTANCE ( mΩ ) BATTERY RESISTANCE (Ω) Fig. 9 Gain vs Temperature 4 60 10 3.0 0 VOLTAGE GAIN (dB) 3.5 POWER (mW) 2.5 2.0 1.5 1.0 -10 -20 -30 -40 -50 0.5 -60 0 100 1k 10k 10 100k 100 1k 10k 100k FREQUENCY (Hz) LOAD IMPEDANCE (Ω) Fig. 10 Power Output vs Load Impedance at 7% Distortion Fig. 11 Voltage Gain vs Frequency 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. REVISION NOTES Correction to Fig. 1 Pb/Sn Bump removed 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 September 1981 Gennum Corporation. All rights reserved. 5 Printed in Canada. 500 - 37 - 8