AN7124 PANASONIC
Document overview
- Manufacturer or author: Provided By digicamel.com
- PDF pages: 5
Technical content
Dual 3.1 W Audio Power Amplifier n Overview The AN7124 is a monolithic integrated circuit designed for dual audio power amplifier of portable radio cassette. n Features
- Audio output : 3.1 W · 2 channel
- Built-in standby and muting circuit
- Built-in thermal shut down protection circuit
- Low pop noise during standby and mute ON/OFF
- No negative feedback pin n Applications
- Radio-cassette n Block Diagram n Pin Descriptions HSIP012-P-0000A Unit : mm 7.7±0.3 (12.5) 19.1±0.3 21.9±0.3 (1.2) (10.0)(10.0) 29.6±0.3 20.0±0.3 0.6 28.0±0.3 29.75±0.30 f3.6 R1.8 121 +0.15 –0.052.540.25 1.45±0.151.80±0.15 1.2±0.1 3.5±0.3 +0.10 –0.05 Pin No. Description
1 Stand-by
2 Muting
3 ch.2 input 4 ch.1 input
5 Input GND
6 Ripple filter
Pin No. Description 7 ch.1 output 8 ch.1 bootstrap
9 Output GND
10 V CC
11 ch.2 bootstrap 12 ch.2 output Over current thermal protection circuit Ripple filter GND GND V CC STB Mute 45 dB 45 dB
AN7124 ICs for Audio Common Use n Absolute Maximum Ratings Parameter Symbol Rating Unit Supply voltage V CC 24 V Supply current I CC 4.0 A Power dissipation P D 37.5 W Operating ambient temperature T opr -25 to +75 °C Storage temperature T stg -55 to +150 °C n Recommended Operating Range Parameter Symbol Range Unit Supply voltage V CC 6.0 to 18.0 V n Electrical Characteristics at VCC = 12 V, RL = 3 W , f = 1 kHz, Ta = 25 °C Parameter Symbol Conditions Min Typ Max Unit Quiescent current I CQ V IN = 0 mV 12 19 26 mA Output noise voltage *1 V NO V IN = 0 mV,PG = 10 kW¾ 0.27 0.5 mVrms Voltage gain G V V IN = 3 mV 43 45 47 dB Total harmonic distortion *2 THD V IN = 3 mV ¾ 0.05 0.5 % Maximum output 1 P O1 THD = 10 % 4.3 5.0 ¾ W Channel balance CB V IN = 3 mV -10 1d B Ripple rejection *1 RR R G = 0 W,V R = 280 mVrms,fR = 120 Hz 45 50 ¾ dB Standby current I STB V IN = 0 mV ¾ 11 0 mA Muting effects *1 Mut V IN = 10 mV 60 80 ¾ dB Maximum output 2 *3 PO2 THD = 10 %,VCC = 9 V 2.5 3.0 ¾ W Crosstalk *1,*3 CT R G = 10 kW,V IN = 10 mV,f = 1 kHz 50 64 ¾ dB Note) *1 : With a filter band from 20 Hz to 20 kHz (12 dB/OCT) used. *2 : With a filter band from 400 Hz to 30 kHz used. *3 : Reference data for design.
ICs for Audio Common Use AN7124 n Application Circuit Example n Characteristics Curve PD ¾ Ta 1. TC = Ta (qj-c = 2 °C/W) With a 100 cm2 · 3 mm Al heat sink (black colour coated) or a 200 cm 2 · 2 mm Al heat sink (not lacquered) With a 100 cm2 · 2 mm Al heat sink(not lacquered) 4. 3.0 W at Ta = 25 °C (qj-a = 42 °C/W) Without heat sink Power dissipation PD (W) 0 120 160 Ambient temperature Ta (°C) 40 80 20.8 W 15.6 W 3.0 W (1) (2) (3) (4) 62.5 W STB Mute V IN2V IN1 V CC = 9 V/12 V 22 mF 33 mF 100 mF 47 mF 47 mF R L R L 47 nF1 000 mF 1 000 mF1 000 mF 1 mF 1 mF 47 nF 3.9 kW 8.2 kW 2.2 W2.2 W
0 V(Off)
5 V(On)(Off)5 V
(On)0 V
AN7124 ICs for Audio Common Use n Application Note 1.Voltage gain The close loop gain of AN7124 is fixed at 45 dB(typ.) G V = 20 log( ) R2 2.Standby function Standby is ON when Pin1 is set to "L". By applying a 5 V to the standby pin, transistor Q1 will be turned ON to provide a constant current (I) for driving other parts of the circuit. The RC is to create a TIME CONSTANT for the standby pulse during charging and discharging. Threshold voltage (at Pin1) : ON <2.8 V<OFF Impedance, ZSTBY » 1 kHz 3.Muting By controlling Pin2 from "H" to "L", the mute function is set from ON to OFF. When Pin2 is floating, DC » 0.02 V. The threshold is set » 2.8 V. The RC is to create a TIME CONSTANT for the mute pulse during charging and discharging. Threshold voltage (at Pin2) : 10 % mute = 1.5 V 90 % mute = 2.8 V Impedance, ZMUTE ¥ 45 kW 15 kW84 W R 1 R 2 R C 1StbOff On ZSTBY V CC Q 1 I 5 V R C Bias MuteOff On ZMUTE5 V
ICs for Audio Common Use AN7124 n Application Note (continued) 4.Oscillation To prevent oscillation, it is advisable to use C (Zobel network capacitor). Using polyester film capacitor has small characteristic fluctuation with temperature and the frequency.The resistor R connected in series with C is effective for phase correction at high frequency, as a result, it improves the oscillation allowance. 5.Bootstrap The capacitor C connected between the output and bootstrap pin helps to increase the output dynamic range and hence increases the output power of the IC. Pin7,12 2.2 W 1 000 mF 47 nFC R pp Pin8,11 Pin7,12 C47 mF V CC