BA4228L

The BA4228L is a single-chip FM/AM IF system designed for use in 3 V radios.The FM block of the device consists of a differential IF amplifier,quadrature detector and IF soft muting circuit for weak input.The AM block consists of a local oscillator,IF amplifier,detector and AGC network.The device also contains an audio amplifier.The typical applications include FM/AM portable radios and headphone radio cassette recorders.

There are some features BA4228L as follows.First is capable of withstanding supply voltage drops (down to VCC=1.5 V typ when VOUT=-3 dB).Secondly,built-in FM muting network suppresses inter-station noise and off-tuned side peaks.The muting level can be adjusted with an external resistor.Besides,single-pin output for FM and AM circuits allow coupling to the following stage (MPX,etc) without the need for a selector switch.Furthermore,low-pass filter pin dedicated to the AM circuitry enables independent frequency response settings for FM and AM blocks.This facilitates coupling to the demultiplexer circuit.At last,the switching between FM and AM modes can be controlled by a DC level (on/off).

What comes next is about the BA4228L absolute maximum ratings (T_a=25).The V_CC (supply voltage) is 4.5 V.The Pd (power dissipation) is 500 mW.The T_opr (operating temperature range) is from -25 to 75.The T_stg (storage temperature range) is from -55 to +125.Then is about the recommended operating conditions (T_a=25).The minimum V_CC (supply voltage) is 1.8 V,the typical is 3 V and the maximum is 3.6 V.

The following is about the BA4228L electrical characteristics of FM Block (T_a=25,V_CC=3 V).The typical I_Q (quiescent current) is 7 mA and the maximum is 12 mA when muting off.The minimum V_OUT (detector output) is 55 mV,the typical is 85 mV and the maximum is 115 mV at V_IN=100 dBV,10.7 MHz,f=22.5 kHz,fm=1 kHz.The typical THD (total harmonic distortion) is 0.25% and the maximum is 0.75% at V_IN=100 dBV,10.7 MHz,f=22.5 kHz,fm=1 kHz.The minimum S/N (signal to noise ratio) is 60 dB and the typical is 68 dB at V_IN=100 dBV,10.7 MHz,f=22.5 kHz,fm=1 kHz.