BA4424N Datasheet | ROHM

Audio ICs FM / TV front end The BA4424N is a monolithic IC designed for FM front end use. It consists of an RF amplifier circuit, mixer circuit, local oscillation circuit, IF buffer amplifier, and a variable capacitor-diode for AFC. FFeatures 1) An RF amplifier, mixer, local oscillator, IF buffer amplifier, and AFC diode are included on-chip. 2) Reception of VHF terrestrial TV channels is possible. 3) Uses a double balance mixer to improve intermodulation characteristics. 4) Includes a clamp diode in the mixer output. 5) Local oscillation buffer on-chip for improved response to strong input. 6) The output impedance of the IF buffer amplifier is matched with the ceramic filter impedance at 330Ω. FAbsolute maximum ratings (Ta = 25_C) 7) A resistive load can also be used for the mixer output. 8) Mixer input coupling capacitor included on-chip. 9) Includes a feedback capacitor for the local oscillation circuit. 10) pact 9-pin SIP package. Pins arranged for convenient mounting. FRemended operating conditions (Ta = 25_C) Audio ICs FBlock diagram FElectrical characteristics DC characteristics (unless otherwise noted, Ta = 25_C, VCC = 4V, no input) AC characteristics (unless otherwise noted, Ta = 25_C and VCC = 4V) Audio ICs FMeasurement circuit FPin connections 1 FM ANT input pin 2 3 4 5 : Connect to BPF ZIN = 75Ω RF amplifier bypass pin : Connect to bypass capacitor RF amplifier output load pin : Connect to RF tuning circuit MIX output pin : IFT or resistor load GND pin : IC ground pin 6 IF amplifier output pin 7 AFC diode pin 8 OSC pin 9 VCC pin : ZOUT = 330Ω : Cathode pin (anode pin is connected internally to ground) : Connect to resonating circuit : IC voltage supply pin FCircuit operation (1) RF amplifier circuit The RF amplifier consists of a mon base transistor. A band pass filter (BPF) is used in the ANT circuit, and as the RF amplifier is base-grounded, a BPF with an output impedance of 75Ω should be used. If a BPF...