TBA120 FM IF Amplifier and Demodulator DIP-14 (TBA120 IC)
The TBA120 series is a high-performance integrated circuit specifically designed for FM IF amplification and demodulation in television sound sections and FM radio receivers. Housed in a 14-pin DIP package, it combines an 8-stage limiting amplifier and a coincidence demodulator (quadrature detector) on a single chip. It is renowned for its excellent limiting properties and high AM suppression, making it a staple in analog consumer electronics.
The series includes several variants, such as the TBA120S, TBA120T, and TBA120U, each optimized for specific circuit configurations. The TBA120S features an additional electronic volume control and an auxiliary Zener diode/transistor circuit, while the TBA120T and TBA120U are specialized for use with ceramic resonators and LC-circuits, respectively.
Key Features
- High Sensitivity: Features a low limiting threshold, typically 30uV, ensuring clear reception of weak signals.
- Excellent AM Suppression: Effectively filters out amplitude noise, providing a clean audio output.
- Integrated Electronic Volume Control: (S, T, and U variants) Allows for remote DC volume adjustment with a range of over 70dB.
- Wide Supply Range: Operates reliably on supply voltages from 6V to 18V (12V typical).
- Low External Component Count: Integrated phase-shift capacitors simplify the design of the demodulator stage.
- Auxiliary Circuitry: (S variant) Includes a 12V Zener diode for voltage stabilization and a transistor for AF pre-amplification.
- Versatile Application: Can be used in TV intercarrier sound systems (5.5MHz/6MHz) and standard FM radio (10.7MHz).
Specifications
- IC Type: FM IF Amplifier and Demodulator
- Supply Voltage ($V_{CC}$): 6V to 18V (Recommended 12V)
- Operating Frequency: Up to 12 MHz
- Current Consumption: 14 mA (Typical)
- IF Voltage Gain: 68 dB
- AF Output Voltage: ~1.1 V rms
- AM Suppression: 55 dB (Typical)
- Package Type: PDIP-14 (Through-Hole)
- Operating Temperature: -10 to +70 degrees Celsius
Pinout Configuration (14-Pin DIP)
- Pin 1: Ground (EARTH)
- Pin 2: Feedback / IF Limiter Output 1
- Pin 3: Feedback / AF Input (SCART)
- Pin 4: Reference Voltage Output
- Pin 5: Electronic Volume Control Input
- Pin 6: FM Demodulator Filter / IF Output 2
- Pin 7: Phase Shifter Tank Circuit Connection 1
- Pin 8: Audio Output (Controlled/Regulated)
- Pin 9: Phase Shifter Tank Circuit Connection 2
- Pin 10: IF Limiter Output 2
- Pin 11: Positive Supply Voltage ($V_{CC}$)
- Pin 12: Uncontrolled Audio Output / Zener Diode Output
- Pin 13: Feedback Bias / Internal Transistor Base
- Pin 14: IF Input
Variant Comparison
- TBA120S: Standard version with 12V Zener and auxiliary transistor.
- TBA120T: Optimized for ceramic resonators and includes independent sound outputs for headphones/VTR.
- TBA120U: Similar to the T version but optimized for use with standard LC-circuits.
