The U4280BM is a frequency synthesizer IC manufactured by Telefunken Semiconductors. It has AM and FM preamplifiers and can fine-tune AM and FM bands. The adjustable frequency range is 150 MHz, and it has two 16-bit programmable dividers with a range of 2-65535. It can be used for the frequency synthesizer and RDS applications of radios.
The U4280BM is an integrated BICMOS circuit designed for AM/FM radio receivers and PLL tuning systems. It is controlled via a 2‑wire I²C bus and provides five programmable open‑drain switching outputs, a pre‑amplifier for AM and FM, and separate phase‑detector outputs.
The datasheet details pin functions, electrical characteristics, timing diagrams, and package dimensions (DIP20). It also includes an application circuit example and the manufacturer’s ozone‑depleting substances policy.
| Frequency range | up to 150 MHz |
|---|---|
| Supply voltage range | ‑0.3 V to +6 V |
| Output current (open‑drain) | ‑1 µA to +5 mA |
| Ambient temperature range | ‑25 °C to +85 °C |
| Package type | DIP20 (CEI) |
The U4280BM is controlled via the 2‑wire I²C bus.
The supply voltage can range from ‑0.3 V to +6 V.
The device is supplied in a DIP20 (CEI) package.