MC44CM373/4 Audio Video RF CMOS Modulator

The MC44CM373/MC44CM374 CMOS family of RF modulators is the latest generation of the legacy MC44BS373/4 family of devices.

The MC44CM373/4 RF modulators are designed for use in VCRs, set-top boxes and similar devices. They support multiple standards and can be programmed to support PAL, SECAM or NTSC formats.

The devices are programmed by a highspeed I²C bus. The MC44CM373/374 family is backward compatible with the previous I²C control software, providing a smooth transition for system upgrades.

A programmable, internal Phase-Lock Loop (PLL), with an on-chip, cost-effective tank covers the full UHF range. The modulators incorporate a programmable, on-chip, sound subcarrier oscillator that covers all broadcast standards. No external tank circuit components are required, reducing PCB complexity and the need for external adjustments. The PLL obtains its reference from a cost-effective 4 MHz crystal oscillator.

The devices are available in a 16-pin SOIC, Pb-free package. These parts are functionally equivalent to the MC44BS373/4 series, but are not direct drop-in replacements.

All devices now include the aux input found previously only on the 20-pin package option. This is a direct input for a modulated subcarrier and is useful in BTSC or NICAM stereo sound or other subcarrier applications. The MC44CM373CASEF has a secondary I²C address for applications using two modulators on one I²C Bus.

Typical Applications
The MC44CM373 and MC44CM374 RF modulators are intended for applications within IP/DSL, digital terrestrial, satellite or cable set-top boxes, VCRs and DVD players or recorders, game consoles or audio/video redistribution.