NXP USA Inc. MC44BS373CAFC

The MC44BS373CA converts baseband audio and video into a modulated RF television signal for equipment such as VCRs and set-top boxes. Its on-chip PLL tunes the RF modulator, while a second PLL derives the selected sound subcarrier. The NXP-hosted ordering table explicitly lists MC44BS373CAFC as the QFN20 lead-free variant for −20 to +85 °C ambient operation. NXP's current product page marks the family no longer manufactured.

• High-speed I²C-compatible bus receiver for channel and modulation control.
• PLL-tuned UHF and VHF RF modulator with integrated sound oscillator.
• Bus-selectable positive or negative video modulation.
• Adjustable picture-to-sound ratio.
• On-chip video test pattern and 1 kHz audio test signal options.
• Typical television RF output level of 82 dBµV under manufacturer test conditions.

MC44BS373CAFC is listed by the manufacturer in QFN20, lead-free, with a −20 to +85 °C order grade. The local catalog calls it 20-VQFN Exposed Pad. The registered generic illustration `/upload/package/20-VQFN-Exposed-Pad.jpg` is absent locally; do not use its missing image as a mechanical reference. Match the QFN20 case outline, pad geometry, exposed-pad handling, and pin-1 marking in the controlled data sheet before PCB layout.

Assembly checks

• Verify QFN20 land pattern and pin-1 orientation.
• Review exposed-pad soldering and board thermal path.
• Observe the data-sheet moisture-handling requirements.

The QFN20 pin diagram identifies VIDEO and AUDIO inputs, TVOUT RF output, SDA/SCL control lines, crystal and PLL-filter connections, power and ground pins, and auxiliary/CAS functions. Use the QFN20-specific numbered top-view drawing: the SO16NB arrangement is different. Check supplies and RF layout against the manufacturer's evaluation schematic rather than this signal summary.

Electrical values are conditional; consult the complete Rev. 2.6 tables, loads, and application guidance for limits.

The SO16NB MC44BS373CAD/CAEF variants are different packages and not footprint-compatible with the FC QFN20. NXP describes the later MC44CM373/374 family as functionally equivalent but not direct drop-in replacements. Compare pinout, auxiliary input, I²C register behavior, supply, RF and sound standards, case outline, and lifecycle before selecting a substitute. No unverified internal alternative product link is provided.

The NXP-hosted Freescale MC44BS373CA data sheet, Rev. 2.6 (June 2004), explicitly identifies MC44BS373CAFC as the QFN20, lead-free, −20 to +85 °C option. The same sheet provides function, electrical conditions, QFN20 pinout and case details. NXP's product page confirms multistandard modulation and lists the family as no longer manufactured.

Confirm the exact FC code, QFN20 marking, lot traceability, lead-free finish, and MSL 3 handling. Inspect the QFN exposed-pad geometry and run electrical RF tests against the application's programmed standard. A generic package image is not a substitute for controlled case drawings.

Before release, restore and inspect the registered QFN20 JPG, confirm the local catalog's exposed-pad mapping against the controlled manufacturer case outline, and validate the rendered product page. For system use, verify programmed RF channel, broadcast standard, sound subcarrier, EMC performance, and obsolete-product sourcing controls.