MC44BS373CAEF - NTSC/PAL Audio/Video RF Modulator | NXP SOIC-16
MPN: MC44BS373CAEF ✗ End of Life| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $4.5 | $4.50 |
| 10 | $3.85 | $38.50 |
| 100 | $3.2 | $320.00 |
| 500 | $2.75 | $1,375.00 |
| 1,000 | $2.35 | $2,350.00 |
MC44BS373CAEF Overview
A modulator is the final analog stage of a baseband audio/video chain: it translates a composite baseband video signal and an audio subcarrier up to a select UHF/VHF RF channel suitable for direct connection to a television antenna input. Inside this product family (MC44BS373/4 and the newer MC44CC373/4 generation), the modulator replaces discrete RF upconverter designs with a small, programmable silicon block, saving board area and reducing assembly cost. The device sits at the boundary between analog baseband ICs and the antenna/RF domain, so engineers typically consider it as a "system" component rather than a generic op-amp or logic IC.
Key features include multi-standard video modulation (B/G/I/D/K/L depending on firmware settings), an on-chip audio FM modulator at 4.5 MHz, 5.5 MHz, or 6.0 MHz subcarrier frequencies, I2C control up to 400 kHz, low power consumption on a single 5 V supply, and integrated RF output stage with selectable gain. A flexible test/calibration mode is also exposed through the I2C registers to support factory alignment procedures. The CMOS process allows the entire modulator to operate from a single supply rail while keeping heat dissipation minimal for set-top and DVD recorder applications.
Typical applications include VCR RF output stages, set-top box down-stream modulators, DVD recorder modulators, PC TV tuner cards, and video game consoles that need to feed an analog TV. The I2C interface also makes this modulator attractive for factory-aligned consumer electronics where channel alignment and audio deviation must be set without mechanical adjustment.
Drop-in alternatives for MC44BS373CAEF — same package, pin-to-pin compatible. Different-package parts requiring PCB rework are excluded.
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MC44BS374CAEF
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MC44BS373CAF
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MC44CC374CAF
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MC44BS373CAEF Specifications
| Product Type | Audio/Video RF Modulator IC |
| Manufacturer | NXP Semiconductors (formerly Motorola, Freescale) |
| Modulation Standards | NTSC, PAL (multi-standard via I2C) |
| TV Output Level | 82 dBuV typical |
| Supply Voltage | 5 V single supply |
| I2C Bus Voltage | 3.3 V and 5 V compatible |
| Package | 16-SOIC (SO16 NB) |
| Pin Count | 16 |
| Terminal Form | GULL WING |
| Package Code | SOP |
| Package Shape | RECTANGULAR |
| Temperature Grade | OTHER (consumer) |
| Mounting Type | Surface Mount |
MC44BS373CAEF Pin Configuration
| Pin 1 | AUDIO IN — Audio baseband input |
| Pin 2 | GND — Analog ground |
| Pin 3 | VIDEO IN — Composite video baseband input |
| Pin 4 | RF OUT — Modulated RF output to antenna |
| Pin 5 | VCC — +5 V power supply |
| Pin 6 | SDA — I2C serial data (3.3 V/5 V) |
| Pin 7 | SCL — I2C serial clock (3.3 V/5 V) |
| Pin 8 | NC — Not connected |
| Pin 9 | GND — Ground |
| Pin 10 | NC — Not connected |
| Pin 11 | NC — Not connected |
| Pin 12 | NC — Not connected |
| Pin 13 | NC — Not connected |
| Pin 14 | GND — Ground |
| Pin 15 | TEST — Factory test pin |
| Pin 16 | NC — Not connected |
Typical Applications
MC44BS373CAEF is suitable for 6 applications: VCR RF Modulator Output Stage, Set-Top Box Downstream RF Output, DVD Recorder Modulator, PC TV Tuner Card RF Output, Video Game Console AV Output, Surveillance DVR RF Modulator.
VCR RF Modulator Output Stage
The MC44BS373CAEF was designed for VCR RF output stages where composite baseband video must be modulated onto an analog TV channel. Its 82 dBuV typical output level drives a short antenna pigtail directly, and the integrated audio FM subcarrier (4.5/5.5/6.0 MHz depending on standard) eliminates the need for a separate sound modulator IC. The I2C control interface permits factory programming of channel and deviation, which removes mechanical alignment costs in VCR manufacturing. The SO16 NB package and 5 V single-supply operation suit consumer VCR power budgets and PCB density targets.
Recommended
Set-Top Box Downstream RF Output
Set-top boxes use the MC44BS373CAEF to feed decoded video/audio into a TV that lacks HDMI or composite inputs, using a legacy RF chain. The multi-standard capability (NTSC/PAL variants configured via I2C) lets a single BOM serve global SKUs, which simplifies inventory and reduces SKU fragmentation. The 3.3 V/5 V compatible I2C interface pairs directly with typical set-top-box microcontrollers, removing level shifters and reducing BOM cost. Output level of 82 dBuV is sufficient for direct antenna-jack connection without an external amplifier in short-cable installations.
Recommended
DVD Recorder Modulator
DVD recorders integrate the MC44BS373CAEF to provide a backwards-compatible analog RF output for older TV sets. The I2C-programmable channel selection and audio subcarrier frequency (4.5 MHz NTSC-M, 5.5 MHz PAL B/G, 6.0 MHz PAL I) allow the recorder to ship the same hardware worldwide with regional firmware. The 82 dBuV output drives a 75-ohm antenna input, and the SO16 NB package is small enough to fit the dense rear-panel PCB of typical DVD recorders. Compared to discrete RF upconverters, this IC shrinks the modulator section from roughly 25 square centimeters to under 2 square centimeters.
Recommended
PC TV Tuner Card RF Output
PC TV tuner cards historically included the MC44BS373CAEF to convert captured video into an RF signal for analog TVs. The I2C interface allowed the host software to change channels through PCI/USB bridge registers, avoiding mechanical tuning. Its single 5 V supply is compatible with the internal PC power rails available on tuner cards, and its SO16 NB package occupies minimal board area. Engineers designing new tuner cards should evaluate the MC44CC373/374 family for lower power consumption in always-on HTPC applications.
Recommended
Video Game Console AV Output
Older video game consoles rely on the MC44BS373CAEF to deliver composite video to RF-only televisions. The integrated audio FM modulator at 4.5/5.5/6.0 MHz matches the broadcast standard of the target market, which lets one console design ship worldwide. I2C channel programming permits factory-only channel locking, an FCC-friendly feature for consumer RF devices. The SO16 NB footprint consumes limited PCB real estate, which is at a premium inside a console's densely packed mainboard.
Recommended
Surveillance DVR RF Modulator
Surveillance DVRs use the MC44BS373CAEF to feed composite video from multiple cameras into a single analog TV channel for live monitoring on legacy displays. The I2C interface supports multi-channel switching, allowing operators to cycle cameras through one RF output without rewiring. The 82 dBuV output level is sufficient for short cable runs in residential or small-business surveillance installations. The CMOS process keeps standby power low for always-on security applications, which reduces thermal stress inside enclosed DVR chassis.
Recommended
Recommended Products Summary
Engineering reference data for MC44BS373CAEF — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | MC44BS374CAEF | MC44BS373CAF | MC44CC373CAF | MC44CC374CAF |
|---|---|---|---|---|---|
| Brand | NXP Semiconductors | NXP Semiconductors | NXP Semiconductors | NXP Semiconductors | NXP Semiconductors |
| Package | 16-SOIC (SO16 NB) | 16-SOIC (SO16 NB) | 16-SOIC (SO16 NB) | 16-SOIC (SO16 NB) | 16-SOIC (SO16 NB) |
| Supply Voltage | 5 V | 5 V | 5 V | 5 V | 5 V |
| Broadcast Standard | Multi-standard NTSC/PAL via I2C | Multi-standard; complementary regional variants | Multi-standard NTSC/PAL via I2C | Multi-standard; updated register map | Multi-standard; updated register map |
| I2C Compatibility | 3.3 V and 5 V | 3.3 V and 5 V | 3.3 V and 5 V | 3.3 V and 5 V (register map updated) | 3.3 V and 5 V (register map updated) |
| Process Technology | CMOS (legacy) | CMOS (legacy) | CMOS (legacy) | CMOS (latest generation) | CMOS (latest generation) |
| Lifecycle | NRND / legacy | NRND / legacy | NRND / legacy | Active successor | Active successor |
Key Differentiators
- Factory-programmable multi-standard NTSC/PAL output via single 5 V supply (vs Discrete RF upconverter using mixer + SAW filter + VCO)
- 82 dBuV typical TV output level on-chip (vs Discrete modulator stages typically achieve 70-75 dBuV without a buffer amplifier)
- 3.3 V/5 V compatible I2C interface on a 5 V modulator (vs Legacy 5 V-only I2C modulators requiring external level shifters)
Design Notes
Provide a clean 5 V supply with at least 100 mA of headroom for the modulator's RF output stage. Decouple VCC to ground with a 10 uF bulk capacitor close to pin 5 and a 0.1 uF ceramic capacitor to suppress switching noise from the I2C bus and from adjacent digital circuitry. The CMOS modulator output current spikes during channel changes, so undersized local regulation will show up as RF output level drift and channel-to-channel variation.
Keep the SO16 NB footprint on a single continuous ground pour with vias stitched around the RF output pin (pin 4). Route the RF output as a 50-ohm controlled-impedance trace to the antenna connector, and avoid running the I2C bus lines parallel to it for more than a few millimeters. The 16-SOIC NB gull-wing leads allow hand-rework with a hot-air station, which simplifies lab bring-up but also means the footprint should tolerate a generous thermal relief pattern to avoid lifted pads during rework.
Do not assume MC44CC373/374 is a software-transparent replacement; the I2C register map was revised between the BS3 and CC3 generations. Reprogram any MCU-side configuration code when migrating. Also, do not exceed 82 dBuV when chaining the modulator output with an external RF amplifier, or harmonic distortion will degrade adjacent-channel TV reception.
Compliance Information
Lead-free SO16 NB package per alldatasheet marking data (SO16 NB Lead Free Marking). RoHS status not explicitly stated in the verified web data snippets; AEC-Q100 not applicable for a consumer RF modulator IC.
