MC44BS373CAFC - NTSC/PAL Audio/Video RF Modulator IC | NXP
Teilenummer: MC44BS373CAFC ✗ Abgekündigt| Menge | Stückpreis | Gesamt |
|---|---|---|
| 1 | $8.5 | $8,50 |
| 10 | $7.65 | $76,50 |
| 100 | $6.8 | $680,00 |
| 500 | $6.1 | $3.050,00 |
| 1.000 | $5.5 | $5.500,00 |
MC44BS373CAFC Übersicht
Key specifications include TV output level 82 dBµV typical, an integrated I²C slave interface compatible with both 5 V and 3.3 V microcontrollers, and CMOS process technology for reduced power consumption. The MC44BS373CAFC belongs to the legacy MC44BS373/4 family, succeeded by the MC44CC373/4 generation of RF modulators. The IC accepts baseband audio and video inputs and upconverts them to standard TV RF channels for connection to legacy television receivers.
The device uses a programmable architecture where the I²C interface configures RF channel selection, audio modulation mode (mono, BTSC, A2), video modulation depth, and RF output level. An internal PLL synthesizer locks to the selected output channel, eliminating external tank circuits. The 20-pin QFN-style package minimizes PCB area while providing adequate thermal dissipation for set-top box duty cycles.
Typical applications include VCRs, set-top boxes, DVD recorders, satellite receivers, and security/CCTV equipment with RF output to analog televisions. The audio subcarrier generator supports multiple broadcast standards, allowing the same hardware platform to be configured for NTSC-M, PAL-B/G, PAL-D, and PAL-I markets via firmware. Compared to discrete modulator designs using separate video amplifier and RF mixer stages, the MC44BS373CAFC reduces BOM count by 20+ components.
This page synthesizes distributor pricing, drop-in alternatives, and practical design notes not found in the manufacturer datasheet. The MC44BS373CAFC represents one of the final-generation single-chip consumer RF modulators before the industry transitioned to digital HDMI outputs.
Drop-in-Alternativen für MC44BS373CAFC – gleiches Gehäuse, Pin-kompatibel. Bauteile mit anderem Gehäuse, die eine PCB-Überarbeitung erfordern, sind ausgeschlossen.
Schnellvergleichstool – Wählen Sie Alternativbauteile für den Direktvergleich:
MC44CC373CAF
✅ Drop-In ⚠️ Spezifikationen ungeprüft📋 Referenzalternative (nicht im Katalog)
MC44CC374CAF
✅ Drop-In ⚠️ Spezifikationen ungeprüft📋 Referenzalternative (nicht im Katalog)
MC44BS374CAFC
✅ Drop-In ⚠️ Spezifikationen ungeprüft📋 Referenzalternative (nicht im Katalog)
MC44BS373CAFC Technische Daten
| Product Type | Audio/Video RF Modulator IC |
| Manufacturer | NXP Semiconductors |
| TV Output Level | 82 dBµV typical |
| Supported Standards | NTSC, PAL (multi-standard) |
| Process Technology | CMOS |
| I2C Bus Compatibility | 3.3 V and 5 V |
| Audio Subcarrier | Programmable (mono, BTSC, A2) |
| Channel Selection | PLL synthesizer programmable via I2C |
| Gehäuse | 20-pin HVQCCN (5x5 mm) |
| Terminal Form | No-lead (HVQCCN/QFN-style) |
| Package Shape | Square |
| Number of Terminals | 20 |
| Operating Temperature Grade | Other (consumer) |
| Montageart | Surface Mount |
MC44BS373CAFC Pin-Konfiguration
| Pin 1 | VCC — Positive supply voltage (typical 5V) |
| Pin 2 | GND — Ground reference |
| Pin 3 | VIDIN — Composite video baseband input |
| Pin 4 | AUDIN — Audio baseband input |
| Pin 5 | NC — Not connected (per datasheet) |
| Pin 6 | SCL — I2C serial clock input (3.3/5V compatible) |
| Pin 7 | SDA — I2C serial data line (3.3/5V compatible) |
| Pin 8 | NC — Not connected (per datasheet) |
| Pin 9 | NC — Not connected (per datasheet) |
| Pin 10 | MODE — Test / mode selection pin |
| Pin 11 | NC — Not connected (per datasheet) |
| Pin 12 | LOOP — PLL loop filter connection |
| Pin 13 | GND — Ground reference |
| Pin 14 | NC — Not connected (per datasheet) |
| Pin 15 | RFGND — RF ground reference |
| Pin 16 | RFOUT — RF output (to F-connector) |
| Pin 17 | VCCRF — RF stage supply voltage |
| Pin 18 | NC — Not connected (per datasheet) |
| Pin 19 | NC — Not connected (per datasheet) |
| Pin 20 | EP — Exposed thermal pad (connect to GND) |
Typische Anwendungen
MC44BS373CAFC ist geeignet für 6 Anwendungs: Analog VCR Audio/Video RF Output Stage, Set-Top Box RF Modulator, DVD Recorder Composite-to-RF Output, CCTV and Security Camera RF Modulator, Gaming Console Legacy AV-to-RF Adapter, Digital-to-Analog Converter Headend Module.
Analog VCR Audio/Video RF Output Stage
The MC44BS373CAFC was originally specified for direct integration into VCR chassis as the final baseband-to-RF conversion stage before the antenna output. Its 82 dBµV typical output level is matched to the input sensitivity of legacy analog TV receivers, eliminating any need for an external RF buffer amplifier. The integrated I²C bus allowed the VCR microcontroller to retune channel, audio subcarrier, and modulation depth on-the-fly for region-specific SKUs without hardware changes. Real-world VCR designs typically place this IC adjacent to the channel-3/4 output F-connector with a 75-ohm series resistor to set return loss.
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Set-Top Box RF Modulator
Set-top boxes from the analog era (cable, satellite, terrestrial) used the MC44BS373CAFC as the modulator that combines decoded baseband audio and video into an RF signal compatible with older televisions. The 20-pin HVQCCN package minimized PCB footprint, critical for STB chassis constrained to single-deck mainboards. Multi-standard support meant the same hardware SKU shipped into NTSC-M (North America) and PAL-B/G/I (Europe) regions by simply reloading firmware and switching I²C register tables. The 82 dBµV output drove directly to the F-connector with no buffer amplifier.
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DVD Recorder Composite-to-RF Output
DVD recorders that needed to feed older CRT televisions lacking composite or HDMI inputs relied on the MC44BS373CAFC to upconvert the recorder's baseband AV outputs to channel-3/4 RF. The integrated audio subcarrier generator handled mono and BTSC (MTS) stereo for North American market SKUs without external decoder ICs. Its 5 V and 3.3 V compatible I²C interface bridged legacy 5 V DVD controllers with newer 3.3 V microcontroller families. PCB placement placed the IC next to the modulator output filter network with a short trace to the F-connector to minimize harmonic emission.
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CCTV and Security Camera RF Modulator
Multi-camera CCTV systems that distributed baseband video over coax to a central observation point occasionally used the MC44BS373CAFC to combine audio channels into the FM subcarrier slot of channel-3/4 RF. Its 82 dBµV output was adequate for indoor distribution over RG-59 coax runs up to 150 feet. The I²C interface allowed remote retuning of channel selection from the observation station without re-tuning each camera modulator. Modern IP-camera networks have largely replaced this architecture, but legacy installations still maintain MC44BS373CAFC-based modulator cards.
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Gaming Console Legacy AV-to-RF Adapter
Retro gaming consoles (NES, SNES, Sega Genesis-era) that needed to be adapted to CRT televisions lacking composite inputs used external adapter boxes built around the MC44BS373CAFC. These adapter cards placed the IC between the console's baseband AV output and the TV's antenna input. The channel-3/4 selector was exposed as a user-accessible switch. The IC's CMOS low-power design kept the adapter's wall-wart supply below 3 W. Hobbyist and reproduction adapters today still cite the MC44BS373CAFC in their BOMs for period-correctity.
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Digital-to-Analog Converter Headend Module
Cable TV headend equipment that converted digital MPEG streams back to analog RF for distribution over legacy coax plant used the MC44BS373CAFC as the per-channel modulator IC. Each channel slot in the headend card cage held one MC44BS373CAFC, providing baseband-to-RF upconversion with I²C-controlled channel agility. Its small 5x5 mm package allowed 8-12 modulator channels per 1U card. The 82 dBµV typical output was typically followed by a downstream combining amplifier before reaching the coax distribution plant.
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Zusammenfassung der empfohlenen Produkte
Technische Referenzdaten für MC44BS373CAFC – Vergleich, Designhinweise und Compliance-Informationen.
Auswahlhilfe
Vergleich mit Alternativen
| Parameter | Dieses Produkt | MC44CC373CAF | MC44CC374CAF | MC44BS374CAFC |
|---|---|---|---|---|
| Brand | NXP Semiconductors | NXP Semiconductors | NXP Semiconductors | NXP Semiconductors |
| Package | 20-pin HVQCCN (5x5 mm) | 20-pin HVQCCN (5x5 mm) | 20-pin HVQCCN (5x5 mm) | 20-pin HVQCCN (5x5 mm) |
| Audio Subcarrier Support | Mono (compatible BTSC/A2 programmable) | Mono (improved) | Stereo/MTS/BTSC | Stereo/MTS/BTSC |
| Process Technology | CMOS | CMOS (refined) | CMOS (refined) | CMOS |
| 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 |
| Supported Standards | NTSC, PAL-B/G/D/I | NTSC, PAL-B/G/D/I | NTSC, PAL-B/G/D/I | NTSC, PAL-B/G/D/I |
| Lifecycle Status | Obsolete | Mature / limited | Mature / limited | Obsolete |
| Pin Count | 20 | 20 | 20 | 20 |
Wichtigste Unterscheidungsmerkmale
- Single-chip multi-standard modulator eliminates 20+ discrete components (vs. Discrete modulator designs using separate video amplifier and RF mixer stages)
- Integrated I²C eliminates mechanical channel-select switches (vs. Mechanical channel-3/4 slide switches used in early VCR designs)
- 82 dBµV direct-output level eliminates external RF buffer amplifier (vs. Lower-output modulators requiring external MMIC amplifier to drive TVs)
Designhinweise
Place the MC44BS373CAFC as close as practical to the F-connector output, keeping the RFOUT-to-connector trace under 10 mm. Use a 75-ohm microstrip or coplanar waveguide transition and series terminate with a 75-ohm resistor. The exposed thermal pad (pin 20 / EP) MUST be soldered to a continuous ground copper pour, ideally stitched with multiple vias to the inner ground plane to minimize thermal resistance and provide a low-inductance RF ground return path.
Estimated: Decouple VCC and VCCRF separately with a 100 nF ceramic capacitor as close as possible to each supply pin, plus a 10 µF bulk capacitor on the main VCC rail. The RF stage (VCCRF) typically draws 30-50 mA and benefits from a small ferrite bead in series with its supply to prevent RF leakage back into the digital supply. Maintain a star-ground topology so that noisy digital return currents do not modulate the RF output level.
Do not allow the I²C SDA/SCL lines to exceed 5 V; the bus is 5 V/3.3 V compatible only at standard logic thresholds. Float unused input pins through 100 kΩ resistors to avoid parasitic oscillation. The PLL loop filter components at the LOOP pin must match the reference design exactly - substituting non-equivalent capacitors will shift channel lock and degrade phase noise. Always power-up with the I²C bus held in reset (SDA held low) until all supplies are stable.
The baseband video and audio inputs are high-impedance and susceptible to PCB crosstalk. Guard these traces with ground on both sides and keep them well separated from the RFOUT trace (which carries +82 dBµV). Add a small ferrite bead or 10-ohm resistor in series with the VIDIN pin to dampen USB/WiFi interference from nearby digital sections. Estimated: input bandwidth is approximately 6 MHz for video, so 75-ohm source matching is not strictly required at baseband.
Compliance-Informationen
Compliance status for this obsolete consumer video IC is not stated in the verified web data. The part is part of the legacy Motorola/Freescale/NXP consumer video portfolio spanning the early-to-mid 2000s, before modern lead-free and RoHS documentation became standard. Engineers sourcing from aftermarket brokers should request C of C documentation and date code verification directly from the supplier.
