NXP Semiconductors MC44BS374T1AEF

Overview

MC44BS374T1AEF from Freescale Semiconductor is a PAL/NTSC audio/video modulator IC with integrated UHF VCO and dual PLL architecture, delivering 82 dBµV typical TV output level, 460–880 MHz UHF tuning range, and I²C-bus (800 kHz, 3.3 V/5 V compatible) programmability for set-top boxes and VCRs.

For engineers reviewing the MC44BS374T1AEF datasheet, MC44BS374T1AEF pinout, MC44BS374T1AEF application, or MC44BS374T1AEF equivalent, this page provides verified functional identity, SO16NB package mapping, confirmed 16-pin terminal roles, real-world video/audio modulation specs, and two validated alternative modulators for legacy broadcast system designs.

Technical Context

The MC44BS374T1AEF implements a high-speed I²C-compatible bus interface (800 kHz) controlling both RF and sound PLLs - one synthesizing the UHF/VHF carrier (460–880 MHz, extendable to 45–460 MHz via internal dividers), the other generating selectable sound subcarriers (4.5/5.5/6.0/6.5 MHz). It integrates a video test pattern generator with 1 kHz audio tone and supports programmable picture-to-sound ratio (12 dB or 16 dB).

Its BiCMOS process enables on-chip UHF tank circuit integration, eliminating external varicaps and tuned components. The device features transient output inhibit at power-on, logical output port (pin 3), peak white clip disable via I²C, and ESD protection rated at 4 kV HBM.

Key Specifications

Pinout & Package

MC44BS374T1AEF is housed in a 16-pin SOIC package with narrow body (SO16NB), 1.27 mm pitch, and standard JEDEC MS-012AC footprint. Pin 1 is located at the top-left corner adjacent to the index mark.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar audio/video modulator applications.

Compared with MC44BC374T1R2 and SA7750HN/N1,118, the MC44BS374T1AEF offers superior RF output level, broader frequency coverage (UHF + VHF), and full I²C programmability - making it the preferred choice for new designs targeting global broadcast compliance and future-proofing.

Availability

MC44BS374T1AEF is available at Aetrix Electronics and suitable for set-top box manufacturing, VCR production, broadcast encoder development, and legacy TV interface modules requiring stable component supply across extended product lifecycles.

Supply support for MC44BS374T1AEF includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.

Manufacturer

Freescale Semiconductor (now part of NXP Semiconductors) is a fabless semiconductor company specializing in embedded processing, analog, and mixed-signal solutions for automotive, industrial, and consumer markets.

The MC44BS374T1AEF belongs to Freescale's broadcast analog modulator product line, designed specifically for high-integration, low-component-count PAL/NTSC RF encoding in space-constrained consumer electronics.

FAQ

What is the primary function of the MC44BS374T1AEF?

The MC44BS374T1AEF is a fully integrated PAL/NTSC audio/video modulator IC that converts baseband CVBS video and mono audio signals into a broadcast-compliant UHF or VHF RF output. It incorporates dual PLLs, an on-chip UHF VCO, programmable sound subcarrier generation, and I²C-based configuration - all in a single SO16NB package. Its 82 dBµV typical output level and multi-standard support make it ideal for set-top boxes and VCRs.

Does the MC44BS374T1AEF support both 3.3 V and 5 V I²C buses?

Yes, the MC44BS374T1AEF supports 3.3 V and 5 V I²C bus operation. Its SCL and SDA pins are designed for mixed-voltage system interfacing, enabling direct connection to microcontrollers or FPGAs operating at either logic level without level-shifting circuitry. This dual-voltage compatibility is explicitly confirmed in the Advance Information document under "Features" and "Electrical Characteristics."

What is the purpose of Pin 3 (LOP) on the MC44BS374T1AEF?

Pin 3 (LOP) on the MC44BS374T1AEF is the Logic Output Port, a programmable digital output controlled via I²C register bit. It replaces the external standby pin used in earlier generations (e.g., MC44BC374T1). When configured via I²C, LOP can drive low or enter high-impedance state - enabling flexible system-level control of peripheral functions without adding discrete logic or GPIO expanders.

Can the MC44BS374T1AEF operate in VHF bands?

Yes, the MC44BS374T1AEF supports VHF operation from 45 MHz to 460 MHz by internally dividing its UHF oscillator output (460–880 MHz). This division is controlled via I²C test mode bits (X2–X0), allowing seamless switching between UHF and VHF ranges without hardware modification - a key advantage over fixed-range modulators.

What video and audio performance metrics are guaranteed for the MC44BS374T1AEF?

The MC44BS374T1AEF guarantees 82% typical video modulation depth, 56 dB weighted video signal-to-noise ratio (with CCIR Rec. 567 filter), ±5° differential phase, and 80% typical audio modulation depth at 1 kHz. These values are measured per defined characterization conditions (e.g., 1 Vpp video, 205 mVrms audio, 75 Ω load) and documented in Tables 5 and 6 of the Advance Information datasheet.