NXP Semiconductors TDA8501/N1,112

Overview

TDA8501/N1,112 from NXP Semiconductors (formerly Philips) is a monolithic PAL/NTSC video encoder IC designed for RGB or YUV-to-composite video conversion in consumer AV equipment. It supports dual-input path selection (RGB or −(R−Y)/−(B−Y)/Y), integrates chrominance modulation with 4.433618 MHz (PAL) or 3.579545 MHz (NTSC) oscillator, and delivers CVBS (2 V p-p), Y+SYNC (2 V p-p), and CHROMA outputs for SVHS. It operates at 5 V supply with 40 mA typical current draw.

For engineers reviewing the TDA8501/N1,112 datasheet, TDA8501/N1,112 pinout, TDA8501/N1,112 application, or TDA8501/N1,112 equivalent, key selection considerations include PAL/NTSC mode configuration via pin 17, H/2 phase control in PAL systems, external delay-line timing for Y+C alignment, and compliance with EBU 75% color bar input levels (0.7 V p-p RGB, 1.05–1.33 V p-p color difference signals).

Technical Context

The TDA8501/N1,112 implements a fully integrated encoder architecture comprising three functional blocks: a dual-path analog multiplexer (MCONTROL-controlled), quadrature modulators with internal 0°/90° carriers and capacitor-based offset tuning (pins 6 and 12), and a sync separator driving clamping, blanking, burst, and H/2 generation. Its oscillator (pin 23) supports crystal or external subcarrier injection, directly controlling both low-pass filter bandwidths (PAL: 1.35 MHz, NTSC: 1.1 MHz) and bandpass center frequency.

Chrominance processing includes active carrier suppression via H/2-triggered control loops, notch filtering capability (pin 18), and burst phase accuracy of ±135° (PAL) or 180° (NTSC). The four-level pin 17 enables precise mode selection-PAL/NTSC and Y-with/Y-without-sync-with defined voltage thresholds (0 V, 1.8 V, 3.2 V, 5 V) dictating black/blanking level behavior (0 mV vs. 53 mV difference in NTSC).

Key Specifications

Pinout & Package

Package: SOT234-1 - 24-pin plastic shrink dual in-line package (SDIP), 400 mil width, 22.3 mm × 9.1 mm body, 2.8 mm height, 1.27 mm lead pitch.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar video encoder applications.

Compared with TDA8501/N1,112, the TDA8505T/N1,112 omits dual-standard capability and H/2 synchronization-making it unsuitable for global deployments-while the AD723ARZ trades analog flexibility (external delay, notch filter, VREF-driven biasing) for integration density and lower voltage operation.

Availability

TDA8501/N1,112 is available at Aetrix Electronics and suitable for consumer set-top boxes, professional video recorders, and automotive rear-seat entertainment systems requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for TDA8501/N1,112 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

NXP Semiconductors is a global semiconductor leader specializing in secure connectivity solutions for automotive, industrial, and consumer applications, with roots in Philips' pioneering analog IC development.

The TDA8501/N1,112 belongs to NXP's legacy video encoder product line, engineered specifically for high-fidelity analog video generation in broadcast-adjacent equipment where PAL/NTSC dual-standard support, precise timing control, and robust composite/SVHS output interfaces are essential.

FAQ

What video standards does the TDA8501/N1,112 support?

The TDA8501/N1,112 supports both PAL and NTSC analog television standards through hardware configuration-specifically via the four-level voltage applied to pin 17. In PAL mode, it uses a 4.433618 MHz subcarrier and 1.35 MHz low-pass filter bandwidth; in NTSC mode, it switches to 3.579545 MHz and 1.1 MHz bandwidth. The TDA8501/N1,112 does not support SECAM; that function is handled by the related TDA8505 device.

How is the H/2 signal used in PAL mode on the TDA8501/N1,112?

In PAL mode, pin 4 (H/2) serves as an output for the internally generated line-division pulse, which controls V-signal alternation and modulator offset calibration. An external HIGH-level pulse applied to pin 4 forces the internal H/2 into a specific phase-critical for synchronizing multiple TDA8501/N1,112 encoders in studio or broadcast equipment. If unused, pin 4 may be left open-circuit, allowing the internal H/2 to appear at the pin.

What are the input signal requirements for RGB versus YUV operation on the TDA8501/N1,112?

For RGB input (selected via MCONTROL = HIGH), pins 7 (R), 9 (G), and 11 (B) require 0.7 V p-p EBU 75% color bar signals. For YUV-style input (MCONTROL = LOW), pins 1 (−(R−Y)), 3 (−(B−Y)), and 5 (Y) accept 1.05 V p-p, 1.33 V p-p, and 1 V p-p signals respectively. All inputs use 47 nF AC coupling capacitors and are clamped internally; the TDA8501/N1,112 does not accept DC-coupled video signals.

Can the TDA8501/N1,112 generate SVHS (Y+C) output without external components?

No-the TDA8501/N1,112 requires an external delay line between pins 22 (Y+SYNC OUT) and 20 (Y+SYNC IN) to align Y and chrominance timing for proper SVHS output. Pins 14 (CHROMA) and 19 (Y+SYNC OUT) together form the Y+C pair, but the delay line (typically 100–200 ns) is mandatory to compensate for chrominance group delay. The TDA8501/N1,112 provides dedicated pins and internal biasing (2.5 V black level at pin 20) to simplify this interface.

What is the purpose of the NOTCH pin (pin 18) on the TDA8501/N1,112?

Pin 18 (NOTCH) provides access to the Y+SYNC signal path just before the CVBS adder stage, enabling connection of an external notch filter to suppress the chrominance subcarrier frequency (4.43 MHz or 3.58 MHz) from the composite output. This improves luminance signal purity in CVBS by reducing cross-color artifacts. The pin presents a 2 kΩ internal series resistance, allowing direct connection of passive LC or ceramic resonator notch networks without buffering.