This document describes the features of the LA7687A integrated circuit used in the A6 movement of Sanyo Company. The integrated circuit has a simple color decoding circuit, few peripheral pins and components, integrated color decoding circuit, no adjustable components, bus control mode, integrated chroma bandpass filter, etc. The chip is widely used in various product series of Hisense Electric Co., Ltd.
The LA7687A is a large‑scale integration (LSI) video processing IC used in Sanyo's A6 TV chassis. It replaces traditional PAL‑D decoding with a novel PAL‑S method, integrating color decoding, AFC, and various video processing functions on a single chip, which reduces external components and simplifies manufacturing and service.
The chip is employed in many Hisense TV series (e.g., TC2139, TC2146, TC2151) and provides bus‑controlled brightness, contrast, color saturation, hue, and video standards. Integrated functions include chroma band‑pass and notch filters, luminance delay line, FM audio demodulator, and internal phase‑locked AFC, improving reliability and performance. This manual is written in Chinese.
| Color decoding method | PAL‑S |
|---|---|
| AFC implementation | Internal phase‑lock (no external coil) |
| Control of video parameters | Bus‑controlled brightness, contrast, color saturation, hue, and video standard |
| Integrated filters | Chroma band‑pass, chroma notch, luminance delay line, FM audio demodulator |
It uses the PAL‑S color decoding method.
No, the AFC circuit uses internal lock‑in technology instead of an external coil.
They are controlled via a bus interface, eliminating the need for many external components.