LA7693X chip usage overview

Crystal oscillator

Quartz Oscillator 3225 20M OSC

The LA7693X is a series of color TV large-scale integrated circuits developed by Sanyo in Japan at the beginning of this century. It's known as a "super chip" due to its high integration, combining functions of the small signal processing chip LA76820 and microprocessor LC85F4538 into one VLSI. This series includes models such as LA76930, LA76931, and LA76932, which were widely used in Chinese brands like Xiahua, Konka, TCL Ace, and Skyworth. The LA76930 was used in various models including Xoceco TS, TF, MT series TVs, and also in TCL Ace models like AT2116Y and AT21266Y. After masking, these models became LA76930, 13-WS9301-AOP, and 13-WS9302-AOP respectively. The LA76931 found its way into Konka SA series TVs, with models like T21SA120/236/267/026/027 and P21SA281/282/390, and was also used in TCL Ace Y12 series, where it was re-masked as 13-LA7693-17PR. Skyworth applied it in the 6D92 series with digital engine V12, such as the 29T61HT model, where the masked chip was LA76931N-7F-4HD4B. The LA76932 was mainly used in TCL Ace for Y movement models like AT2516Y and AT2916Y, which were re-masked as 13-WS9303-AOP. Other models, like N25B5 and N25B6B, had different re-masking, such as 13-TOOY22-01MO1 on N25B5 and 13-LA7693-2NPRO on 29V88. The LA7693X features four built-in oscillators: a system clock formed by external crystals 33 and 34, a 4.43MHz voltage-controlled oscillator from pin 50, a 4MHz line voltage-controlled oscillator, and a 38MHz image intermediate frequency carrier oscillator. The internal structure of LA76930, LA76931, and LA76932 is similar, but they differ in ROM and RAM capacity, as well as crystal frequencies. For example, LA76930 and LA76931 use 32kHz crystals and are suitable for smaller screens, while LA76932 uses 32.768kHz and is used in larger screens. One notable feature is that the I/O ports (pins 23–32 and 36–39) can be configured via software, meaning even the same model may have different functionalities depending on the TV model. This table shows some I/O configurations for LA76930, LA76931, and LA76932, which is important for technicians during service. The LA7693X improves integration, reduces peripheral components, and lowers failure rates. It also enhances power efficiency and supports DVD component inputs (Y, Cr, Cb), resulting in better image quality. Additionally, it often uses digital frequency synthesis tuners, leading to more stable operation and accurate tuning.