Toshiba 2691 / Toshiba TMP47C634N-2691 - Japan

The Toshiba TMP47C634N-2691 is a 4-bit CMOS microcontroller part of the TLCS-470 series, commonly used in consumer electronics like televisions for on-screen displays and remote control processing. 

Technical Details

• Architecture: 4-bit CMOS Single-Chip Microprocessor.
• Package Type: SDIP-42 (Shrink Dual In-line Package with 42 pins).
• Memory: Includes 6144 x 8-bit ROM and 384 x 8-bit RAM.
• On-Screen Display (OSD): Features built-in OSD circuitry for displaying characters and marks on a TV screen.
• I/O and Conversion:
• 9 I/O ports.
• Built-in A/D converter input and D/A converter (Pulse Width Modulation) outputs with 14-bit and 6-bit resolution.
• Operating Frequency: Typically 4.2 MHz.
• Key Functions: Remote control signal preprocessing, LED direct drive capability, and a HOLD function for battery/capacitor backup. 

Note: The suffix -2691 denotes specific factory-programmed mask ROM code. If you are replacing a defective chip in a specific device, you usually must match this suffix exactly for the device to function correctly.