LC75700T-MPB-E

Specialized Overview

The LC75700T is a key scanning LSI designed to accept input from up to 30 keys and control up to four general-purpose output ports. It reduces front panel wiring complexity by integrating key scanning and output control functions. The device supports serial data I/O using the Computer Control Bus (CCB) format for communication with system controllers. An internal RC oscillator circuit operates at frequencies between 19 kHz and 76 kHz, requiring external components of 39 kΩ and 1000 pF. The IC operates within a supply voltage range of 2.7 V to 5.5 V and features an operating temperature range of -40°C to +85°C.

Specialized Feature Summary

• Supports key input for up to 30 keys with power-efficient scanning that activates only upon key press.
• Provides four general-purpose output pins configurable via control data.
• Enables switching between key scan output and general-purpose output functions through control data settings.
• Includes a dedicated reset pin to disable key scanning and force outputs low.

Specialized Applications

• Consumer electronics systems requiring reduced front panel wiring
• Appliances utilizing matrix keypads
• Industrial control panels

Specialized Procurement Notes

Verify the specific ordering suffix to confirm package type and shipping quantity. The MPB-E suffix indicates a TSSOP20 package shipped in fan-fold quantities of 70 units. Confirm lead times and availability directly with authorized distributors as these details are subject to change based on manufacturing schedules.

Specialized Selection Notes

Select this component when designing systems that require integrated key scanning and limited output control without complex microcontroller overhead. Ensure the application utilizes the CCB interface protocol for data transfer. Verify that the external resistor and capacitor values match the recommended oscillator specifications to maintain timing accuracy.

Specialized Part Context

This part belongs to the LC75700 series of key scanning LSIs manufactured by ON Semiconductor. It is functionally similar to the LC75700TS variant but may differ in packaging or shipping configuration. The series is designed for applications needing efficient key matrix management with minimal external logic.

Specialized Replacement Considerations

The LC75700TS-MPB-E is a related variant within the same product family. Verify compatibility regarding package dimensions and electrical characteristics before substitution. Other parts in the LC75700 series should be evaluated against specific application requirements.

Specialized FAQ

How does the device handle multiple key presses?

The LSI recognizes multiple key presses by determining if multiple key data bits are set. However, diodes must be inserted in series with keys to prevent incorrect operations due to sneak currents during triple key presses or multiple presses on different lines.

What is the function of the DO pin?

The DO pin is an open-drain output that signals a key data read request by going low. It requires an external pull-up resistor between 1 kΩ and 10 kΩ to function correctly.

How is the internal oscillator configured?

The internal RC oscillator circuit is formed by connecting an external resistor of 39 kΩ and a capacitor of 1000 pF to the OSC pin. This setup guarantees an oscillator frequency range of 19 kHz to 76 kHz.