LM8500IMT9B/NOPB

Overview

The LM8500IMT9B/NOPB is a four-wire resistive touchscreen controller manufactured by Texas Instruments. It features an integrated 10-bit analog-to-digital converter capable of sampling up to 500 coordinate pairs per second at a maximum operating frequency of 10 MHz. The device communicates via a UART interface set at 38400 bps and includes internal non-volatile memory for storing calibration data and configuration settings. Designed for low power consumption, it offers a standby current typically less than 2 µA and supports automatic wake-up from power-saving modes upon touch detection or UART activity.

Feature Summary

• Integrated 10-bit A/D converter with a maximum throughput of 500 coordinate pairs per second
• Internal non-volatile storage element for retaining calibration points and controller configurations
• Low power standby mode with typical current draw of less than 2 µA at 5.5 V
• Supports automatic wake-up from halt mode via touch screen detection or UART communication

Applications

• Personal Digital Assistants
• Smart Hand-Held Devices
• Point-of-Sales Terminals
• KIOSK Systems
• Cell Phones

Procurement Notes

Verify the package type matches the required design footprint, as the LM8500 is available in 44-pin WQFN, 44-pin PLCC, and 48-pin TSSOP packages. Confirm that the specific ordering suffix corresponds to the desired packaging format. Ensure the supply voltage range aligns with the system's power rails, as the device operates within specified limits for reliable performance.

Selection Notes

Select the LM8500 over the LM8300 when higher processing speeds are required, as the LM8500 supports clock frequencies up to 10 MHz compared to the LM8300's 3.27 MHz limit. Verify that the application environment stays within the 0°C to +70°C operating temperature range. Ensure the host processor can interface with the inverted UART signals provided by the controller.

Part Context

This component belongs to the LM8300/LM8500 family of four-wire resistive touchscreen controllers. While functionally similar, the LM8500 variant is distinguished by its support for higher clock frequencies, enabling faster coordinate sampling rates. Both devices share the same pinout architecture and core functionality, differing primarily in their maximum operational speed capabilities.

Replacement Considerations

The LM8300 serves as a lower-speed alternative within the same family. When replacing this part, ensure the new component supports the required clock frequency if high-speed sampling is necessary. Verify compatibility with existing UART baud rates and package dimensions.