MAX1234EGI+

Overview

The MAX1234EGI+ is a complete PDA controller housed in a 5mm × 5mm, 28-pin QFN package. It integrates a 12-bit analog-to-digital converter (ADC), an 8-bit digital-to-analog converter (DAC), and a keypad controller with GPIO capability. The device supports single-supply operation from +4.75V to +5.25V and features a 10MHz SPI-compatible serial interface. Key specifications include ±15kV ESD protection on analog inputs, programmable resolution up to 12 bits, and sampling rates up to 50ksps. Supply current consumption is 260µA at 50ksps, dropping below 50µA at 10ksps.

Feature Summary

• Integrated 12-bit ADC with programmable resolution (8/10/12 bits) and sampling rates up to 50ksps
• Single-supply operation for +4.75V to +5.25V systems
• ±15kV IEC 1000-4-2 air-gap discharge ESD protection on all analog inputs
• Internal +1.0V/+2.5V reference or external reference support

Applications

• Personal Digital Assistants
• Cellular Phones
• Touch-Screen Monitors
• Portable Instruments

Procurement Notes

Verify the component matches the specific MAX1234 variant requiring +4.75V to +5.25V supply voltage, distinct from the MAX1233 which operates at lower voltages. Confirm the 'EGI+' suffix indicates the 28-pin QFN package and compliance with RoHS standards as per the manufacturer's ordering information.

Selection Notes

Select this model when a system requires a 5V supply rail rather than the 3V range supported by the MAX1233. Ensure the application utilizes the integrated touch-screen controller and battery monitoring features to minimize external component count. Verify that the 28-pin QFN footprint fits the PCB layout constraints.

Part Context

The MAX1234 is part of the MAX1233/MAX1234 family of touch-screen controllers manufactured by Maxim Integrated. While functionally similar to the MAX1233, the MAX1234 is specifically designed for +5V applications. Both devices share the same pinout and feature set, differing primarily in their operating voltage ranges.

Replacement Considerations

The MAX1233EGI+ serves as a functional substitute if the system design allows for a reduced supply voltage range of +2.7V to +3.6V instead of the standard +5V requirement.

FAQ

What is the maximum input voltage for the battery monitor pins?

The BAT1 and BAT2 pins can measure battery voltages up to 6.0V.

How does the device handle power consumption during idle states?

The device features AutoShutdown mode between conversions, reducing supply current to below 50µA at 10ksps and down to 0.3µA in shutdown mode.

Can the keypad controller pins be used for other purposes?

Yes, the eight row and column inputs of the keypad controller can be reconfigured as general-purpose parallel I/O (GPIO) pins.