AK4188VN

Overview

The AK4188VN is a touch screen controller featuring an integrated 12-bit SAR A/D converter. It supports dual touch gestures, detecting pressed locations and pressure for two simultaneous points. The device includes a calculator to output the center location of dual touches and parameters related to the distance between them. It operates with VDD from 2.7V to 3.6V and TVDD from 1.6V to 3.6V. Typical power consumption is 276uA at 450Hz. The component is housed in a 16-pin QFN package (3.0mm x 3.0mm) and functions within an ambient temperature range of -40°C to 85°C.

Feature Summary

• Dual Touch Functions: Detects center location and distance parameters for two simultaneous touch points.
• 12-bit SAR A/D Converter: Includes sample/hold circuitry and median averaging filter for accurate position measurement.
• SPI Interface: Supports Mode 0 and Mode 3 with clock frequencies up to 5MHz.
• Low Voltage Operation: Analog supply (VDD) 2.7V-3.6V; Digital I/F supply (TVDD) 1.6V-3.6V.

Applications

• Mobile phones
• Digital Still Cameras (DSC)
• Digital Video Cameras (DVC)
• Smartphones
• Portable devices

Procurement Notes

Verify the ordering suffix VN against the official datasheet to confirm the specific package variant and temperature rating. Ensure the TEST pin is connected to VSS during implementation, as it contains an internal pull-down device. Confirm that unused analog input pins are handled appropriately according to the datasheet guidelines.

Selection Notes

Select this component for applications requiring dual touch gesture recognition on 4-wire resistive screens. The AK4188VN requires external resistors (R1-R4) connected to RXP and RYP pins for dual touch operation. Ensure the microprocessor SPI interface supports the required voltage levels (TVDD 1.6V-3.6V) and timing constraints.

Part Context

The AK4188VN is part of the AK4188 family produced by Asahi Kasei Microdevices (AKM). It shares the same functional specifications and package dimensions as the AK4188EN variant. Both versions utilize a 16-pin QFN package and operate within the same electrical and thermal limits.

Replacement Considerations

Publicly confirmed substitute part numbers are not available in the provided documentation. Designers should verify compatibility with existing system requirements if considering alternative components.

FAQ

How does the AK4188 detect dual touch?

It uses additional RXP and RYP pins connected via external resistors to the touch panel. When SEQM bits are set to '1010', it calculates the center location and distance parameters for two simultaneous touch points.

What is the function of the PENIRQN pin?

The PENIRQN pin outputs a low signal when a touch is detected. During sequence measurements or calculations, it acts as a busy signal. In sleep mode, it remains high or high-impedance.

Can the AK4188 measure pen pressure?

Yes, it measures contact resistance between the touch plates to derive pen pressure. This is calculated using X-position, Y-position, and Z1/Z2 measurements.