Texas Instruments ADS7846E

Overview

ADS7846E from Texas Instruments is a 12-bit successive-approximation ADC touch screen controller with integrated 2.5V reference, battery monitoring (0.5V–6.0V), on-chip temperature sensing, and touch-pressure measurement. It operates from 2.2V to 5.25V, delivers up to 125kHz throughput, and supports QSPI/SPI 3-wire interface. Used in PDAs, portable instruments, and cellular phones for resistive touch panel digitization.

For engineers reviewing the ADS7846E datasheet, ADS7846E pinout, ADS7846E application, or ADS7846E equivalent, this page provides verified technical context, package-specific pin mapping (SSOP-16), real-world use-value per application, and two validated alternative parts with documented functional and selection differences.

Technical Context

The ADS7846E implements a capacitive redistribution SAR architecture with integrated sample-and-hold, enabling ratiometric differential measurements for X/Y position via SER/DFR-controlled switch drivers (Y+/Y–, X+/X–). Its internal 2.5V reference (±2.5mV accuracy, 15ppm/°C drift) powers auxiliary, battery, and temperature channels but is disabled by default for ADS7843 compatibility.

It features six-channel analog MUX routing (X+, Y+, X–, Y–, VBAT, AUX, TEMP0/TEMP1), programmable power-down (3µA standby), and PENIRQ open-drain interrupt output. Conversion timing uses 12 clock cycles for acquisition + 12 for conversion (24 total), with optional 15-cycle mode to maintain driver bias during settling.

Key Specifications

Pinout & Package

ADS7846E is packaged in SSOP-16 (DBQ), with 0.65mm pitch, 5.0mm × 6.2mm body size, and exposed thermal pad (not electrically connected). Pinout matches ADS7843 for drop-in replacement.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar touch screen controller applications.

Compared with ADS7843E, ADS7846E adds integrated reference and auxiliary measurement capability without changing footprint; compared with MAX11803A, it offers direct battery monitoring and PENIRQ interrupt in smaller SSOP-16, simplifying power and interrupt management in portable designs.

Availability

ADS7846E is available at Aetrix Electronics and suitable for personal digital assistants, point-of-sale terminals, and cellular phones requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for ADS7846E includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.

Manufacturer

Texas Instruments is a global semiconductor leader focused on analog, embedded processing, and connectivity technologies.

The ADS7846E belongs to TI's precision data converter product line, designed specifically for low-power, high-accuracy resistive touch screen interfaces in portable and industrial human-machine interaction systems.

FAQ

What is the primary function of the ADS7846E in a touch screen system?

The ADS7846E serves as a dedicated 12-bit analog-to-digital converter and controller for 4-wire resistive touch screens. It digitizes X/Y coordinates, measures touch pressure via Z1/Z2 sampling, monitors battery voltage (0.5–6.0V), and senses temperature using on-chip diodes-all within a single SSOP-16 package. Its ratiometric differential mode eliminates position errors caused by touch panel resistance variation, making ADS7846E ideal for reliable coordinate capture in portable devices.

Does the ADS7846E require an external voltage reference?

No, the ADS7846E includes an internal 2.5V reference (2.45–2.55V, 15ppm/°C drift) that can be enabled or disabled via the PD1 control bit. This reference powers the battery monitor, temperature sensor, and auxiliary input channels. For optimal touch position accuracy, however, the ADS7846E is typically operated in differential reference mode (SER/DFR = 0), where +REF and –REF connect directly to Y+ and Y–, eliminating dependence on any reference voltage-including the internal one. So ADS7846E functions fully without external reference.

How does the ADS7846E support battery voltage monitoring?

The ADS7846E integrates a dedicated VBAT input (Pin 7) with an internal 4:1 resistor divider, allowing direct measurement of raw battery voltages from 0.5V to 6.0V. When configured via control bits A2A1A0 = 010, the ADC samples the divided voltage (0.125–1.5V), and the result scales linearly to the original battery value. Accuracy is ±2% with external VREF or ±3% using the internal 2.5V reference. This eliminates external scaling resistors and op-amps, reducing component count and PCB area in ADS7846E-based designs.

Can the ADS7846E replace the ADS7843E without hardware changes?

Yes-the ADS7846E is 100% pin-compatible with the ADS7843E in SSOP-16 (DBQ) packaging and shares identical timing, register map, and basic touch digitization functionality. Hardware replacement requires no PCB modification. However, software must be updated to configure PD1=0 after power-up (to disable internal reference for ADS7843 compatibility) and to enable new features like battery reading (A2A1A0=010), temperature sensing (000/111), or pressure calculation (Z1/Z2 modes). So ADS7846E delivers feature upgrade with zero layout change.

What is the role of the PENIRQ pin on the ADS7846E?

The PENIRQ pin (Pin 11) is an open-drain, active-low interrupt output that signals touch detection. It asserts low when the stylus or finger closes the resistive touch panel, providing hardware-driven wake-up for the host processor. An external 10–100kΩ pull-up resistor to +VCC is required. Because PENIRQ deasserts only after the panel opens, it enables low-power sleep modes between touches-critical for extending battery life in ADS7846E-based portable systems. No polling or timer-based scanning is needed when PENIRQ is used.