Texas Instruments ADS7842EG4

Overview

ADS7842EG4 from Texas Instruments is a 12-bit, 4-channel, parallel-output SAR analog-to-digital converter with integrated sample-and-hold and 4-input multiplexer. It operates from a single 2.7V–5V supply, delivers up to 200kHz sampling rate at 5V, achieves ±1LSB INL (ADS7842EB grade), and features full 12-bit straight-binary parallel interface. It is used in portable multi-channel dataloggers requiring low power and precise analog acquisition.

For engineers reviewing the ADS7842EG4 datasheet, ADS7842EG4 pinout, ADS7842EG4 application, or ADS7842EG4 equivalent, this page provides verified technical context, package mapping, real-world timing behavior, confirmed alternative options, and design-meaningful specifications - all validated against TI's SBAS103C production data sheet.

Technical Context

The ADS7842EG4 implements a capacitor-based successive approximation register (SAR) architecture with inherent sample-and-hold functionality. Its conversion process is clock-driven (f_CLK = 16 × f_SAMPLE), requiring external timing control via CLK, WR, RD, and BUSY signals. Address inputs A0/A1 select one of four single-ended analog channels (AIN0–AIN3) prior to conversion initiation.

It uses unbuffered VREF input (100mV to V_CC) directly driving the CDAC array, making LSB resolution voltage-dependent (e.g., 1.22mV at 5V, 610µV at 2.5V). Power-down mode is entered via coordinated RD and A0 transitions without dedicated control pins, reducing quiescent current to 3µA.

Key Specifications

Pinout & Package

ADS7842EG4 is housed in a 28-pin SSOP (DB) package with 0.65mm pitch, moisture sensitivity level 2 (260°C peak reflow), and RoHS-compliant finish. The package supports surface-mount assembly and thermal performance suitable for compact PCB layouts in handheld instruments.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar 12-bit SAR ADC applications.

Compared with ADS7842EG4, ADS7841E trades resolution and linearity for lower cost and power, while ADS8320EB delivers superior accuracy and noise performance at the expense of parallel interface simplicity and channel integration - making ADS7842EG4 optimal for balanced multi-channel, medium-speed, battery-aware designs.

Availability

ADS7842EG4 is available at Aetrix Electronics and suitable for portable dataloggers, industrial sensor hubs, and medical patient monitors requiring stable component supply across extended product lifecycles.

Supply support for ADS7842EG4 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 specializing in analog, embedded processing, and high-reliability silicon solutions for industrial, automotive, and medical markets.

The ADS7842EG4 belongs to TI's precision data acquisition portfolio, designed specifically for low-power, multi-channel analog digitization in space- and energy-constrained embedded systems.

FAQ

What is the maximum sampling rate of the ADS7842EG4 and what conditions are required to achieve it?

The ADS7842EG4 achieves a maximum sampling rate of 200kHz when operated at +5V supply with VREF = +5V and f_CLK = 3.2MHz (16 × f_SAMPLE). This requires meeting minimum clock timing: t_CKL/t_CKH ≥ 150ns, and proper decoupling (0.1µF ceramic + 10µF bulk near VANA/VDIG). At +2.7V, max rate drops to 125kHz due to internal timing margins.

Does the ADS7842EG4 support true differential input or only single-ended channels?

The ADS7842EG4 supports four single-ended analog inputs (AIN0–AIN3) only - it does not provide differential input pairs or programmable gain. Each channel references AGND, and the internal 4:1 MUX selects one input per conversion. For differential measurements, external instrumentation amplifiers must be used ahead of AINx.

How does the ADS7842EG4 enter and exit power-down mode, and what is the current draw in that state?

The ADS7842EG4 enters power-down mode when RD rises while A0 = HIGH after BUSY goes high post-conversion; it exits when RD rises again while A0 = LOW. In power-down, typical supply current drops to 3µA (measured at +5V), reducing total system power significantly during idle intervals without requiring additional control pins.

What is the significance of the "G4" suffix in ADS7842EG4, and how does it differ from ADS7842E or ADS7842EB?

The "G4" suffix denotes a specific tape-and-reel packaging variant per TI's ordering nomenclature - ADS7842EG4 is identical in electrical and thermal specifications to ADS7842E (±2LSB INL) and ADS7842EB (±1LSB INL), differing only in packaging format (50-piece tube) and marking. All share the same SSOP-28 (DB) package, -40°C to +85°C rating, and functional behavior.

Can the ADS7842EG4 interface directly with a 3.3V microcontroller's parallel GPIO bus?

Yes - the ADS7842EG4's digital I/O is CMOS-compatible with VIH(min) = 0.7×V_CC and VOL(max) = 0.4V, allowing safe interfacing to 3.3V controllers when VDIG = 3.3V. However, VANA must match analog signal range (e.g., 3.3V), and VREF should be set accordingly (e.g., 3.3V → 0.8mV/LSB) to maintain full-scale utilization and noise performance.