Texas Instruments ADS7842EB/1K

Overview

ADS7842EB/1K from Texas Instruments is a 12-bit, 4-channel SAR analog-to-digital converter with parallel output, ±1 LSB INL/DNL accuracy, 200 kHz sampling rate at 5 V, and SSOP-28 package. It integrates a sample-and-hold amplifier, 4-channel multiplexer, and 3-state parallel drivers for direct microprocessor interface - used in portable data loggers and battery-powered test equipment.

For engineers reviewing the ADS7842EB/1K datasheet, ADS7842EB/1K pinout, ADS7842EB/1K application, or ADS7842EB/1K equivalent, key selection criteria include its single-supply 2.7–5 V operation, 72 dB SINAD at 10 kHz, low 2 mW power dissipation, and support for external reference voltages from 100 mV to VCC.

Technical Context

The ADS7842EB/1K implements a capacitor-based successive approximation register (SAR) architecture with integrated sample-and-hold, requiring an external clock (0.2–3.2 MHz) and reference voltage. Its 4-channel single-ended analog multiplexer is controlled via A0/A1 address inputs synchronized with WR and CS signals.

Conversion timing is deterministic: 12 clock cycles per conversion, with BUSY signal indicating active conversion and rising edge enabling data latching. Power-down mode reduces supply current to 3 µA using RD and A0 coordination - no dedicated shutdown pin required.

Key Specifications

Pinout & Package

ADS7842EB/1K is housed in a 28-pin SSOP (DB) package with 0.65 mm pitch, optimized for compact PCB layouts and automated assembly. Pin functions are validated per TI SBAS103C datasheet revision C.

Key Features

Applications

Equivalent & Alternatives

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

Compared with ADS7841EB/1K and ADS8320EB/1K, the ADS7842EB/1K uniquely balances 12-bit precision, parallel microprocessor compatibility, and ultra-low 2 mW active power - making it optimal for portable, multi-channel systems needing deterministic timing and minimal BOM count.

Availability

ADS7842EB/1K is available at Aetrix Electronics and suitable for portable instrumentation, industrial sensor nodes, and medical monitoring devices requiring stable component supply and long-term lifecycle support.

Supply support for ADS7842EB/1K 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 connectivity technologies, with decades of expertise in precision data converters and industrial-grade ICs.

The ADS7842EB/1K belongs to TI's precision SAR ADC product line, designed specifically for low-power, multi-channel data acquisition in battery-operated and space-constrained measurement systems.

FAQ

What is the maximum sampling rate of the ADS7842EB/1K and what clock frequency is required?

The ADS7842EB/1K achieves a maximum sampling rate of 200 kHz when operated at +5 V, requiring an external clock frequency of 3.2 MHz (fCLK = 16 × fSAMPLE). At +2.7 V, the maximum rate drops to 125 kHz with a 2 MHz clock. The device uses a fixed 16-clock-cycle conversion cycle, so clock frequency directly determines throughput.

Does the ADS7842EB/1K support true differential input or only single-ended channels?

The ADS7842EB/1K 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 multiplexer selects one channel per conversion. Differential measurements require external instrumentation amplifiers or resistor networks.

How does the reference voltage affect LSB size and measurement accuracy in the ADS7842EB/1K?

In the ADS7842EB/1K, LSB size equals VREF / 4096 - e.g., 1.22 mV at 5 V, 610 µV at 2.5 V, or 24 µV at 100 mV. While offset and gain errors remain fixed in volts, their LSB-equivalent magnitude increases as VREF decreases, potentially degrading effective resolution below 12 bits at very low references due to internal noise floor.

Can the ADS7842EB/1K be interfaced directly with a 3.3 V microcontroller without level shifters?

Yes - the ADS7842EB/1K supports 2.7–5 V digital supply (VDIG) and has CMOS-compatible logic thresholds: VIH ≥ 0.7 × VDIG and VIL ≤ 0.3 × VDIG. When powered at 3.3 V, it accepts 3.3 V logic levels directly, and its 3-state outputs drive 3.3 V-tolerant MCU GPIOs without level translation.

What is the purpose of the A0 pin beyond channel selection in the ADS7842EB/1K?

In addition to selecting AIN2/AIN3, the A0 pin serves a dual function in the ADS7842EB/1K: when held HIGH during RD's rising edge after conversion, it triggers power-down mode (reducing current to 3 µA); when LOW during the second RD rising edge, it wakes the device. This eliminates need for a dedicated shutdown pin.