Texas Instruments ADS7822PB

Overview

ADS7822PB from Texas Instruments is a 12-bit, pseudo-differential SAR analog-to-digital converter with 1 LSB integral linearity error, 200 kHz max throughput at 5 V, and microPower operation (0.54 mW at 75 kHz). It features a synchronous 3-wire serial interface, operates from 2.7 V to 5.25 V, and is used in battery-powered remote data acquisition systems requiring low-power precision sampling.

For engineers reviewing the ADS7822PB datasheet, ADS7822PB pinout, ADS7822PB application, or ADS7822PB equivalent, key selection criteria include its ±1 LSB INL specification, DIP-8 package compatibility, 2.7–5.25 V supply range, and pseudo-differential input architecture for noise-rejected signal conditioning in isolated sensor interfaces.

Technical Context

The ADS7822PB implements a capacitive redistribution successive approximation register (SAR) architecture on a 0.6 µm CMOS process, integrating sample-and-hold functionality. Its conversion cycle requires exactly 12 clock cycles after acquisition, with 1.5 clock cycles dedicated to analog input sampling.

It uses a synchronous 3-wire serial interface (CS/SHDN, DCLOCK, DOUT) where data is output MSB-first on the falling edge of DCLOCK. The pseudo-differential input (+In/–In) captures voltage difference directly onto an internal capacitor array without resampling –In during hold, limiting –In to –0.2 V to +1.0 V for linearity compliance.

Key Specifications

Pinout & Package

ADS7822PB is housed in an 8-pin plastic DIP (Dual In-line Package) with through-hole mounting and 0.3-inch body width. Pin spacing follows JEDEC MS-001 standard.

Key Features

Applications

Equivalent & Alternatives

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

Compared with ADS7822U and ADS7822EB, the ADS7822PB provides identical analog performance and timing but delivers mechanical reliability and serviceability advantages in through-hole designs-making it preferred for field-deployable instrumentation, educational kits, and low-volume industrial controllers where solder joint integrity and replacement simplicity matter.

Availability

ADS7822PB is available at Aetrix Electronics and suitable for battery-operated systems, remote data acquisition, and isolated industrial monitoring requiring stable component supply across extended product lifecycles.

Supply support for ADS7822PB 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 and embedded processing technologies, with decades of expertise in precision data converters and low-power design.

The ADS7822PB belongs to TI's legacy SAR ADC portfolio designed for cost-sensitive, power-constrained applications where 12-bit resolution, pseudo-differential input, and DIP packaging meet industrial and instrumentation requirements.

FAQ

What is the maximum sampling rate of the ADS7822PB?

The ADS7822PB achieves a maximum throughput rate of 200 kHz when operated at +5 V supply with fCLK = 3.2 MHz. At lower supply voltages (e.g., 2.7 V), the maximum sample rate drops to 75 kHz due to internal timing constraints. This is confirmed in the Electrical Characteristics tables for both +2.7 V and +5 V conditions, where throughput is explicitly specified as 75 kHz and 200 kHz respectively.

Does the ADS7822PB support true differential input operation?

No, the ADS7822PB implements a pseudo-differential input architecture. While it accepts two analog inputs (+In and –In), the –In pin is not actively resampled during conversion and is restricted to –0.2 V to +1.0 V. It functions primarily as a remote ground reference-not a symmetrical differential pair-so common-mode rejection is limited compared to fully differential ADCs.

What is the power consumption of the ADS7822PB at 7.5 kHz sampling?

At 7.5 kHz sampling rate, the ADS7822PB consumes less than 60 µW total power, corresponding to approximately 20 µA quiescent current from a 2.7 V supply. This ultra-low power state is achieved by spending most of the time in power-down mode between conversions, as documented in the Power Dissipation section and Figure 25 of the SBAS062C datasheet.

Can the ADS7822PB operate with a 2.0 V supply?

Yes, the ADS7822PB is specified to operate down to 2.0 V supply voltage, though full 200 kHz performance is only guaranteed from 4.75 V to 5.25 V. At 2.0 V, the maximum sample rate is reduced, and certain parameters (e.g., power supply rejection) degrade. The datasheet explicitly lists "2.0 V" under VCC operating range in the Electrical Characteristics table for +2.7 V conditions.

How does the reference voltage affect LSB size in the ADS7822PB?

The LSB size of the ADS7822PB equals VREF / 4096. For example, with VREF = 2.5 V, one LSB = 0.61 mV; with VREF = 5.0 V, one LSB = 1.22 mV. Lower reference voltages proportionally reduce LSB weight but amplify the impact of internal noise and offset errors-e.g., 33 µVrms noise becomes ~16 LSBs at 50 mV reference, as noted in the Theory of Operation section.