Texas Instruments ADS7822P

Overview

ADS7822P from Texas Instruments is a 12-bit, 200kHz successive approximation register (SAR) analog-to-digital converter with pseudo-differential input, serial CMOS interface, and microPower operation. It delivers ±2 LSB integral linearity over –40°C to +85°C, operates from 2.7V to 5.25V, and consumes only 1.6mW at full rate-enabling high-precision data acquisition in battery-powered remote sensors and isolated industrial monitoring systems.

For engineers reviewing the ADS7822P datasheet, ADS7822P pinout, ADS7822P application, or ADS7822P equivalent, key selection considerations include its 8-pin DIP package, 3μA power-down current, 25pF analog input capacitance, reference voltage flexibility (50mV to VCC), and synchronous 3-wire serial timing compatibility with low-power MCUs.

Technical Context

The ADS7822P implements a capacitive redistribution SAR architecture on a 0.6μm CMOS process, integrating sample/hold, comparator, and CDAC functions. Conversion is initiated by CS/SHDN falling edge, with 12-clock-cycle conversion time and 1.5-clock-cycle acquisition window synchronized to DCLOCK.

Its pseudo-differential input accepts +In and –In signals where –In is fixed during sampling (not resampled), limiting –In range to –0.2V to +1.0V while supporting common-mode rejection for remote ground sensing. The DOUT output provides straight-binary 12-bit data MSB-first on DCLOCK falling edges, with no pipeline delay.

Key Specifications

Pinout & Package

ADS7822P is housed in an 8-pin plastic DIP (P package) with 0.3-inch body width and through-hole mounting. Pin spacing complies with 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 ADS7822P offers the lowest cost DIP-8 option with verified ±2 LSB performance-ideal for cost-sensitive industrial controls where SO-8 rework or enhanced linearity are unnecessary.

Availability

ADS7822P is available at Aetrix Electronics and suitable for battery-operated systems, remote data acquisition, isolated industrial monitoring, and simultaneous multichannel systems requiring stable component supply across extended production lifecycles.

Supply support for ADS7822P 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 ADS7822P belongs to TI's legacy SAR ADC product line, engineered specifically for ultra-low-power, high-accuracy data acquisition in resource-constrained environments-from portable medical devices to distributed industrial sensors.

FAQ

What is the maximum sampling rate supported by the ADS7822P?

The ADS7822P supports a maximum sampling rate of 200kHz when operated at VCC = 5V and fCLK = 3.2MHz. At lower supply voltages (e.g., 2.7V), the maximum rate drops to 75kHz due to internal timing constraints. The ADS7822P achieves this rate using a 12-clock-cycle conversion cycle synchronized to DCLOCK, with throughput directly proportional to clock frequency.

Does the ADS7822P require an external reference voltage?

Yes, the ADS7822P requires an external reference voltage applied to the VREF pin. It accepts any stable voltage from 50mV to VCC, which directly sets the full-scale input range and LSB size (e.g., 1.22mV per LSB at 5V reference). No internal reference is provided-designers must supply a low-noise, well-bypassed reference source matching system accuracy requirements.

How does the pseudo-differential input of the ADS7822P differ from true differential input?

The ADS7822P's pseudo-differential input samples the voltage difference between +In and –In, but –In is held fixed during conversion-not actively subtracted in a second phase. Its –In range is limited to –0.2V to +1.0V, making it suitable for remote ground sensing but not for rejecting large common-mode signals. True differential ADCs resample –In independently, enabling higher CMRR; the ADS7822P does not provide that capability.

What is the power consumption of the ADS7822P in shutdown mode?

The ADS7822P draws a maximum of 3μA in shutdown mode when the CS/SHDN pin is driven high (to VCC). This ultra-low current enables multi-year battery operation in intermittent-sampling applications. During active conversion at 200kHz, total supply current is 320–550μA (depending on VCC), resulting in 1.6mW power dissipation at 5V.

Can the ADS7822P interface directly with a 3.3V microcontroller?

Yes, the ADS7822P can interface directly with a 3.3V microcontroller. Its digital I/O pins (CS/SHDN, DCLOCK, DOUT) tolerate logic levels up to 6V regardless of VCC, and DOUT swings rail-to-rail from 0V to VCC. When powered at 3.3V, DOUT outputs 0–3.3V CMOS levels compatible with standard 3.3V MCU inputs-no level-shifting circuitry is required.