Texas Instruments ADS7816UB

Overview

ADS7816UB from Burr-Brown (now Texas Instruments) is a 12-bit, 200kHz SAR analog-to-digital converter with differential input, synchronous serial interface, and programmable reference range (100mV–5V). It delivers 1.9mW power consumption at full speed, 3µA shutdown current, and ±2 LSB integral linearity - ideal for battery-powered remote data acquisition systems requiring high resolution in compact SOIC-8 packaging.

For engineers reviewing the ADS7816UB datasheet, ADS7816UB pinout, ADS7816UB application, or ADS7816UB equivalent, this page provides verified technical context, package-specific pin functions, real-world use scenarios, and two validated alternative parts - all grounded in the original Burr-Brown PDS-1355B datasheet and TI's legacy product documentation.

Technical Context

The ADS7816UB implements a capacitive redistribution successive approximation register (SAR) architecture fabricated in 0.6µm CMOS, enabling single-supply +5V operation with no internal reference. Its conversion cycle begins on CS falling edge, samples the differential voltage (+In – –In) in 1.5 clock cycles, completes conversion in 12 DCLOCK cycles, and outputs 12-bit straight-binary data MSB-first on DOUT synchronized to DCLOCK falling edges.

Reference voltage directly defines full-scale span (VREF) and LSB size (VREF/4096), with performance trade-offs confirmed across curves: ENOB drops from ~11.8 bits at 5V VREF to ~10.3 bits at 0.1V VREF; offset/gain errors scale inversely with VREF; and peak-to-peak noise increases from <1 LSB to ~8 LSBs as VREF decreases - all measured under –40°C to +85°C conditions.

Key Specifications

Pinout & Package

ADS7816UB is housed in an 8-lead SOIC package (drawing number 182), with gull-wing leads, 1.27mm pitch, and JEDEC MS-012AC compliance. Pin functions are electrically identical across ADS7816U/UB/UC variants, differing only in linearity grade.

Key Features

Applications

Equivalent & Alternatives

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

Compared with ADS7816UC, the ADS7816UB trades 1 LSB linearity for lower cost and broader availability; versus ADS7822U, it retains external VREF control and true differential input - critical for remote ground sensing and multi-sensor range scaling.

Availability

ADS7816UB is available at Aetrix Electronics and suitable for battery-operated systems, remote data acquisition, and isolated analog input modules requiring stable component supply across industrial temperature ranges and long production lifecycles.

Supply support for ADS7816UB 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

Burr-Brown Corporation, acquired by Texas Instruments in 2000, specialized in precision analog ICs including data converters, op amps, and interface products for industrial and instrumentation markets.

The ADS7816UB belongs to Burr-Brown's micropower SAR ADC family designed specifically for high-resolution, low-power data acquisition in space- and energy-constrained environments - emphasizing differential input integrity, reference flexibility, and robust serial interfacing.

FAQ

What is the maximum sampling rate supported by the ADS7816UB?

The ADS7816UB supports a maximum sampling rate of 200kHz, achieved when driven by a 3.2MHz DCLOCK signal (f_CLK = 16 × f_SAMPLE). At this rate, conversion time is fixed at 12 clock cycles, and acquisition time is 1.5 clock cycles. Lower sample rates reduce power consumption proportionally - e.g., 12.5kHz operation draws only 30µA quiescent current.

Does the ADS7816UB require an external reference voltage?

Yes, the ADS7816UB requires an external reference voltage applied to the VREF pin. It operates with VREF ranging from 0.1V to 5V, which directly defines the full-scale input span and LSB size (VREF/4096). No internal reference is provided; reference current draw varies from 2.4µA at 12.5kHz to 100µA at 200kHz depending on output code.

What is the function of the –In pin on the ADS7816UB?

The –In pin on the ADS7816UB serves as the inverting input for true differential sampling, but its voltage range is strictly limited to ±200mV relative to GND. It is intended for remote ground sensing - connecting to the signal source's local ground to reject small potential differences - not for general-purpose common-mode rejection. Exceeding ±200mV violates absolute maximum ratings.

How does power-down mode work on the ADS7816UB?

Power-down mode on the ADS7816UB activates automatically after conversion completion and fully engages when CS/SHDN is driven HIGH, reducing supply current to ≤3µA. While CS is LOW, the device remains partially active - digital circuitry stays powered, preventing deep sleep. For minimum power, assert CS HIGH between conversions; leaving CS LOW during idle periods increases current draw unnecessarily.

Is the ADS7816UB pin-compatible with other ADS7816 variants?

Yes, the ADS7816UB is pin-compatible with all ADS7816 variants (e.g., ADS7816U, ADS7816UC, ADS7816P) across SOIC, PDIP, and MSOP packages. Pin functions, electrical characteristics, and timing behavior are identical; only grade-specific parameters differ - notably integral linearity (±2 LSB for UB vs ±1 LSB for UC) and differential linearity (±1 LSB for UB vs ±0.75 LSB for UC).