Texas Instruments ADS7816UB/2K5

Overview

ADS7816UB/2K5 from Burr-Brown (now Texas Instruments) is a 12-bit, 200kHz sampling SAR analog-to-digital converter with differential input, synchronous serial interface, and programmable reference range (100mV–5V). It delivers 1.9mW power at full speed, 3µA shutdown current, and ±2 LSB integral linearity - optimized for remote, isolated, or battery-powered data acquisition systems.

For engineers reviewing the ADS7816UB/2K5 datasheet, ADS7816UB/2K5 pinout, ADS7816UB/2K5 application, or ADS7816UB/2K5 equivalent, key selection considerations include its SOIC-8 package, micro-power operation at variable sample rates (12.5kHz–200kHz), differential input rejection capability, reference voltage scalability, and CMOS-compatible serial timing with CS/SHDN-controlled power-down.

Technical Context

The ADS7816UB/2K5 implements a capacitive redistribution successive approximation register (SAR) architecture on a 0.6µm CMOS process, integrating sample-and-hold functionality. It requires an external clock (10kHz–3.2MHz), single +5V supply, and external reference - with conversion time fixed at 12 clock cycles and acquisition time of 1.5 clock cycles.

Its differential analog input (+In/–In) captures voltage difference during hold mode without resampling –– with –In limited to ±200mV for remote ground sensing. Serial output is straight binary, MSB-first, enabled after second falling edge of DCLOCK following CS low assertion.

Key Specifications

Pinout & Package

ADS7816UB/2K5 is housed in an 8-lead SOIC package (JEDEC MS-012, drawing 182), measuring 3.9mm × 4.9mm × 1.75mm, with gull-wing leads and standard 1.27mm pitch.

Key Features

Applications

Equivalent & Alternatives

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

Compared with ADS7816U and ADS7822U, the ADS7816UB/2K5 uniquely combines guaranteed ±1 LSB INL, true differential input, and 3-wire serial simplicity - making it optimal for precision, low-noise, space-constrained remote DAQ where reference flexibility and micro-power shutdown are mandatory.

Availability

ADS7816UB/2K5 is available at Aetrix Electronics and suitable for battery-operated instrumentation, remote sensor networks, and isolated industrial data acquisition requiring stable component supply and long-term manufacturability.

Supply support for ADS7816UB/2K5 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 high-precision analog ICs including data converters, amplifiers, and references.

The ADS7816UB/2K5 belongs to Burr-Brown's micro-power SAR ADC product line, designed specifically for portable, remote, and isolated data acquisition systems demanding low power, small size, and flexible reference scaling.

FAQ

What is the maximum sampling rate supported by the ADS7816UB/2K5?

The ADS7816UB/2K5 supports a maximum sampling rate of 200kHz, achieved with a 3.2MHz DCLOCK input (16× oversampling ratio). At this rate, conversion time is fixed at 12 clock cycles and acquisition time at 1.5 cycles, delivering full 12-bit results every 5µs. Lower rates (e.g., 12.5kHz) reduce power to 150µW while maintaining specification compliance.

Does the ADS7816UB/2K5 require an external clock source?

Yes, the ADS7816UB/2K5 requires an external DCLOCK signal ranging from 10kHz to 3.2MHz. The clock duty cycle is flexible as long as high and low times exceed 150ns. Clock frequency directly determines throughput: fSAMPLE = fCLK / 16. No internal oscillator is present - all timing is externally controlled for system-level synchronization.

How does the reference voltage affect resolution and noise performance of the ADS7816UB/2K5?

Reference voltage sets LSB size: VREF / 4096. At 5V, LSB = 1.22mV; at 100mV, LSB = 24µV. However, internal noise (~33µVrms) becomes proportionally larger - contributing ~0.16 LSB at 5V but ~8 LSB at 100mV. ENOB drops from ~12 bits at 5V to ~10.25 bits at 100mV, as confirmed in the "Effective Number of Bits vs Reference Voltage" curve.

Can the ADS7816UB/2K5 perform partial conversions to save power?

Yes - the ADS7816UB/2K5 supports short-cycling: pulling CS HIGH at any point during serial output terminates conversion and forces shutdown. For example, reading only the first 4 bits allows early decision-making (e.g., out-of-range detection) while skipping remaining bit decisions, reducing both active time and total energy per sample.

What is the function of the –In pin on the ADS7816UB/2K5?

The –In pin serves as the inverting input for true differential measurement. Unlike pseudo-differential ADCs, –In is sampled simultaneously with +In and held - not resampled later. Its voltage must remain within GND ±200mV, making it ideal for remote ground sensing in long-cable or isolated applications, rather than high-common-mode rejection.