Texas Instruments ADS7816UC/2K5

Overview

ADS7816UC/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 voltage (100mV–5V). It delivers 1.9mW power at full rate, 3µA shutdown current, and ±0.75 LSB differential linearity - ideal for low-power remote data acquisition systems requiring high resolution in compact SOIC-8 packaging.

For engineers reviewing the ADS7816UC/2K5 datasheet, ADS7816UC/2K5 pinout, ADS7816UC/2K5 application, or ADS7816UC/2K5 equivalent, key selection considerations include its micro-power operation at variable sample rates (12.5kHz–200kHz), differential input rejection capability, reference-voltage-dependent LSB sizing (24µV–1.22mV), and compatibility with CMOS-level serial host controllers using CS/DCLOCK/DOUT timing.

Technical Context

The ADS7816UC/2K5 implements a capacitive redistribution successive approximation register (SAR) architecture on 0.6µm CMOS, integrating sample-and-hold functionality. It requires external clock (10kHz–3.2MHz), single +5V supply, and external reference - with no internal reference or buffer.

Its differential analog input (+In/–In) captures voltage difference during hold mode; –In is limited to ±200mV and intended for remote ground sensing, not full-scale common-mode rejection. Serial output is straight binary, MSB-first, with null-bit preamble and tri-state DOUT after completion.

Key Specifications

Pinout & Package

ADS7816UC/2K5 is housed in an 8-lead SOIC package (Package Drawing 182), measuring 4.9mm × 3.9mm × 1.75mm, with gull-wing leads and standard JEDEC MS-012AC footprint.

Key Features

Applications

Equivalent & Alternatives

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

Compared with ADS7816UB/2K5, the ADS7816UC/2K5 offers tighter differential linearity for demanding metrology; versus ADS7822U, it retains differential input and external reference control - essential for precision ratiometric or low-voltage sensor systems.

Availability

ADS7816UC/2K5 is available at Aetrix Electronics and suitable for battery-powered instrumentation, isolated data acquisition, and portable medical devices requiring stable component supply across extended production lifecycles.

Supply support for ADS7816UC/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 precision analog ICs including data converters, amplifiers, and references for industrial and instrumentation markets.

The ADS7816UC/2K5 belongs to Burr-Brown's micro-power SAR ADC product line, designed specifically for high-resolution, low-quiescent-current data acquisition in space- and energy-constrained systems.

FAQ

What is the minimum external reference voltage supported by the ADS7816UC/2K5?

The ADS7816UC/2K5 supports an external reference voltage from 100mV to 5V. At 100mV, LSB size is 24µV - enabling high-resolution digitization of low-level signals like thermocouples. Operation below 100mV is not specified and may violate linearity or missing-code guarantees. The ADS7816UC/2K5 reference input presents 5GΩ impedance when CS is grounded, minimizing loading on precision reference sources.

Does the ADS7816UC/2K5 include an internal reference or require an external one?

The ADS7816UC/2K5 requires an external reference voltage applied to the VREF pin; it contains no internal reference. This design allows full flexibility in setting full-scale range (100mV–5V) and supports ratiometric measurements where reference tracks sensor excitation. The ADS7816UC/2K5 reference current varies with code and sample rate (2.4–100µA), so the external reference must drive this dynamic load without droop or noise.

How does the differential input of the ADS7816UC/2K5 function, and what are its limitations?

The ADS7816UC/2K5 accepts true differential input via +In and –In pins, capturing the voltage difference during hold phase without resampling –In. However, –In is restricted to ±200mV relative to local GND - making it suitable for remote ground sensing, not full common-mode rejection. Exceeding this range risks nonlinearity. The ADS7816UC/2K5 input capacitance is 25pF, requiring low-impedance drive for 12-bit settling.

What is the power-down behavior of the ADS7816UC/2K5, and how is it controlled?

The ADS7816UC/2K5 enters full shutdown (3µA max) when CS is driven HIGH, disabling both analog and digital sections. When CS returns LOW, a new conversion initiates automatically. During normal operation, it also enters low-power analog-only shutdown after conversion completion - but digital circuitry remains active unless CS is asserted high. This dual-mode control makes the ADS7816UC/2K5 highly adaptable for burst-mode sensing.

Can the ADS7816UC/2K5 be used with microcontrollers lacking dedicated SPI hardware?

Yes - the ADS7816UC/2K5 uses a simple 3-wire synchronous serial interface (CS/DCLOCK/DOUT) compatible with bit-banged GPIOs. Data is MSB-first straight binary, with null-bit preamble and defined setup/hold times (e.g., tdDO = 85–150ns). Its CMOS logic levels (VIH ≥3V, VIL ≤0.8V at 5V supply) ensure reliable interfacing with most 5V MCUs without level shifters. The ADS7816UC/2K5 timing is deterministic and well-documented in the datasheet's Table I.