Analog Devices Inc. AD7951BSTZ

Overview

AD7951BSTZ from Analog Devices is a 14-bit, 1 MSPS PulSAR® successive approximation register (SAR) ADC with programmable unipolar/bipolar input ranges (±5 V, ±10 V, 0–5 V, 0–10 V), iCMOS® process technology, and dual parallel/serial (SPI-/QSPI™-/MICROWIRE™-compatible) interface - used in high-speed data acquisition systems requiring no pipeline delay and precise DC/AC accuracy.

For engineers reviewing the AD7951BSTZ datasheet, AD7951BSTZ pinout, AD7951BSTZ application, or AD7951BSTZ equivalent, this page delivers verified technical context, real-world interface timing behavior, confirmed analog input range selection logic, and validated alternative options for medical instrumentation, spectrum analysis, and ATE signal chain design.

Technical Context

The AD7951BSTZ implements a charge redistribution SAR architecture with no pipeline delay, enabling deterministic latency critical for closed-loop control. It integrates an internal 5 V reference (±3 ppm/°C drift), temperature sensor (311 mV @ 25°C, 1 mV/°C), and configurable conversion modes: warp (1 MSPS), normal (800 kSPS), and impulse (670 kSPS).

Hardware configuration uses dedicated pins (WARP, IMPULSE, BIPOLAR, TEN, SER/PAR) to set input range and mode without serial overhead; software configuration via dedicated SPI-compatible serial port supports dynamic reconfiguration. The device supports both 14-bit parallel bus and serial output with MSB-first format, OB/2C-selectable straight binary or twos-complement coding.

Key Specifications

Pinout & Package

AD7951BSTZ is housed in a 48-lead LQFP package (7 mm × 7 mm, exposed pad). Pin functions are validated per Analog Devices' Rev. B datasheet (2015), with AGND/DGND/OGND separation supporting mixed-signal noise isolation.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar high-speed SAR ADC applications.

Compared with AD7951BSTZ, AD7654ASTZ trades speed and input flexibility for higher resolution in static applications, while AD7960BCPZ delivers superior speed and resolution at the cost of increased system integration effort and loss of on-chip reference/temperature features.

Availability

AD7951BSTZ is available at Aetrix Electronics and suitable for medical instrumentation, automated test equipment, spectrum analysis systems, and digital signal processing platforms requiring stable component supply, long-lifecycle support, and guaranteed traceability.

Supply support for AD7951BSTZ 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

Analog Devices, Inc. is a global leader in high-performance analog, mixed-signal, and digital signal processing semiconductors, headquartered in Norwood, MA, with R&D and manufacturing operations worldwide.

The AD7951BSTZ belongs to Analog Devices' PulSAR® family of precision SAR ADCs, designed specifically for high-speed, low-latency data acquisition in industrial, medical, and test equipment where accuracy, configurability, and robustness are critical.

FAQ

What input voltage ranges does the AD7951BSTZ support, and how are they selected?

The AD7951BSTZ supports four input ranges: 0–5 V, 0–10 V, ±5 V, and ±10 V. Selection is performed via hardware using the BIPOLAR and TEN pins (e.g., BIPOLAR=high/TEN=high → ±10 V) or via software through its serial configuration port. This dual-mode flexibility allows fixed-range systems to avoid firmware dependencies while retaining reconfigurability for lab-grade instruments. All ranges maintain 14-bit no-missing-codes performance and specified INL.

Does the AD7951BSTZ include an internal voltage reference, and what are its key specs?

Yes, the AD7951BSTZ integrates a 5 V internal reference with typical output of 5.000 V (range: 4.965 V to 5.035 V at 25°C), ±3 ppm/°C temperature drift, and 10 ms turn-on settling time with a 22 µF capacitor. When PDREF and PDBUF are low, the REF pin delivers this buffered reference; when high, the device accepts an external reference up to AVDD. This eliminates external reference ICs in most applications while maintaining <0.006% full-scale error drift over −40°C to +85°C.

How does the AD7951BSTZ achieve 1 MSPS throughput, and what is the latency in warp mode?

The AD7951BSTZ achieves 1 MSPS in warp mode via optimized SAR conversion timing: complete cycle time is 1 µs, with conversion time of 850 ns and acquisition time of 148 ns. There is no pipeline delay - the BUSY signal goes high on CNVST falling edge and low 850 ns later, signaling immediate data availability. This fixed, sub-microsecond latency enables deterministic sampling in real-time control loops and burst-mode acquisition without FIFO buffering.

Can the AD7951BSTZ operate with different digital interface voltages, and what are the OVDD requirements?

Yes, the AD7951BSTZ supports OVDD from 2.7 V to 5.25 V, allowing direct interfacing with 2.5 V, 3.3 V, or 5 V host processors. Digital outputs (D[13:0], SDOUT, SYNC, etc.) are level-shifted to OVDD, while logic thresholds scale accordingly (VIH = 2.1 V min, VOH = OVDD − 0.6 V). This eliminates level translators in mixed-voltage systems. OVDD must be decoupled with 10 µF and 100 nF capacitors, and OGND must be tied to system digital ground at same potential as AGND/DGND.

What is the function of the TEMP pin on the AD7951BSTZ, and how is it calibrated?

The TEMP pin provides an analog voltage proportional to die temperature: 311 mV at 25°C with 1 mV/°C sensitivity and 4.33 kΩ output resistance. It is enabled only when the internal reference is active (PDREF = PDBUF = low). No factory calibration is required - users compute temperature as T(°C) = (V_TEMP − 311 mV) / 1 mV/°C. This on-chip sensor supports thermal derating of ADC performance, ambient monitoring in medical devices, and system-level thermal management without adding discrete components.