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Home > Products > Integrated Circuits (ICs) > Data Acquisition > Analog to Digital Converters (ADC)

Analog Devices Inc. AD7631BSTZ

Name: AD7631BSTZ
Brand: Analog Devices Inc.
SKU: AD7631BSTZ
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: AD7631BSTZ

Manufacturer:: Analog Devices Inc.

Category:: Analog to Digital Converters (ADC)

Package:: 48-LQFP

Datasheet:: AD7631BSTZ.pdf

Description:: IC ADC 18BIT SAR 48LQFP

Quantity:: RFQ Add To RFQ list

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Product details

Overview

AD7631BSTZ from Analog Devices is an 18-bit, 250 kSPS, fully differential successive approximation register (SAR) ADC with programmable input ranges (±10 V, ±5 V, 0–10 V, 0–5 V), integrated 5 V reference (3 ppm/°C drift), and dual parallel/serial (SPI/QSPI/MICROWIRE/DSP-compatible) interface. It delivers 102.5 dB dynamic range and −112 dB THD at 2 kHz for high-fidelity data acquisition in process control and spectrum analysis systems.

For engineers reviewing the AD7631BSTZ datasheet, AD7631BSTZ pinout, AD7631BSTZ application, or AD7631BSTZ equivalent, key selection considerations include its iCMOS® high-voltage architecture (±15 V supplies), no-pipeline-delay SAR conversion, hardware/software-configurable input range and interface mode, and 48-lead LQFP package with dedicated TEMP output for on-chip temperature monitoring.

Technical Context

The AD7631BSTZ implements a charge redistribution SAR architecture with internal conversion clock, error correction circuitry, and configurable analog front-end. Its four selectable differential input ranges are set via BIPOLAR/TEN pins or serial configuration port, and it supports simultaneous hardware- and software-based mode selection through MODE[1:0], HW/SW, and EXT/INT pins.

It integrates dual power domains (AVDD/DVDD for logic, VCC/VEE for analog front-end), independent digital I/O supply (OVDD), and flexible reference handling-enabling internal 5 V reference (PDREF/PDBUF low), external reference (PDREF/PDBUF high), or buffered external reference (PDBUF low). Conversion is initiated by CNVST falling edge, with BUSY signaling completion and RD/CS enabling data readout.

Key Specifications

Parameter	Value and Actual Design Meaning
Resolution	18-bit with no missing codes-guarantees monotonicity and full code coverage across all input ranges.
Throughput Rate	250 kSPS maximum-supports real-time capture of signals up to ~125 kHz Nyquist bandwidth.
INL Error	±2.5 LSB max (±9.5 ppm FSR)-enables precise DC measurement and calibration-critical applications.
Dynamic Range	102.5 dB (all ranges, 2 kHz)-provides >16.5 effective number of bits (ENOB) for high-SNR signal chain design.
THD	−112 dB @ 2 kHz-minimizes harmonic distortion in spectral analysis and audio-grade acquisition.
Reference Drift	±3 ppm/°C (internal 5 V ref)-reduces system-level temperature-induced gain error without external trimming.
Power Dissipation	73 mW @ 250 kSPS (internal ref disabled)-enables low-power high-resolution operation in thermally constrained systems.
Supply Voltages	VCC = +15 V, VEE = −15 V, AVDD/DVDD = 5 V, OVDD = 2.7–5.5 V-supports industrial bipolar signal conditioning and mixed-voltage interfacing.

Pinout & Package

AD7631BSTZ is housed in a Pb-free, 48-lead LQFP (7 mm × 7 mm, 0.5 mm pitch) with exposed thermal pad (not electrically connected). Pin 1 is marked by dot; AGND/DGND/OGND must be tied at single-point analog/digital ground plane per layout guidelines.

Pin/Terminal	Circuit Role	Design Meaning
IN+, IN−	Differential analog inputs	Accept fully differential signals up to ±10 V p-p; require matched 180° phase drive and common-mode voltage within specified range (e.g., 0 V for bipolar modes).
CNVST	Conversion start trigger	Falling-edge sensitive; initiates sample-to-hold transition and SAR conversion sequence-no minimum pulse width required beyond 10 ns.
BUSY	Conversion status indicator	Active-high open-drain output; falling edge marks valid data latch-used as hardware-ready strobe for synchronous readout.
RD, CS	Parallel/serial data enable	Both low to enable D[17:0]/SDOUT output; CS also gates external SDCLK in slave serial mode.
MODE[1:0]	Interface configuration select	Defines bus width: 00 = 18-bit, 01 = 16-bit, 10 = 8-bit, 11 = serial-determines pin function mapping for D0–D17.
TEMP	On-chip temperature sensor output	Analog voltage (311 mV @ 25°C, 1 mV/°C slope)-enables system-level thermal monitoring without external sensor.
REF, REFGND	Reference input/output	5 V reference source/sink; requires ≥22 μF decoupling capacitor regardless of internal/external reference use.
VCC, VEE	High-voltage analog supplies	Support ±15 V operation for true bipolar input stages-critical for ±10 V range and wide common-mode rejection.

Key Features

Feature	Design Value
Programmable input ranges	Four hardware-selectable differential ranges (0–5 V, 0–10 V, ±5 V, ±10 V) eliminate external gain-switching circuitry and reduce BOM count.
iCMOS® process technology	Enables integration of ±15 V analog front-end with 5 V logic-reducing need for level-shifting and isolation in high-voltage industrial interfaces.
No pipeline delay	SAR architecture ensures deterministic 4.0 μs conversion time-critical for closed-loop control and time-triggered acquisition systems.
Dual interface flexibility	Simultaneous parallel (18/16/8-bit) and serial (SPI/QSPI/MICROWIRE) ports allow migration between speed-optimized and pin-count-constrained designs.
Integrated temperature sensor	Monolithic TEMP pin provides calibrated 1 mV/°C output-enables real-time thermal compensation of gain/offset errors in precision systems.
Configurable reference path	Internal 5 V ref (3 ppm/°C), external ref support (4.75–5.25 V), and buffer enable/disable (PDREF/PDBUF) simplify reference subsystem design and improve PSRR.

Applications

Process Control Systems	High-Speed Data Acquisition
Use Scenario: Monitoring multi-channel analog sensor outputs (pressure, flow, temperature) in PLC-based industrial automation with <10 ppm linearity requirement. IC Role / Device Role / Timing Role: Primary high-resolution ADC capturing synchronized samples across 4–8 channels at 100–250 kSPS with deterministic latency. Use Value: 18-bit no-missing-codes resolution and ±2.5 LSB INL ensure accurate calibration traceability to NIST standards without post-acquisition correction.	Use Scenario: Digitizing transient waveforms from oscilloscope front-ends or vibration sensors in predictive maintenance equipment. IC Role / Device Role / Timing Role: Standalone SAR ADC providing burst-mode sampling with CNVST-triggered acquisition and BUSY-synchronized readout. Use Value: 102.5 dB dynamic range and −112 dB THD preserve signal integrity for FFT-based spectral analysis up to 100 kHz.
Spectrum Analysis Instruments	Automated Test Equipment (ATE)
Use Scenario: RF signal analyzer digitizing IF outputs in 50 Ω systems requiring wide input range and low distortion. IC Role / Device Role / Timing Role: Differential input ADC operating in ±10 V mode with matched IN+/IN− drive to maximize CMRR (>75 dB @ 100 kHz). Use Value: iCMOS® high-voltage architecture enables direct connection to ±10 V IF stages without attenuators or op-amp buffers-reducing noise and component count.	Use Scenario: Modular ATE slot card acquiring DC parametric measurements (V_GS, V_DS) and AC waveforms from DUTs under test. IC Role / Device Role / Timing Role: Precision ADC supporting both unipolar (0–10 V) and bipolar (±5 V) test signal routing via hardware pin control (BIPOLAR/TEN). Use Value: Hardware-configurable input range eliminates FPGA-based range switching logic-reducing test head complexity and improving channel density.

Process Control Systems

High-Speed Data Acquisition

Use Scenario: Monitoring multi-channel analog sensor outputs (pressure, flow, temperature) in PLC-based industrial automation with <10 ppm linearity requirement.

IC Role / Device Role / Timing Role: Primary high-resolution ADC capturing synchronized samples across 4–8 channels at 100–250 kSPS with deterministic latency.

Use Value: 18-bit no-missing-codes resolution and ±2.5 LSB INL ensure accurate calibration traceability to NIST standards without post-acquisition correction.

Use Scenario: Digitizing transient waveforms from oscilloscope front-ends or vibration sensors in predictive maintenance equipment.

IC Role / Device Role / Timing Role: Standalone SAR ADC providing burst-mode sampling with CNVST-triggered acquisition and BUSY-synchronized readout.

Use Value: 102.5 dB dynamic range and −112 dB THD preserve signal integrity for FFT-based spectral analysis up to 100 kHz.

Spectrum Analysis Instruments

Automated Test Equipment (ATE)

Use Scenario: RF signal analyzer digitizing IF outputs in 50 Ω systems requiring wide input range and low distortion.

IC Role / Device Role / Timing Role: Differential input ADC operating in ±10 V mode with matched IN+/IN− drive to maximize CMRR (>75 dB @ 100 kHz).

Use Value: iCMOS® high-voltage architecture enables direct connection to ±10 V IF stages without attenuators or op-amp buffers-reducing noise and component count.

Use Scenario: Modular ATE slot card acquiring DC parametric measurements (V_GS, V_DS) and AC waveforms from DUTs under test.

IC Role / Device Role / Timing Role: Precision ADC supporting both unipolar (0–10 V) and bipolar (±5 V) test signal routing via hardware pin control (BIPOLAR/TEN).

Use Value: Hardware-configurable input range eliminates FPGA-based range switching logic-reducing test head complexity and improving channel density.

Equivalent & Alternatives

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

Alternative Part	Technical Difference	Application Difference	Selection Advice
AD7679ASTZ	18-bit, 570 kSPS, 48-lead LQFP; higher throughput but no internal reference or TEMP output.	Used where speed >250 kSPS is mandatory and external reference/temperature sensing are handled separately.	Select AD7679ASTZ when system requires >250 kSPS with identical resolution and package footprint-accepting added external reference and thermal sensor components.
AD7641BSTZ	18-bit, 250 kSPS, 48-lead LQFP; includes internal reference but lacks TEMP pin and has lower THD (−105 dB vs. −112 dB).	Targeted at cost-sensitive instrumentation where temperature monitoring is not required and moderate distortion is acceptable.	Choose AD7641BSTZ for simplified BOM in portable test gear where 105 dB THD suffices and on-chip temperature sensing is unnecessary.

Compared with AD7679ASTZ and AD7641BSTZ, the AD7631BSTZ uniquely combines 250 kSPS throughput, integrated 5 V reference with low drift, on-die temperature sensor, and −112 dB THD-making it optimal for space-constrained, self-calibrating industrial DAQ systems requiring minimal external components.

Availability

AD7631BSTZ is available at Aetrix Electronics and suitable for process control systems, high-speed data acquisition modules, and automated test equipment requiring stable component supply, long-term lifecycle support, and guaranteed traceable sourcing.

Supply support for AD7631BSTZ 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 design centers worldwide and ISO 9001-certified manufacturing.

The AD7631BSTZ belongs to Analog Devices' PulSAR® family of precision SAR ADCs, engineered specifically for industrial process control, test instrumentation, and high-fidelity data acquisition where accuracy, reliability, and configurability outweigh raw speed requirements.

FAQ

What input voltage ranges does the AD7631BSTZ support, and how are they selected?

The AD7631BSTZ supports four differential input ranges: 0 V to 5 V, 0 V to 10 V, ±5 V, and ±10 V. Selection is achieved via hardware using the BIPOLAR and TEN pins (per Table in datasheet Pin 30/36), or through software configuration via the serial configuration port when HW/SW = low. The AD7631BSTZ automatically scales internal reference usage accordingly-e.g., ±10 V mode uses 4× VREF-ensuring full-scale utilization without external scaling resistors.

Does the AD7631BSTZ require an external reference, or does it include one?

The AD7631BSTZ includes a precision internal 5 V reference with ±3 ppm/°C temperature drift and 10 ms turn-on settling time. It can operate with this reference enabled (PDREF = PDBUF = low), with external reference applied to REF pin (PDREF = PDBUF = high), or with external reference buffered (PDBUF = low). The AD7631BSTZ does not require an external reference for basic operation, reducing system component count and board area.

What is the purpose of the TEMP pin on the AD7631BSTZ, and how is it used?

The TEMP pin on the AD7631BSTZ provides a calibrated analog voltage output proportional to die temperature: 311 mV at 25°C with 1 mV/°C sensitivity. It is intended for system-level thermal monitoring and compensation-e.g., correcting gain/offset drift in precision measurement chains. No external components are needed; the output drives standard ADC inputs or op-amp buffers directly. This feature is unique to the AD7631BSTZ within its 18-bit PulSAR® generation.

Can the AD7631BSTZ interface with 3.3 V microcontrollers, and what interface modes are supported?

Yes, the AD7631BSTZ supports 3.3 V logic levels via its OVDD supply pin (2.7 V to 5.5 V range) and SPI-/QSPI-/MICROWIRE-/DSP-compatible serial interface. It also offers parallel modes (18-/16-/8-bit) with configurable data format (straight binary or two's complement via OB/2C pin). The AD7631BSTZ maintains full functionality-including all input ranges and timing specs-at OVDD = 3.3 V, enabling direct interfacing with modern low-voltage MCUs and FPGAs.

What are the power supply requirements for the AD7631BSTZ, and how does power consumption scale with throughput?

The AD7631BSTZ requires five supplies: AVDD/DVDD = 4.75–5.25 V (analog/digital core), OVDD = 2.7–5.5 V (I/O interface), and VCC/VEE = +7–15 V / −15–0 V (high-voltage analog front-end). Power dissipation scales linearly with throughput: 73 mW at 250 kSPS (internal ref disabled), 10 mW at 1 kSPS, and only 10 μW in power-down mode (PD = high). This scalability allows dynamic power management in battery-operated or thermally constrained DAQ systems using the AD7631BSTZ.

AD7631BSTZ Specifications

Product attributes: Attribute value

Manufacturer:: Analog Devices Inc.

Series:: PulSAR®

Package/Case:: 48-LQFP

Packaging:: Tray

Product Status:: Active

Number of Bits:: 18

Sampling Rate (Per Second):: 250k

Number of Inputs:: 1

Input Type:: Differential

Data Interface:: SPI, Parallel, DSP

Configuration:: S/H-ADC

Ratio - S/H:ADC:: 1:1

Number of A/D Converters:: 1

Architecture:: SAR

Reference Type:: External, Internal

Voltage - Supply, Analog:: 5V

Voltage - Supply, Digital:: 5V

Features:: -

Operating Temperature:: -40°C ~ 85°C

Supplier Device Package:: 48-LQFP (7x7)

Mounting Type:: Surface Mount

Grade:: -

Qualification:: -

AD7631BSTZ FAQ

1.How can I place an order for AD7631BSTZ through Aetrix?

Please submit a Request for Quotation (RFQ) for AD7631BSTZ on Aetrix. Our sales agent will provide a competitive quotation and guide you through the order confirmation once you accept the terms.

2.Are the price and stock information for AD7631BSTZ reliable?

The price and inventory of AD7631BSTZ are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for AD7631BSTZ is usually 5 days.

3.What payment methods are accepted for AD7631BSTZ?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for AD7631BSTZ transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for AD7631BSTZ?

AD7631BSTZ orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your AD7631BSTZ order is processed, you will receive an email with the shipment details and tracking number.

Note: Tracking information may take up to 24 hours to appear. Express delivery typically takes 3–5 business days.

5.How can I obtain technical support or documentation for AD7631BSTZ?

For technical support, including AD7631BSTZ datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your AD7631BSTZ requirements.

6.How does Aetrix verify that AD7631BSTZ is sourced from the original manufacturer or authorized distributors?

All AD7631BSTZ products on Aetrix are procured from qualified distributors and authorized channels. Our dedicated quality assurance team conducts strict verification, including traceability checks and, if necessary, third-party testing. This ensures that AD7631BSTZ meets industry standards.

7.What is the process for return or replacement of AD7631BSTZ?

All AD7631BSTZ units undergo pre-shipment inspection (PSI). If there is an issue with AD7631BSTZ, returns or replacements are accepted under the following conditions:

1.Quantity discrepancies, incorrect items, or visible external defects (such as breakage or corrosion), acknowledged by Aetrix.

2.The issue is reported within 90 days of delivery.

3.The AD7631BSTZ part is unused and in its original packaging.

Return procedure for AD7631BSTZ:

1.Submit a request within 90 days.

2.Obtain a Return Material Authorization (RMA) from Aetrix.

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