Analog Devices Inc. AD7621ASTZ

Overview

AD7621ASTZ from Analog Devices is a 16-bit, 3 MSPS, fully differential SAR analog-to-digital converter with ±2 LSB INL, 2.048 V internal reference, and dual-mode serial/parallel interface. It operates from a single 2.5 V supply and delivers 89 dB SINAD at 100 kHz - optimized for high-speed data acquisition in medical instrumentation and spectrum analysis systems.

For engineers reviewing the AD7621ASTZ datasheet, AD7621ASTZ pinout, AD7621ASTZ application, or AD7621ASTZ equivalent, this page provides verified technical context, mode-specific timing behavior, real-world interface configuration options (SPI/QSPI/MICROWIRE-compatible), and validated alternative ADCs for throughput- and linearity-critical signal chain designs.

Technical Context

The AD7621ASTZ implements a charge redistribution SAR architecture with no pipeline delay, enabling deterministic latency and true real-time sampling. Its three selectable conversion modes - wideband warp (3 MSPS), normal (2 MSPS), and impulse (1.25 MSPS) - directly scale power dissipation (65–86 mW) while maintaining ±2 LSB INL and 16-bit no-missing-codes performance across all modes.

It integrates a 2.048 V internal reference with ±7 ppm/°C drift, configurable reference buffer (REFBUFIN/REF), and dual-domain power supplies (AVDD/DVDD/OVDD) supporting mixed-voltage interfacing. The device supports both parallel (16-/8-bit bus) and serial (master/slave) readout, with BUSY-driven timing synchronization and RD/CS-controlled data latching.

Key Specifications

Pinout & Package

AD7621ASTZ is packaged in a 48-lead LFCSP (7 mm × 7 mm, 0.5 mm pitch) with exposed thermal pad. Pin functions are validated per Analog Devices Rev. A datasheet Figure 4 and Table 6.

Key Features

Applications

Equivalent & Alternatives

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

Compared with AD7621ASTZ, AD7622BCPZ trades 0.5 MSPS for tighter ±1.5 LSB INL and identical packaging, while AD7626BCPZ sacrifices reference integration and linearity to achieve 10 MSPS - making AD7621ASTZ the optimal balance of speed, on-chip reference, and 16-bit integrity for mid-range high-fidelity acquisition.

Availability

AD7621ASTZ is available at Aetrix Electronics and suitable for medical instruments, high-speed data acquisition systems, and digital signal processing platforms requiring stable component supply, long-term lifecycle assurance, and traceable sourcing.

Supply support for AD7621ASTZ 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.

The AD7621ASTZ belongs to Analog Devices' PulSAR® family of precision SAR ADCs, engineered for applications demanding high speed, low latency, and exceptional DC/AC accuracy without pipeline architecture compromises.

FAQ

What is the maximum sampling rate of the AD7621ASTZ and under what conditions is it achieved?

The AD7621ASTZ achieves a maximum throughput of 3 MSPS in wideband warp mode, confirmed in the Rev. A datasheet Table 2. This rate requires WARP = high and IMPULSE = high, with AVDD = DVDD = 2.5 V and proper decoupling. At this rate, the device maintains ±2 LSB INL and 89 dB SINAD at 100 kHz, and power dissipation is typically 65 mW with the internal reference enabled.

Does the AD7621ASTZ include an internal voltage reference, and what are its key specifications?

Yes, the AD7621ASTZ integrates a 2.048 V internal reference with ±7 ppm/°C temperature drift over −40°C to +85°C, as specified in Table 2 and Product Highlights. When PDREF and PDBUF are low, REF outputs 2.048 V ±10 mV at 25°C, and REFBUFIN provides a buffered 1.2 V bandgap output for external reference conditioning.

How does the AD7621ASTZ handle interface selection between serial and parallel modes?

The AD7621ASTZ uses the SER/PAR pin to select interface mode: low enables 16-bit (or 8-bit with BYTESWAP) parallel output on D[15:0], while high configures pins D2–D11 for serial functions (SCLK, SDOUT, SYNC, etc.). This hardware-selectable dual interface allows flexible integration with FPGAs, microcontrollers, or ASICs without redesigning PCB layout.

What are the supported operating temperature ranges for the AD7621ASTZ?

The AD7621ASTZ is specified for operation from −40°C to +85°C ambient temperature, as stated in Table 2 and General Description. All key AC/DC performance parameters - including INL, SINAD, and throughput - are guaranteed across this range. Extended temperature versions are not listed in the Rev. A datasheet and require factory consultation.

Can the AD7621ASTZ operate with an external reference, and how is it configured?

Yes, the AD7621ASTZ supports external references via the REF pin. To enable external reference mode, set PDREF = high and PDBUF = high, then apply 1.8 V to AVDD to REF. The device draws up to 250 μA from the reference source at 3 MSPS. External reference operation disables the internal 2.048 V reference and requires external decoupling per the Voltage Reference Input section.