Analog Devices Inc. AD7665ASTZ

Overview

AD7665ASTZ from Analog Devices is a 16-bit, 570 kSPS charge redistribution SAR analog-to-digital converter operating from a single 5 V supply. It delivers ±2.5 LSB INL, 90 dB SNR at 180 kHz, and supports bipolar (±10 V, ±5 V) and unipolar (0–10 V) input ranges. Its dual serial/parallel interface and hardware-calibrated accuracy make it suitable for high-fidelity data acquisition in spectrum analyzers and medical instrumentation.

For engineers reviewing the AD7665ASTZ datasheet, AD7665ASTZ pinout, AD7665ASTZ application, or AD7665ASTZ equivalent, key selection factors include Warp/Normal/Impulse mode throughput trade-offs, 48-lead LQFP package compatibility, reference voltage flexibility (2.3–2.5 V), and absence of pipeline delay in real-time control loops.

Technical Context

The AD7665ASTZ implements a charge redistribution SAR architecture with an integrated resistor-based input scaler enabling programmable analog input ranges. Its conversion core uses a 16-bit capacitive DAC array and precision comparator with aperture jitter of 5 ps rms.

Three operational modes-Warp (570 kSPS), Normal (500 kSPS), and Impulse (444 kSPS)-dynamically scale power consumption: 64 mW typical in Warp mode, dropping to 15 µW at 100 SPS. The device features both parallel (8/16-bit) and SPI/QSPI/MICROWIRE-compatible serial interfaces, with OVDD supporting 2.7–5.25 V logic levels.

Key Specifications

Pinout & Package

AD7665ASTZ is housed in a 48-lead LQFP (Lead Quad Flatpack) package with exposed paddle thermally connected to AGND. Pin 1 identifier located at top-left corner; all ground pins (AGND, DGND, OGND, REFGND, INGND) must be individually routed to low-impedance ground planes per layout guidelines.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar 16-bit SAR ADC applications.

Compared with AD7664ASTZ, the AD7665ASTZ provides 14% higher throughput and 0.5 LSB better INL at identical package and interface compatibility; versus AD7671ASTZ, it trades 2 bits of resolution for >5× speed and 30% lower power-making it optimal for speed-critical 16-bit applications.

Availability

AD7665ASTZ is available at Aetrix Electronics and suitable for data acquisition, spectrum analysis, and medical instrumentation requiring stable component supply, long-term lifecycle support, and traceable sourcing from authorized channels.

Supply support for AD7665ASTZ 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 is a global leader in high-performance analog, mixed-signal, and digital signal processing semiconductors, headquartered in Norwood, MA.

The AD7665ASTZ belongs to the PulSAR® family of precision SAR ADCs designed for applications demanding high speed, low power, and exceptional DC/AC accuracy without pipeline latency.

FAQ

What are the supported analog input voltage ranges for the AD7665ASTZ?

The AD7665ASTZ supports bipolar input ranges of ±10 V, ±5 V, and ±2.5 V, and unipolar ranges of 0–10 V, 0–5 V, and 0–2.5 V. These are configured using the external resistor network connected to pins IND, INC, INB, and INA per Table I in the datasheet. The AD7665ASTZ scales all inputs to a 0–2.5 V internal range before conversion, ensuring consistent performance across ranges.

Does the AD7665ASTZ require an external reference voltage?

Yes, the AD7665ASTZ requires an external precision reference voltage applied to the REF pin. The specified range is 2.3 V to 2.5 V, with typical operation at 2.5 V. Reference current draw is 114 µA at 570 kSPS. Using a low-noise, low-drift reference such as the ADR431 ensures the AD7665ASTZ achieves its guaranteed 90 dB SNR and ±2.5 LSB INL performance.

How does the Warp Mode affect timing and accuracy of the AD7665ASTZ?

In Warp Mode (WARP = HIGH, IMPULSE = LOW), the AD7665ASTZ achieves 570 kSPS throughput with a 1.75 µs conversion cycle. However, full accuracy specifications-including ±2.5 LSB INL and 90 dB SNR-are only guaranteed when a minimum conversion rate is maintained. If conversions are spaced too far apart, thermal settling effects may degrade performance. The AD7665ASTZ datasheet specifies timing constraints to ensure compliance.

Can the AD7665ASTZ interface directly with a 3 V microcontroller?

Yes, the AD7665ASTZ supports 3 V logic interfacing via its OVDD supply pin (2.7–5.25 V), which powers all digital outputs including D[15:0], BUSY, and RD. When OVDD = 3 V, output VOH is ≥2.4 V and VOL is ≤0.4 V-compatible with standard 3 V CMOS inputs. The SER/PAR and OB/2C pins also accept 3 V–compatible logic levels, enabling seamless integration with 3 V host processors without level shifters.

What is the significance of the BYTESWAP pin on the AD7665ASTZ?

BYTESWAP on the AD7665ASTZ controls the byte ordering of the 16-bit parallel output on D[15:0]. When BYTESWAP = LOW, D[7:0] carries the LSB byte and D[15:8] the MSB byte; when HIGH, the assignment is reversed. This feature allows the AD7665ASTZ to match native endianness expectations of different microcontrollers (e.g., ARM vs. legacy x86), eliminating software byte-swapping overhead and reducing firmware complexity.