Analog Devices Inc. AD7683ARMZ

Overview

AD7683ARMZ from Analog Devices is a 16-bit, pseudo-differential, successive-approximation analog-to-digital converter (ADC) with 100 kSPS throughput, ±1 LSB typical INL, SPI-compatible serial interface, and single-supply operation from 2.7 V to 5.5 V. It delivers no missing codes (B grade), 150 µW power at 10 kSPS/2.7 V, and operates across −40°C to +85°C - ideal for portable instrumentation and low-power data acquisition.

For engineers reviewing the AD7683ARMZ datasheet, AD7683ARMZ pinout, AD7683ARMZ application, or AD7683ARMZ equivalent, key selection considerations include its MSOP/QFN-8 package compatibility, external reference flexibility (0.5 V to VDD), track-and-hold architecture with zero pipeline latency, and verified performance in battery-powered medical sensors and industrial process monitoring.

Technical Context

The AD7683ARMZ implements a charge redistribution SAR architecture with integrated track-and-hold, enabling true 16-bit accuracy without missing codes and eliminating pipeline delay. Its conversion is initiated on the CS falling edge, sampling the differential voltage between +IN and –IN referenced to GND.

It uses an internal conversion clock synchronized to DCLOCK, supports 16-bit straight-binary output over SPI/QSPI/MICROWIRE, and scales power linearly with throughput - drawing only 560 µA at 2.7 V/100 kSPS and dropping to 1 nA standby current.

Key Specifications

Pinout & Package

AD7683ARMZ is available in an 8-lead MSOP (3 mm × 3 mm) or 8-lead QFN (LFCSP) package, both with identical pinout and exposed pad (connected to GND). The MSOP variant is designated by the "ARMZ" suffix per Analog Devices' ordering guide.

Key Features

Applications

Equivalent & Alternatives

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

Compared with AD7683ARMZ, AD7685BRMZ provides higher throughput and better linearity at increased power, while ADS8325IP requires more complex supply and driver design - making AD7683ARMZ the optimal balance of precision, integration, and ultra-low power for new portable and battery-operated systems.

Availability

AD7683ARMZ is available at Aetrix Electronics and suitable for battery-powered equipment, medical instruments, and industrial process control requiring stable component supply, long-lifecycle assurance, and RoHS-compliant packaging.

Supply support for AD7683ARMZ 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 AD7683ARMZ belongs to Analog Devices' PulSAR® family of precision SAR ADCs, designed specifically for low-power, high-accuracy data acquisition in portable, medical, and industrial instrumentation where size, energy efficiency, and DC precision are critical.

FAQ

What is the maximum recommended reference voltage for AD7683ARMZ?

The AD7683ARMZ supports an external reference voltage (REF) from 0.5 V up to VDD. When VDD = 5.5 V, REF may be as high as 5.5 V; however, the datasheet specifies optimal performance with REF ≤ VDD and recommends decoupling with a 2.2–10 µF ceramic capacitor. For best INL and SNR, REF should be stable, low-noise, and sourced from a low-impedance buffer such as the AD8605 or ADR435. The AD7683ARMZ does not regulate or clamp REF - exceeding VDD risks damage per absolute maximum ratings.

Does AD7683ARMZ require an external driver amplifier?

The AD7683ARMZ can be driven directly by low-impedance sources (<100 Ω), but a driver amplifier is recommended for high-impedance sensors (e.g., thermocouples, piezoresistive bridges) to maintain THD and SNR. The internal 600 Ω R_IN/30 pF C_IN network forms a 1-pole filter that limits bandwidth and increases settling time. For 16-bit accuracy, the driver must settle to 0.0015% (16-bit level) within the 400 ns acquisition window - a stricter requirement than typical 0.1% op-amp specs. Recommended drivers include ADA4841-1 (low noise) and AD8605 (single-supply).

Is AD7683ARMZ pin-compatible with ADS8320 or ADS8325?

No - AD7683ARMZ is not pin-compatible with ADS8320 or ADS8325. While the datasheet states AD7683ARMZ is an "improved second source" to those TI parts, it uses an 8-lead MSOP/QFN package with REF/+IN/–IN/GND/CS/DOUT/DCLOCK/VDD pinout, whereas ADS8325IP uses a 16-pin SOIC with different pin assignments (e.g., separate AVDD/DVDD, /RD, /WR, BUSY). Signal mapping, power architecture, and timing protocols differ significantly; PCB redesign is required for substitution.

What is the meaning of "pseudo-differential" input in AD7683ARMZ?

"Pseudo-differential" means AD7683ARMZ measures the voltage difference between +IN and –IN, but –IN is not a true differential input with equal drive strength or common-mode rejection like a fully differential ADC. Instead, –IN serves as a dedicated ground-sense node - typically tied to local analog ground or a remote sensor ground - allowing rejection of ground potential differences. The input range is defined as (+IN − –IN) = 0 V to VREF. This architecture simplifies sensor interfacing while retaining some common-mode noise immunity, unlike single-ended inputs, but does not support true bipolar or fully symmetrical differential signaling.

How does power consumption scale with throughput in AD7683ARMZ?

AD7683ARMZ power scales linearly with throughput due to automatic power-down between conversions. At 100 kSPS and VDD = 2.7 V, operating current is 560 µA (1.5 mW); at 10 kSPS, it drops to ~56 µA (150 µW); at 1 kSPS, ~5.6 µA (~15 µW). Standby current remains 1 nA regardless of rate. This behavior is confirmed in Figure 25 of the datasheet and enables adaptive power management - e.g., a microcontroller can dynamically adjust sampling rate to extend battery life without changing hardware. No external power gating is needed.