Analog Devices Inc. ADM690AARNZ-REEL

Overview

ADM690AARNZ-REEL from Analog Devices is a precision microprocessor supervisory circuit in an 8-pin microSOIC package, providing active-low reset (RESET), watchdog timer (1.6 s timeout), battery switchover, and power-fail detection (1.25 V threshold). It asserts reset down to 1 V VCC and supports CMOS RAM backup with <0.05 µA battery standby current. Used in embedded controllers requiring reliable power-up sequencing and brownout protection.

For engineers reviewing the ADM690AARNZ-REEL datasheet, ADM690AARNZ-REEL pinout, ADM690AARNZ-REEL application, or ADM690AARNZ-REEL equivalent, key selection criteria include reset threshold accuracy (4.65 V ±150 mV), guaranteed operation at VCC = 1 V, microSOIC footprint compatibility, and integrated battery switchover with <20 mV switchover hysteresis.

Technical Context

The ADM690AARNZ-REEL integrates four core functions on a single die: a precision voltage monitor with 4.65 V reset threshold, a 1.6 s watchdog timer triggered by WDI transitions, automatic battery switchover with PMOS switch (typical R_ON < 1 Ω), and a 1.25 V reference-based power-fail comparator (PFI/PFO). All functions operate across –40°C to +85°C.

Its RESET output remains functional down to VCC = 1 V, ensuring deterministic microprocessor hold during deep brownout. The watchdog timer resets on any WDI transition (high-to-low or low-to-high) and disables when WDI is floating - no external pull-up required. Battery switchover activates when VCC falls 20 mV below VBATT, with 40 mV hysteresis to prevent chatter.

Key Specifications

Pinout & Package

ADM690AARNZ-REEL is housed in an 8-lead microSOIC (RM-8) package measuring 3.10 mm × 3.05 mm × 0.80 mm, optimized for space-constrained industrial and portable designs.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar microprocessor supervisory applications.

Compared with MAX690AASA+, ADM690AARNZ-REEL delivers tighter reset threshold accuracy, lower battery drain, and guaranteed sub-1.5 V operation - critical for fail-safe industrial control. Versus TPS3808G33DBVR, it offers full 5 V system supervision with integrated battery management and power-fail signaling, eliminating four external components.

Availability

ADM690AARNZ-REEL is available at Aetrix Electronics and suitable for industrial PLCs, medical diagnostic instruments, telecom remote terminals, smart energy meters, and embedded controllers requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for ADM690AARNZ-REEL 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, serving industrial, automotive, communications, and healthcare markets since 1965.

The ADM690AARNZ-REEL belongs to Analog Devices' microprocessor supervisory IC product line, engineered specifically for deterministic power monitoring, battery-backed memory retention, and watchdog safety in mission-critical embedded systems.

FAQ

What is the exact reset voltage threshold for ADM690AARNZ-REEL?

The ADM690AARNZ-REEL has a nominal reset voltage threshold of 4.65 V, with guaranteed minimum and maximum values of 4.50 V and 4.75 V respectively over the full –40°C to +85°C operating range. This threshold is factory-trimmed and applies specifically to the ADM690A variant, distinguishing it from the 4.40 V threshold of the ADM692A series.

Does ADM690AARNZ-REEL support battery switchover, and what is its switchover behavior?

Yes, ADM690AARNZ-REEL supports automatic battery switchover. When VCC falls below VBATT by 20 mV, the internal PMOS switch connects VBATT to VOUT. Switchover hysteresis is 40 mV, preventing oscillation during slow VCC decay. In battery backup mode, VOUT tracks VBATT with <5 mV dropout at 250 µA load, and battery standby current is as low as 0.05 µA.

Can ADM690AARNZ-REEL operate with VCC below 2.0 V, and what happens to RESET?

Yes, ADM690AARNZ-REEL guarantees RESET assertion down to VCC = 1.0 V. As VCC declines, RESET remains low until VCC rises above 4.65 V, then stays low for a guaranteed 200 ms timeout. Even at VCC = 1.1 V, RESET can source 4 µA while maintaining logic-high level ≥0.8 V - ensuring robust microprocessor hold during deep brownout.

How is the watchdog timer enabled or disabled on ADM690AARNZ-REEL?

The watchdog timer on ADM690AARNZ-REEL is enabled by applying regular transitions (high-to-low or low-to-high) to the WDI pin within 1.6 s intervals. It is disabled by leaving WDI floating or connecting it to a high-impedance (three-state) output - no pull-up or pull-down resistor is required. No register programming or external components are needed for enable/disable control.

What package type is used for ADM690AARNZ-REEL, and how does it compare to other variants?

ADM690AARNZ-REEL uses the 8-lead microSOIC (RM-8) package, measuring 3.10 mm × 3.05 mm. It shares identical pinout with the SO-8 (ADM690AARN) and PDIP (ADM690AAN) variants but reduces board area by ~50%. The "Z" suffix indicates lead-free and RoHS-compliant construction, and "REEL" denotes tape-and-reel packaging for automated assembly.