Analog Devices Inc. ADM690AARN-REEL

Overview

ADM690AARN-REEL from Analog Devices is a precision microprocessor supervisory circuit in SO-8 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 ADM690AARN-REEL datasheet, ADM690AARN-REEL pinout, ADM690AARN-REEL application, or ADM690AARN-REEL equivalent, key selection criteria include 4.65 V reset threshold tolerance (±150 mV), 200 ms reset timeout, battery switchover hysteresis (40 mV), and compatibility with +5 V systems operating from –40°C to +85°C.

Technical Context

The ADM690AARN-REEL integrates four core functions on a single die: a precision voltage monitor with 4.65 V reset threshold, a transition-detecting watchdog timer with 1.6 s timeout and 50 ns minimum WDI pulse width, an automatic battery switchover circuit with 20 mV switchover threshold and 40 mV hysteresis, and a 1.25 V reference-based power-fail comparator with PFI/PFO interface.

Its internal architecture uses an epitaxial CMOS process enabling operation down to 1 V VCC while maintaining RESET assertion, and features a low-dropout PMOS switch (<1 Ω typical R_ON) for VOUT switching between VCC and VBATT. The RESET output guarantees logic-low state at 0.3 V (100 µA sink) even at VCC = 1 V.

Key Specifications

Pinout & Package

ADM690AARN-REEL is housed in an 8-lead SOIC (SO-8) package measuring 4.90 mm × 3.90 mm × 1.75 mm, with standard 1.27 mm pitch and gull-wing leads. Pin 1 marked by notch or dot; device oriented with marking side up and pin 1 at top-left corner.

Key Features

Applications

Equivalent & Alternatives

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

Compared with ADM690AARN-REEL, MAX690AESA+ offers identical supervision functionality but higher supply current and less precise PFI support, while TPS3808G18DBVR trades battery and power-fail features for wider voltage range and programmable timing - neither matches the integrated +5 V supervisory + backup + fail-warning capability of the ADM690AARN-REEL.

Availability

ADM690AARN-REEL is available at Aetrix Electronics and suitable for industrial PLC controllers, medical diagnostic instruments, telecom remote terminal units, automotive infotainment head units, and embedded computing modules requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for ADM690AARN-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 semiconductor leader specializing in high-performance analog, mixed-signal, and digital signal processing technologies for precision measurement and control systems.

The ADM690AARN-REEL belongs to Analog Devices' microprocessor supervisory circuits product line, engineered to deliver integrated power monitoring, reset generation, watchdog supervision, and battery backup management for industrial and embedded systems operating from –40°C to +85°C.

FAQ

What is the reset voltage threshold specification for ADM690AARN-REEL?

The ADM690AARN-REEL has a nominal reset voltage threshold of 4.65 V, with guaranteed minimum and maximum values of 4.5 V and 4.75 V respectively over the full –40°C to +85°C temperature range. This threshold applies specifically to the ADM690A variant and distinguishes it from the 4.4 V threshold of the ADM692A series. The ADM690AARN-REEL maintains this specification in its SO-8 package configuration.

Does ADM690AARN-REEL support battery backup switchover, and what are the key parameters?

Yes, ADM690AARN-REEL supports automatic battery backup switchover between VCC and VBATT. Key parameters include a 20 mV switchover threshold (power-up and power-down), 40 mV hysteresis to prevent chatter, and <0.05 µA typical battery standby current. During switchover, VOUT connects to VBATT, and the internal PMOS switch exhibits <1 Ω typical on-resistance - enabling direct drive of CMOS RAM without external FETs. The ADM690AARN-REEL implements this function without requiring external control signals.

How does the watchdog timer in ADM690AARN-REEL operate, and what is its timeout period?

The ADM690AARN-REEL watchdog timer monitors transitions on the WDI pin and resets the system if no edge (rising or falling) occurs within 1.6 seconds (nominal; 1.0–2.25 s range). It features 50 ns minimum pulse width detection and three-level input logic (high/low/floating), where floating WDI disables the timer. Unlike edge-only timers, the ADM690AARN-REEL's transition detector tolerates software timing jitter and allows flexible GPIO assignment - making it suitable for diverse microcontroller architectures.

Can ADM690AARN-REEL be used with power supplies other than +5 V?

Yes, ADM690AARN-REEL supports VCC operation from 4.75 V to 5.5 V, and its PFI input accepts external voltage monitoring via a resistor divider referenced to the internal 1.25 V precision reference. This allows detection of power failure on any supply rail - including unregulated inputs or preregulator stages - by scaling the monitored voltage to fall below 1.25 V at the desired trip point. The ADM690AARN-REEL itself does not regulate input voltage but provides accurate threshold comparison independent of VCC.

What is the operating temperature range and package type of ADM690AARN-REEL?

The ADM690AARN-REEL is rated for industrial operation from –40°C to +85°C and is supplied in an 8-lead SOIC (SO-8) package with standard 1.27 mm lead pitch and JEDEC MS-012AC dimensions (4.90 mm × 3.90 mm × 1.75 mm). This package is RoHS-compliant, tape-and-reel packaged (REEL suffix), and pin-compatible with legacy DIP and SOIC-based supervisory ICs - enabling drop-in replacement in existing designs without layout modification.