Analog Devices Inc. ADM692AAN

Overview

ADM692AAN from Analog Devices is a precision microprocessor supervisory circuit in 8-pin PDIP package, providing active-low reset at 4.40 V threshold, 200 ms reset timeout, 1.6 s watchdog timer, and automatic battery switchover for CMOS RAM backup. It operates down to 1 V VCC and supports power-fail detection via 1.25 V comparator input (PFI), used in industrial controllers and embedded systems requiring reliable power monitoring.

For engineers reviewing the ADM692AAN datasheet, ADM692AAN pinout, ADM692AAN application, or ADM692AAN equivalent, key selection criteria include its 4.4 V reset threshold (vs. 4.65 V of ADM690A), battery switchover hysteresis (±20 mV), PFO/PFI interface for early power-fail warning, and compatibility with +5 V systems operating from –40°C to +85°C.

Technical Context

The ADM692AAN integrates four core functions: a precision voltage monitor with 4.40 V ±0.15 V reset threshold, a 1.6 s watchdog timer triggered by WDI transitions, a 1.25 V reference-based power-fail comparator (PFI/PFO), and bidirectional battery switchover logic that connects VBATT to VOUT when VCC drops below VBATT by 20 mV.

Its internal PMOS switch delivers <1 Ω on-resistance in normal mode and supports up to 100 mA load on VOUT; in battery backup mode, it draws only 0.05 µA typical standby current while maintaining VOUT regulation within 2 mV of VBATT at 250 µA load.

Key Specifications

Pinout & Package

ADM692AAN uses an 8-pin plastic DIP (N-8) package with 0.300-inch width, 0.100-inch lead pitch, and through-hole mounting. Pin 1 is marked by notch or dot; leads are tin-lead plated for solderability.

Key Features

Applications

Equivalent & Alternatives

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

Compared with ADM690AAN and MAX692A, the ADM692AAN provides the widest VCC brownout coverage (down to 4.25 V min threshold) and lowest battery backup current, making it optimal for energy-constrained or wide-input-range industrial systems where reset timing and power efficiency are co-critical.

Availability

ADM692AAN is available at Aetrix Electronics and suitable for industrial PLC controllers, embedded data loggers, medical diagnostic instruments, and point-of-sale terminals requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for ADM692AAN 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 ADM692AAN belongs to Analog Devices' microprocessor supervisory circuit product line, designed specifically to replace discrete reset generators and manual battery switchover circuits in space- and power-constrained embedded systems.

FAQ

What is the exact reset voltage threshold for ADM692AAN?

The ADM692AAN has a nominal reset voltage threshold of 4.40 V, with guaranteed minimum and maximum values of 4.25 V and 4.50 V respectively over the full –40°C to +85°C temperature range. This threshold is factory-trimmed and specified under VCC falling conditions, ensuring consistent brownout detection across operating conditions.

Does ADM692AAN support battery backup for CMOS RAM, and how does switchover work?

Yes, ADM692AAN supports automatic battery backup for CMOS RAM via its VBATT and VOUT pins. When VCC falls below VBATT by 20 mV, the internal PMOS switch connects VBATT to VOUT; on power-up, VOUT reconnects to VCC once VCC rises 20 mV above VBATT. This hysteresis prevents chatter and ensures seamless RAM retention without external components.

Can ADM692AAN operate with VCC below 4.5 V, and what happens to RESET functionality?

Yes, ADM692AAN guarantees RESET assertion functionality down to VCC = 1 V, meaning the RESET output remains valid and actively drives low even during severe brownout. However, the device requires VCC ≥ 4.5 V for normal operation per datasheet specifications; operation below this is limited to reset-hold functionality only.

How is the power-fail detection implemented on ADM692AAN, and what is the PFI input reference?

The ADM692AAN implements power-fail detection using an internal 1.25 V precision reference connected to the inverting input of a comparator; the non-inverting input is exposed as the PFI pin. When voltage at PFI drops below 1.25 V, the open-drain PFO output pulls low, enabling early warning of supply decay via external resistor divider networks.

Is ADM692AAN pin-compatible with other members of the ADM690A/ADM692A family?

Yes, ADM692AAN is fully pin-compatible with ADM690AAN, ADM802MAN, and ADM805MAN in the same N-8 package. All share identical pin assignments, electrical characteristics (except reset threshold and RESET polarity), and functional block diagram - enabling direct substitution where 4.40 V reset threshold is required.