Analog Devices Inc. ADM8692AN

Overview

ADM8692AN from Analog Devices is a microprocessor supervisory circuit providing power-on reset, battery backup switchover, watchdog timer, and power-fail detection in a single 8-lead PDIP package. It asserts RESET down to 1 V VCC, delivers up to 100 mA from VOUT, features 4.65 V reset threshold with 40 mV hysteresis, and supports 1.6 sec watchdog timeout - used in industrial controllers and embedded systems requiring reliable power sequencing and brownout protection.

For engineers reviewing the ADM8692AN datasheet, ADM8692AN pinout, ADM8692AN application, or ADM8692AN equivalent, key selection criteria include guaranteed reset assertion at 1 V VCC, 0.7 Ω internal PMOS switch on VOUT, 400 nA standby current, 3 ns CE gating (on ADM8691/ADM8695 variants), and compatibility with 5 V ±5% supplies - all critical for fail-safe microcontroller boot and memory retention design.

Technical Context

The ADM8692AN implements a precision voltage monitor with 4.65 V reset threshold and 40 mV hysteresis, ensuring stable reset deassertion during supply recovery. Its internal PMOS battery switchover switch operates with 0.7 Ω on-resistance in normal mode and 7 Ω in backup mode, enabling 100 mA VOUT drive while maintaining <100 mV dropout under load.

It integrates a fixed 1.6 sec watchdog timer with transition-sensitive WDI input and guarantees RESET output functionality down to 1 V VCC - a key differentiator from standard reset ICs. The device uses an epitaxial CMOS process to achieve 0.7 mW typical power consumption and 400 nA battery standby current, supporting long-term RAM backup in power-loss scenarios.

Key Specifications

Pinout & Package

ADM8692AN is housed in an 8-lead plastic dual in-line package (PDIP) with 0.3 inch body width and standard 0.1 inch pin pitch. Pin 1 is VBATT (backup battery input), Pin 2 is VOUT (switched output), Pin 3 is VCC (main supply input), Pin 4 is GND, Pin 5 is PFI (power-fail input), Pin 6 is PFO (power-fail output), Pin 7 is WDI (watchdog input), and Pin 8 is RESET (active-low reset output).

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX690CPA+ and TPS3823-46DBVR, ADM8692AN uniquely integrates battery switchover, power-fail warning, and watchdog timer in one 8-pin PDIP - reducing system component count by three discrete ICs while enabling robust data retention during extended outages.

Availability

ADM8692AN is available at Aetrix Electronics and suitable for industrial PLC controllers, automotive body control modules, medical infusion pumps, and point-of-sale terminals requiring stable component supply and long-term lifecycle support.

Supply support for ADM8692AN 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 ADM869x family was designed specifically for microprocessor system supervision - integrating reset generation, battery backup, watchdog timing, and power-fail detection into compact packages to simplify power management in resource-constrained embedded systems.

FAQ

What is the minimum VCC voltage at which ADM8692AN guarantees RESET assertion?

ADM8692AN guarantees RESET assertion down to 1 V VCC, ensuring the microprocessor remains held in reset during deep brownout conditions. This capability is confirmed in the datasheet's "RESET Output Voltage at VCC = 1 V" specification (20 mV max sink voltage at 10 μA load). Unlike many supervisory ICs that cease functioning below 2.5 V, ADM8692AN maintains full reset functionality through final stages of power collapse - a critical feature for fail-safe embedded systems.

Does ADM8692AN support adjustable watchdog timeout periods?

No, ADM8692AN does not support adjustable watchdog timeout periods. Its watchdog timer is fixed at 1.6 seconds, as stated in the Product Highlights and Table 1 of the datasheet. Adjustable watchdog and reset timing are exclusive to the 16-lead ADM8691 and ADM8695 variants, which offer 100 ms/1.6 sec selection via OSC IN pin or external capacitor. ADM8692AN - like ADM8690 - provides only the fixed 1.6 sec timeout and 50 ms reset pulse width.

Can ADM8692AN drive CMOS RAM directly without external components?

Yes, ADM8692AN can drive CMOS RAM directly via its VOUT pin, which delivers up to 100 mA with ≤0.2 V dropout at full load. The internal 0.7 Ω PMOS switch eliminates need for external pass transistors in most applications. For peak current demands exceeding 100 mA, a 0.1 μF bypass capacitor on VOUT is recommended to supply transient currents. ADM8692AN's VOUT is electrically identical to ADM8690's output, and both are validated for direct RAM powering in the datasheet's "Battery Switchover Section" and Figure 5.

What is the function of the PFI and PFO pins on ADM8692AN?

The PFI (Pin 5) is a 1.3 V precision comparator input used to monitor auxiliary supplies or battery voltage; when PFI falls below 1.3 V, the PFO (Pin 6) output goes low to signal impending power loss. This allows early warning and controlled shutdown before VCC collapses. PFO is an open-drain output capable of sinking 3.2 mA, and the comparator is disabled when VCC drops below VBATT - preventing false triggers during battery switchover. These functions are fully implemented in ADM8692AN per Figures 1 and 3, and Table 4 of the datasheet.

Is ADM8692AN pin-compatible with ADM690 or MAX690?

ADM8692AN is functionally compatible but not pin-compatible with ADM690 or MAX690. While all three provide 4.65 V reset supervision, ADM8692AN adds integrated battery switchover (VBATT/VOUT), power-fail detection (PFI/PFO), and watchdog timer (WDI/RESET) - requiring additional pins not present on the 8-pin ADM690/MAX690. ADM8692AN uses Pin 1 for VBATT and Pin 5–6 for PFI/PFO, whereas ADM690 dedicates those positions to GND and VCC. Direct replacement would require PCB redesign to accommodate the expanded functionality.