Analog Devices Inc. ADM692AN

Overview

ADM692AN from Analog Devices is an 8-pin DIP microprocessor supervisory circuit providing power-on reset, battery backup switchover, watchdog timer (1.6 s nominal), 4.4 V reset threshold, and power-fail warning for +5 V systems. It asserts RESET down to VCC = 1 V, delivers up to 100 mA at VOUT, and supports automatic VBATT/VCC switching with 70 mV turn-on hysteresis - used in industrial controllers requiring reliable brownout recovery and nonvolatile memory retention.

For engineers reviewing the ADM692AN datasheet, ADM692AN pinout, ADM692AN application, or ADM692AN equivalent, key selection considerations include its fixed 4.4 V reset threshold (±5% tolerance compatible with ±10% 5 V supplies), 50 ms reset pulse width, battery switchover behavior in backup mode, and absence of CE gating or adjustable timeout features found only in 16-pin variants.

Technical Context

The ADM692AN integrates a precision voltage detector (4.4 V threshold, 40 mV hysteresis), a fixed-period watchdog timer (1.6 s timeout, triggered by WDI transitions), and a low-dropout PMOS/NMOS battery switchover circuit that connects VOUT to VBATT when VCC falls below VBATT − 50 mV. Its RESET output remains functional down to 1 V VCC and drives CMOS loads directly without external pull-up.

It lacks CEIN/CEOUT, OSC SEL, OSC IN, RESET (active-high), and BATT ON pins - distinguishing it from 16-pin ADM693/ADM695 variants. The device operates across −40°C to +85°C, draws ≤1.95 mA under full load, and consumes only 0.6 µA in battery-backup mode with VCC = 0 V.

Key Specifications

Pinout & Package

ADM692AN uses an 8-pin plastic DIP (N-8) package with 0.3-inch width and through-hole mounting. Pin functions are validated per Analog Devices ADM690–ADM695 Rev. A datasheet, Figure –5 (top view).

Key Features

Applications

Equivalent & Alternatives

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

Compared with ADM692AN, MAX692CPD+ offers configurable watchdog but higher reset threshold and no guaranteed 1 V operation; TPS3823-44DBVR reduces footprint and cost but removes all supervisory functions beyond reset, requiring discrete implementation of battery control and power-fail warning.

Availability

ADM692AN is available at Aetrix Electronics and suitable for industrial PLC controllers, automotive body control modules, medical handheld diagnostics, and point-of-sale terminals requiring stable component supply with long-term lifecycle support.

Supply support for ADM692AN 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 company specializing in high-performance analog, mixed-signal, and digital signal processing technologies for precision measurement and control.

The ADM690–ADM695 family was designed specifically for microprocessor system supervision - integrating reset, battery switchover, watchdog, and power-fail detection in single-chip solutions for industrial, automotive, and computing applications.

FAQ

What is the guaranteed reset voltage threshold range for ADM692AN?

The ADM692AN has a guaranteed reset voltage threshold of 4.25 V to 4.48 V at +25°C, with typical value 4.4 V. This range ensures compatibility with 5 V ±10% power supplies. The device maintains RESET assertion down to VCC = 1 V, guaranteeing controlled shutdown during severe brownout. All specifications are validated per Analog Devices ADM690–ADM695 Rev. A datasheet, page –2.

Does ADM692AN support adjustable watchdog timeout or reset pulse width?

No, ADM692AN does not support adjustable watchdog timeout or reset pulse width. It provides fixed 1.6 s watchdog timeout and fixed 50 ms reset pulse width. Adjustable functionality requires 16-pin variants (ADM693AN or ADM695AN) with OSC SEL and OSC IN pins. ADM692AN's 8-pin N-8 package omits these pins entirely, as confirmed in the pin configuration diagram (Rev. A, page –5).

What is the maximum continuous output current ADM692AN can deliver at VOUT?

ADM692AN delivers up to 100 mA continuously at VOUT with a maximum VCC–VOUT drop of 0.5 V. At 100 mA load, VOUT = VCC − 0.25 V (typical). For higher currents or lower dropout, an external PNP transistor driven by BATT ON is required - though ADM692AN lacks BATT ON (available only on 16-pin variants). This limitation is explicitly stated in the Product Selection Guide (Rev. A, page –5).

How does ADM692AN handle battery backup switchover hysteresis?

ADM692AN switches VOUT from VCC to VBATT when VCC falls to VBATT − 50 mV (power-down), and back to VCC when VCC rises to VBATT + 70 mV (power-up), yielding 20 mV hysteresis. This prevents chattering during slow VCC transitions near VBATT. The switchover MOSFET exhibits ~20 Ω on-resistance in backup mode, resulting in <50 mV drop at 250 µA - verified in Table I and Circuit Information (Rev. A, pages –2, –5).

Can ADM692AN be used with a 3.3 V microprocessor system?

No, ADM692AN is not suitable for 3.3 V systems. Its reset threshold is fixed at 4.4 V (min 4.25 V), and VCC operating range is 4.5 V to 5.5 V. Applying 3.3 V to VCC will prevent proper reset assertion and may violate absolute maximum ratings. For 3.3 V supervision, consider Analog Devices ADM809/ADM810 series or TI TPS3808G12, which are specified for lower supply voltages.