Analog Devices Inc. ADM692AARNZ

Overview

ADM692AARNZ from Analog Devices is a precision microprocessor supervisory circuit providing reset generation, watchdog timer, battery switchover, and power-fail detection in a single 8-lead SOIC package. It asserts active-low RESET at 4.40 V threshold with 200 ms timeout, monitors VCC down to 1 V, delivers up to 100 mA on VOUT, and supports automatic VBATT backup switching for CMOS RAM retention during main supply failure.

For engineers reviewing the ADM692AARNZ datasheet, ADM692AARNZ pinout, ADM692AARNZ application, or ADM692AARNZ equivalent, key selection criteria include its 4.40 V reset threshold, 1.6 s watchdog timeout, 1.25 V PFI reference, battery switchover hysteresis of 40 mV, and guaranteed operation from –40°C to +85°C in industrial environments.

Technical Context

The ADM692AARNZ integrates four core functions: a precision voltage monitor with 4.40 V reset threshold (±0.15 V tolerance), a 1.6 s watchdog timer triggered by WDI transitions, a battery switchover circuit with 20 mV power-down threshold and 40 mV hysteresis, and a 1.25 V reference-based power-fail comparator accepting external PFI input.

Its internal PMOS switch connects VCC to VOUT during normal operation (R_ON < 1 Ω) and seamlessly transfers to VBATT when VCC drops below VBATT − 20 mV; RESET remains functional down to VCC = 1 V, ensuring reliable microprocessor hold during brownout.

Key Specifications

Pinout & Package

ADM692AARNZ 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 is marked by a notch or dot; device orientation follows JEDEC MS-012.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX692AESA+, ADM692AARNZ offers superior reset accuracy, lower supply current, and guaranteed 1 V operation; versus TPS3808G12DBVR, it delivers full supervisory integration-eliminating board space, BOM count, and qualification effort for multi-function designs.

Availability

ADM692AARNZ is available at Aetrix Electronics and suitable for industrial PLC control units, embedded medical data loggers, network router management modules, and automotive infotainment head units requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for ADM692AARNZ 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 ADM692AARNZ belongs to Analog Devices' microprocessor supervisory circuits product line, designed to consolidate power monitoring, reset generation, battery backup, and watchdog functions into compact, industrial-grade ICs for mission-critical embedded systems.

FAQ

What is the exact reset voltage threshold for ADM692AARNZ and how tightly is it specified?

The ADM692AARNZ has a nominal reset voltage threshold of 4.40 V, with a guaranteed range of 4.25 V minimum to 4.50 V maximum over the full –40°C to +85°C operating temperature range. This specification is explicitly defined in the Absolute Maximum Ratings and Electrical Characteristics tables of the official Analog Devices datasheet Rev. 0, confirming its suitability for 5 V systems requiring precise brownout detection.

Does ADM692AARNZ support operation with VCC below 2 V, and what happens to RESET at low VCC?

Yes, ADM692AARNZ guarantees RESET assertion and functionality down to VCC = 1.0 V. As VCC falls below the 4.40 V threshold, RESET goes low and remains low until VCC rises above the threshold plus hysteresis; critically, the output stage continues driving low even at 1 V, ensuring the microprocessor stays held in reset during deep undervoltage events.

How does the battery switchover function work in ADM692AARNZ, and what is the switchover hysteresis?

The ADM692AARNZ switches VOUT from VCC to VBATT when VCC drops below VBATT by 20 mV (power-down threshold), and switches back to VCC when VCC rises above VBATT by 20 mV (power-up threshold), resulting in 40 mV total hysteresis. This prevents oscillation during slow VCC transitions and is implemented via internal PMOS switches with sub-1 Ω on-resistance.

Can the watchdog timer in ADM692AARNZ be disabled, and if so, how?

Yes, the watchdog timer in ADM692AARNZ can be fully disabled by leaving the WDI pin unconnected (floating) or connecting it to a high-impedance tri-state output. The datasheet confirms that floating WDI deactivates the watchdog function, eliminating risk of spurious reset during firmware updates or diagnostic modes without requiring external pull resistors.

What is the role of the PFI and PFO pins in ADM692AARNZ, and what reference voltage do they use?

The PFI pin accepts an external voltage for power-fail monitoring, compared internally against a precision 1.25 V reference; when PFI falls below this threshold, the open-drain PFO pin pulls low to signal impending supply collapse. This 1.25 V reference is trimmed and stable over temperature, enabling accurate early-warning detection using simple resistor dividers on any input rail.