Analog Devices Inc. ADM693AARN

Overview

ADM693AARN from Analog Devices is a microprocessor supervisory circuit providing precision 4.4 V ±3% reset threshold, 200 ms or adjustable reset timeout, 100 ms/1.6 s watchdog timer, automatic battery backup switchover (VBATT to VOUT), and chip-enable gating - all in a 16-pin narrow SOIC package. It ensures reliable power-up/down/brownout reset, RAM write protection, and early power-fail warning in embedded controllers and industrial systems.

For engineers reviewing the ADM693AARN datasheet, ADM693AARN pinout, ADM693AARN application, or ADM693AARN equivalent, this device delivers verified voltage monitoring, battery-backed memory integrity, watchdog supervision, and CE signal control - with confirmed operation down to VCC = 1 V and battery standby current as low as 0.04 µA.

Technical Context

The ADM693AARN integrates a precision 4.4 V voltage detector with 15 mV hysteresis, an internal oscillator supporting fixed (100 ms / 1.6 s) or capacitor-adjustable watchdog timing, and dual-mode reset generation (200 ms internal or external clock/capacitor programmable). Its battery switchover uses PMOS (VCC→VOUT, R_ON = 0.8–1.2 Ω) and NMOS (VBATT→VOUT, R_ON = 12–25 Ω) switches with 60 mV hysteresis and <1 µA battery standby current.

It features active-low open-drain RESET and complementary active-high RESET outputs, a dedicated BATT ON logic output for external PNP base drive, and a 1.25 V power-fail comparator (PFI/PFO) with 25 µs response. CEIN-to-CEOUT propagation delay is 6–10 ns, and WDI accepts three-level input (floating disables watchdog).

Key Specifications

Pinout & Package

ADM693AARN is housed in a 16-pin narrow SOIC (R-16N) package with 1.27 mm pitch, JEDEC MS-012AC compliant, and 10.3 mm × 5.3 mm footprint.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX693AESA+ and TPS3823-44DBVR, ADM693AARN uniquely integrates battery switchover, watchdog timer, and CE gating in one SOIC package - reducing BOM count by ≥3 discrete ICs while enabling robust, self-contained µP supervision in memory-critical applications.

Availability

ADM693AARN is available at Aetrix Electronics and suitable for industrial PLC controllers, automotive telematics modules, medical patient monitors, and point-of-sale terminals requiring stable component supply, long-term lifecycle support, and guaranteed industrial temperature performance.

Supply support for ADM693AARN 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 ADM69x family was designed specifically for microprocessor system supervision - integrating reset, watchdog, battery backup, and memory protection in a single IC to eliminate design complexity and improve reliability in mission-critical embedded applications.

FAQ

What is the exact reset voltage threshold and tolerance for ADM693AARN?

The ADM693AARN has a guaranteed reset voltage threshold of 4.40 V with ±3% tolerance (4.25 V to 4.50 V), specified over –40°C to +85°C. This matches +5 V ±10% power supplies and is distinct from the 4.65 V threshold of the ADM691A variant. The threshold is internally trimmed and does not require external calibration.

Does ADM693AARN support adjustable watchdog timeout, and how is it configured?

Yes, ADM693AARN supports adjustable watchdog timeout via the OSC SEL and OSC IN pins. With OSC SEL grounded, connecting a capacitor (C) from OSC IN to GND yields a timeout of 600 × (C/47 pF) ms. Alternatively, applying an external clock to OSC IN gives T_wd = 1024 / f_CLK. The default is 1.6 s (OSC SEL floating, OSC IN floating).

How does ADM693AARN handle battery backup switching, and what is its minimum operating voltage?

ADM693AARN automatically switches VOUT between VCC and VBATT based on relative voltage and reset threshold status. It operates with VCC as low as 1 V - ensuring RESET remains asserted during deep brownouts. In battery backup mode, it draws only 0.04 µA from VBATT and maintains VOUT regulation down to VBATT = 2.0 V at 5 mA load.

Can ADM693AARN protect CMOS RAM during power transitions, and how?

Yes, ADM693AARN protects CMOS RAM using hardware-enforced CE gating. When VCC falls below 4.4 V, CEOUT is forced high regardless of CEIN state - preventing write operations to RAM. This occurs with 12 µs propagation delay and requires no firmware intervention, ensuring data integrity during power-up, brownout, or shutdown.

What is the function of the PFI and PFO pins on ADM693AARN, and what voltage threshold do they use?

The PFI (Power Fail Input) and PFO (Power Fail Output) provide early warning of impending power loss. PFI compares an external voltage (e.g., from a resistor divider) against an internal 1.25 V reference. When PFI drops below 1.25 V, PFO goes low within 25 µs - enabling the µP to save critical data before VCC crosses the 4.4 V reset threshold.