Analog Devices Inc. ADM693AANZ

Overview

ADM693AANZ from Analog Devices is a microprocessor supervisory circuit integrating power-on reset, battery backup switchover, watchdog timer, chip enable gating, and power-fail detection. It features a 4.4 V ±3% reset threshold, 200 ms or adjustable reset timeout, 1.6 s/100 ms selectable watchdog timeout, and supports VCC down to 1 V operation. It is used in industrial controllers and automotive ECUs for reliable power monitoring and data retention during brownouts.

For engineers reviewing the ADM693AANZ datasheet, ADM693AANZ pinout, ADM693AANZ application, or ADM693AANZ equivalent, key selection criteria include its 4.4 V reset threshold compatibility with ±10% 5 V supplies, battery switchover hysteresis of 60 mV, 0.75 Ω VCC-to-VOUT on-resistance at 25 mA, and dual RESET/RESET outputs for active-low and active-high processor interfaces.

Technical Context

The ADM693AANZ implements a precision bandgap-based voltage detector for reset generation, with internal hysteresis (15 mV) and guaranteed operation down to VCC = 1 V. Its battery switchover uses complementary PMOS/NMOS switches: a low-R_ON (0.75 Ω typ) PMOS for main supply and a 7 Ω NMOS for backup mode, enabling seamless transition without external components.

Watchdog timing is configurable via OSC SEL and OSC IN: internal oscillator (1.6 s or 100 ms), external capacitor (adjustable 600×C/47 pF), or external clock (1024/f_CLK). The CE gating circuit provides 5 ns propagation delay and forces CEOUT high during reset, ensuring RAM write protection independent of CEIN state.

Key Specifications

Pinout & Package

ADM693AANZ is packaged in a 16-pin narrow-body SOIC (R-16N) with 0.3 inch width and standard JEDEC MS-012 footprint. Pin 1 is VBATT; pin 16 is RESET (open-drain). All pins are electrically defined per Analog Devices ADM691A/ADM693A/ADM800L/M Rev. 0 datasheet.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX693AESA+ and TPS3823MPW, ADM693AANZ uniquely integrates battery switchover, CE gating, and dual watchdog modes in a single 16-pin SOIC - reducing BOM count and PCB area while enabling robust data retention in brownout-prone embedded systems.

Availability

ADM693AANZ is available at Aetrix Electronics and suitable for industrial PLC controllers, automotive body control modules, medical infusion pumps, and telecom remote terminal units requiring stable component supply and long-term lifecycle support.

Supply support for ADM693AANZ 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 - combining reset, watchdog, battery backup, and memory protection in one IC to simplify power integrity design in resource-constrained embedded applications.

FAQ

What is the reset voltage threshold of the ADM693AANZ?

The ADM693AANZ has a guaranteed reset voltage threshold of 4.25 V (minimum) to 4.50 V (maximum), with a typical value of 4.40 V ±3%. This threshold is optimized for compatibility with 5 V ±10% power supplies. The device asserts RESET low when VCC falls below this threshold and holds it low for at least 200 ms after VCC rises above the threshold. The ADM693AANZ datasheet specifies this behavior across the full –40°C to +85°C operating temperature range.

How does the ADM693AANZ handle battery backup switchover?

The ADM693AANZ automatically switches VOUT between VCC and VBATT based on relative voltage levels and reset status. When VCC exceeds VBATT + 0.03 V and remains above the 4.4 V reset threshold, VCC is routed to VOUT. When VCC drops below VBATT – 0.03 V and falls below 4.4 V, VBATT is connected to VOUT via a 7 Ω NMOS switch. Switchover hysteresis is 60 mV to prevent oscillation. In battery mode, supply current drops to 0.04 µA typical, enabling multi-year backup with coin cells.

Can the watchdog timeout period of the ADM693AANZ be adjusted?

Yes, the ADM693AANZ supports three watchdog timeout configurations: fixed 100 ms (OSC IN grounded), fixed 1.6 s (OSC IN and OSC SEL floating), or adjustable via external capacitor or clock. With an external capacitor C on OSC IN to GND, timeout = 600 × (C/47 pF) ms. With an external clock f_CLK, timeout = 1024/f_CLK. The first timeout after any reset is always 1.6 s to allow firmware initialization, regardless of configuration.

What is the function of the CEIN and CEOUT pins on the ADM693AANZ?

CEIN accepts the microprocessor's chip enable signal, and CEOUT delivers a gated version to RAM or peripheral devices. As long as VCC remains above the 4.4 V reset threshold, CEOUT replicates CEIN with 5 ns propagation delay. If VCC drops below threshold, CEOUT is forced high - blocking write operations to protect SRAM/EEPROM contents during power faults. This integrated gating eliminates need for external logic or pull-up resistors in memory protection circuits.

Does the ADM693AANZ support power-fail warning functionality?

Yes, the ADM693AANZ includes a dedicated power-fail comparator with 1.25 V internal reference. The PFI pin accepts a scaled-down version of the system supply (e.g., via resistor divider from unregulated input), and PFO asserts low when PFI falls below 1.25 V. This provides early warning - typically 10–100 ms before VCC reaches the 4.4 V reset threshold - allowing the microprocessor to execute safe shutdown routines and save critical data to nonvolatile memory.