Analog Devices Inc. ADM693AARW-REEL

Overview

ADM693AARW-REEL 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 fixed reset timeout (adjustable), 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 requiring reliable brownout protection and nonvolatile memory retention.

For engineers reviewing the ADM693AARW-REEL datasheet, ADM693AARW-REEL pinout, ADM693AARW-REEL application, or ADM693AARW-REEL equivalent, key selection criteria include its dual-supply switchover capability (VCC/VBATT), open-drain RESET and complementary active-high RESET outputs, low 100 µA standby current, and integrated CEIN/CEOUT write-protection logic for CMOS RAM.

Technical Context

The ADM693AARW-REEL implements a precision voltage detector with 4.4 V threshold and 15 mV hysteresis, paired with an internal oscillator that sets both reset delay (200 ms typ) and watchdog timeout (1.6 s default, 100 ms selectable). Its battery switchover uses PMOS (VCC→VOUT, R_ON = 0.75 Ω) and NMOS (VBATT→VOUT, R_ON = 7 Ω) switches, enabling seamless transition at VCC < VBATT – 0.03 V.

It integrates three independent functional blocks: (1) a power-fail comparator with 1.25 V reference and 25 µs PFI→PFO delay; (2) a three-level WDI input supporting watchdog disable via floating; and (3) CE gating with 6 ns propagation delay and 40–150 Ω ON-resistance, asserting CEOUT high during reset regardless of CEIN state.

Key Specifications

Pinout & Package

ADM693AARW-REEL is housed in a 16-pin wide-body SOIC (R-16W) package, 7.5 mm × 10.3 mm, with standard 1.27 mm pitch. Pin 1 is VBATT; pin 16 is RESET (open-drain); all digital outputs are CMOS-compatible with rail-to-rail swing.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX693AESA+ and TPS3823MPW, ADM693AARW-REEL uniquely integrates battery switchover, watchdog, CE gating, and dual RESET outputs in one SOIC-16 package - reducing system-level component count and eliminating timing skew between functions.

Availability

ADM693AARW-REEL is available at Aetrix Electronics and suitable for industrial PLCs, automotive body control modules, medical infusion pumps, and smart energy meters requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for ADM693AARW-REEL 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 robust microprocessor supervision in harsh environments - combining reset, watchdog, battery backup, and memory protection in a single IC to eliminate discrete solutions and improve system reliability.

FAQ

What is the reset threshold voltage of the ADM693AARW-REEL?

The ADM693AARW-REEL has a guaranteed reset threshold of 4.25 V minimum and 4.50 V maximum, with a typical value of 4.40 V ±3%. This makes it compatible with +5 V supplies operating over a ±10% tolerance range. The threshold is internally trimmed and stable over temperature (±15 mV hysteresis ensures clean release).

Does the ADM693AARW-REEL support adjustable watchdog timeout periods?

Yes, the ADM693AARW-REEL supports multiple watchdog timeout configurations. With OSC SEL floating and OSC IN grounded, it delivers a 100 ms short timeout. With both pins floating, it defaults to 1.6 s. Connecting OSC SEL to GND enables external timing via capacitor (T_wd = 600 × C/47 pF) or clock (T_wd = 1024/f_CLK).

How does the ADM693AARW-REEL handle battery backup switchover?

The ADM693AARW-REEL automatically switches VOUT from VCC to VBATT when VCC falls below VBATT – 0.03 V (power-up) or VBATT + 0.03 V (power-down), with 60 mV hysteresis. In battery mode, VOUT tracks VBATT with ≤0.15 V dropout at 5 mA, and supply current drops to 0.04 µA typical - enabling multi-year operation on coin cells.

Can the ADM693AARW-REEL drive CMOS RAM write-enable signals directly?

Yes, the ADM693AARW-REEL provides dedicated CEIN and CEOUT pins for RAM write protection. CEOUT follows CEIN with 6 ns delay when VCC is valid, but forces high during reset or brownout - preventing invalid writes to battery-backed CMOS RAM. CEOUT can source/sink 1 µA and drives standard TTL/CMOS inputs directly.

What is the function of the PFI and PFO pins on the ADM693AARW-REEL?

PFI is the noninverting input of a 1.25 V comparator used for early power-fail detection; connecting it to a resistor divider on the main supply allows triggering PFO low before VCC reaches the 4.4 V reset threshold. PFO is an open-drain output that asserts low within 25 µs of PFI falling below 1.25 V - typically used to trigger µP NMI for last-chance data save.