Analog Devices Inc. ADM697ARZ-REEL

Overview

ADM697ARZ-REEL from Analog Devices is a microprocessor supervisory circuit with integrated chip-enable gating, watchdog timer, low-line voltage monitor, power-fail detection, and reset generation. It operates from 3.0 V to 5.5 V VCC, asserts RESET down to 1 V, provides 5 ns CE propagation delay, and supports adjustable watchdog timeout (100 ms or 1.6 s). It is used in embedded controllers and intelligent instruments requiring reliable power sequencing and memory write protection.

For engineers reviewing the ADM697ARZ-REEL datasheet, ADM697ARZ-REEL pinout, ADM697ARZ-REEL application, or ADM697ARZ-REEL equivalent, key selection criteria include CEIN/CEOUT timing integrity under brownout, LLIN threshold accuracy (1.3 V ±50 mV), PFI comparator hysteresis, battery backup compatibility (VBATT = 2.0 V to VCC–0.3 V), and industrial temperature operation (–40°C to +85°C).

Technical Context

The ADM697ARZ-REEL implements dual-reset logic (active-low RESET and active-high RESET) with 50 ms minimum pulse width, triggered by either LLIN falling below 1.3 V or unserviced watchdog timeout. Its CE gating path uses internal CMOS logic with 5 ns propagation delay and forces CEOUT high during low-line conditions to prevent RAM writes.

Watchdog operation supports three modes: internal oscillator (100 ms/1.6 s), external clock (4032/960 cycles), or external capacitor timing. The WDI input is a three-level interface biased at 38% of VCC with ~125 kΩ impedance, and watchdog disable is achieved by floating WDI or driving it to midsupply - not by logic level assertion.

Key Specifications

Pinout & Package

ADM697ARZ-REEL is housed in a 16-lead SOIC (R-16) package with 1.27 mm pitch, RoHS-compliant, and moisture sensitivity level 3.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX697CPE+ and TPS3808G33DBVR, ADM697ARZ-REEL uniquely integrates CE gating with sub-5 ns delay, dual reset outputs, and coordinated low-line/watchdog/PFI response - making it irreplaceable in designs requiring hardware-enforced memory integrity during power anomaly.

Availability

ADM697ARZ-REEL is available at Aetrix Electronics and suitable for industrial controllers, automotive infotainment modules, medical diagnostic instruments, and network edge routers requiring stable component supply across extended lifecycle programs.

Supply support for ADM697ARZ-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.

The ADM697ARZ-REEL belongs to the ADM696/ADM697 family of microprocessor supervisory circuits, designed specifically to consolidate power monitoring, reset generation, watchdog supervision, and hardware memory write protection into a single IC for space-constrained embedded systems.

FAQ

What is the function of the TEST pin on the ADM697ARZ-REEL?

The TEST pin (Pin 1) is a factory test node used during wafer sort and final test. It has no user-accessible function in normal operation and must be connected to GND per the datasheet. Leaving it floating may cause undefined behavior or increased susceptibility to noise. ADM697ARZ-REEL functionality is fully operational only when TEST is grounded.

Can the ADM697ARZ-REEL generate a reset pulse shorter than 50 ms?

No - the ADM697ARZ-REEL guarantees a minimum RESET pulse width of 50 ms after LLIN rises above 1.3 V, and this duration is fixed by internal timing architecture. External capacitor or clock adjustments affect watchdog timeout and reset delay only when OSC SEL is low; they do not reduce the 50 ms minimum assertion time. ADM697ARZ-REEL's reset timing is designed for robust microprocessor stabilization.

How does the ADM697ARZ-REEL handle CEIN when LLIN falls below 1.3 V?

When LLIN drops below 1.3 V, the ADM697ARZ-REEL forces CEOUT high regardless of CEIN state - effectively disabling memory writes. CEIN is internally disconnected from its pullup and becomes inactive; its voltage does not affect supply current as long as it remains between GND and VOUT. This hardware-enforced behavior ensures ADM697ARZ-REEL blocks SRAM/EEPROM writes even if firmware fails.

Is the ADM697ARZ-REEL compatible with 3.3 V-only systems without a 5 V rail?

Yes - ADM697ARZ-REEL operates over VCC = 3.0 V to 5.5 V, and all specifications (including LLIN = 1.30 V ±50 mV, PFI threshold, and CEOUT drive strength) are validated at 3.3 V. The 1.3 V reference is ratiometrically stable, and CEOUT delivers full rail voltage (3.3 V) with 800 µA source capability - sufficient to drive standard 3.3 V CMOS inputs. ADM697ARZ-REEL is fully functional in 3.3 V-only designs.

What happens to WDI input behavior during battery backup mode in the ADM697ARZ-REEL?

In battery backup mode (VCC = 0 V), the WDI input is internally disconnected from its bias network and draws no current as long as its voltage stays between GND and VOUT. ADM697ARZ-REEL ignores WDI transitions entirely during backup - the watchdog timer is disabled, and WDO remains high. This prevents spurious resets while the system runs from backup power, preserving ADM697ARZ-REEL's role as a passive supervisor during extended outages.