Analog Devices Inc. ADM697SQ

Overview

ADM697SQ from Analog Devices is a high-reliability microprocessor supervisory circuit with integrated chip-enable gating, watchdog timer, low-line detection, and power-fail monitoring. 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 –55°C to +125°C extended temperature operation in a 16-lead CERDIP (Q-16) package. It is used in aerospace-grade avionics controllers requiring deterministic reset timing and RAM write protection during brownout.

For engineers reviewing the ADM697SQ datasheet, ADM697SQ pinout, ADM697SQ application, or ADM697SQ equivalent, this page delivers verified functional identity, validated pin roles, confirmed timing parameters (50 ms reset timeout, 100 ms/1.6 s watchdog), real-world CEIN-to-CEOUT gating behavior, and temperature-hardened performance data - all specific to the ADM697SQ variant.

Technical Context

The ADM697SQ implements dual-reset generation: one triggered by LLIN falling below 1.3 V (with 12 mV hysteresis), and another via watchdog timeout (100 ms short or 1.6 s long period, selectable via OSC SEL/OSC IN). Its CE gating path uses internal CMOS logic with 5 ns typical propagation delay and forces CEOUT high when LLIN < 1.3 V - ensuring write-protection of battery-backed RAM independent of CEIN state.

It features separate active-low RESET and active-high RESET outputs, a dedicated WDO status flag, and PFO/PFI comparator circuitry referenced to a stable 1.3 V bandgap. All timing functions derive from either an internal 10.24 kHz oscillator or an external clock/capacitor, with reset assertion guaranteed down to VCC = 1 V and battery backup mode entering at VCC < VBATT – 0.2 V.

Key Specifications

Pinout & Package

ADM697SQ is housed in a hermetically sealed 16-lead CERDIP (Q-16) package rated for extended temperature operation (–55°C to +125°C) and high reliability in harsh environments.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX697CPE+ and TPS3823MPWPT, ADM697SQ uniquely combines extended temperature operation, deterministic 5 ns CE gating, and dual-comparator (LLIN + PFI) supervision - making it irreplaceable in safety-critical, write-protected, and thermally demanding deployments.

Availability

ADM697SQ is available at Aetrix Electronics and suitable for avionics power monitoring, spacecraft onboard controllers, automotive engine control units, ruggedized industrial PLCs, and defense electronics requiring stable component supply across extended temperature ranges and long lifecycle support.

Supply support for ADM697SQ 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 precision instrumentation, industrial automation, aerospace, and communications markets.

The ADM697SQ belongs to the ADM696/ADM697 family of microprocessor supervisory circuits, designed specifically for fault-tolerant power monitoring and memory protection in mission-critical embedded systems operating under extreme environmental stress.

FAQ

What is the guaranteed minimum VCC voltage at which ADM697SQ asserts RESET?

The ADM697SQ guarantees RESET assertion down to 1 V VCC, as confirmed in the Absolute Maximum Ratings and Functional Specifications sections of the official Analog Devices datasheet. This ensures the microprocessor remains held in reset during deep brownout conditions where other supervisors would release prematurely. The ADM697SQ maintains this behavior across its full –55°C to +125°C operating range, making it suitable for applications where supply collapse must trigger fail-safe shutdown without exception.

Does ADM697SQ provide both active-low and active-high RESET outputs?

Yes, ADM697SQ provides two complementary reset outputs: RESET (Pin 15, active-low) and RESET (Pin 16, active-high). Both are asserted simultaneously when LLIN falls below 1.3 V or when the watchdog timer times out. The active-high RESET output eliminates the need for external inverters when interfacing with processors that require high-true reset signaling, and both outputs remain functional down to VCC = 1 V. This dual-output architecture is explicitly documented in the Pin Function Description and Typical Applications sections.

How does the CE gating function of ADM697SQ protect memory during low-voltage events?

The ADM697SQ's CE gating forces CEOUT (Pin 12) high whenever LLIN drops below 1.3 V - regardless of CEIN (Pin 13) state - thereby blocking write access to battery-backed RAM or EEPROM. This hardware-enforced write protection activates within nanoseconds of voltage sag detection and requires no firmware intervention. With a 5 ns propagation delay and guaranteed operation down to 1 V VCC, the ADM697SQ ensures memory integrity even during rapid transients that would corrupt data in software-managed schemes.

What are the valid watchdog timeout periods supported by ADM697SQ?

The ADM697SQ supports three watchdog timeout configurations: 100 ms (short period), 1.6 s (long period), or user-adjustable via external capacitor on OSC IN (Pin 7). Selection is controlled by OSC SEL (Pin 8): floating/high selects internal oscillator modes; low enables external timing. Immediately after reset, the watchdog defaults to 1.6 s to allow safe system initialization, then switches to the configured short period upon first WDI transition. These values are measured and specified across temperature in the ADM696/ADM697 datasheet Rev. 0.

Is ADM697SQ pin-compatible with ADM696SQ?

No, ADM697SQ is not pin-compatible with ADM696SQ. While both share the same Q-16 package footprint, their pin assignments differ significantly: ADM696SQ uses Pin 1 for VBATT and Pin 5 for BATT ON, whereas ADM697SQ assigns Pin 1 to TEST and Pin 5 to GND. Additionally, ADM697SQ replaces BATT ON with CEIN (Pin 13) and CEOUT (Pin 12), and relocates RESET/RESET outputs. These differences are unambiguous in the Pin Configurations and Pin Function Description diagrams of the official datasheet.