Analog Devices Inc. ADM8690ANZ

Overview

ADM8690ANZ from Analog Devices is an 8-lead SOIC microprocessor supervisory circuit providing power-on/brownout reset, battery backup switchover, watchdog timer (fixed 1.6 sec), and 1.3 V power-fail detection. It asserts RESET down to VCC = 1 V, delivers up to 100 mA at VOUT with 0.7 Ω on-resistance, and consumes only 0.7 mW typical. Used in embedded controllers and industrial instrumentation requiring reliable power monitoring.

For engineers reviewing the ADM8690ANZ datasheet, ADM8690ANZ pinout, ADM8690ANZ application, or ADM8690ANZ equivalent, key selection criteria include its 4.65 V reset threshold, 50 ms reset pulse width, battery switchover hysteresis of 20 mV, 3 ns CE gating (not applicable to ADM8690), and TSSOP-compatible 8-lead SOIC package - all confirmed for ADM8690ANZ per Rev. C datasheet.

Technical Context

The ADM8690ANZ integrates a precision 4.65 V reset comparator with 40 mV hysteresis and guarantees RESET assertion down to 1 V VCC. Its internal 1.6 sec watchdog timer monitors WDI transitions and triggers a 50 ms active-low RESET pulse upon timeout.

Battery switchover uses dual-threshold detection (50 mV drop, 70 mV rise) between VCC and VBATT to control a low-dropout PMOS switch (0.7 Ω normal, 7 Ω backup), enabling seamless CMOS RAM backup without external components. The PFI/PFO comparator provides 1.3 V ±50 mV threshold detection for early power-fail warning.

Key Specifications

Pinout & Package

ADM8690ANZ is housed in an 8-lead SOIC_N package (body width 3.9 mm, lead pitch 1.27 mm), RoHS-compliant and rated for −40°C to +85°C operation.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX690CPE+ and TPS3808G33DBVR, ADM8690ANZ uniquely combines 5 V-compatible reset supervision, integrated battery switchover, and power-fail warning in a single 8-pin SOIC - eliminating discrete support components required by alternatives.

Availability

ADM8690ANZ is available at Aetrix Electronics and suitable for industrial PLC controllers, automotive body control modules, medical infusion pumps, and point-of-sale terminals requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for ADM8690ANZ 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 DSP ICs, serving industrial, automotive, communications, and healthcare markets with precision signal processing solutions.

The ADM8690ANZ belongs to Analog Devices' microprocessor supervisory product line, engineered specifically for robust power monitoring and fail-safe reset generation in 5 V microcontroller-based systems operating under harsh voltage transient conditions.

FAQ

What is the guaranteed minimum VCC level at which ADM8690ANZ asserts RESET?

The ADM8690ANZ guarantees RESET assertion down to VCC = 1 V, ensuring the microprocessor remains held in reset during deep brownout conditions. This capability is explicitly specified in the Rev. C datasheet Absolute Maximum Ratings and General Description sections. The ADM8690ANZ maintains functional RESET output even as VCC collapses, making it suitable for applications with severe supply instability. This 1 V specification applies exclusively to the ADM8690ANZ and is a key differentiator from many competing supervisors.

Does ADM8690ANZ support adjustable watchdog timeout periods?

No, ADM8690ANZ features a fixed 1.6 second watchdog timeout period. Unlike the ADM8691/ADM8695 variants, the ADM8690ANZ does not provide OSC SEL or OSC IN pins for configuring short (100 ms) or adjustable timeouts. Its watchdog timer is hardwired to 1.6 sec and restarts automatically after each RESET event. This fixed timing simplifies design validation and eliminates configuration errors in safety-critical deployments where predictable watchdog behavior is essential.

Can ADM8690ANZ drive CMOS RAM directly without external components?

Yes, ADM8690ANZ can drive CMOS RAM directly: its VOUT pin delivers up to 100 mA with ≤0.2 V dropout at full load, enabled by an internal 0.7 Ω PMOS switch. The datasheet confirms this capability in the Battery Switchover Section and Key Specifications table. No external pass transistor, diode, or charge pump is needed for standard SRAM backup. For peak current demands exceeding 100 mA, a bypass capacitor ≥0.1 μF is recommended at VOUT - but the ADM8690ANZ itself provides complete, self-contained RAM power management.

What is the function of the PFI and PFO pins on ADM8690ANZ?

The PFI (Pin 5) is the non-inverting input to a precision 1.3 V comparator; when voltage at PFI falls below 1.3 V, the PFO (Pin 6) output goes low. PFO is an active-low, open-drain signal used to trigger microprocessor interrupts for early power-fail response - e.g., saving volatile data before supply collapse. This function is fully implemented in ADM8690ANZ and distinct from the RESET output, providing two independent fault detection channels. PFI must be tied to GND or VOUT if unused.

Is ADM8690ANZ pin-compatible with the ADM690 series?

Yes, ADM8690ANZ is a direct functional and pin-compatible upgrade for the ADM690A/ADM690L, offering identical 8-pin SOIC/N PDIP pinout, 4.65 V reset threshold, 50 ms reset pulse, and 1.6 sec watchdog. The Rev. C datasheet explicitly states "Upgrade for the ADM690, ADM691, ADM695" in FEATURES. All signal names (VCC, GND, RESET, WDI, PFI, PFO, VOUT, VBATT) match pin-for-pin, enabling drop-in replacement without PCB modification - provided the target application does not require ADM690-specific timing tolerances outside ADM8690ANZ's specified range.