Analog Devices Inc. ADM9690ARN

Overview

ADM9690ARN from Analog Devices is a precision power supply and watchdog timer monitoring circuit designed for 5 V microprocessor systems. It features a 4.31 V voltage monitor with 30 mV hysteresis, dual independent reset outputs (RESET(1) = 50 ms, RESET(2) = 60 ms), and selectable watchdog timeout periods (0.75 ms to 25 ms via SEL1/SEL2). It operates down to 2 V VCC and is used in embedded controllers requiring reliable power-up sequencing and stall detection.

For engineers reviewing the ADM9690ARN datasheet, ADM9690ARN pinout, ADM9690ARN application, or ADM9690ARN equivalent, key selection considerations include its dual-reset timing asymmetry, industrial-temperature SOIC-8 packaging, watchdog disable capability via floating WDI, and guaranteed 4.3 V–4.5 V reset threshold range across –40°C to +85°C.

Technical Context

The ADM9690ARN integrates two independent monitoring functions: a precision voltage comparator on VMON with fixed 4.31 V threshold and 30 mV hysteresis, and a transition-triggered watchdog timer with four discrete timeout options (0.75/1.5/12.5/25 ms) selected by SEL1 and SEL2 logic inputs. Both functions drive two synchronized but time-differentiated active-low reset outputs.

RESET(1) asserts for exactly 50 ms after VMON recovers or WDI timeout; RESET(2) extends that assertion by 10 ms, enabling staged system initialization. The watchdog restarts only after RESET(1) goes high-ensuring reset completion before re-enabling monitoring-and accepts either edge on WDI, supporting both software-toggled and hardware-generated strobes.

Key Specifications

Pinout & Package

The ADM9690ARN is housed in an 8-lead narrow-body SOIC (SO-8) package, 3.9 mm × 4.9 mm, with standard JEDEC MS-012AC footprint and 1.27 mm pitch.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar power supply and watchdog monitoring applications.

Compared with MAX692AESA+ and TPS3823DBVR, the ADM9690ARN uniquely delivers dual-timed reset outputs and four factory-calibrated watchdog intervals in a single SOIC-8 package-enabling compact, deterministic recovery in µP-based systems where both power integrity and software liveliness must be verified.

Availability

ADM9690ARN is available at Aetrix Electronics and suitable for industrial PLC controllers, embedded print engines, medical diagnostic instruments, and networked HVAC controllers requiring stable component supply, long-term lifecycle support, and guaranteed industrial-temperature performance.

Supply support for ADM9690ARN 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, Inc. is a global semiconductor leader specializing in high-performance analog, mixed-signal, and digital signal processing technologies for precision measurement and control.

The ADM9690ARN belongs to Analog Devices' power supervision IC product line, engineered specifically for reliable microprocessor system startup, brown-out protection, and runtime watchdog monitoring in harsh industrial environments.

FAQ

What is the exact reset voltage threshold of the ADM9690ARN, and how does it vary with temperature?

The ADM9690ARN has a nominal reset voltage threshold of 4.31 V, with a guaranteed range of 4.2 V to 4.42 V over the full industrial temperature range (–40°C to +85°C). Typical performance curves show minimal drift: threshold varies only ±0.006 V from –40°C to +85°C, confirming high stability essential for consistent brown-out detection across operating conditions. This precision is achieved through laser-trimmed internal references, not external resistor dividers.

How does the ADM9690ARN handle watchdog timer restart after a reset event?

The ADM9690ARN restarts its watchdog timer only when RESET(1) transitions from low to high-regardless of whether the preceding reset was triggered by VMON undervoltage or WDI timeout. This ensures the watchdog remains disabled during the entire reset period and begins fresh timing only after the microprocessor has fully recovered and asserted its first WDI edge post-reset. This behavior prevents spurious timeouts during boot sequences.

Can the ADM9690ARN watchdog be disabled, and if so, how?

Yes, the ADM9690ARN watchdog can be disabled by leaving the WDI pin floating or driving it to approximately midsupply (e.g., 2.5 V on a 5 V system). The datasheet explicitly states this condition disables watchdog monitoring while preserving voltage monitoring functionality. This allows safe debug modes, factory test sequences, or legacy firmware integration where watchdog service is not implemented.

What are the absolute maximum ratings for VMON input voltage on the ADM9690ARN?

The ADM9690ARN specifies an absolute maximum VMON input voltage of VCC + 0.3 V, with VCC itself rated up to +6 V. Therefore, VMON must not exceed 6.3 V under any condition-even transiently-to avoid permanent damage. This rating reflects internal ESD protection design and differs from the functional operating range (4.3 V to 5.5 V on VCC); exceeding VMON limits risks latch-up or junction breakdown regardless of VCC level.

Does the ADM9690ARN support operation below 4.3 V VCC, and what functions remain active?

Yes, the ADM9690ARN remains functional down to 2 V VCC, though only the voltage monitor and reset generation operate in this sub-nominal range-the watchdog timer is disabled below 4.3 V. The datasheet confirms the voltage comparator continues detecting VMON drops and asserting RESET(1)/RESET(2) with full timing accuracy, enabling fail-safe shutdown even during severe brown-out events where the microprocessor may already be nonfunctional.