Analog Devices Inc./Maxim Integrated DS1831A

Overview

DS1831A from Maxim Integrated is a multisupply voltage monitor and watchdog timer IC that supervises 5V and 3.3V power rails, provides two user-configurable sense inputs (IN1/IN2), delivers open-drain reset outputs (RST5V/RST3.3V), and asserts WDS on software stall detection via ST input strobing. It operates from −40°C to +85°C in 16-pin DIP or SO packages and draws internal power from the higher of IN5V or IN3.3V.

For engineers reviewing the DS1831A datasheet, DS1831A pinout, DS1831A application, or DS1831A equivalent, this page details its dual-supply monitoring architecture, watchdog timeout configuration via TDWD, tolerance selection via TOL5V/TOL3.3V, reset delay programming (10ms/100ms/1s), and integration with microprocessor address/data/control lines for reliable system-level fault recovery.

Technical Context

The DS1831A implements independent voltage comparators referenced to a precision 1.25V temperature-compensated bandgap, enabling accurate trip-point detection for IN5V (4.00–4.75V), IN3.3V (2.47–3.15V), and two external sense inputs (IN1/IN2). Its watchdog logic monitors ST input transitions and forces WDS low if no edge occurs within the TDWD-selected timeout window (10ms/100ms/1s).

Reset timing is fully configurable: TOL5V/TOL3.3V select ±5%/±10%/±15% or ±20% tolerance thresholds at power-up, while TD5V/TD3.3V set corresponding RST5V/RST3.3V active durations. All outputs are open-drain, require external pull-ups, and remain valid as long as ≥1 supply exceeds 1.0V - with full monitoring accuracy requiring ≥1.5V on either IN5V or IN3.3V.

Key Specifications

Pinout & Package

DS1831A is available in 16-pin 300mil DIP and 16-pin 150mil SO packages. Both share identical pin functions and electrical characteristics.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar multisupply monitoring applications.

Compared with DS1831A, MAX6369 and TPS3808G33 offer lower channel count and reduced feature depth - neither supports concurrent 5V/3.3V monitoring, dual external sense inputs, or non-maskable interrupts, making them unsuitable replacements in systems relying on DS1831A's integrated multisupply fault detection architecture.

Availability

DS1831A is available at Aetrix Electronics and suitable for industrial automation, medical diagnostics, telecom infrastructure, and automotive infotainment applications requiring stable component supply, long-term lifecycle support, and guaranteed traceability.

Supply support for DS1831A 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

Maxim Integrated (now part of Analog Devices) designs precision analog and mixed-signal ICs for power management, sensing, and interface applications in demanding industrial and automotive environments.

The DS1831A belongs to Maxim's Micromonitor® family - engineered specifically for robust, multi-rail power supervision in systems where reliability under voltage transients, thermal stress, and software faults is mission-critical.

FAQ

What is the watchdog timeout behavior of the DS1831A when the ST input remains static?

If the ST input of the DS1831A receives no high-to-low or low-to-high transition within the TDWD-selected window (10ms/100ms/1s), the WDS output pulses low for ≥100µs. This pulse is intended to drive a PBRST input and force a system reset. The DS1831A watchdog cannot be disabled in hardware - disconnecting WDS is the only way to suppress its effect, but ST must still be driven to prevent spurious timeouts.

Can DS1831A monitor voltages other than 5V and 3.3V?

Yes - the DS1831A includes two dedicated sense inputs (IN1 and IN2) referenced to its internal 1.25V bandgap. By using external resistor dividers, users can configure these inputs to monitor arbitrary voltages (e.g., 12V, 24V, or battery levels). The trip point is fixed at 1.15V–1.30V, so divider ratios must scale target voltages down to that range.

How does DS1831A determine which supply powers its internal circuitry?

The DS1831A automatically selects the higher voltage between IN5V and IN3.3V to power its internal comparators, reference, and logic. As long as at least one supply exceeds 1.0V, the device remains functional - though accurate voltage monitoring requires ≥1.5V on either IN5V or IN3.3V to stabilize the reference and bias circuits.

What happens to DS1831A outputs during power-up or brownout?

During power-up, DS1831A holds RST5V and RST3.3V active until their respective supplies reach valid trip thresholds and remain stable for the TD5V/TD3.3V-selected delay. During brownout, any supply falling below its configured tolerance immediately forces the corresponding RST output low and maintains it for the programmed delay after recovery - preventing premature release during marginal conditions.

Is DS1831A pin-compatible with DS1831 or DS1831B?

No - DS1831A has a unique pinout: Pin 7 is WDS (watchdog status) and Pin 8 is TDWD (watchdog delay select), whereas DS1831 uses Pin 7 for NMI2 and Pin 8 for MPBRST, and DS1831B uses Pin 7 for PBST and Pin 8 for MPBRST. Substituting DS1831A for DS1831 or DS1831B requires PCB layout changes and firmware updates to route ST and interpret WDS instead of NMI2 or PBST.