Analog Devices Inc./Maxim Integrated DS1831AS+T&R

Overview

DS1831AS+T&R from Maxim Integrated is a multisupply voltage monitor IC with integrated watchdog timer, designed to supervise 5V and 3.3V power rails plus two user-configurable analog inputs (IN1/IN2). It delivers open-drain RST5V and RST3.3V reset outputs with selectable 10ms/100ms/1s delays, precision 1.25V bandgap reference, and watchdog timeout triggered by ST input strobe failure. Used in embedded systems requiring reliable power sequencing and software fault detection.

For engineers reviewing the DS1831AS+T&R datasheet, DS1831AS+T&R pinout, DS1831AS+T&R application, or DS1831AS+T&R equivalent, key selection criteria include its dual-supply monitoring capability, watchdog timer integration (DS1831A variant), SO-16 150mil surface-mount package, -40°C to +85°C industrial temperature range, and tolerance-selectable trip points for both 5V and 3.3V rails.

Technical Context

The DS1831AS+T&R implements two independent voltage comparators referenced to a precision 1.25V temperature-compensated bandgap, enabling accurate monitoring of IN5V (trip range 4.00–4.75V) and IN3.3V (2.47–3.15V) with user-selectable tolerances (5%/10%/20%). Its internal power is autonomously drawn from the higher of IN5V or IN3.3V, requiring only ≥1.0V on either for basic output validity and ≥1.5V for full monitoring accuracy.

It integrates a watchdog timer with TDWD-controlled timeout (10ms/100ms/1s), strobed via ST input, and provides non-maskable interrupt outputs (NMI1 only - DS1831A lacks NMI2) that pulse low for ≥20µs when sensed voltages fall below 1.25V. Reset timing is fully configurable per rail using TOLx and TDx pins, and all open-drain outputs require external pull-ups.

Key Specifications

Pinout & Package

DS1831AS+T&R is supplied in a 16-pin SOIC (150mil body width, 1.27mm pitch), compatible with standard surface-mount reflow profiles. Pin functions are identical to DS1831A per Maxim's datasheet revision.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX6361KA29D3+T and TPS3808G33DBVR, DS1831AS+T&R uniquely integrates dual-rail supervision, watchdog timer, and two analog sense inputs in one SO-16 package - enabling consolidated power integrity management without external components or firmware overhead.

Availability

DS1831AS+T&R is available at Aetrix Electronics and suitable for industrial control systems, medical diagnostics equipment, automotive infotainment modules, and telecom infrastructure requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for DS1831AS+T&R 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) is a semiconductor company specializing in high-performance analog, mixed-signal, and power management ICs for industrial, automotive, and communications markets.

The DS1831AS+T&R belongs to Maxim's Micromonitor™ family of power-supply supervisors, engineered for robust, multi-rail voltage monitoring and fail-safe system recovery in mission-critical embedded applications.

FAQ

What is the primary function of the DS1831AS+T&R?

The DS1831AS+T&R is a multisupply voltage monitor IC that supervises both 5V and 3.3V power rails while providing independent reset outputs, a watchdog timer, and two analog sense inputs. It ensures reliable power-up sequencing, detects brownouts, and triggers hardware resets or interrupts - all within a single 16-pin SOIC package. Its design eliminates the need for multiple discrete supervisors in complex embedded systems.

Does the DS1831AS+T&R support both 5V and 3.3V monitoring simultaneously?

Yes, the DS1831AS+T&R monitors IN5V and IN3.3V concurrently using separate precision comparators. Each rail has dedicated TOL and TD pins to configure trip tolerance (5%/10%/20%) and reset delay (10ms/100ms/1s). The device draws internal power from whichever supply is higher, ensuring operation even during asymmetric power sequencing - a key capability confirmed in the DS1831AS+T&R datasheet.

How does the watchdog timer in the DS1831AS+T&R operate?

The DS1831AS+T&R watchdog timer asserts the WDS output low if the ST input fails to toggle within a timeout period set by TDWD (10ms/100ms/1000ms). Time-out begins when any RST output goes inactive (high), and each ST edge resets the timer. WDS is open-drain and typically connected to a PBRST input to trigger automatic system reset - a hardware-enforced recovery mechanism built into the DS1831AS+T&R.

Can the DS1831AS+T&R monitor voltages other than 5V and 3.3V?

Yes, the DS1831AS+T&R includes two additional analog inputs - IN1 and IN2 - each referenced to its internal 1.25V bandgap. By using external resistor dividers, users can scale higher voltages (e.g., 12V, 24V) down to the 1.25V trip point. When the divided voltage falls below 1.25V, NMI1 pulses low - enabling DS1831AS+T&R to supervise auxiliary supplies, battery levels, or sensor thresholds beyond its native 5V/3.3V rails.

What package and reel format does DS1831AS+T&R use?

The DS1831AS+T&R is supplied in a 16-pin SOIC package with 150mil body width and 1.27mm lead pitch, optimized for automated SMT assembly. The "+T&R" suffix indicates it is factory tape-and-reel packaged - standard for high-volume production. This package matches the pinout and thermal characteristics of the through-hole DS1831A DIP variant, allowing layout reuse across prototyping and production stages for DS1831AS+T&R.