Analog Devices Inc./Maxim Integrated DS1831S+T&R

Overview

DS1831S+T&R from Maxim Integrated is a multisupply voltage monitor IC that detects out-of-tolerance conditions on 5V and 3.3V power rails, provides open-drain reset outputs (RST5V, RST3.3V), supports user-configurable reset time delays (10ms/100ms/1s), and includes two precision voltage-sense comparators for monitoring auxiliary supplies (IN1, IN2) referenced to a 1.25V internal bandgap. It operates from −40°C to +85°C and is used in embedded systems requiring reliable power sequencing and fault detection.

For engineers reviewing the DS1831S+T&R datasheet, DS1831S+T&R pinout, DS1831S+T&R application, or DS1831S+T&R equivalent, this page delivers verified technical context, real-world design meaning of tolerance select (TOL5V/TOL3.3V), time-delay configuration (TD5V/TD3.3V), pushbutton reset behavior, and precise comparator trip-point dependencies - all confirmed for the DS1831S variant.

Technical Context

The DS1831S is the SO-150mil surface-mount variant of the DS1831 family without watchdog or pushbutton status functions. Its internal operation draws power from the higher of IN5V or IN3.3V (≥1.0V required), and it uses dual independent tolerance-select inputs (TOL5V, TOL3.3V) to set trip-point accuracy at 5%, 10%, or 15% (5V) and 5%, 10%, or 20% (3.3V). Reset time delays are configured via TD5V and TD3.3V pins with three discrete options per rail.

It features two non-maskable interrupt (NMI1, NMI2) outputs driven by comparators referenced to a 1.25V temperature-compensated bandgap, enabling external voltage monitoring via resistor dividers. All reset and NMI outputs are open-drain and require external pull-ups; no internal pull-ups exist on these outputs.

Key Specifications

Pinout & Package

DS1831S is housed in a 16-pin SOIC package (150mil body width, 1.27mm lead pitch), optimized for high-density PCB layouts and reflow-compatible assembly. Pin numbering follows standard SOIC convention (pin 1 at top-left corner, counterclockwise).

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX6369ESA+ and TPS3808G33DBVR, DS1831S+T&R uniquely integrates dual-voltage supervision, user-selectable trip tolerances and reset delays, and two auxiliary comparators in one SOIC-16 package - making it irreplaceable for systems requiring coordinated reset timing across multiple rails and external voltage domain monitoring.

Availability

DS1831S+T&R is available at Aetrix Electronics and suitable for industrial automation, telecom infrastructure, medical diagnostics, and automotive ADAS applications requiring stable component supply, long-term lifecycle support, and RoHS-compliant tape-and-reel packaging for SMT production.

Supply support for DS1831S+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 precision analog, mixed-signal, and power management ICs for industrial, communications, and computing markets.

The DS1831S+T&R belongs to Maxim's Micromonitor™ family of power-supply supervisors, designed specifically for systems with multiple voltage rails and stringent reliability requirements in harsh thermal and electrical environments.

FAQ

What is the function of the MPBRST pin on the DS1831S+T&R?

The MPBRST pin on the DS1831S+T&R is an active-low master pushbutton reset input that forces both RST5V and RST3.3V outputs low simultaneously. It is internally pulled up to the higher of IN5V or IN3.3V via a 100kΩ resistor and requires a low pulse ≥20µs to initiate a full reset cycle. This pin enables system-level emergency reset independent of individual rail status.

Can the DS1831S+T&R monitor voltages other than 5V and 3.3V?

Yes, the DS1831S+T&R can monitor additional voltages using its IN1 and IN2 pins, each connected to a comparator referenced to a precision 1.25V internal bandgap. By applying a resistor divider to scale higher voltages (e.g., 12V, 24V) down to ≤1.25V at these inputs, the device generates NMI1 or NMI2 pulses when the monitored voltage falls below the 1.25V threshold - supporting custom trip-point configurations.

How does the DS1831S+T&R determine which supply powers its internal circuitry?

The DS1831S+T&R automatically selects the higher voltage between IN5V and IN3.3V to power its internal circuitry. As long as at least one of these inputs is ≥1.0V, the device remains operational. If both fall below 1.0V, all outputs remain asserted; if either rises above 1.5V, comparator-based NMI outputs become active and voltage monitoring resumes - ensuring robust behavior during asymmetric brownouts.

What are the valid configurations for TOL5V and TOL3.3V on the DS1831S+T&R?

On the DS1831S+T&R, TOL5V and TOL3.3V each support three configurations: tied to their respective supply rail (IN5V or IN3.3V) for ±5% tolerance, tied to GND for ±10% tolerance, or left floating for ±15% (5V) or ±20% (3.3V) tolerance. These settings are sampled and latched at power-up and cannot be changed dynamically - requiring power cycling to update.

Does the DS1831S+T&R include a watchdog timer function?

No, the DS1831S+T&R does not include a watchdog timer. That feature is exclusive to the DS1831A and DS1831AS variants, which replace the MPBRST and NMI2 functions with watchdog strobe (ST) and watchdog status (WDS) pins. The DS1831S+T&R retains full MPBRST, NMI1, and NMI2 functionality but omits watchdog circuitry entirely - confirmed by its ordering code and functional block diagram.