Analog Devices Inc./Maxim Integrated DS1831S

Overview

DS1831S from Maxim Integrated is a multisupply voltage monitor IC that simultaneously supervises 5V and 3.3V power rails plus two user-configurable analog inputs (IN1, IN2), delivers open-drain reset outputs (RST5V, RST3.3V) with selectable 10ms/100ms/1s delays, features pushbutton reset inputs (PBRST5V, PBRST3.3V, MPBRST), and operates from −40°C to +85°C in 16-pin 150mil SO package. It is used in embedded systems requiring robust multi-rail power sequencing and failure detection.

For engineers reviewing the DS1831S datasheet, DS1831S pinout, DS1831S application, or DS1831S equivalent, key selection criteria include dual-supply monitoring tolerance configuration (5%/10%/20% per rail), reset delay select via TD pins, internal 1.25V precision reference for NMI comparators, master pushbutton reset coordination, and compatibility with 5V/3.3V system architectures.

Technical Context

The DS1831S uses dual independent voltage comparators referenced to a temperature-compensated 1.25V bandgap reference to monitor IN5V and IN3.3V against user-selectable trip thresholds (via TOL5V/TOL3.3V), while two additional sense inputs (IN1, IN2) support custom voltage monitoring down to 1.15V. Internal power is autonomously drawn from the higher of IN5V or IN3.3V, requiring only one supply ≥1.0V for basic output validity.

Reset timing is controlled by external TD5V and TD3.3V pins, each selecting 10ms, 100ms, or 1s active-low durations; pushbutton functionality includes per-rail manual reset and a master pushbutton (MPBRST) forcing all resets/NMIs active. The device lacks watchdog or PBST functions-those are exclusive to DS1831A/DS1831B variants.

Key Specifications

Pinout & Package

DS1831S is housed in a 16-pin SOIC package (150mil width, 0.050" pitch), compatible with standard reflow soldering profiles and IPC/JEDEC J-STD-020A guidelines.

Key Features

Applications

Equivalent & Alternatives

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

Compared with DS1831S, MAX6369ESA+ reduces feature count but saves PCB area and BOM cost for simpler systems, while TPS3808G33DBVR offers superior delay resolution for 3.3V-only use cases but cannot replace DS1831S's integrated dual-rail, NMI, and pushbutton architecture without redesign.

Availability

DS1831S is available at Aetrix Electronics and suitable for industrial automation, medical diagnostics, telecom infrastructure, and automotive infotainment systems requiring stable component supply, long-term lifecycle support, and guaranteed traceability.

Supply support for DS1831S 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 demanding industrial, medical, and communications applications, emphasizing reliability, integration, and thermal stability.

The DS1831S belongs to Maxim's Micromonitor™ family of power-supervisory ICs, engineered specifically for multi-rail embedded systems requiring coordinated reset, flexible tolerance, and auxiliary voltage monitoring without software dependency.

FAQ

What is the primary function of the DS1831S in a power management system?

The DS1831S serves as a hardware-based multisupply monitor that independently supervises 5V and 3.3V power rails, asserts open-drain reset signals (RST5V/RST3.3V) when either rail falls outside user-configured tolerance bands, and supports manual override via three pushbutton inputs. Its role is to ensure deterministic, glitch-free system initialization and recovery without firmware involvement-critical for fail-safe embedded operation.

Does the DS1831S include a watchdog timer function?

No, the DS1831S does not include a watchdog timer. That feature is exclusive to the DS1831A and DS1831AS variants, which add ST (strobe) and WDS (watchdog status) pins. The DS1831S pinout and functional description confirm absence of TDWD, ST, or WDS terminals-its supervision is limited to voltage monitoring, reset generation, and pushbutton coordination.

How does the DS1831S determine its internal power source?

The DS1831S autonomously draws internal operating current from whichever supply-IN5V or IN3.3V-is at the higher voltage level. This design eliminates the need for an external VCC rail. As long as at least one of those inputs is ≥1.0V, the device maintains valid reset and NMI outputs; however, accurate voltage monitoring requires at least one supply ≥1.5V to activate the internal reference and comparators.

Can the DS1831S monitor voltages other than 5V and 3.3V?

Yes, the DS1831S includes two dedicated sense inputs-IN1 and IN2-that interface with external resistor dividers to monitor arbitrary voltages (e.g., 12V, 2.5V, or 1.8V). Each input compares the divided voltage against the internal 1.25V bandgap reference; when the sensed voltage drops below ~1.25V, the corresponding NMI1 or NMI2 output pulses low, enabling custom fault detection beyond the primary rails.

What are the valid logic levels for pushbutton inputs on the DS1831S?

The DS1831S pushbutton inputs (PBRST5V, PBRST3.3V, MPBRST) accept logic-low assertions defined relative to the greater of IN5V or IN3.3V: VIH ≥ 0.7 × VINT and VIL ≤ 0.3 × VINT, where VINT is that higher supply voltage. All three inputs feature internal 100kΩ pull-up resistors-PBRST5V to IN5V, PBRST3.3V to IN3.3V, and MPBRST to the higher of the two-so external pull-ups are unnecessary unless faster edge response is required.