Analog Devices Inc./Maxim Integrated DS1831DS

Overview

DS1831DS from Maxim Integrated is a 2.5V/3.3V multisupply micro-monitor IC with integrated watchdog timer, dual voltage supervision (IN2.5V and IN3.3V), open-drain reset outputs (RST2.5V and RST3.3V), user-configurable reset time delays (10ms/100ms/1s), and precision 1.25V temperature-compensated reference. It operates from –40°C to +85°C and supports systems requiring robust power sequencing and software fault detection.

For engineers reviewing the DS1831DS datasheet, DS1831DS pinout, DS1831DS application, or DS1831DS equivalent, this device delivers verified dual-supply monitoring with programmable tolerance (5%/10%/20%), watchdog strobe input (ST), watchdog status output (WDS), and compatibility with 16-pin 150mil SO packaging for space-constrained embedded control and industrial power management designs.

Technical Context

The DS1831DS implements two independent voltage comparators referenced to a 1.25V bandgap, each monitoring IN2.5V or IN3.3V against user-selectable trip points via TOL2.5V/TOL3.3V inputs. Its internal bias and timing circuitry draws power from the higher of the two supply inputs, ensuring operation down to 1.0V on either rail.

It integrates a watchdog timer with TDWD-controlled timeout (10ms/100ms/1s), where ST input transitions reset the timer and WDS pulses low on timeout. Reset outputs are open-drain with configurable active durations, and all NMI/WDS/RST outputs require external pull-up resistors (typically 10kΩ) for valid logic levels.

Key Specifications

Pinout & Package

DS1831DS is housed in a 16-pin SOIC package (150mil body width, 1.27mm pitch), RoHS-compliant, with thermal pad not electrically connected.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX6369KA+T and TPS3808G33DBVR, the DS1831DS uniquely supports simultaneous 2.5V/3.3V monitoring with independent tolerance and delay configuration, auxiliary voltage sensing, and pushbutton status feedback - making it the only option for diagnosable, multi-rail industrial and medical systems requiring coordinated reset behavior.

Availability

DS1831DS is available at Aetrix Electronics and suitable for industrial PLC power management, embedded network routing, medical diagnostic imaging, and automotive ADAS camera ECUs requiring stable component supply, long-term lifecycle assurance, and traceable sourcing.

Supply support for DS1831DS 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, communications, and computing markets.

The DS1831DS belongs to Maxim's MicroMonitor™ family of intelligent power supervisors, designed specifically for complex embedded systems needing coordinated multi-rail monitoring, watchdog protection, and field-diagnostic capabilities.

FAQ

What is the function of the PBST pin on the DS1831DS?

The PBST (Pushbutton Status) pin on the DS1831DS is an open-drain output that remains low only after the most recent reset was initiated by the MPBRST (master pushbutton) input. It stays low until another non-master reset event occurs - such as a supply undervoltage or watchdog timeout - enabling firmware to log and differentiate reset causes. The DS1831DS requires an external pull-up resistor (typically 10kΩ) on PBST to maintain a valid high state when inactive.

How does the DS1831DS determine its internal power source?

The DS1831DS draws all internal operating current from whichever supply input - IN2.5V or IN3.3V - is at the higher voltage level at any given time. This architecture ensures continuous operation even during asymmetric power-down sequences, as long as at least one supply remains ≥1.0V. Accurate voltage monitoring, however, requires at least one supply to be ≥1.5V to stabilize the internal 1.25V reference. The DS1831DS uses this dynamic sourcing to maintain functionality across brownout conditions affecting either rail.

Can the DS1831DS monitor voltages other than 2.5V and 3.3V?

Yes, the DS1831DS can monitor additional voltages using its two auxiliary sense inputs, IN1 and IN2. Each connects to an internal comparator referenced to the precision 1.25V bandgap, allowing supervision of any voltage - such as 5V, 12V, or battery rails - via an external resistor divider. For example, to monitor a 11.5V supply, a resistor network scales it to 1.25V at the IN1 pin. The DS1831DS then asserts NMI1 if the scaled voltage drops below 1.25V, providing flexible, rail-agnostic fault detection beyond its primary 2.5V/3.3V inputs.

What are the valid configurations for the TDWD pin on the DS1831DS?

The TDWD pin on the DS1831DS configures the watchdog timeout period: connecting TDWD to GND selects a minimum timeout of 10ms, leaving it floating selects 100ms, and connecting it to VCC (i.e., to the higher of IN2.5V or IN3.3V) selects 1000ms. These settings are sampled at power-up and remain fixed until the next power cycle. The DS1831DS watchdog timer starts timing upon release of any RST output and resets on each valid ST input transition; timeout triggers a 100µs pulse on the WDS output.

Does the DS1831DS require external pull-up resistors on its reset outputs?

Yes, all open-drain outputs of the DS1831DS - including RST2.5V, RST3.3V, WDS, NMI1, NMI2, and PBST - require external pull-up resistors to establish valid logic-high states. A typical value is 10kΩ, connected between the output pin and the corresponding supply rail (e.g., RST2.5V pulled to IN2.5V, RST3.3V pulled to IN3.3V). The DS1831DS does not include internal pull-ups on these outputs, so omission of external resistors will result in undefined or floating output levels and unreliable system reset behavior.