Analog Devices Inc./Maxim Integrated DS1831D

Overview

DS1831D from Maxim Integrated is a multisupply voltage monitor and watchdog timer IC that supervises 2.5V and 3.3V power rails while providing open-drain reset outputs, user-configurable tolerance (5%/10%/15% for 2.5V; 5%/10%/20% for 3.3V), selectable reset delays (10ms/100ms/1s), and a dedicated watchdog function with ST strobe input and WDS status output. It operates from −40°C to +85°C in embedded industrial control systems requiring dual-rail monitoring and software fault detection.

For engineers reviewing the DS1831D datasheet, DS1831D pinout, DS1831D application, or DS1831D equivalent, this page delivers verified functional identity, exact pin roles, confirmed watchdog timing behavior, real-world reset delay configurations, and validated alternative options for multisupply monitoring with integrated watchdog capability.

Technical Context

The DS1831D integrates two precision voltage comparators referenced to a 1.25V temperature-compensated bandgap, enabling accurate monitoring of IN2.5V and IN3.3V supply inputs. Its internal power is drawn from the higher of the two supply inputs, requiring ≥1.0V on at least one supply for operation and ≥1.5V on either for valid voltage sensing.

Unlike the DS1831C/E variants, the DS1831D replaces the master pushbutton reset (MPBRST) and second NMI comparator with the ST (strobe) input and WDS (watchdog status) output. Watchdog timeout is determined solely by TDWD pin state (GND/float/VCC), and timing begins only after at least one RST output transitions high.

Key Specifications

Pinout & Package

DS1831D is available in 16-pin 300mil DIP and 16-pin 150mil SO packages. Both share identical pin mapping and electrical behavior.

Key Features

Applications

Equivalent & Alternatives

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

Compared with DS1831D, MAX6369 and TPS3808G33 offer watchdog functionality but lack its dual-supply independence, per-rail tolerance/delay configurability, and 2.5V/3.3V co-monitoring - making DS1831D uniquely suited for systems where both rails must be validated separately under varying noise and stability conditions.

Availability

DS1831D is available at Aetrix Electronics and suitable for industrial automation controllers, medical instrumentation, automotive infotainment units, and network infrastructure equipment requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for DS1831D 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 industrial, communications, and computing applications, emphasizing reliability, integration, and thermal robustness.

The DS1831D belongs to Maxim's MicroMonitor™ family of power-supervisory ICs, engineered specifically for systems with multiple voltage domains needing coordinated reset generation, voltage margining, and software fault detection in harsh environments.

FAQ

What is the key functional distinction between DS1831D and DS1831C?

The DS1831D replaces the DS1831C's master pushbutton reset (MPBRST) and second non-maskable interrupt (NMI2) with the ST (strobe) input and WDS (watchdog status) output. This reconfiguration enables hardware-based software watchdog functionality while removing manual global reset capability - making DS1831D optimal for autonomous fault recovery rather than operator-initiated reset.

How does the DS1831D determine which supply powers its internal circuitry?

The DS1831D draws internal operating current from the higher voltage level between IN2.5V and IN3.3V. If IN3.3V = 3.4V and IN2.5V = 2.4V, the device uses IN3.3V as its internal power source. At least one supply must exceed 1.0V for basic operation, and ≥1.5V on either supply is required for accurate voltage monitoring.

Can the watchdog timeout period of DS1831D be changed dynamically during operation?

No. The DS1831D watchdog timeout period is fixed at power-up based on the TDWD pin state (GND/float/VCC) and cannot be altered without cycling power. The timeout values are 10ms (TDWD = GND), 100ms (TDWD = float), or 1000ms (TDWD = VCC), with actual minimums matching those values.

What happens to DS1831D outputs when both IN2.5V and IN3.3V drop below 1.0V?

When both IN2.5V and IN3.3V fall below 1.0V, the DS1831D loses internal power and all outputs (RST2.5V, RST3.3V, WDS) enter high-impedance state. However, if at least one supply remains ≥1.0V, all outputs remain active (low) - ensuring failsafe reset assertion during brownout conditions.

Is an external pull-up resistor required for the WDS output of DS1831D?

Yes - the WDS output is open-drain and requires an external pull-up resistor to establish a valid high state. In typical implementations, WDS is connected to a PBRST input (e.g., PBRST2.5V), which already has an internal 100kΩ pull-up to its associated supply, eliminating the need for an additional resistor. For standalone use, a 10kΩ pull-up to the target logic supply is recommended.