Analog Devices Inc./Maxim Integrated DS1831CS+

Overview

DS1831CS+ from Maxim Integrated is a 2.5V/3.3V multisupply micro-monitor IC with dual open-drain reset outputs (RST2.5V, RST3.3V), two user-configurable voltage sense inputs (IN1, IN2), and non-maskable interrupt outputs (NMI1, NMI2). It draws internal power from the higher of IN2.5V or IN3.3V (≥1.0V required), supports 5%/10%/15% tolerance selection per supply, and provides 10ms/100ms/1s reset time delays via TD inputs. Used in embedded systems requiring reliable multi-rail power supervision.

For engineers reviewing the DS1831CS+ datasheet, DS1831CS+ pinout, DS1831CS+ application, or DS1831CS+ equivalent, this page delivers verified specifications including trip point accuracy (±2.5% at 3.3V with TOL tied to rail), open-drain output drive capability (10mA sink), operating current (60–85µA at 3.6V), and -40°C to +85°C industrial temperature range - all critical for power sequencing, brownout detection, and system-level fault response design.

Technical Context

The DS1831CS+ integrates two precision voltage comparators referenced to a 1.25V temperature-compensated bandgap, enabling accurate monitoring of 2.5V and 3.3V rails plus two external supplies via IN1/IN2. Each comparator drives an open-drain NMI output with 100µV hysteresis and 2µs noise immunity threshold.

Tolerance (TOL) and time-delay (TD) pins configure trip points and reset hold times independently per rail: TOL2.5V/TOL3.3V select 5%, 10%, or 15% (2.5V) / 5%, 10%, or 20% (3.3V) tolerances; TD2.5V/TD3.3V set 10ms, 100ms, or 1s delays. Internal biasing ensures operation as long as either IN2.5V or IN3.3V exceeds 1.0V.

Key Specifications

Pinout & Package

DS1831CS+ is supplied in a 16-pin SOIC package (150mil width, JEDEC MS-012AC), with 1.27mm pitch and standard gull-wing leads. Pin 1 marked by notch or dot; pin 16 is GND.

Key Features

Applications

Equivalent & Alternatives

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

Compared with DS1831CS+, MAX6369ESA+ offers watchdog functionality but omits dual-supply monitoring and external sense capability, while TPS3808G33DBVR provides tighter 3.3V threshold accuracy but sacrifices configurability, NMI generation, and 2.5V supervision - making DS1831CS+ uniquely suited for complex, multi-domain embedded systems requiring coordinated power integrity management.

Availability

DS1831CS+ is available at Aetrix Electronics and suitable for industrial automation, network infrastructure, medical imaging, and automotive infotainment applications requiring stable component supply, long-term lifecycle support, and guaranteed traceable sourcing.

Supply support for DS1831CS+ 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 high-performance analog and mixed-signal semiconductor solutions for industrial, communications, and computing markets.

The DS1831CS+ belongs to Maxim's MicroMonitor™ family of power-supervisory ICs, engineered specifically for robust, multi-rail voltage monitoring and reset generation in mission-critical embedded systems.

FAQ

What is the minimum supply voltage required for DS1831CS+ to function?

The DS1831CS+ requires at least one of its supply inputs - IN2.5V or IN3.3V - to be ≥1.0V to maintain internal operation and valid outputs. Accurate voltage monitoring, however, demands that either IN2.5V or IN3.3V exceed 1.5V. Below 1.5V, the device holds all outputs active but cannot reliably detect out-of-tolerance conditions on monitored rails. This behavior ensures fail-safe reset assertion during deep brownout.

How does DS1831CS+ handle simultaneous undervoltage on both 2.5V and 3.3V rails?

When both IN2.5V and IN3.3V fall below their respective trip thresholds, DS1831CS+ asserts RST2.5V and RST3.3V independently based on their configured tolerances and time delays. The reset outputs remain active for their individual TD-selected durations (e.g., 100ms each) after their respective rails recover. This preserves independent power-domain control and avoids forced synchronization unless explicitly wired via external logic.

Can DS1831CS+ monitor a 5V supply, and how is it configured?

Yes, DS1831CS+ can monitor a 5V supply using either IN1 or IN2 with an external resistor divider. Since the internal comparator reference is 1.25V, a 5V rail requires a 4:1 divider (e.g., 30kΩ top, 10kΩ bottom) to scale 5V down to 1.25V at the input pin. The DS1831CS+ then asserts NMI1 or NMI2 when the divided voltage drops below 1.15–1.30V, providing precise, adjustable trip-point supervision for non-standard rails.

What is the purpose of the MPBRST pin on DS1831CS+?

The MPBRST (Master Pushbutton Reset) pin on DS1831CS+ provides a hardware-initiated global reset that forces both RST2.5V and RST3.3V outputs low, regardless of rail status. It is internally pulled up to the higher of IN2.5V or IN3.3V via a 100kΩ resistor and debounced. Asserting MPBRST for ≥20µs initiates a full-system reset cycle with configurable hold time - essential for field service, firmware recovery, or emergency shutdown.

Does DS1831CS+ include a watchdog timer function?

No, DS1831CS+ does not include a watchdog timer. That feature is exclusive to the DS1831D and DS1831DS variants. The DS1831CS+ is the base version of the family - offering dual-supply monitoring, two NMI outputs, master pushbutton reset, and configurable tolerances/delays - but omits the ST input, WDS output, and TDWD pin found on watchdog-enabled variants.