Analog Devices Inc./Maxim Integrated DS1232S+

Overview

DS1232S+ from Maxim Integrated (formerly Dallas Semiconductor) is a microprocessor supervisory circuit that monitors VCC, implements watchdog timer functionality, and manages pushbutton reset with debouncing. It provides dual active-high and open-drain active-low reset outputs, supports 5% or 10% VCC tolerance selection via TOL pin, and delivers guaranteed 250 ms minimum reset pulse width during power-up, power-down, or manual reset - used in embedded control systems requiring reliable boot and runtime fault recovery.

For engineers reviewing the DS1232S+ datasheet, DS1232S+ pinout, DS1232S+ application, or DS1232S+ equivalent, key selection criteria include its dual-reset output architecture, selectable VCC trip points (4.25 V or 4.50 V), programmable watchdog timeout (150/600/1200 ms), industrial temperature range (–40°C to +85°C), and SOIC-16 package compatibility with legacy DIP-8 footprints via adapter.

Technical Context

The DS1232S+ integrates three independent monitoring functions: precision voltage detection using a temperature-compensated bandgap reference and comparator, edge-triggered watchdog timer with three timeout options set by TD pin state (GND/floating/VCC), and hardware-debounced pushbutton reset input (PBRST) that initiates a 250 ms minimum reset pulse on release. All reset outputs (RST and RST) are asserted synchronously during fault conditions.

Its dual-reset topology enables direct interface to both standard microprocessors requiring active-high reset and legacy or mixed-signal systems needing open-drain active-low reset for wired-OR configurations. The device operates exclusively at 5 V nominal supply (4.5–5.5 V), with no internal regulation or brown-out hysteresis beyond the specified trip tolerances.

Key Specifications

Pinout & Package

DS1232S+ is packaged in a 16-pin SOIC (300-mil width), pin-compatible with DS1232S but offering enhanced layout density over the 8-pin DIP variant. Pin assignments are fully defined per Maxim's official mechanical drawings and functional specification.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar microprocessor supervisory applications.

Compared with MAX692AESA+ and TPS3823DBVR, DS1232S+ uniquely delivers dual-reset signaling, user-selectable VCC trip tolerance, and integrated pushbutton debounce - enabling full supervisory functionality in a single 16-pin SOIC without external components or firmware overhead.

Availability

DS1232S+ is available at Aetrix Electronics and suitable for industrial control systems, medical instrumentation, point-of-sale terminals, and smart energy meters requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for DS1232S+ 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, mixed-signal, and power management ICs for industrial, automotive, communications, and computing applications.

The DS1232S+ belongs to Maxim's MicroMonitor™ family of supervisory circuits, engineered specifically to replace discrete reset generators and watchdog timers in 5 V microprocessor-based systems with guaranteed timing and robust noise immunity.

FAQ

What is the function of the TOL pin on the DS1232S+?

The TOL pin on the DS1232S+ selects the VCC detection tolerance: when tied to GND, DS1232S+ triggers reset at 4.50 V (5% drop from 5 V); when tied to VCC, it triggers at 4.25 V (10% drop). This allows system designers to match the DS1232S+ trip point precisely to their power supply's regulation spec and noise margin - a feature not found in most fixed-threshold supervisors.

Does the DS1232S+ require external components to operate?

No, the DS1232S+ operates autonomously with no external capacitors, resistors, or crystals required. Its internal bandgap reference, precision comparator, RC-timed watchdog, and debounced input logic eliminate discrete BOM items. Only pull-up resistors on the open-drain RST output and optional external capacitor on TD for noise filtering are recommended - not mandatory - for typical implementations.

Can the watchdog timer in the DS1232S+ be disabled?

No, the watchdog timer in the DS1232S+ cannot be disabled. It must be periodically strobed via the ST input to prevent timeout. If ST remains inactive beyond the selected timeout interval (150/600/1200 ms), DS1232S+ will assert both reset outputs. This design enforces fail-safe behavior - unlike some supervisors offering watchdog disable options - making DS1232S+ appropriate for safety-critical applications.

What is the difference between the two RST pins on the DS1232S+?

The DS1232S+ features two physically separate RST pins: one is a push-pull active-high output (drives high during reset), the other is an open-drain active-low output (pulls low during reset, requires external pull-up). This dual-output architecture allows DS1232S+ to interface directly with processors requiring either reset polarity - eliminating level translators or inverters - and supports wired-OR reset buses in multi-IC systems.

Is the DS1232S+ compatible with 3.3 V microcontrollers?

The DS1232S+ is designed for 5 V operation only (4.5–5.5 V supply) and is not 3.3 V compatible. Its VCC trip points, input thresholds, and output drive levels are specified exclusively for 5 V systems. For 3.3 V applications, designers should select purpose-built supervisors such as the MAX6361 or TPS3808 - using DS1232S+ in 3.3 V environments risks unreliable reset assertion and potential damage due to overvoltage on inputs.