Analog Devices Inc./Maxim Integrated DS1232+

Overview

DS1232+ from Maxim Integrated (formerly Dallas Semiconductor) is a microprocessor supervisory circuit that monitors VCC, implements pushbutton reset with 250 ms debounced output, and provides a configurable watchdog timer with 150 ms / 600 ms / 1.2 s timeout options. It delivers active-high and open-drain active-low reset outputs, supports 5% or 10% VCC tolerance selection via TOL pin, and operates across industrial temperature range (–40°C to +85°C) in 8-pin mini-DIP.

For engineers reviewing the DS1232+ datasheet, DS1232+ pinout, DS1232+ application, or DS1232+ equivalent, key selection considerations include dual-reset output polarity, programmable VCC trip point (4.25 V or 4.50 V), watchdog strobe timing constraints, industrial-grade thermal rating, and compatibility with 5 V ±10% supply systems in embedded control and instrumentation designs.

Technical Context

The DS1232+ integrates three independent monitoring functions: precision voltage detection using a temperature-compensated bandgap reference and comparator, hardware-debounced pushbutton reset with guaranteed 250 ms minimum pulse width, and a non-disableable watchdog timer whose timeout is selected by TD pin state (GND/float/VCC). All functions drive dual RST outputs - one active-high CMOS, one active-low open-drain - enabling direct interface to diverse microprocessor reset inputs.

Power-on reset is asserted for ≥250 ms after VCC rises above trip threshold; power-fail detection asserts reset within 175 μs of VCC falling below threshold. The ST input requires high-to-low transitions at intervals ≤ specified timeout minima (e.g., ≤62.5 ms for 150 ms setting) to prevent spurious resets, ensuring robust software execution supervision.

Key Specifications

Pinout & Package

DS1232+ is supplied in an 8-pin plastic mini-DIP (300-mil) package with through-hole mounting. Pin 1 is PBRST; pins 5 and 6 are dual RST outputs (active-high and open-drain active-low, respectively); pin 3 is TOL for VCC tolerance selection; pin 2 is TD for watchdog timeout configuration; pin 4 is GND; pin 8 is VCC; pin 7 is ST (strobe input); pin 1 is PBRST (pushbutton reset input).

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX692A+ and TPS3823-50DBVR, the DS1232+ uniquely combines dual-polarity reset outputs, user-selectable VCC trip points, hardware-debounced pushbutton support, and multi-range watchdog timing - making it suitable for systems requiring comprehensive, configurable supervision without external components.

Availability

DS1232+ is available at Aetrix Electronics and suitable for industrial automation, medical instrumentation, telecom infrastructure, and energy metering applications requiring stable component supply, long-term lifecycle support, and guaranteed industrial temperature performance.

Supply support for DS1232+ 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 markets.

The DS1232+ belongs to Maxim's MicroMonitor™ family of supervisory circuits, engineered specifically to replace discrete reset generators and watchdog solutions in 5 V microprocessor systems with guaranteed timing, voltage accuracy, and reliability.

FAQ

What is the function of the TOL pin on the DS1232+?

The TOL pin on the DS1232+ selects the VCC detection threshold: connecting TOL to GND sets a 4.50 V trip point (±5% of 5 V), while connecting it to VCC sets a 4.25 V trip point (±10%). This allows system designers to match the DS1232+'s brown-out response precisely to their power supply tolerance. The DS1232+ uses this setting to determine when to assert its dual RST outputs during power failure or startup sequences.

Does the DS1232+ support both active-high and active-low reset outputs simultaneously?

Yes, the DS1232+ provides two independent reset outputs: Pin 5 (RST) is an active-high CMOS output, and Pin 6 (RST) is an active-low open-drain output. This dual-output architecture enables direct interfacing with microprocessors requiring either reset polarity without external components. The DS1232+ asserts both outputs synchronously during power-up, power-down, pushbutton activation, or watchdog timeout events.

How is the watchdog timeout configured on the DS1232+?

The watchdog timeout on the DS1232+ is set by the TD pin: grounding TD selects ~150 ms, leaving TD floating selects ~600 ms, and connecting TD to VCC selects ~1.2 s. The DS1232+ requires a high-to-low transition on the ST pin before each timeout expires to reset the watchdog timer. If missed, the DS1232+ asserts both RST outputs for ≥250 ms to force system recovery.

Can the DS1232+ operate outside the standard 0°C to +70°C commercial temperature range?

Yes, the DS1232+ is qualified for industrial operation from –40°C to +85°C when ordered with the 'N' suffix (e.g., DS1232N+). This extended temperature grade is explicitly documented in the datasheet and validated across the full range. The DS1232+ maintains specified timing, voltage thresholds, and output drive strength throughout this range, making it suitable for deployment in demanding environmental conditions.

Is the DS1232+ pin-compatible with the DS1232S surface-mount variant?

No, the DS1232+ (8-pin DIP) and DS1232S (16-pin SOIC) are not pin-compatible. The DS1232S uses a 16-pin layout with multiple NC pins and rearranged signal placement, while the DS1232+ uses an 8-pin configuration with direct mapping of all functional pins. Although both share identical electrical functionality and timing, PCB layout and footprint must be redesigned to migrate from DS1232+ to DS1232S. The DS1232+ remains the through-hole option for legacy or prototyping use cases.