Analog Devices Inc./Maxim Integrated DS1232LPN+

Overview

DS1232LPN+ from Maxim Integrated (acquired by Analog Devices) is a low-power microprocessor supervisory IC that monitors VCC supply voltage, detects software lockups via watchdog timer, and accepts pushbutton reset inputs. It delivers active-high and open-drain active-low reset outputs, supports 5% or 10% VCC tolerance selection, and guarantees ≥250 ms reset pulse width. Used in embedded controllers requiring reliable power-up/power-down sequencing and fail-safe restart.

For engineers reviewing the DS1232LPN+ datasheet, DS1232LPN+ pinout, DS1232LPN+ application, or DS1232LPN+ equivalent, key selection criteria include quiescent current (50 µA), dual-reset output polarity, TOL-selectable trip points (4.25 V or 4.50 V), watchdog timeout options (150/600/1200 ms), and industrial temperature support (–40°C to +85°C).

Technical Context

The DS1232LPN+ integrates three independent monitoring functions: precision voltage detection using a temperature-compensated bandgap reference and comparator, debounced pushbutton reset with 250 ms minimum pulse generation, and a programmable watchdog timer with three timeout settings determined by TD pin state (GND, float, or VCC). All functions drive dual RST outputs with synchronized timing.

Reset assertion occurs on VCC dropout below threshold (set by TOL), on PBRST release, or on watchdog timeout - each forcing both RST (active-high) and RST̅ (open-drain active-low) into active state for ≥250 ms. Power-up reset remains active for ≥250 ms after VCC exceeds threshold to ensure processor stabilization.

Key Specifications

Pinout & Package

DS1232LPN+ is supplied in an 8-pin plastic DIP (300-mil) package. Pin assignments are validated per Maxim's official mechanical drawings and functional description.

Key Features

Applications

Equivalent & Alternatives

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

Compared with DS1232LPN+, MAX6326US29D3+ offers lower quiescent current but omits watchdog, pushbutton, and dual-reset outputs; TPS3808G33DBVR provides precise delay tuning at 3.3 V but cannot replace DS1232LPN+ in 5 V systems or where software hang detection is mandatory.

Availability

DS1232LPN+ is available at Aetrix Electronics and suitable for industrial automation, medical diagnostics, automotive telematics, and smart metering applications requiring stable component supply, long-term lifecycle support, and guaranteed industrial temperature performance.

Supply support for DS1232LPN+ 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 DS1232LPN+ belongs to Maxim's MicroMonitor™ family - engineered specifically for robust microprocessor supervision in harsh environments where power integrity, software reliability, and manual intervention must coexist in one compact IC.

FAQ

What is the function of the TOL pin on the DS1232LPN+?

The TOL pin on the DS1232LPN+ selects the VCC detection threshold tolerance: connecting TOL to GND sets a 5% trip point (~4.75 V), while connecting it to VCC selects a 10% trip point (~4.50 V). This allows system designers to match the DS1232LPN+'s brownout response to their microcontroller's voltage operating margin and noise environment without changing the DS1232LPN+ footprint or bill of materials.

Does the DS1232LPN+ require external components to operate?

No, the DS1232LPN+ operates autonomously with no external capacitors or resistors required for core functions. The TD, TOL, and PBRST pins use internal pull-ups or logic-level sensing; RST̅ only requires an external pull-up resistor if driving a shared reset bus. The DS1232LPN+ integrates precision reference, comparator, watchdog timer, and debounce logic - making it a true single-chip supervisory solution.

How does the watchdog timer in the DS1232LPN+ work?

The DS1232LPN+ watchdog timer forces reset if the ST pin is not strobed low before timeout. Timeout duration is set by TD pin state: ~150 ms (TD=GND), ~600 ms (TD=float), or ~1.2 s (TD=VCC). Each high-to-low ST transition resets the timer. If timeout occurs, both RST and RST̅ assert for ≥250 ms. The DS1232LPN+ watchdog cannot be disabled - it must be actively serviced to prevent unintended reset.

What is the difference between the RST and RST̅ outputs on the DS1232LPN+?

The DS1232LPN+ provides two complementary reset outputs: RST is an active-high push-pull CMOS output, while RST̅ is an active-low open-drain output. RST drives high directly; RST̅ requires an external pull-up and can be wire-OR'd with other open-drain reset sources. This dual-output architecture lets the DS1232LPN+ interface seamlessly with diverse microcontrollers - including those needing active-low reset only, active-high reset only, or shared reset busses.

Is the DS1232LPN+ suitable for automotive applications?

The DS1232LPN+ is rated for –40°C to +85°C operation and meets industrial reliability standards, but it is not AEC-Q100 qualified. It has been widely deployed in automotive telematics gateways and infotainment submodules where extended temperature range and robust reset behavior are needed, though formal automotive qualification requires additional validation. For DS1232LPN+ use in safety-critical vehicle domains, consult Analog Devices' automotive-grade alternatives.