Analog Devices Inc./Maxim Integrated DS1232LPS

Overview

DS1232LPS from Maxim Integrated (formerly Dallas Semiconductor) is a low-power microprocessor supervisory IC that monitors VCC supply voltage, implements a watchdog timer, and debounces pushbutton reset inputs. It delivers 50 µA quiescent current, supports 5% or 10% VCC detection thresholds (4.75 V or 4.5 V), and provides dual active-high/active-low reset outputs in an 8-pin SOIC (150-mil) package for embedded microcontroller systems.

For engineers reviewing the DS1232LPS datasheet, DS1232LPS pinout, DS1232LPS application, or DS1232LPS equivalent, key selection considerations include its 250 ms minimum reset pulse width, selectable watchdog timeout (150 ms / 600 ms / 1.2 s), dual RST outputs (push-pull and open-drain), TOL-selectable trip point, and industrial-grade operation up to +85°C.

Technical Context

The DS1232LPS integrates three independent monitoring functions: precision VCC detection using a temperature-compensated bandgap reference and comparator, a programmable watchdog timer triggered by ST strobe input, and a debounced PBRST input with guaranteed 250 ms reset assertion on release. All functions drive two complementary reset outputs - RST (active-high) and RST (active-low, open-drain).

Its power-fail detection asserts reset when VCC falls below threshold (set via TOL pin), holds reset active for ≥250 ms during power-up, and maintains output validity down to VCC = 2.0 V. The watchdog timeout is selected by TD pin state (GND/float/VCC), and cannot be disabled - requiring periodic ST strobing to prevent spurious resets.

Key Specifications

Pinout & Package

DS1232LPS is supplied in an 8-pin SOIC package (150-mil width), with pin 1 at top-left corner when notch is oriented upward. Package meets JEDEC MS-012 standards and is RoHS-compliant.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX6326US29D3+ and TPS3808G33DBVR, the DS1232LPS uniquely combines ultra-low 50 µA quiescent current with integrated pushbutton debounce, dual reset outputs, and factory-programmed watchdog intervals - making it optimal for cost-sensitive, space-constrained industrial controllers where all three functions are required without external components.

Availability

DS1232LPS is available at Aetrix Electronics and suitable for industrial automation, medical handheld devices, smart energy metering, and automotive body electronics requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for DS1232LPS 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 (acquired by Analog Devices in 2021) designs precision analog, mixed-signal, and power management ICs for industrial, automotive, communications, and computing markets.

The DS1232LPS belongs to Maxim's MicroMonitor™ family of supervisory circuits, engineered specifically for robust, low-power microprocessor reset and watchdog functionality in harsh or battery-limited embedded systems.

FAQ

What is the function of the TOL pin on the DS1232LPS?

The TOL pin on the DS1232LPS selects the VCC detection threshold: connecting TOL to GND sets a 4.75 V trip point (5% tolerance for 5 V supply), while connecting TOL to VCC sets a 4.5 V trip point (10% tolerance). This configuration determines when the DS1232LPS asserts reset during power failure or brownout conditions, and is validated across the full −40°C to +85°C operating range.

Does the DS1232LPS provide both active-high and active-low reset outputs?

Yes, the DS1232LPS provides two independent reset outputs: RST is an active-high push-pull output, and RST is an active-low open-drain output. This dual-output architecture allows direct connection to MCUs requiring either polarity, supports wired-OR reset buses via the open-drain RST, and eliminates the need for external inverters or level shifters in mixed-voltage designs.

How is the watchdog timeout configured on the DS1232LPS?

The watchdog timeout on the DS1232LPS is configured solely by the TD pin state: grounded TD selects ~150 ms, floating TD selects ~600 ms, and TD tied to VCC selects ~1.2 s. The DS1232LPS does not support disabling the watchdog - ST must be strobed with a high-to-low transition at least once per timeout interval to prevent automatic reset assertion.

What is the guaranteed minimum reset pulse width for the DS1232LPS?

The DS1232LPS guarantees a minimum reset pulse width of 250 ms for both RST and RST outputs, whether triggered by power-up, power-down, pushbutton release, or watchdog timeout. This duration is specified across temperature and supply voltage (4.5–5.5 V) and ensures sufficient time for microprocessor core, PLLs, and peripherals to stabilize before release.

Is the DS1232LPS pin-compatible with other members of the DS1232 family?

Yes, the DS1232LPS shares identical pinout and function mapping with the DS1232LP (DIP) and DS1232L (µ-SOP) variants in the 8-pin configuration. All share the same PBRST, TD, TOL, GND, VCC, ST, RST, and RST assignments and electrical behavior - enabling drop-in replacement across SOIC, DIP, and µ-SOP packages without PCB redesign.