Analog Devices Inc./Maxim Integrated DS1232LPSN+

Overview

DS1232LPSN+ from Maxim Integrated (formerly Dallas Semiconductor) is a low-power microprocessor supervisory IC that monitors VCC, implements watchdog timer functionality, and provides pushbutton reset control. It delivers 50 µA quiescent current, 250 ms minimum reset pulse width, and selectable 5% or 10% VCC trip thresholds (4.75 V or 4.5 V), used in embedded systems requiring reliable power-up/power-down sequencing and software fault recovery.

For engineers reviewing the DS1232LPSN+ datasheet, DS1232LPSN+ pinout, DS1232LPSN+ application, or DS1232LPSN+ equivalent, key selection considerations include its dual active-high/active-low RST outputs, industrial temperature range (–40°C to +85°C), 8-pin SOIC package, and fixed watchdog timeout options (150 ms / 600 ms / 1.2 s) set via TD pin configuration.

Technical Context

The DS1232LPSN+ integrates three independent monitoring functions: precision voltage detection using an internal temperature-compensated reference, a hardware watchdog timer with three user-selectable timeouts (TD = GND/float/VCC), and a debounced pushbutton reset input (PBRST) that guarantees ≥250 ms active reset assertion on release. All reset outputs remain active for ≥250 ms after VCC recovery.

It features dual RST outputs - one active-high CMOS, one active-low open-drain - enabling direct interface to both standard and legacy microcontrollers. The TOL pin selects VCC threshold tolerance (5% or 10%), directly setting trip points at 4.75 V or 4.5 V respectively, with hysteresis ensuring noise immunity during brownout conditions.

Key Specifications

Pinout & Package

DS1232LPSN+ is supplied in an 8-pin SOIC (150-mil) package, pin-compatible with DS1232LPS-2 variant. Pin assignments are identical across DS1232LP/LPS family 8-pin variants.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX6326US29D3+ and TPS3808G33DBVR, DS1232LPSN+ uniquely combines VCC monitoring, hardware watchdog, and pushbutton reset in a single 8-pin SOIC - eliminating need for discrete timing components or secondary reset logic in resource-constrained designs.

Availability

DS1232LPSN+ is available at Aetrix Electronics and suitable for industrial automation, medical instrumentation, automotive body electronics, and point-of-sale terminal designs requiring stable component supply and long-term lifecycle support.

Supply support for DS1232LPSN+ 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, and computing applications.

The DS1232LPSN+ belongs to Maxim's MicroMonitor™ supervisory IC product line, engineered specifically for robust microprocessor reset and watchdog functionality in harsh, unattended, or safety-critical embedded systems.

FAQ

What is the function of the TOL pin on the DS1232LPSN+?

The TOL pin on the DS1232LPSN+ selects the VCC detection threshold tolerance: connecting TOL to GND sets a 5% trip point (4.75 V), while connecting it to VCC sets a 10% trip point (4.5 V). This allows system designers to match the DS1232LPSN+ reset behavior precisely to their power supply regulation specification and noise margin requirements without external components.

Does the DS1232LPSN+ require external components to operate?

No, the DS1232LPSN+ operates autonomously with no external timing or biasing components required. Its internal temperature-compensated reference, debounced PBRST input, and programmable watchdog timer (set via TD pin) eliminate the need for external RC networks, pull-ups (except for RST̅), or discrete logic. Only VCC decoupling capacitance is recommended per standard PCB layout practice.

Can the watchdog timer in the DS1232LPSN+ be disabled?

No, the watchdog timer in the DS1232LPSN+ cannot be disabled. As stated in the datasheet note "Watchdog can not be disabled. It must be strobed to avoid resets," the ST input must receive a high-to-low transition at least once per selected timeout interval (150 ms / 600 ms / 1.2 s) to prevent automatic reset assertion. This design enforces fail-safe behavior in safety-critical firmware.

What is the difference between the RST and RST̅ outputs on the DS1232LPSN+?

The DS1232LPSN+ provides two complementary reset outputs: RST is a CMOS active-high output that drives high during reset and requires no external pull-up; RST̅ is an open-drain active-low output requiring an external pull-up resistor. This dual-output architecture supports direct connection to MCUs with either active-high or active-low reset inputs, and enables wired-OR reset busing in multi-controller systems.

Is the DS1232LPSN+ suitable for automotive applications?

Yes, the DS1232LPSN+ is rated for industrial temperature range (–40°C to +85°C) and features robust VCC monitoring with hysteresis, making it suitable for under-hood or cabin-mounted automotive body control modules. While not AEC-Q100 qualified, its electrical specifications and thermal performance align with non-safety-critical automotive subsystems such as lighting controllers, HVAC interfaces, and infotainment power sequencing where DS1232LPSN+ has been deployed in production designs.