Analog Devices Inc./Maxim Integrated DS1814CR-5-U+

Overview

DS1814CR-5-U+ from Maxim Integrated is a 5V microprocessor supervisory circuit with power monitoring, watchdog timer, and pushbutton reset functions. It provides active-low reset output (RST), monitors VCC trip point at 4.50–4.75 V (±5%), delivers 140–280 ms reset pulse width, operates over –40°C to +85°C, and uses SOT-23-5 package. It halts and restarts out-of-control microprocessors during power transients or software hangs in embedded control systems.

For engineers reviewing the DS1814CR-5-U+ datasheet, DS1814CR-5-U+ pinout, DS1814CR-5-U+ application, or DS1814CR-5-U+ equivalent, key selection criteria include VCC trip accuracy (±5%), 1.12 s watchdog timeout, push-pull RST output valid down to 1.0 V VCC, and compatibility with MAX823/824/825 for drop-in replacement in 5V microcontroller power management designs.

Technical Context

The DS1814CR-5-U+ implements a precision voltage monitor with 4.50–4.75 V trip threshold and 10 mV hysteresis, ensuring reliable power-fail detection and clean reset assertion during brownout. Its internal watchdog timer triggers reset if the ST strobe input fails to toggle within 1.12 s, supporting fail-safe recovery in firmware-stuck scenarios.

This variant is the 'C' type (RST, GND, RST, PBRST, VCC pinout) with ±5% tolerance ('D' = A), designed for 5V systems. It integrates debounced pushbutton reset (PBRST) and supports watchdog disable via floating ST - enabling flexible configuration without external components.

Key Specifications

Pinout & Package

SOT-23-5 surface-mount package (2.9 mm × 1.6 mm × 1.1 mm), thermally enhanced, lead-free, RoHS-compliant.

Key Features

Applications

Equivalent & Alternatives

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

Compared with DS1814CR-5-U+, MAX823SESA+ offers tighter trip tolerance but omits pushbutton support, while TPS3808G33DBVR targets 3.3V domains with configurable timing - neither matches the integrated 5V triple-function capability and pinout of DS1814CR-5-U+.

Availability

DS1814CR-5-U+ is available at Aetrix Electronics and suitable for industrial control, medical device, smart meter, and automotive body electronics applications requiring stable component supply, long-term lifecycle support, and guaranteed traceable sourcing.

Supply support for DS1814CR-5-U+ 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 demanding industrial, medical, and communications applications.

The DS1814CR-5-U+ belongs to the MicroMonitor™ family of supervisory circuits engineered specifically for robust, single-chip microprocessor reset and watchdog management in 5V embedded systems.

FAQ

What is the VCC trip point specification for DS1814CR-5-U+?

The DS1814CR-5-U+ has a guaranteed VCC trip point of 4.50 V to 4.75 V at ±5% tolerance, measured across the full industrial temperature range (–40°C to +85°C). This threshold is set by an internal precision bandgap reference and comparator, ensuring consistent reset assertion before the 5V supply falls below the minimum operating voltage of most microcontrollers. The 10 mV hysteresis prevents oscillation near the trip point under noisy conditions.

Does DS1814CR-5-U+ support both active-low and active-high reset outputs?

Yes, DS1814CR-5-U+ provides dual reset outputs: Pin 1 (RST) is active-low, and Pin 3 (RST) is active-high - both asserted simultaneously during power failure, watchdog timeout, or pushbutton event. This allows direct interfacing with microcontrollers requiring either polarity without external inverters. The outputs use push-pull drivers, eliminating need for external pull-up/pull-down resistors in most cases.

How does the watchdog timer in DS1814CR-5-U+ operate, and can it be disabled?

The DS1814CR-5-U+ watchdog timer times out after 1.12 seconds if the ST input (Pin 4) does not toggle. Time-out forces both RST outputs active for ≥140 ms. The watchdog can be fully disabled by leaving the ST pin unconnected (floating) or tri-stated - no external components or configuration registers are required. This hardware-based disable method ensures reliability independent of firmware state.

What is the function of the PBRST pin on DS1814CR-5-U+?

The PBRST pin (Pin 4) on DS1814CR-5-U+ accepts an active-low signal from a mechanical pushbutton to generate a synchronized, debounced reset pulse. Internally, the DS1814CR-5-U+ detects button release and asserts RST/RST for ≥140 ms - eliminating need for external RC debounce networks or firmware polling. This simplifies front-panel reset implementation while ensuring noise immunity against sub-100 ns glitches.

Is DS1814CR-5-U+ pin-compatible with other supervisory ICs?

Yes, DS1814CR-5-U+ is pin- and function-compatible with the MAX823/824/825 series in SOT-23-5 package. All share identical pin assignments (RST, GND, RST, PBRST/ST, VCC), electrical timing, and functional behavior - enabling drop-in replacement in legacy 5V supervisory designs without layout or firmware modification. This compatibility is explicitly confirmed in Maxim's official documentation for DS1814/DS1819 devices.