Analog Devices Inc./Maxim Integrated DS1819AR-20-U

Overview

DS1819AR-20-U from Maxim Integrated is a 3.3V microprocessor supervisory circuit with watchdog timer, pushbutton reset control, and precision power supply monitoring. It provides active-low reset output (RST), strobe input (ST), and pushbutton reset input (PBRST) in SOT-23-5 package, with 20% VCC trip point tolerance (2.55V–2.70V), 140ms minimum reset pulse width, and 1.12s watchdog timeout-used in embedded systems requiring reliable power-up sequencing and software fault recovery.

For engineers reviewing the DS1819AR-20-U datasheet, DS1819AR-20-U pinout, DS1819AR-20-U application, or DS1819AR-20-U equivalent, key selection criteria include its 3.3V-specific trip point accuracy, integrated debounced pushbutton interface, watchdog disable capability via floating ST, and compatibility with industrial temperature range (-40°C to +85°C) designs.

Technical Context

The DS1819AR-20-U implements a precision voltage monitor with 5mV hysteresis, a 1.12s watchdog timer that resets on ST edge transitions, and a hardware-debounced PBRST input generating ≥140ms active-low reset pulses. Its RST output uses a push-pull driver valid down to 1.0V VCC and supports 0V operation with external pull-down resistor.

It operates across 1.0V–5.5V supply range, draws only 8–12μA typical quiescent current at 3.6V, and features noise immunity against <100ns glitches on PBRST and <2μs transients at VCCTP threshold-enabling robust operation in electrically noisy industrial environments.

Key Specifications

Pinout & Package

SOT-23-5 surface-mount package (2.9mm × 1.6mm × 1.1mm), lead-free and RoHS-compliant, optimized for space-constrained PCB layouts in portable and industrial controllers.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX823SEUR+T and TPS3808G12DBVR, DS1819AR-20-U delivers native 3.3V supervision with hardware pushbutton handling and lower typical operating current-making it optimal for cost-sensitive, space-constrained 3.0V embedded systems where discrete debounce or external timing components must be avoided.

Availability

DS1819AR-20-U is available at Aetrix Electronics and suitable for industrial PLC controllers, medical infusion pumps, smart energy meters, and automotive body control modules requiring stable component supply and long-term lifecycle support.

Supply support for DS1819AR-20-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 industrial, medical, communications, and computing applications.

The DS1819AR-20-U belongs to the MicroMonitor™ family of supervisory circuits engineered specifically for reliable microprocessor reset generation, power-fail detection, and watchdog supervision in 3.3V embedded systems.

FAQ

What is the exact VCC trip point range for DS1819AR-20-U?

The DS1819AR-20-U has a guaranteed VCC trip point range of 2.55V to 2.70V at -40°C to +85°C, corresponding to its 20% tolerance specification for 3.0V systems. This range is validated per the device's DC electrical characteristics table and ensures reset assertion before critical brownout conditions occur in 3.3V logic rails.

Does DS1819AR-20-U support both watchdog and pushbutton reset functions simultaneously?

Yes, DS1819AR-20-U supports both functions simultaneously: it includes ST (strobe input) for watchdog supervision and PBRST (pushbutton reset input) for hardware-initiated reset. The 'A' variant designation confirms dual functionality, and internal logic ensures independent operation-watchdog timeout does not interfere with PBRST-triggered reset pulses.

Can DS1819AR-20-U operate reliably below 1.0V VCC?

The DS1819AR-20-U RST output remains valid down to 1.0V VCC in standard configuration. To extend validity to 0V, a 100kΩ pull-down resistor from RST to GND is recommended per the datasheet-this maintains defined logic levels during deep brownout while drawing minimal current (≤33nA at 3.3V).

Is DS1819AR-20-U pin-compatible with MAX823 series devices?

Yes, DS1819AR-20-U is pin- and function-compatible with the MAX823/24/25 family per official documentation. Pin 1 (RST), Pin 2 (GND), Pin 3 (PBRST), Pin 4 (ST), and Pin 5 (VCC) match identically in SOT-23-5 package, enabling direct replacement in 3.3V designs where MAX823 variants were used with external level-shifting.

What is the maximum allowable VCC slew rate during power-up for DS1819AR-20-U?

The DS1819AR-20-U specifies a minimum VCC slew rate of 12.5V/s during rising edge to ensure proper power-on reset behavior. Slower ramp rates may cause premature release of RST before the microprocessor's internal regulators stabilize, risking undefined startup states.