Analog Devices Inc./Maxim Integrated DS1819BR-5/T&R

Overview

DS1819BR-5/T&R from Maxim Integrated is a 3.3V microprocessor supervisory circuit in SOT-23-5 package, providing precision power monitoring (±5% trip point at 3.00 V), watchdog timer (1.12 s timeout), and active-low reset output. It halts and restarts out-of-control microprocessors during power transients or software lockup, and supports pushbutton override via debounced PBRST input - used in embedded industrial controllers and battery-powered IoT nodes.

For engineers reviewing the DS1819BR-5/T&R datasheet, DS1819BR-5/T&R pinout, DS1819BR-5/T&R application, or DS1819BR-5/T&R equivalent, key selection considerations include its 3.00 V ±5% V_CC trip point, 140 ms minimum reset pulse width, watchdog strobe input (ST), pushbutton reset input (PBRST), and SOT-23-5 pin-compatible footprint with MAX823/24/25 series.

Technical Context

The DS1819BR-5/T&R implements a precision voltage monitor with 5 mV hysteresis, a 1.12 s watchdog timer triggered by ST input transitions, and a debounced PBRST input that generates ≥140 ms active-low reset pulses on button release. Its push-pull RST output remains valid down to 1.0 V V_CC, and supports 0 V operation with external pull-down.

It belongs to the DS1819 'B' variant family: pin 1 = RST (active-low), pin 2 = GND, pin 3 = RST (active-high), pin 4 = ST (watchdog strobe), pin 5 = V_CC. The 'B' version excludes PBRST but includes dual reset outputs and watchdog functionality - distinguishing it from 'A' (PBRST + RST) and 'C' (PBRST + dual RST) variants.

Key Specifications

Pinout & Package

SOT-23-5 surface-mount package (2.9 mm × 1.6 mm × 1.1 mm), thermally enhanced, RoHS-compliant, tape-and-reel format (T&R).

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX823SEUK+T and TPS3808G12DBVR, the DS1819BR-5/T&R uniquely combines 3.00 V ±5% accuracy, integrated watchdog with ST input, dual-reset outputs, and ultra-low 8 µA supply current - making it optimal for space-constrained, battery-sensitive 3.3V embedded systems requiring robust, self-contained supervision.

Availability

DS1819BR-5/T&R is available at Aetrix Electronics and suitable for industrial automation, smart metering, medical sensor nodes, and POS terminal controllers requiring stable component supply across extended product lifecycles.

Supply support for DS1819BR-5/T&R 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, and communications applications.

The DS1819BR-5/T&R belongs to the MicroMonitor™ supervisory IC family, engineered specifically for reliable microprocessor reset and watchdog control in 3.3V embedded systems with stringent power and space constraints.

FAQ

What is the exact V_CC trip point tolerance and nominal value for DS1819BR-5/T&R?

The DS1819BR-5/T&R has a nominal V_CC trip point of 3.00 V with ±5% tolerance, meaning it asserts reset when V_CC falls below 2.85 V (min) and releases reset when V_CC rises above 3.15 V (max). This 5 mV hysteresis prevents oscillation near the threshold and is specified across −40 °C to +85 °C.

Does DS1819BR-5/T&R support both active-low and active-high reset outputs?

Yes, DS1819BR-5/T&R provides two independent reset outputs: pin 1 (RST) is active-low, and pin 3 (RST) is active-high. Both outputs are push-pull, share the same 140–280 ms pulse width, and remain valid down to 1.0 V V_CC, enabling direct interface with diverse microcontroller reset architectures.

How is the watchdog timer enabled or disabled on DS1819BR-5/T&R?

The watchdog timer on DS1819BR-5/T&R is enabled by driving the ST pin (pin 4) with periodic edges - it times out after 1.12 s if no transition occurs. To disable it, leave ST floating (high-impedance) or tri-state the driving signal. No external components or configuration registers are needed - the function is purely hardware-based and immediate.

Can DS1819BR-5/T&R operate below 3.3V, and what is its minimum functional V_CC?

Yes, DS1819BR-5/T&R operates from 1.0 V to 5.5 V. Its reset outputs remain valid down to 1.0 V V_CC; below that, an external 100 kΩ pull-down resistor from RST to GND extends valid reset assertion to 0 V - critical for battery-dead detection and graceful shutdown in portable systems using DS1819BR-5/T&R.

Is DS1819BR-5/T&R pin-compatible with other MicroMonitor devices?

Yes, DS1819BR-5/T&R is pin- and function-compatible with the MAX823/24/25 series and other DS181x 'B' variants (e.g., DS1814B, DS1819B) in SOT-23-5. Pin assignments (RST, GND, RST, ST, V_CC) match exactly, enabling drop-in replacement in existing layouts - provided the 3.3V trip point and watchdog functionality meet system requirements.