Analog Devices Inc./Maxim Integrated DS1819BR-20/T&R

Overview

DS1819BR-20/T&R from Maxim Integrated is a 3.3V microprocessor supervisory circuit with watchdog timer, pushbutton reset control, and precise 20% VCC trip point (2.55V–2.70V). It delivers active-low reset output, 140ms minimum reset pulse width, and operates across –40°C to +85°C in SOT-23-5 package. Used in embedded systems requiring reliable power-up sequencing and software fault recovery.

For engineers reviewing the DS1819BR-20/T&R datasheet, DS1819BR-20/T&R pinout, DS1819BR-20/T&R application, or DS1819BR-20/T&R equivalent, key selection criteria include VCC trip accuracy (±20% at 3.0V), watchdog timeout (1.12s), pushbutton debounce capability, reset pulse duration (140–280ms), and SOT-23-5 thermal and layout compatibility.

Technical Context

The DS1819BR-20/T&R implements a precision voltage monitor with 5mV hysteresis, a 1.12s watchdog timer triggered by ST input transitions, and internal pushbutton debouncing with 140ms minimum active reset pulse. Its RST output uses a push-pull driver valid down to 1.0V VCC and supports 0V operation with external pull-down.

It integrates three core supervision functions-power-fail detection, software execution monitoring via strobe input, and manual reset initiation-within a single 5-pin SOT-23-5 footprint. The 'B' variant provides active-low RST (Pin 1) and active-high RST (Pin 3), with ST (Pin 4) enabling watchdog control and PBRST omitted.

Key Specifications

Pinout & Package

SOT-23-5 surface-mount package (2.9mm × 1.6mm × 1.1mm), thermally optimized for PCB space-constrained applications and compatible with standard reflow profiles.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX823TRD3+T and TPS3808G33DBVR, the DS1819BR-20/T&R uniquely combines 3.0V-system optimization, integrated pushbutton debouncing, dual active-high/low reset outputs, and factory-trimmed 20% trip tolerance-all in a pin-identical drop-in replacement for MAX823/24/25 family designs.

Availability

DS1819BR-20/T&R is available at Aetrix Electronics and suitable for industrial automation, medical device, smart metering, and automotive body electronics requiring stable component supply and long-term lifecycle assurance.

Supply support for DS1819BR-20/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 demanding industrial, medical, and communications applications.

The DS1819BR-20/T&R belongs to the MicroMonitor™ supervisory product line, engineered specifically for reliable microprocessor reset, watchdog supervision, and manual reset control in 3.0V embedded systems.

FAQ

What is the exact VCC trip point range for DS1819BR-20/T&R?

The DS1819BR-20/T&R has a guaranteed VCC trip point range of 2.55V to 2.70V at 25°C, corresponding to ±20% tolerance around a nominal 3.0V supply. This range is factory-trimmed and includes 5mV hysteresis to prevent oscillation near the threshold. The trip point remains stable across the full –40°C to +85°C operating temperature range, making DS1819BR-20/T&R suitable for harsh environmental deployments where supply rails may drift.

Does DS1819BR-20/T&R support both active-high and active-low reset outputs?

Yes, DS1819BR-20/T&R provides dual reset outputs: Pin 1 (RST) is active-low, and Pin 3 (RST) is active-high. This allows direct interfacing with microprocessors that require either polarity without external inverters. Both outputs are synchronized and asserted simultaneously during power failure, watchdog timeout, or pushbutton event - though DS1819BR-20/T&R does not include PBRST (it is a 'B' variant), so only ST-triggered and power-monitoring resets activate both outputs.

Can the watchdog timer in DS1819BR-20/T&R be disabled, and how?

Yes, the watchdog timer in DS1819BR-20/T&R can be disabled by leaving the ST pin (Pin 4) floating or tri-stated. No external pull-up or pull-down is required. When ST is unconnected, the internal watchdog circuit remains inactive, and DS1819BR-20/T&R functions solely as a power supervisor. This behavior is documented in the official DS1814/DS1819 datasheet and verified across production lots.

What is the minimum reset pulse width guaranteed by DS1819BR-20/T&R?

DS1819BR-20/T&R guarantees a minimum reset pulse width of 140ms for both RST and RST outputs, with a maximum of 280ms under worst-case conditions. This duration is maintained regardless of VCC slew rate or temperature, ensuring sufficient time for microprocessor power stabilization and internal register initialization. The 140ms specification applies to all reset sources: power-up, power-down, and watchdog timeout events.

Is DS1819BR-20/T&R pin-compatible with the MAX823 series?

Yes, DS1819BR-20/T&R is pin- and function-compatible with the MAX823/24/25 family in SOT-23-5 package. Pin assignments (VCC, GND, RST, RST, ST) match exactly, and electrical characteristics-including trip point, reset timing, and drive strength-are aligned for drop-in replacement in existing 3.0V designs. This compatibility is explicitly stated in the DS1814/DS1819 datasheet and validated across multiple board-level implementations.