Analog Devices Inc./Maxim Integrated DS1819BR-5-U

Overview

DS1819BR-5-U from Maxim Integrated is a 3.3V microprocessor supervisory circuit in SOT-23-5 package, providing precision power monitoring (±5% VCC trip at 3.00–3.15V), watchdog timer (1.12s 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 controllers requiring reliable power-up sequencing and fault recovery.

For engineers reviewing the DS1819BR-5-U datasheet, DS1819BR-5-U pinout, DS1819BR-5-U application, or DS1819BR-5-U equivalent, key selection criteria include its 3.0V nominal supply monitoring accuracy, 140ms minimum reset pulse width, watchdog strobe timing compatibility with MCU I/O signals, and SOT-23-5 footprint for space-constrained designs.

Technical Context

The DS1819BR-5-U implements a precision bandgap-based voltage comparator with 5mV hysteresis to detect VCC drops below 3.00V, holding RST low for ≥140ms after recovery. Its internal watchdog timer triggers reset if ST input fails to toggle within 1.12s, and supports disable-by-float configuration.

This variant ('B' type) provides dual reset outputs: active-low RST on Pin 1 and active-high RST on Pin 3 - enabling direct interface with both NMOS- and PMOS-gated reset logic. The ST and PBRST inputs meet VIH ≥ 0.8×VCC and VIL ≤ 0.3×VCC thresholds across -40°C to +85°C.

Key Specifications

Pinout & Package

SOT-23-5 surface-mount package (2.9mm × 1.6mm × 1.1mm), thermally enhanced with exposed pad not connected internally; RoHS-compliant, moisture sensitivity level 1.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX823SEUR+T and TPS3808G12DBVR, the DS1819BR-5-U uniquely delivers factory-trimmed 3.0V ±5% monitoring, simultaneous active-low/active-high reset outputs, and guaranteed 140ms pulse width - making it optimal for compact, dual-rail, or safety-critical 3.3V microcontroller systems without design compromises.

Availability

DS1819BR-5-U is available at Aetrix Electronics and suitable for industrial automation, medical handheld devices, automotive body electronics, and smart metering applications requiring stable component supply and long-term lifecycle support.

Supply support for DS1819BR-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 and mixed-signal ICs for industrial, automotive, and communications markets, with emphasis on reliability and integration.

The DS1819BR-5-U belongs to the MicroMonitor™ family of supervisory circuits engineered specifically for robust microprocessor reset and watchdog control in 3.3V embedded systems operating across extended temperature ranges.

FAQ

What is the exact VCC trip voltage range for DS1819BR-5-U?

The DS1819BR-5-U has a factory-trimmed VCC trip point of 3.00V to 3.15V, corresponding to ±5% tolerance at 3.0V nominal. This specification is guaranteed over the full -40°C to +85°C operating temperature range and is measured with VCC ramped at ≥12.5V/s. The DS1819BR-5-U uses an internal temperature-compensated bandgap reference to maintain accuracy across voltage and temperature variations.

Does DS1819BR-5-U support both watchdog and pushbutton reset functions?

No - the DS1819BR-5-U is a 'B' variant and supports watchdog timer functionality via the ST pin but does not include the PBRST (pushbutton reset) input. Only DS1819A and DS1819C variants provide PBRST. The DS1819BR-5-U features RST (Pin 1), RST (Pin 3), ST (Pin 4), and GND/VCC - confirming its dedicated watchdog + dual-reset role without pushbutton capability.

Can DS1819BR-5-U operate below 3.0V?

Yes - the DS1819BR-5-U functions down to VCC = 1.0V, with guaranteed RST output validity to that level. Its push-pull RST output remains logically valid (low/high) even as VCC declines, and can be extended to 0V using an external 100kΩ pull-down resistor. Operating current drops to sub-μA levels below 1.2V, though watchdog timing and trip accuracy are not specified below 1.2V per datasheet limits.

Is DS1819BR-5-U pin-compatible with MAX823 series devices?

Yes - the DS1819BR-5-U is explicitly documented as pin- and function-compatible with MAX823/824/825 products in SOT-23-5 package. Pin assignments match exactly: Pin 1=RST, Pin 2=GND, Pin 3=RST, Pin 4=ST, Pin 5=VCC. However, note that MAX823 variants are 5V-only (4.5V trip), so electrical compatibility requires verifying VCC domain alignment in the target design.

What is the maximum recommended slew rate for VCC during power-up?

The DS1819BR-5-U specifies a minimum VCC slew rate of 12.5V/s during rising edge to ensure accurate trip-point detection and avoid metastability in the internal comparator. Slower ramps may cause delayed or inconsistent reset assertion. For systems with slow-ramping supplies (e.g., capacitor-charged rails), adding a small RC network at VCC or using a dedicated power-good sequencer is advised to meet this requirement.