Analog Devices Inc./Maxim Integrated DS1819BR-10-U+

Overview

DS1819BR-10-U+ from Maxim Integrated is a 3.3V microprocessor supervisory circuit with watchdog timer and pushbutton reset functionality. It monitors VCC (trip point 2.85–3.00 V), provides active-low reset output, delivers 140–280 ms reset pulse width, and features 1.12 s watchdog timeout. It operates across –40°C to +85°C in SOT-23-5 for embedded microcontroller power integrity.

For engineers reviewing the DS1819BR-10-U+ datasheet, DS1819BR-10-U+ pinout, DS1819BR-10-U+ application, or DS1819BR-10-U+ equivalent, key selection criteria include 3V supply monitoring tolerance (±10%), watchdog strobe timing compliance, pushbutton debouncing behavior, and SOT-23-5 footprint compatibility with MAX823/24/25 family designs.

Technical Context

The DS1819BR-10-U+ implements a precision voltage monitor with 5 mV hysteresis, a 1.12 s watchdog timer triggered by ST input transitions, and internal pushbutton debounce logic generating ≥140 ms active-low reset pulses. Its RST output uses a push-pull driver valid down to 1.0 V VCC.

It supports three functional variants: 'A' (RST, PBRST, ST), 'B' (RST, RST, ST), and 'C' (RST, RST, PBRST). DS1819BR-10-U+ is a 'B' variant - featuring dual active-low and active-high reset outputs, ST watchdog input, and no PBRST - enabling flexible reset signaling in 3.3V systems without external buttons.

Key Specifications

Pinout & Package

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

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX823SEUK+T and TPS3808G12DBVR, DS1819BR-10-U+ uniquely delivers factory-trimmed 3.3V supervision (±10%), dual RST outputs, and watchdog functionality in one SOT-23-5 package-reducing board area and eliminating discrete reset logic in compact 3V embedded systems.

Availability

DS1819BR-10-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 assurance.

Supply support for DS1819BR-10-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, and communications applications.

The DS1819BR-10-U+ belongs to the MicroMonitor™ supervisory product line, engineered specifically for robust microprocessor reset generation, voltage monitoring, and watchdog protection in 3.3V embedded systems.

FAQ

What is the exact VCC trip point range for DS1819BR-10-U+?

The DS1819BR-10-U+ has a guaranteed VCC trip point of 2.85 V to 3.00 V, corresponding to its ±10% tolerance rating for 3.3V systems. This range is factory-trimmed and specified over the full –40°C to +85°C temperature range. The 5 mV hysteresis prevents reset oscillation during marginal supply conditions. DS1819BR-10-U+ does not support adjustable thresholds - its trip point is fixed and unchangeable.

Does DS1819BR-10-U+ support pushbutton reset functionality?

No, DS1819BR-10-U+ does not support pushbutton reset. As a 'B' variant, it includes RST (active-low), RST (active-high), ST (watchdog strobe), GND, and VCC pins - but omits the PBRST pin found on 'A' and 'C' variants. DS1819BR-10-U+ is intended for watchdog-only supervision in systems where external reset buttons are handled separately. For pushbutton capability, consider DS1819AR-10-U+ or DS1819CR-10-U+ instead.

Can the watchdog timer in DS1819BR-10-U+ be disabled?

Yes, the watchdog timer in DS1819BR-10-U+ can be disabled by leaving the ST pin floating (high-impedance) or actively driving it to a constant logic high or low level. When ST is static, the internal timer never resets and times out after ~1.12 s, asserting reset. To permanently disable watchdog behavior, tie ST to VCC or GND through a 10 kΩ resistor - this prevents unintended toggling while avoiding excessive current draw. DS1819BR-10-U+ requires no configuration register writes to disable the watchdog.

What is the minimum VCC required for DS1819BR-10-U+ to assert a valid RST signal?

DS1819BR-10-U+ maintains valid RST output down to 1.0 V VCC using its push-pull driver architecture. Below 1.0 V, a 100 kΩ pull-down resistor from RST to GND extends validity to 0 V VCC - enabling reliable reset assertion during complete power collapse. This behavior is explicitly characterized in the datasheet (Figure 9) and distinguishes DS1819BR-10-U+ from open-drain supervisors that fail below 1.5 V. DS1819BR-10-U+ does not require external capacitors or bias networks to achieve this.

Is DS1819BR-10-U+ pin-compatible with MAX823 series devices?

Yes, DS1819BR-10-U+ is pin- and function-compatible with the MAX823/24/25 family in SOT-23-5 package. Pin 1 (RST), Pin 2 (GND), Pin 4 (ST), and Pin 5 (VCC) map identically. Pin 3 is RST (active-high) in DS1819BR-10-U+, matching the MAX823's Pin 3 function. This allows drop-in replacement in existing MAX823-based layouts designed for 3.3V operation - provided the original design used a 'B' variant or accommodated dual-reset signaling. DS1819BR-10-U+ retains identical timing and electrical specs for seamless integration.