Analog Devices Inc./Maxim Integrated DS1819AR-5-U

Overview

DS1819AR-5-U from Maxim Integrated is a 3.3V microprocessor supervisory circuit in SOT-23-5 package, providing precision power monitoring (±5% trip point at 3.00–3.15 V), watchdog timer (1.12 s timeout), and pushbutton reset control with 140 ms minimum active-reset pulse width. It halts and restarts out-of-control microprocessors during power transients or software hangs in embedded industrial controllers.

For engineers reviewing the DS1819AR-5-U datasheet, DS1819AR-5-U pinout, DS1819AR-5-U application, or DS1819AR-5-U equivalent, key selection criteria include its 3.0V supply monitoring accuracy, integrated watchdog strobe input (ST), pushbutton reset debouncing, active-low RST output with push-pull drive down to 1.0V VCC, and compatibility with MAX823/24/25 functional equivalents.

Technical Context

The DS1819AR-5-U 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 a guaranteed 140 ms reset pulse on button release. Its RST output uses a push-pull driver capable of valid logic levels down to 1.0 V VCC.

It operates across -40°C to +85°C, draws only 8–12 µA quiescent current at 3.6 V, and supports noise-immune operation: <100 ns pulses on PBRST are ignored, and VCC detection rejects <2 µs transients when VCCTP − VCC = 100 mV.

Key Specifications

Pinout & Package

SOT-23-5 surface-mount package with 1.6 mm × 2.9 mm footprint and 0.95 mm height; lead-free, RoHS-compliant.

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 DS1819AR-5-U uniquely combines 3.0 V ±5% monitoring, integrated pushbutton debounce, and watchdog strobe in one SOT-23-5 device-eliminating external components while maintaining pin-and-function compatibility with industry-standard supervisory ICs.

Availability

DS1819AR-5-U is available at Aetrix Electronics and suitable for industrial automation, medical instrumentation, smart metering, and automotive body electronics requiring stable component supply and long-term lifecycle support.

Supply support for DS1819AR-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, mixed-signal, and power management ICs for demanding industrial, medical, and communications applications.

The DS1819AR-5-U belongs to the MicroMonitor™ family of supervisory circuits engineered specifically for reliable microprocessor reset and watchdog functionality in 3.3 V embedded systems with stringent power integrity requirements.

FAQ

What is the exact VCC trip point range for DS1819AR-5-U?

The DS1819AR-5-U has a guaranteed VCC trip point of 3.00 V to 3.15 V at room temperature, corresponding to ±5% tolerance around 3.0 V. This specification is validated across the full -40°C to +85°C operating range and ensures consistent brown-out detection in 3.3 V systems without external calibration. The DS1819AR-5-U achieves this using an internal temperature-compensated bandgap reference and comparator circuit.

Does DS1819AR-5-U support both active-low and active-high reset outputs?

No, the DS1819AR-5-U provides only an active-low reset output (RST) on Pin 1. Unlike DS1819B or DS1819C variants, the 'A' version does not include an active-high RST output. Its RST pin uses a push-pull driver that actively drives low during reset and high otherwise, and remains valid down to 1.0 V VCC. The DS1819AR-5-U is functionally identical to DS1814A but optimized for 3.0 V operation.

How is the watchdog timer enabled or disabled on DS1819AR-5-U?

The watchdog timer on DS1819AR-5-U is enabled by connecting the ST pin (Pin 4) to a microprocessor output that toggles at least once every 1.12 seconds. To disable it, leave the ST pin floating (unconnected) or tri-state it-no pull-up or pull-down is required. The DS1819AR-5-U datasheet confirms that floating ST places the watchdog in a permanently disabled state. This behavior is intrinsic to the DS1819AR-5-U silicon design and requires no configuration register access.

Can DS1819AR-5-U drive a reset line directly without external components?

Yes, the DS1819AR-5-U's push-pull RST output can directly drive standard CMOS or TTL reset inputs without external pull-up resistors. It sources up to 350 µA at 2.4 V and sinks up to 6 mA at 0.4 V, meeting typical microcontroller reset input requirements. For operation below 1.0 V VCC, a 100 kΩ pull-down resistor from RST to GND maintains valid logic low down to 0 V, as documented in Figure 9 of the DS1819AR-5-U datasheet.

Is DS1819AR-5-U pin-compatible with MAX823 series devices?

Yes, the DS1819AR-5-U is explicitly stated in its datasheet to be pin- and function-compatible with the MAX823/24/25 family. All five pins map identically: RST (1), GND (2), PBRST (3), ST (4), and VCC (5). Functionally, it replicates the same power monitoring, watchdog, and pushbutton reset capabilities. This compatibility allows drop-in replacement in existing MAX823-based designs operating at 3.0 V, provided the trip voltage tolerance matches system requirements.