Analog Devices Inc./Maxim Integrated DS1834AU+

Overview

DS1834AU+ from Analog Devices (acquired Maxim Integrated, formerly Dallas Semiconductor) is a dual-voltage power-on reset supervisor IC monitoring both 5V and 3.3V supplies with independent tolerance selection, pushbutton reset input, and CMOS push-pull outputs. It asserts active-low reset signals for each rail during out-of-tolerance conditions or manual override, with guaranteed 350 ms reset pulse width after recovery. Used in embedded systems with dual-supply microcontrollers requiring reliable power sequencing and brownout protection.

For engineers reviewing the DS1834AU+ datasheet, DS1834AU+ pinout, DS1834AU+ application, or DS1834AU+ equivalent, key selection criteria include dual-rail trip point configurability (5% or 10% for 5V; 10% or 20% for 3.3V), internal 40 kΩ pull-up on PBRST, push-pull output drive capability (10 mA sink), and operation down to 1.2 V supply while maintaining valid reset states.

Technical Context

The DS1834AU+ integrates two independent voltage monitors with selectable trip thresholds via dedicated TOL pins tied to either GND or respective supply rails. Each monitor uses a precision temperature-compensated bandgap reference and comparator to detect undervoltage on 5VIN (trip range 4.25–4.75 V) or 3.3VIN (2.47–2.97 V).

Its internal power routing draws operating current from the higher of the two supply inputs, and both RST outputs remain active for 200–500 ms after supply recovery. The PBRST pin features internal debouncing and forces both resets active for ~350 ms after release, with a 2 ms minimum low pulse width requirement.

Key Specifications

Pinout & Package

DS1834AU+ is available in 8-pin SOIC (150-mil) package. Pin functions are identical across DIP, SOIC, and µ-SOP variants per manufacturer documentation.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar dual-rail voltage supervisor applications.

Compared with MAX6816EPA+ and TPS3808G33DBVR, the DS1834AU+ uniquely integrates dual-rail monitoring, user-selectable thresholds per rail, and hardware-debounced pushbutton reset in a single 8-pin package - reducing BOM count, PCB area, and firmware complexity in multi-voltage embedded designs.

Availability

DS1834AU+ is available at Aetrix Electronics and suitable for industrial PLC controllers, medical diagnostic devices, telecom base station cards, and automotive infotainment head units requiring stable component supply and long-term lifecycle support.

Supply support for DS1834AU+ 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

Analog Devices, Inc. (ADI) is a global semiconductor leader specializing in high-performance analog, mixed-signal, and digital signal processing technologies for precision measurement and control.

The DS1834AU+ belongs to ADI's legacy voltage supervisor product line, originally developed by Dallas Semiconductor, targeting robust power sequencing and fail-safe reset generation in multi-rail embedded systems.

FAQ

What is the function of the 5V TOL and 3.3V TOL pins on the DS1834AU+?

The 5V TOL and 3.3V TOL pins on the DS1834AU+ configure the undervoltage detection threshold for their respective supply rails. When tied to GND, 5V TOL selects a 5% tolerance (4.50–4.75 V trip), and 3.3V TOL selects 10% (2.80–2.97 V). When tied to their corresponding supply inputs, they select 10% for 5V (4.25–4.49 V) and 20% for 3.3V (2.47–2.64 V). This eliminates external resistor dividers and enables field-configurable reset points without redesigning the DS1834AU+ circuit.

Does the DS1834AU+ require external pull-up resistors on its RST outputs?

No, the DS1834AU+ does not require external pull-up resistors on its RST outputs. It uses CMOS push-pull drivers capable of sourcing and sinking current - specifically, it can sink up to 10 mA at 0.4 V and source 350 µA at 2.4 V. This allows direct connection to standard logic reset inputs without additional components, unlike open-drain alternatives such as the DS1834A variant which mandates external pull-ups.

How does the DS1834AU+ handle power failure when both 5VIN and 3.3VIN drop simultaneously?

When both 5VIN and 3.3VIN fall below their configured thresholds, the DS1834AU+ asserts both 5V RST and 3.3V RST outputs low simultaneously. Its internal circuitry continues operating as long as at least one supply remains above 1.2 V. Even if both supplies collapse to 0 V, the push-pull outputs maintain valid logic states due to internal charge retention - ensuring the reset condition persists through full power loss, which is critical for safe MCU shutdown in the DS1834AU+ application.

What is the minimum pulse width required on the PBRST pin to trigger a manual reset on the DS1834AU+?

The DS1834AU+ requires a minimum low pulse width of 2 ms on the PBRST pin to initiate a manual reset. This specification is verified across -40°C to +85°C and ensures immunity to contact bounce or noise spikes. Once triggered, both RST outputs remain active for 200–500 ms after PBRST returns high, providing a guaranteed reset hold time independent of software or external timing circuits - a key reliability feature of the DS1834AU+ design.

Can the DS1834AU+ operate with only one supply connected (e.g., 3.3VIN only)?

Yes, the DS1834AU+ can operate with only 3.3VIN applied, provided it remains within the 1.2–5.5 V range. In this configuration, the 5V monitor circuitry remains inactive, but the 3.3V RST output functions normally with full threshold accuracy and 350 ms reset pulse width. The device draws internal current solely from 3.3VIN, and the 5VIN and 5V TOL pins may be left unconnected or tied to GND. This single-rail mode retains full functionality for the active supply, making the DS1834AU+ adaptable to evolving power architecture requirements.