Analog Devices Inc./Maxim Integrated DS1834AX/T&R

Overview

DS1834AX/T&R from Maxim Integrated is a dual-voltage power-on reset supervisor IC monitoring both 5V and 3.3V supplies with independent tolerance selection, pushbutton reset override, and CMOS push-pull outputs. It asserts active-low reset signals for each supply during out-of-tolerance conditions or manual override, maintains reset for 350 ms after recovery, and draws internal current from the higher of the two input voltages. Used in embedded systems requiring reliable dual-rail power sequencing and fail-safe boot initialization.

For engineers reviewing the DS1834AX/T&R datasheet, DS1834AX/T&R pinout, DS1834AX/T&R application, or DS1834AX/T&R equivalent, key selection criteria include dual-supply trip point configurability (5%–10% for 5VIN, 10%–20% for 3.3VIN), 350 ms reset timeout, pushbutton debouncing, operating temperature range (−40°C to +85°C), and SOIC-8 package compatibility with tape-and-reel delivery.

Technical Context

The DS1834AX/T&R integrates two independent voltage comparators with precision temperature-compensated references, enabling simultaneous monitoring of 5VIN and 3.3VIN against user-selectable thresholds via dedicated TOL pins. Each comparator drives a dedicated open-drain or push-pull reset output-DS1834A variant uses NMOS open-drain outputs requiring external pull-ups, while DS1834 and DS1834D use CMOS push-pull outputs.

Its internal power-fail logic prioritizes the higher input voltage (5VIN or 3.3VIN) for biasing, and the PBRST pin features internal 40 kΩ pull-up and hardware debounce. Reset assertion timing is guaranteed at 200–500 ms, with noise immunity rejecting pulses <2 µs, ensuring robust operation during power transients.

Key Specifications

Pinout & Package

DS1834AX/T&R is supplied in an 8-pin SOIC (150-mil) package, RoHS-compliant, tape-and-reel format (2500/reel). Pinout matches standard DS1834A configuration with dedicated inputs/outputs for dual-supply monitoring and manual reset.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar dual-supply reset supervision applications.

Compared with MAX6326–MAX6328 and TPS3808G33, the DS1834AX/T&R uniquely integrates dual-rail monitoring, user-selectable trip tolerances per rail, and hardware-synchronized pushbutton reset in a single SOIC-8 package-reducing design complexity, PCB footprint, and qualification effort for mixed-voltage embedded systems.

Availability

DS1834AX/T&R is available at Aetrix Electronics and suitable for industrial PLC controllers, medical diagnostic equipment, telecom base station cards, and automotive infotainment head units requiring stable component supply, long-lifecycle support, and RoHS-compliant packaging.

Supply support for DS1834AX/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 and mixed-signal ICs for industrial, medical, communications, and automotive applications, emphasizing high reliability and integration.

The DS1834AX/T&R belongs to the EconoReset™ family of power-supply supervisors, engineered specifically for cost-effective, space-constrained dual-rail systems needing configurable voltage monitoring and deterministic reset timing without external passive components.

FAQ

What is the function of the 5V TOL and 3.3V TOL pins on the DS1834AX/T&R?

The 5V TOL and 3.3V TOL pins on the DS1834AX/T&R configure the voltage trip thresholds for their respective supplies. Connecting 5V TOL to GND selects a ±5% tolerance (4.50–4.75 V), while connecting it to 5VIN selects ±10% (4.25–4.49 V). Similarly, 3.3V TOL tied to GND sets ±10% (2.80–2.97 V), and to 3.3VIN sets ±20% (2.47–2.64 V). This eliminates external resistor dividers and allows field-programmable trip points without changing the DS1834AX/T&R hardware.

Does the DS1834AX/T&R support operation when only one supply is present?

Yes, the DS1834AX/T&R remains functional with only 5VIN or only 3.3VIN applied, provided the active input is ≥1.2 V. Its internal circuitry draws bias from the higher available voltage, and the corresponding RST output will assert if that supply falls out of tolerance. The inactive supply's RST remains deasserted, and the PBRST function operates normally-making the DS1834AX/T&R suitable for transitional or single-rail legacy upgrades.

What external components are required for proper operation of the DS1834AX/T&R?

The DS1834AX/T&R requires external pull-up resistors on both 5V RST and 3.3V RST outputs (typically 10 kΩ) because it uses NMOS open-drain outputs. No external capacitors, resistors, or diodes are needed for voltage monitoring or reset timing-the 350 ms timeout, trip thresholds, and pushbutton debounce are fully internal. A simple momentary switch connected between PBRST and GND completes the manual reset interface.

How does the DS1834AX/T&R handle power-down sequences where both supplies collapse simultaneously?

During simultaneous power-down, the DS1834AX/T&R maintains valid reset assertion as long as at least one input remains ≥1.2 V. Its internal architecture ensures both RST outputs stay active until the last supply drops below this threshold. The device continues asserting reset even after both inputs fall to 0 V-provided external pull-ups maintain logic-high states-preventing premature release and ensuring clean shutdown of downstream logic.

Is the DS1834AX/T&R pin-compatible with other variants in the DS1834 family?

Yes, the DS1834AX/T&R shares identical pinout and footprint with all DS1834 family members in SOIC-8 packaging-including DS1834AS, DS1834AS+, and DS1834A. Differences lie solely in output type (open-drain vs. push-pull), RoHS compliance, and reel packaging; electrical behavior, pin functions, and layout are fully interchangeable, enabling drop-in replacement during qualification or sourcing shifts.