Analog Devices Inc./Maxim Integrated DS1834AS+

Overview

DS1834AS+ from Maxim Integrated (now Analog Devices) 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 reset outputs. It asserts active-low resets for 350 ms after supply recovery and supports systems with dual-rail power architectures such as industrial controllers and embedded communication modules.

For engineers reviewing the DS1834AS+ datasheet, DS1834AS+ pinout, DS1834AS+ application, or DS1834AS+ equivalent, key selection criteria include dual-supply trip point configurability (5%–10% for 5V, 10%–20% for 3.3V), internal 40 kΩ pull-up on PBRST, guaranteed 350 ms reset pulse width, and operation down to 1.2V supply.

Technical Context

The DS1834AS+ integrates two independent voltage comparators with temperature-compensated references, each feeding a latch-driven reset generator with fixed 350 ms timeout. Its power arbitration logic draws internal current from the higher of 5VIN or 3.3VIN, while RST outputs are sourced/sunk only from their respective supply rails.

Reset assertion is triggered when either supply falls outside its selected tolerance band; recovery releases reset after 350 ms. The PBRST pin provides debounced manual override-pulling low for ≥2 ms forces both resets active for ~350 ms post-release, with internal 40 kΩ pull-up and noise immunity against <2 µs glitches.

Key Specifications

Pinout & Package

DS1834AS+ is available in 8-pin SOIC (150-mil) package. Pin functions are electrically identical across DIP, SOIC, and µ-SOP variants.

Key Features

Applications

Equivalent & Alternatives

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

Compared with DS1834AS+, MAX6326US29D3+ reduces functionality to single-rail supervision with open-drain output, while TPS3808G33DBVR offers programmable delay but omits 5V monitoring and pushbutton support-neither provides the integrated dual-rail, pushbutton, and tolerance-select capability of DS1834AS+.

Availability

DS1834AS+ is available at Aetrix Electronics and suitable for industrial PLC controllers, network router power management, medical diagnostic instruments, and automotive infotainment head units requiring stable component supply and long-term lifecycle support.

Supply support for DS1834AS+ 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 (via acquisition of Maxim Integrated) designs precision analog, mixed-signal, and power management ICs for industrial, automotive, and communications markets.

The DS1834AS+ belongs to Maxim's EconoReset family-engineered for cost-sensitive, dual-rail embedded systems needing reliable power-on reset without external timing or configuration components.

FAQ

What is the function of the 5V TOL and 3.3V TOL pins on the DS1834AS+?

The 5V TOL and 3.3V TOL pins on the DS1834AS+ configure the voltage trip thresholds for their respective supplies: tying 5V TOL to GND selects a 5% tolerance (4.50–4.75 V), while tying it to 5VIN selects 10% (4.25–4.49 V); similarly, 3.3V TOL selects 10% or 20% tolerance. This eliminates external resistor networks and enables application-specific margin tuning without changing the DS1834AS+ footprint.

Does the DS1834AS+ require external pull-up resistors on its reset outputs?

No, the DS1834AS+ uses CMOS push-pull outputs for both 5V RST and 3.3V RST, so no external pull-up resistors are needed-unlike the DS1834A variant which requires 10 kΩ pull-ups. This simplifies BOM and layout, reduces standby current, and ensures defined logic levels even under light capacitive loads.

How does the DS1834AS+ handle power sequencing when both 5VIN and 3.3VIN are present?

The DS1834AS+ draws internal operating current from the higher of 5VIN or 3.3VIN, ensuring stable biasing during asymmetric power-up. Both reset outputs remain asserted for ~350 ms after the *last* supply reaches its in-tolerance window-preventing premature release if one rail powers up significantly faster than the other, a critical behavior for FPGAs and multi-core processors.

Can the DS1834AS+ generate a valid reset signal when one supply drops below 1.2 V?

Yes-the DS1834AS+ maintains valid RST outputs as long as at least one input remains above 1.2 V. For operation with both supplies at 0 V (e.g., full power loss), a 100 kΩ resistor from either RST output to GND sustains a valid low state, enabling safe shutdown signaling in battery-backed systems without additional supervisors.

What is the minimum pulse width required on PBRST to trigger a reset on the DS1834AS+?

The DS1834AS+ requires the PBRST pin to be held low for at least 2 ms to register a valid pushbutton event. After release, both 5V RST and 3.3V RST are asserted for approximately 350 ms. The internal 40 kΩ pull-up and hardware debouncing eliminate sensitivity to contact bounce, making the DS1834AS+ suitable for unfiltered mechanical switches in harsh environments.