Analog Devices Inc./Maxim Integrated DS1834S

Overview

DS1834S from Maxim Integrated (now Analog Devices) is a dual-voltage supervisor IC that monitors 5V and 3.3V power supplies with independent tolerance selection, pushbutton reset input, and CMOS push-pull reset outputs. It asserts active-low resets for both rails during out-of-tolerance conditions or manual override, with guaranteed 350 ms reset pulse width after recovery. Used in embedded systems requiring reliable dual-rail power sequencing and fail-safe boot initialization.

For engineers reviewing the DS1834S datasheet, DS1834S pinout, DS1834S application, or DS1834S equivalent, key selection criteria include dual-supply trip point configurability (5% or 10% for 5V; 10% or 20% for 3.3V), internal 40 kΩ pull-up on PBRST, push-pull RST outputs capable of valid logic down to 0 V with external GND resistor, and operation across -40°C to +85°C industrial temperature range.

Technical Context

The DS1834S integrates two independent voltage comparators with precision temperature-compensated references, each feeding a dedicated reset generator with fixed 350 ms timeout. Its power-source 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.

Tolerance selection is implemented via hard-wired TOL pins: tying 5V TOL to 5VIN selects ±10% trip (4.25–4.49 V), while grounding it selects ±5% (4.50–4.75 V); similarly, 3.3V TOL tied to 3.3VIN yields ±20% (2.47–2.64 V), grounded yields ±10% (2.80–2.97 V). The PBRST pin features internal debouncing and forces both RST outputs active for ≥350 ms after release.

Key Specifications

Pinout & Package

DS1834S is available in 8-pin SOIC (150-mil) package. Pin functions are electrically identical across DS1834 variants; the "S" suffix denotes SOIC packaging per Maxim's marking convention.

Key Features

Applications

Equivalent & Alternatives

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

Compared with TPS3808G33 and MAX6816, the DS1834S uniquely integrates dual-rail voltage monitoring, configurable trip points, and debounced pushbutton reset in one 8-pin SOIC-reducing BOM count by ≥4 discrete components and eliminating layout-sensitive RC timing networks required by alternatives.

Availability

DS1834S is available at Aetrix Electronics and suitable for industrial PLC controllers, network router boards, medical diagnostic instruments, and automotive infotainment head units requiring stable component supply and long-term lifecycle support.

Supply support for DS1834S 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, communications, and computing applications.

The DS1834S belongs to Maxim's EconoReset™ family of voltage supervisors, engineered specifically for cost-sensitive, space-constrained embedded systems needing reliable dual-rail power monitoring and manual reset integration.

FAQ

What is the function of the 5V TOL and 3.3V TOL pins on the DS1834S?

The 5V TOL and 3.3V TOL pins on the DS1834S configure the voltage trip thresholds for each rail. Grounding 5V TOL sets ±5% tolerance (4.50–4.75 V), while tying it to 5VIN selects ±10% (4.25–4.49 V). Similarly, 3.3V TOL grounded gives ±10% (2.80–2.97 V), and tied to 3.3VIN gives ±20% (2.47–2.64 V). This eliminates external resistor dividers and allows field-configurable monitoring accuracy for the DS1834S.

Does the DS1834S require external pull-up resistors on its RST outputs?

No-the DS1834S features push-pull CMOS outputs on both 5V RST and 3.3V RST pins and does not require external pull-ups. Unlike the open-drain DS1834A variant, the DS1834S (and DS1834D) can actively drive high and low states. External 100 kΩ resistors to GND are optional and only needed to maintain valid logic during full power loss (0 V on both supplies).

How does the DS1834S handle power arbitration between 5VIN and 3.3VIN?

The DS1834S internally selects the higher of 5VIN or 3.3VIN as its primary power source for bias and logic operation. This ensures continued functionality during asymmetric brownouts-for example, if 5VIN drops to 2.5 V while 3.3VIN remains at 3.0 V, the DS1834S stays powered and monitors both rails. Output drivers remain referenced to their respective supply rails, preserving noise immunity and level compatibility.

What is the minimum pulse width of the pushbutton reset signal required for the DS1834S?

The DS1834S requires the PBRST pin to be held low for a minimum of 2 ms to register a valid pushbutton event. After release, both 5V RST and 3.3V RST outputs remain asserted for 200–500 ms (typical 350 ms), independent of the duration of the PBRST low pulse. The internal debounce circuit rejects noise spikes shorter than 2 µs, preventing false triggers during ESD or switching transients.

Can the DS1834S operate with only one supply present (e.g., 5VIN only)?

Yes-the DS1834S operates with either 5VIN or 3.3VIN present, provided the active supply is ≥1.2 V. When only 5VIN is applied, the 3.3V RST output remains in a high-impedance inactive state (not driven), while 5V RST functions normally. The device draws current only from the active supply and continues monitoring that rail. Both RST outputs become valid once their respective supply reaches operational voltage.