Analog Devices Inc./Maxim Integrated DS1834S+

Overview

DS1834S+ from Analog Devices (acquired Maxim Integrated, formerly Dallas Semiconductor) is a dual-voltage supervisor IC that independently monitors 5V and 3.3V power supplies with user-selectable tolerance thresholds (5%/10% for 5V; 10%/20% for 3.3V), asserts active-low reset outputs with 350 ms timeout, and supports debounced pushbutton override. It operates from -40°C to +85°C and is used in embedded systems with dual-rail power domains requiring reliable power-on and brownout reset sequencing.

For engineers reviewing the DS1834S+ datasheet, DS1834S+ pinout, DS1834S+ application, or DS1834S+ equivalent, key selection considerations include dual-supply trip point configurability, internal power sourcing from the higher of two inputs, push-pull RST outputs (DS1834/DS1834D variant), and compatibility with SOIC-8 packaging for industrial control and telecom power management designs.

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 internal power selector automatically draws operating current from the higher of 5VIN or 3.3VIN, eliminating external biasing.

Reset assertion is triggered when either supply falls outside its configured tolerance window; both RST outputs remain active for ≥350 ms after return to tolerance. The PBRST input provides hardware-debounced manual reset with ≥2 ms low pulse detection and synchronized dual-output assertion.

Key Specifications

Pinout & Package

DS1834S+ is supplied in an 8-pin SOIC (150-mil) package with standard JEDEC MS-012AC footprint and 1.27 mm pitch.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX6326–MAX6328 and TPS3808G33, the DS1834S+ uniquely integrates dual-rail monitoring, user-selectable thresholds, and pushbutton override in a single SOIC-8 package-reducing component count, PCB area, and qualification effort for mixed-voltage embedded systems.

Availability

DS1834S+ is available at Aetrix Electronics and suitable for industrial PLC controllers, telecom line cards, medical diagnostic instruments, and automotive infotainment head units requiring stable component supply across extended temperature ranges and long production lifecycles.

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

Analog Devices, Inc. (ADI) is a global leader in high-performance analog, mixed-signal, and digital signal processing technologies, serving industrial, automotive, communications, and healthcare markets.

The DS1834S+ belongs to ADI's legacy power supervision portfolio-originally developed by Dallas Semiconductor-to address reliability-critical dual-rail reset requirements in embedded systems with stringent uptime and fail-safe demands.

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 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% and 20% tolerances respectively. This eliminates external resistor networks and enables application-specific brownout sensitivity without redesigning the DS1834S+ circuit.

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

No, the DS1834S+ does not require external pull-up resistors on its RST outputs because it uses push-pull CMOS drivers-unlike the open-drain DS1834A variant. Each RST pin actively drives high or low, sourcing up to 350 µA and sinking up to 10 mA. This simplifies layout and ensures deterministic reset signaling without additional components or risk of floating states.

How does the DS1834S+ handle power sequencing when both 5VIN and 3.3VIN are present?

The DS1834S+ automatically draws internal operating current from the higher of the two supply inputs (5VIN or 3.3VIN), eliminating the need for external OR-ing diodes or power-path controllers. Both RST outputs remain asserted for ~350 ms after power-up until their respective supplies stabilize within tolerance, ensuring synchronized release regardless of which rail rises first-a critical feature for mixed-voltage SoCs and FPGAs.

What is the minimum pulse width required on the PBRST pin to trigger a manual reset with the DS1834S+?

The DS1834S+ requires a minimum low pulse width of 2 ms on the PBRST pin to register a valid pushbutton reset event. The internal 40 kΩ pull-up and digital debounce circuitry reject shorter noise spikes, ensuring robust field operation. Once detected, both 5V RST and 3.3V RST outputs are asserted for 200–500 ms after the PBRST pin returns high, providing guaranteed reset duration for full system recovery.

Can the DS1834S+ maintain valid reset outputs when supply voltages drop below 1.2V?

Yes, the DS1834S+ maintains valid RST outputs down to 1.2V supply level due to its push-pull architecture. Below 1.2V, connecting a 100 kΩ resistor from RST to GND sustains a valid low state even at 0V supply-enabling safe shutdown sequencing. This behavior is explicitly characterized and supported in the DS1834S+ datasheet, distinguishing it from variants requiring external pull-ups or failing earlier in brownout conditions.