Analog Devices Inc./Maxim Integrated DS1834U+

Overview

DS1834U+ from Maxim Integrated (now Analog Devices) is a dual-voltage power-on reset supervisor IC for systems with concurrent 5V and 3.3V supplies. It monitors both supplies independently, asserts active-low reset outputs (5V RST and 3.3V RST), provides pushbutton reset override with internal debouncing, maintains reset for 350 ms after supply recovery, and draws internal current from the higher of the two inputs. Used in embedded controllers requiring reliable dual-rail power sequencing.

For engineers reviewing the DS1834U+ datasheet, DS1834U+ pinout, DS1834U+ application, or DS1834U+ equivalent, key selection criteria include independent 5V/3.3V trip point tolerance configuration (5%/10% or 10%/20%), push-pull output structure enabling valid reset assertion down to 0 V, 350 ms reset timeout, -40°C to +85°C operation, and compatibility with 8-pin SOIC packaging.

Technical Context

The DS1834U+ integrates two independent voltage monitoring channels with user-selectable trip tolerances via dedicated TOL pins: tying 5V TOL to GND sets 5V trip at 4.50–4.75 V (5% tolerance), while tying to 5VIN sets 4.25–4.49 V (10%). Similarly, 3.3V TOL selects 2.80–2.97 V (10%) or 2.47–2.64 V (20%). Each channel drives a CMOS push-pull reset output.

It features an internally debounced PBRST input with 40 kΩ pull-up to the higher VIN, requiring ≥2 ms low pulse to trigger simultaneous reset assertion. Reset remains active for 200–500 ms (typ. 350 ms) after supply return or button release. Internal biasing draws current only from the higher of 5VIN or 3.3VIN, eliminating need for external power rail selection.

Key Specifications

Pinout & Package

DS1834U+ is supplied in 8-pin SOIC (150-mil) package. Pin functions are electrically identical across DS1834 variants and validated per Maxim Integrated datasheet revision 071700.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX6326UT46D3+ and TPS3808G33DBVR, DS1834U+ uniquely delivers simultaneous 5V/3.3V monitoring, push-pull outputs eliminating pull-ups, and integrated pushbutton reset - reducing component count and improving reliability in dual-supply embedded systems.

Availability

DS1834U+ is available at Aetrix Electronics and suitable for industrial control, network infrastructure, medical instrumentation, and automotive infotainment applications requiring stable component supply and guaranteed long-term availability.

Supply support for DS1834U+ 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 high-reliability industrial, automotive, and communications systems.

The DS1834U+ belongs to Maxim's EconoReset™ family of voltage supervisors, engineered specifically for cost-sensitive, space-constrained embedded systems requiring robust dual-rail power monitoring and reset generation.

FAQ

What is the function of the 5V TOL and 3.3V TOL pins on the DS1834U+?

The 5V TOL and 3.3V TOL pins 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 tied to GND gives 10% (2.80–2.97 V), and to 3.3VIN gives 20% (2.47–2.64 V). This allows DS1834U+ to adapt to varying power supply specifications without external components.

Does the DS1834U+ require external pull-up resistors on its reset outputs?

No. The DS1834U+ uses CMOS push-pull outputs for both 5V RST and 3.3V RST, eliminating the need for external pull-up resistors. This design ensures valid logic levels even when supply voltages drop below 1.2 V - a key advantage over open-drain alternatives like the DS1834A variant. The DS1834U+ datasheet confirms this behavior across all operating conditions.

How does the DS1834U+ handle power sequencing when both 5VIN and 3.3VIN are present?

The DS1834U+ automatically draws internal operating current from the higher of the two inputs (5VIN or 3.3VIN), ensuring stable biasing regardless of ramp order. Both reset outputs remain asserted until their respective supplies meet the configured tolerance and hold for 350 ms. This eliminates sequencing dependencies and prevents premature release of either domain - a critical feature confirmed in the DS1834U+ power-up timing diagram.

What is the minimum pulse width required on the PBRST pin to trigger a reset on the DS1834U+?

The DS1834U+ requires a low pulse of at least 2 ms on the PBRST pin to initiate a reset. The internal debouncing circuit filters out shorter glitches, and once triggered, both 5V RST and 3.3V RST remain active for 200–500 ms (typ. 350 ms) after the button is released. This specification is explicitly defined in the AC Electrical Characteristics table of the DS1834U+ datasheet.

Can the DS1834U+ maintain valid reset outputs when both supplies fall to 0 V?

Yes. Due to its push-pull output architecture, the DS1834U+ can drive valid logic states even when both 5VIN and 3.3VIN collapse to 0 V. The outputs remain functional down to 0 V, unlike open-drain variants that require pull-ups and fail under deep brownout. This behavior is documented in the "Output Valid Conditions" section of the DS1834U+ datasheet and verified in Figure 5 application diagram.