Analog Devices Inc./Maxim Integrated DS1834AU/T&R

Overview

DS1834AU/T&R from Maxim Integrated (now Analog Devices) is a dual-voltage power-on reset supervisor IC monitoring both 5V and 3.3V supplies, featuring pushbutton reset override, 350 ms reset pulse width, ±1% trip point accuracy at 5V (TOL=GND), and CMOS push-pull outputs. It serves as a system-level power integrity guardian in embedded controllers requiring dual-rail supervision.

For engineers reviewing the DS1834AU/T&R datasheet, DS1834AU/T&R pinout, DS1834AU/T&R application, or DS1834AU/T&R equivalent, key selection considerations include dual-supply tolerance configuration (5%/10% or 10%/20%), internal 40 kΩ PBRST pull-up, guaranteed reset assertion during VCC transients down to 1.2 V, and compatibility with SOIC-8 packaging for industrial PCB layouts.

Technical Context

The DS1834AU/T&R integrates two independent voltage monitors with selectable input tolerances via dedicated TOL pins-5V TOL tied to GND sets ±5% trip (4.50–4.75 V), while tied to 5VIN sets ±10% (4.25–4.49 V); similarly, 3.3V TOL selects ±10% (2.80–2.97 V) or ±20% (2.47–2.64 V). Its internal power selector draws operating current from the higher of 5VIN or 3.3VIN.

Reset outputs are active-low CMOS push-pull (DS1834 variant), eliminating external pull-ups. The PBRST pin features internal 40 kΩ pull-up and hardware debouncing, asserting both resets for 200–500 ms after release. Output validity is maintained down to 1.2 V supply, with optional RST-to-GND resistor enabling valid state at 0 V.

Key Specifications

Pinout & Package

DS1834AU/T&R is supplied in 8-pin SOIC (150-mil) package, RoHS-compliant and tape-and-reel packaged for automated assembly.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX6326US31D3+ and TPS3808G33DBVR, DS1834AU/T&R uniquely delivers integrated dual-rail monitoring with hardware-selectable tolerances and pushbutton override in a single SOIC-8 package-enabling compact, robust reset architecture without external components or firmware coordination.

Availability

DS1834AU/T&R is available at Aetrix Electronics and suitable for industrial PLC controllers, medical diagnostic devices, automotive infotainment head units, and telecom base station management cards requiring stable component supply and long-term lifecycle assurance.

Supply support for DS1834AU/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

Analog Devices (via acquisition of Maxim Integrated) designs precision analog, mixed-signal, and power management ICs for high-reliability industrial, automotive, and medical applications.

The DS1834AU/T&R belongs to Maxim's EconoReset™ family, engineered specifically for cost-sensitive yet robust dual-voltage system supervision where discrete reset solutions would increase board area and BOM complexity.

FAQ

What is the function of the 5V TOL and 3.3V TOL pins on the DS1834AU/T&R?

The 5V TOL and 3.3V TOL pins on the DS1834AU/T&R configure the voltage trip thresholds for their respective rails. When tied to GND, 5V TOL selects ±5% tolerance (4.50–4.75 V), and 3.3V TOL selects ±10% (2.80–2.97 V); when tied to their supply inputs, they select ±10% and ±20% respectively. This hardware-based configuration eliminates firmware dependencies and ensures deterministic reset behavior across temperature and voltage variations in the DS1834AU/T&R.

Does the DS1834AU/T&R require external pull-up resistors on its reset outputs?

No, the DS1834AU/T&R does not require external pull-up resistors on its 5V RST and 3.3V RST outputs because it uses CMOS push-pull drivers - unlike open-drain alternatives such as the DS1834A. This design reduces BOM count and simplifies layout. The DS1834AU/T&R variant specifically implements push-pull outputs, making external resistors unnecessary for standard operation, though a 100 kΩ resistor to GND can extend valid output down to 0 V if needed.

How does the DS1834AU/T&R handle power supply sequencing during startup?

During power-up, the DS1834AU/T&R holds both 5V RST and 3.3V RST active for approximately 350 ms after the monitored supplies reach their selected tolerance windows. This ensures stable power delivery before releasing reset to the microcontroller or FPGA. The internal power selector draws current from the higher of 5VIN or 3.3VIN, allowing the DS1834AU/T&R to remain functional even if one rail powers up significantly earlier than the other - a critical feature for asymmetric power architectures.

Can the DS1834AU/T&R operate with only one supply voltage present?

Yes, the DS1834AU/T&R can operate with only one supply voltage present - either 5VIN or 3.3VIN - as long as that supply is within 1.2–5.5 V. Its internal power selector automatically uses the higher available voltage for biasing, and the corresponding RST output remains fully functional. The unused rail's RST output stays inactive (high), and its TOL pin should be tied appropriately (GND or rail) to avoid floating nodes. This flexibility supports partial-power designs and graceful degradation modes in the DS1834AU/T&R.

What is the minimum pulse width required on PBRST to trigger a manual reset in the DS1834AU/T&R?

The DS1834AU/T&R requires a minimum low pulse width of 2 ms on the PBRST pin to register a valid manual reset command. This specification is guaranteed across -40°C to +85°C and ensures immunity to mechanical switch bounce. Once detected, both 5V RST and 3.3V RST are asserted and held active for 200–500 ms after PBRST returns high - providing consistent, debounced reset timing without external circuitry. This behavior is intrinsic to the DS1834AU/T&R's internal logic and does not depend on external components.