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 with independent tolerance selection, pushbutton reset input, and CMOS push-pull outputs. It asserts active-low reset signals for each supply during out-of-tolerance conditions or manual override, maintaining reset for 350 ms after recovery - used in embedded systems requiring reliable dual-rail power sequencing and brownout protection.

For engineers reviewing the DS1834AU+T&R datasheet, DS1834AU+T&R pinout, DS1834AU+T&R application, or DS1834AU+T&R equivalent, key selection criteria include dual-supply trip point configurability (5%–10% for 5VIN, 10%–20% for 3.3VIN), internal 40 kΩ pull-up on PBRST, guaranteed 350 ms reset timeout, operating range of –40°C to +85°C, and SOIC-8 package compatibility with industrial control and telecom power management designs.

Technical Context

The DS1834AU+T&R integrates two independent voltage monitors with selectable trip thresholds via dedicated TOL pins: tying 5V TOL to GND sets 5VIN trip at 4.50–4.75 V (5% tolerance), while tying to 5VIN selects 4.25–4.49 V (10%). Similarly, 3.3V TOL selects 2.80–2.97 V (10%) or 2.47–2.64 V (20%). Internal precision temperature-compensated reference ensures stable threshold accuracy across –40°C to +85°C.

It features an internally debounced pushbutton reset input (PBRST) with 2 ms minimum low pulse detection, forcing both RST outputs active for ~350 ms after release. Power is drawn from the higher of 5VIN or 3.3VIN, and each RST output is sourced/sunk only from its respective supply rail - enabling true dual-rail independence without cross-coupling.

Key Specifications

Pinout & Package

DS1834AU+T&R is supplied in an 8-pin SOIC (150-mil) package with surface-mount footprint and standard JEDEC MS-012AC dimensions (4.9 mm × 3.9 mm × 1.75 mm).

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX6326UT46D3+ and TPS3808G33DBVR, DS1834AU+T&R uniquely delivers simultaneous 5V/3.3V supervision with configurable tolerances, integrated pushbutton support, and guaranteed 350 ms reset hold - making it irreplaceable in mixed-voltage embedded systems requiring coordinated power-up sequencing and field-serviceable reset capability.

Availability

DS1834AU+T&R is available at Aetrix Electronics and suitable for industrial PLC controllers, telecom line cards, medical diagnostic modules, and automotive infotainment head units requiring stable component supply, long-term lifecycle support, and traceable sourcing.

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 high-performance analog, mixed-signal, and power management ICs for precision sensing, power integrity, and reliability-critical systems.

The DS1834AU+T&R belongs to Maxim's EconoReset™ family of cost-optimized power supervisors engineered for robust dual-rail monitoring in industrial, telecom, and medical equipment where predictable reset behavior under voltage transients is mandatory.

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 supply inputs. Tying 5V TOL to GND selects a 5% tolerance (4.50–4.75 V trip), while connecting it to 5VIN selects 10% (4.25–4.49 V). Similarly, 3.3V TOL set to GND yields 10% (2.80–2.97 V), and to 3.3VIN yields 20% (2.47–2.64 V). This configurability allows the DS1834AU+T&R to adapt to varying supply stability requirements across different system designs.

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

No, the DS1834AU+T&R does not require external pull-up resistors on its RST outputs. Unlike the DS1834A variant, the DS1834AU+T&R features CMOS push-pull outputs capable of actively driving both high and low states. This eliminates the need for external pull-ups, reducing component count and simplifying design - a key advantage confirmed in the device's datasheet and functional description.

How long does the DS1834AU+T&R maintain reset after power returns to tolerance?

The DS1834AU+T&R maintains reset for 200–500 ms after the monitored supply returns to tolerance, with a typical value of 350 ms. This guaranteed timeout ensures sufficient time for system clocks, PLLs, and memory subsystems to stabilize before releasing the processor reset - meeting critical boot timing requirements across ARM, x86, and FPGA platforms. The DS1834AU+T&R implements this via internal timing circuitry independent of external components.

Can the DS1834AU+T&R operate if only one supply (e.g., 3.3VIN) is present?

Yes, the DS1834AU+T&R can operate with only one supply present. Its internal circuitry draws power from the higher of 5VIN or 3.3VIN, and valid RST outputs are maintained as long as at least one input remains above 1.2 V. If both supplies drop below 1.2 V, a resistor from RST to GND (≈100 kΩ) can preserve output state down to 0 V - a design option explicitly supported in the DS1834AU+T&R datasheet for zero-volt fail-safe operation.

What is the purpose of the PBRST pin on the DS1834AU+T&R?

The PBRST pin on the DS1834AU+T&R provides a debounced, logic-compatible interface for manual system reset. Internally pulled up to the higher VIN rail (~40 kΩ), it detects a low pulse ≥2 ms and responds by asserting both 5V RST and 3.3V RST for ~350 ms after release. This enables field-serviceable reset without requiring external debounce circuitry - a verified feature of the DS1834AU+T&R used in industrial and telecom applications where operator-initiated recovery is essential.