Analog Devices Inc./Maxim Integrated MAX6825VUK+T

Overview

MAX6825VUK+T from Maxim Integrated is a low-voltage microprocessor supervisory IC in 5-pin SOT23 package, featuring manual reset input (MR), dual push-pull reset outputs (RESET and RESET), and voltage monitoring for +1.58V supply with 140ms minimum reset timeout. It guarantees valid reset assertion down to VCC = +1.0V and operates across –40°C to +125°C, used in critical µP monitoring for portable/battery-powered equipment and embedded controllers.

For engineers reviewing the MAX6825VUK+T datasheet, MAX6825VUK+T pinout, MAX6825VUK+T application, or MAX6825VUK+T equivalent, this page delivers verified circuit role, threshold accuracy (±0.05V at +25°C), watchdog disable capability via WDI floating, MR debounce-free operation, and SOT23-5 thermal performance up to +125°C junction temperature.

Technical Context

The MAX6825VUK+T integrates three core functions: precision voltage monitoring of +1.58V supply (VTH = 1.58V, ±3% over temperature), a debounced manual reset input with internal 50kΩ pullup and 200ns MR-to-reset delay, and dual active-high push-pull reset outputs-RESET asserts high during fault conditions, RESET asserts high synchronously. Reset remains asserted for ≥140ms after VCC recovers above threshold.

Unlike MAX6821–MAX6824, MAX6825VUK+T omits the watchdog timer input (WDI pin is unused), enabling simplified reset-only supervision where software watchdog management is unnecessary. Its reset outputs are fully specified for sink/source currents up to 800µA at VCC ≥ 4.25V and remain functional down to VCC = +1.0V, ensuring robust brownout recovery in ultra-low-power systems.

Key Specifications

Pinout & Package

MAX6825VUK+T uses a 5-pin SOT23-5 package (U5-1 outline, land pattern 91-0174), rated for +150°C junction temperature and RoHS-compliant (+T suffix). Pin 1 is RESET (active-high push-pull), Pin 2 is GND, Pin 3 is MR (active-low manual reset), Pin 4 is unused (no WDI function), Pin 5 is VCC.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar microprocessor supervisory applications.

Compared with MAX6825VUK+T, MAX6823VUK+T adds watchdog capability at the cost of requiring WDI signal integrity, while TPS3808G16DBVR sacrifices MR and dual outputs for lower cost and simpler integration-neither offers identical functionality or pinout.

Availability

MAX6825VUK+T is available at Aetrix Electronics and suitable for portable/battery-powered equipment, critical µP monitoring, and embedded controllers requiring stable component supply, extended temperature support (–40°C to +125°C), and RoHS-compliant packaging.

Supply support for MAX6825VUK+T 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, automotive, and computing applications, with expertise in power management and reliability-critical supervision.

The MAX6821–MAX6825 product line delivers compact, low-power µP supervisors targeting space-constrained, battery-sensitive systems where deterministic reset behavior under brownout is non-negotiable.

FAQ

What is the exact reset threshold voltage of the MAX6825VUK+T and how tightly is it specified?

The MAX6825VUK+T has a nominal reset threshold voltage of 1.58V, with a guaranteed tolerance of ±3% over the full operating temperature range (–40°C to +125°C). At +25°C, typical variation is ±0.05V. This value corresponds to the "V" suffix in the part number and is factory-trimmed-no external adjustment is possible. The threshold hysteresis is 2 × VTH mV, ensuring clean release without chatter during slow VCC recovery.

Does the MAX6825VUK+T include a watchdog timer, and what happens to Pin 4?

No, the MAX6825VUK+T does not include a watchdog timer function. Pin 4 is designated NC (no connect) and is not internally bonded-it serves no electrical purpose. Unlike MAX6821–MAX6824 variants, MAX6825VUK+T omits the WDI input entirely, simplifying design where software-level watchdog supervision is handled elsewhere or unnecessary.

How do the two reset outputs (RESET and RESET) on the MAX6825VUK+T differ in behavior and drive capability?

Both RESET and RESET on the MAX6825VUK+T are active-high push-pull outputs with identical timing and drive strength: they assert high during VCC undervoltage, MR assertion, or brownout, and remain high for ≥140ms after recovery. Each output sources up to 800µA at VCC ≥ 4.25V and sinks 500µA when inactive. They are electrically identical and intended for driving separate subsystems-e.g., one to the µP, the other to an FPGA or peripheral ASIC.

Can the MAX6825VUK+T operate reliably at VCC = +1.0V, and what is guaranteed at that level?

Yes, the MAX6825VUK+T guarantees correct reset output state (i.e., RESET and RESET remain asserted as expected) down to VCC = +1.0V. This includes valid logic levels, timing compliance (≥140ms timeout), and MR responsiveness-even at the absolute lower limit of its operating range. This specification ensures fail-safe behavior during extreme brownout conditions common in lithium primary battery applications.

What is the recommended handling for the MR pin if manual reset is not required in the final design?

If manual reset is unused, the MR pin of the MAX6825VUK+T should be left unconnected-the device includes a 50kΩ internal pullup to VCC, ensuring MR remains at logic high and does not trigger spurious resets. No external resistor or capacitor is needed. Connecting MR directly to VCC is also acceptable but provides no benefit over leaving it open.