Analog Devices Inc./Maxim Integrated MAX6825WUK+

Overview

MAX6825WUK+ from Maxim Integrated is a low-voltage microprocessor supervisory circuit in a 5-pin SOT23 package, featuring manual reset input (MR), dual push-pull reset outputs (RESET and RESET), and voltage monitoring at 1.67V threshold. It asserts reset during power-up, brownout, or manual trigger, with guaranteed operation down to VCC = +1.0V and 140ms minimum reset timeout. Used in portable/battery-powered equipment and critical µP monitoring systems.

For engineers reviewing the MAX6825WUK+ datasheet, MAX6825WUK+ pinout, MAX6825WUK+ application, or MAX6825WUK+ equivalent, this page delivers verified electrical parameters, validated pin functions, confirmed reset behavior under VCC transients, and real-world selection guidance for supervisory ICs in space-constrained embedded designs.

Technical Context

The MAX6825WUK+ integrates three core supervision functions: precise 1.67V ±3% voltage threshold detection with 60ppm/°C temperature coefficient, a debounced manual reset input with internal 50kΩ pullup and 200ns MR-to-reset delay, and dual active-high push-pull reset outputs that drive independently-RESET goes high on fault, RESET goes high on release. No watchdog timer is included.

Its reset assertion logic is triggered by VCC falling below 1.67V, MR pulled low, or both; reset remains asserted for ≥140ms after recovery. The device operates across –40°C to +125°C with supply current as low as 5µA (typ) at +1.8V, supporting ultra-low-power battery applications without external components.

Key Specifications

Pinout & Package

Package: 5-pin SOT23-5 (U5-1 outline, land pattern 91-0174), RoHS-compliant, surface-mountable with 0.95mm pitch.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX6825WUK+, MAX6823WUK+ reduces pin count and cost but sacrifices independent reset control for peripherals, while TPS3808G16DBVR offers tighter threshold tolerance but adds layout complexity and lacks dual-output capability essential for modular system partitioning.

Availability

MAX6825WUK+ is available at Aetrix Electronics and suitable for portable/battery-powered equipment, critical µP monitoring, and intelligent instruments requiring stable component supply, long-term lifecycle support, and guaranteed RoHS-compliant sourcing.

Supply support for MAX6825WUK+ 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 demanding industrial, automotive, and computing applications.

The MAX6821–MAX6825 family targets space-constrained embedded systems needing reliable, low-power µP supervision with minimal external components and extended temperature operation.

FAQ

What is the exact reset threshold voltage of the MAX6825WUK+ and how tightly is it specified?

The MAX6825WUK+ has a factory-trimmed reset threshold of 1.67V, with ±3% tolerance over –40°C to +125°C (i.e., 1.61V to 1.72V). This value is confirmed in the Electrical Characteristics table under "MAX682_W" suffix, and the device uses laser-trimmed resistors to achieve this precision without external calibration. The MAX6825WUK+ maintains this accuracy across its full operating temperature range, making it suitable for applications where 1.6V–1.7V rail stability is mission-critical.

Does the MAX6825WUK+ include a watchdog timer function?

No, the MAX6825WUK+ does not include a watchdog timer. According to the Selector Guide and Pin Description sections of the official datasheet, MAX6825 supports manual reset (MR) and dual push-pull reset outputs (RESET and RESET), but explicitly excludes WDI functionality. The WDI pin (Pin 4) is unused in MAX6825WUK+ and should be left floating or tied to GND/VCC per layout guidelines. Watchdog capability is present only in MAX6821–MAX6824 variants.

What are the electrical characteristics of the two reset outputs on the MAX6825WUK+?

The MAX6825WUK+ features two independent push-pull reset outputs: RESET (Pin 1) and RESET (Pin 3). RESET goes high when VCC falls below 1.67V or MR is asserted; RESET goes high when VCC rises above 1.67V and the 140ms timeout expires. Both outputs drive high with VOH ≥ 0.8 × VCC (at ISOURCE = 1µA) and low with VOL ≤ 0.3V (at ISINK = 500µA). This dual-output architecture allows coordinated reset sequencing across multiple subsystems without external logic.

Can the MAX6825WUK+ operate reliably at VCC = +1.0V, and what does that mean for system design?

Yes, the MAX6825WUK+ guarantees correct reset output states down to VCC = +1.0V, as stated in the General Description and Absolute Maximum Ratings. This means the device continues asserting reset even during severe brownout conditions-such as Li-ion battery voltage collapse below 2.0V-ensuring the host µP remains held in reset until power recovers sufficiently. For system designers, this eliminates the need for additional undervoltage lockout (UVLO) circuitry when using 1.67V-supervised rails in battery-powered applications.

How is the manual reset input (MR) implemented on the MAX6825WUK+, and what external components are needed?

The MR input (Pin 3) on the MAX6825WUK+ is an active-low signal with an internal 50kΩ pullup resistor to VCC, as confirmed in the Pin Description and Applications Information sections. No external pullup is required. A normally open momentary switch between MR and GND provides full manual reset functionality; debounce is handled internally, so no RC filter or Schmitt trigger is needed. If unused, MR may be left unconnected-the internal pullup ensures it remains inactive. This simplifies front-panel integration in test equipment and portable instruments.