Analog Devices Inc./Maxim Integrated MAX6825RUK

Overview

The MAX6825RUK from Maxim Integrated is a low-voltage microprocessor supervisory IC in SOT23-5 package, providing manual reset input, dual push-pull reset outputs (RESET and RESET), and voltage monitoring for +2.63V supply rails. It asserts reset during power-up, brownout, or software fault conditions, with guaranteed operation down to VCC = +1.0V and 140ms minimum reset timeout delay. Used in embedded controllers and portable battery-powered equipment for reliable µP initialization and recovery.

For engineers reviewing the MAX6825RUK datasheet, MAX6825RUK pinout, MAX6825RUK application, or MAX6825RUK equivalent, key selection criteria include its dual active-high/active-low push-pull reset outputs, manual reset capability, watchdog-free architecture, +2.63V threshold accuracy (±30mV over -40°C to +125°C), and immunity to short negative VCC transients - critical for robust power sequencing in space-constrained industrial and automotive systems.

Technical Context

The MAX6825RUK implements a precision bandgap-based voltage monitor with 2.63V reset threshold (R suffix), hysteresis of 2×VTH, and temperature coefficient of 60ppm/°C. Its reset generator uses an internal RC timer to guarantee ≥140ms reset assertion after VCC recovery, with propagation delay under 20µs from VCC falling edge to reset activation.

Unlike MAX6821–MAX6824, the MAX6825RUK omits the watchdog timer but retains MR input with 50kΩ internal pullup, 1µs minimum pulse width support, and 100ns glitch rejection. Both RESET and RESET outputs are push-pull, sourcing up to 800µA at VCC ≥ 4.75V and sinking 3.2mA while asserted, ensuring direct interface with µP reset pins without external pullups.

Key Specifications

Pinout & Package

Package: SOT23-5, surface-mount, 5-pin plastic package with standard footprint (EIAJ SC-74A). Pin 1 marked by beveled corner or dot; device orientation per JEDEC MO-178.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX6823RUK, the MAX6825RUK trades watchdog capability for dual push-pull reset outputs - enabling direct interface with µPs requiring both active-high and active-low reset signals. Against TPS3808G125DBVR, it offers higher threshold precision, manual reset integration, and elimination of external pullup components - reducing design complexity in multi-rail systems.

Availability

MAX6825RUK is available at Aetrix Electronics and suitable for industrial PLC controllers, automotive body control modules, and portable medical monitors requiring stable component supply, long-term lifecycle support, and guaranteed parametric performance across -40°C to +125°C.

Supply support for MAX6825RUK 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, with emphasis on reliability, low power, and small form factor.

The MAX6821–MAX6825 family was engineered specifically for space-constrained microprocessor systems needing robust voltage monitoring, manual reset, and deterministic reset timing - targeting embedded controllers, set-top boxes, and battery-powered instrumentation.

FAQ

What is the exact reset threshold voltage for MAX6825RUK?

The MAX6825RUK has a factory-trimmed reset threshold of +2.63V (R suffix), with guaranteed tolerance of ±30mV over the full operating temperature range (-40°C to +125°C). This value is specified in the Electrical Characteristics table under "VCC Reset Threshold (VCC Falling)" and applies directly to the MAX6825RUK part number as confirmed in the Threshold Suffix Guide and Ordering Information section of the datasheet.

Does MAX6825RUK include a watchdog timer function?

No, the MAX6825RUK does not include a watchdog timer. Per the Selector Guide and Pin Description tables, MAX6825RUK features manual reset input (MR) and dual push-pull reset outputs (RESET and RESET), but explicitly omits the WDI pin functionality present in MAX6821–MAX6824. The WDI pin (Pin 4) is a no-connect terminal in MAX6825RUK and has no internal watchdog circuitry.

How does the dual reset output configuration of MAX6825RUK benefit system design?

The MAX6825RUK provides both active-high (RESET) and active-low (RESET) push-pull outputs simultaneously, eliminating the need for external inverters or pull-up resistors when interfacing with µPs that require complementary reset signals. This simplifies PCB layout, reduces component count, and ensures precise timing alignment between reset domains - a key advantage in systems like automotive ECUs where multiple voltage rails must be synchronized during power-up.

What is the minimum VCC voltage at which MAX6825RUK guarantees correct reset output state?

The MAX6825RUK guarantees correct reset output state down to VCC = +1.0V, as stated in the General Description and confirmed in the Absolute Maximum Ratings and Electrical Characteristics sections. This means the device continues to assert or deassert RESET/RESET outputs reliably even during severe brownout conditions - a critical feature for fail-safe operation in battery-powered or automotive applications where supply voltage may dip below nominal levels.

Can the MR pin of MAX6825RUK be left unconnected without affecting operation?

Yes, the MR pin of MAX6825RUK can be left unconnected because it features an internal 50kΩ pullup resistor to VCC, as documented in the Pin Description and Applications Information sections. When unused, MR remains at logic high, disabling manual reset. If external reset initiation is required, connect a normally open momentary switch from MR to GND - no external debounce circuitry is needed due to built-in 100ns glitch rejection.