Analog Devices Inc./Maxim Integrated MAX6425UK25

Overview

The MAX6425UK25 from Maxim Integrated is a low-power microprocessor supervisor IC with open-drain active-low reset output, 2.5V factory-trimmed reset threshold (±2.5% over -40°C to +125°C), capacitor-adjustable reset timeout (275µs base + 2.73s/F × CSRT), and guaranteed operation down to VCC = 1V. It monitors system supply voltage in portable, automotive, and medical equipment where precise brownout detection and flexible reset timing are required.

For engineers reviewing the MAX6425UK25 datasheet, MAX6425UK25 pinout, MAX6425UK25 application, or MAX6425UK25 equivalent, this device is selected for ultra-low quiescent current (1.6µA typ), immunity to short VCC transients, open-drain logic compatibility with multiple supply rails (0–5.5V), and SOT23-5 packaging suitable for space-constrained embedded controllers.

Technical Context

This supervisor uses an internal 240nA current source to charge an external capacitor on the SRT pin; reset deassertion occurs when the ramp voltage reaches 0.65V, enabling precise timeout tuning. Its laser-trimmed reference ensures ±2.5% reset threshold accuracy across temperature and supply voltage.

The open-drain RESET output requires an external pullup resistor (10kΩ–100kΩ) and supports wired-OR configurations with auxiliary reset sources. The device guarantees valid reset signaling even as VCC falls to 1V, with VOL ≤ 0.3V at ISINK = 1.2mA (VCC ≥ 2.7V).

Key Specifications

Pinout & Package

MAX6425UK25 is housed in a 5-pin SOT23-5 package (2.9mm × 1.6mm × 1.1mm), RoHS-compliant and available in tape-and-reel only.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX6425UK25, the NCP302LSN25T1G offers lower cost and simpler layout but sacrifices timeout adjustability and open-drain versatility, while the TLV803EB25DBZR reduces quiescent current significantly yet compromises robustness in deep undervoltage scenarios critical for medical and industrial safety.

Availability

MAX6425UK25 is available at Aetrix Electronics and suitable for battery-powered medical sensors, automotive body control modules, industrial handheld terminals, smart energy meters, and critical µP monitoring applications requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for MAX6425UK25 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 medical applications, emphasizing reliability, low power, and integration.

The MAX6421–MAX6426 family delivers ultra-low-power, capacitor-programmable reset supervision for space- and energy-constrained embedded systems where deterministic power-up sequencing and brownout resilience are mandatory.

FAQ

What is the exact reset threshold voltage of the MAX6425UK25?

The MAX6425UK25 features a factory-trimmed nominal reset threshold of 2.500V, with tolerance of ±2.5% over the full operating temperature range (-40°C to +125°C). This value is laser-trimmed during production and confirmed in the Electrical Characteristics table under "VCC Reset Threshold Accuracy" with VTH = 2.5V.

How do I calculate the reset timeout period for the MAX6425UK25?

For the MAX6425UK25, use the formula tRP = (2.73 × 10⁶) × CSRT + 275µs, where tRP is the total reset timeout in seconds and CSRT is the capacitor value in farads. For example, a 1500pF capacitor yields tRP ≈ 4.375ms. The SRT pin must use a low-leakage ceramic capacitor (<10nA) for accuracy.

Can the MAX6425UK25 drive a 3.3V microcontroller reset pin directly?

Yes - the MAX6425UK25 has an open-drain RESET output that can interface directly with a 3.3V µP reset pin by connecting a pullup resistor (e.g., 10kΩ) from RESET to the 3.3V rail. The output sinks up to 1.2mA at VOL ≤ 0.3V (VCC ≥ 2.7V), ensuring solid logic-low assertion.

Does the MAX6425UK25 remain functional when VCC drops below 1.8V?

Yes - the MAX6425UK25 is fully specified down to VCC = 1.0V, with guaranteed reset assertion and valid open-drain output behavior. Its "Guaranteed Reset Valid to VCC = 1V" feature ensures deterministic operation during deep brownout, unlike many supervisors that cease functioning below 1.6V.

Is the MAX6425UK25 pin-compatible with other devices in the MAX642x family?

Yes - the MAX6425UK25 shares the identical 5-pin SOT23-5 pinout with MAX6424UKxx and MAX6426UKxx variants. All three use pins 1 (GND), 2 (VCC), 3 (N.C.), 4 (SRT), and 5 (RESET), enabling direct substitution within the same reset threshold variant group when open-drain output is required.