Analog Devices Inc./Maxim Integrated MAX6425UK16

Overview

MAX6425UK16 from Maxim Integrated is a low-power microprocessor supervisor IC that monitors VCC supply voltage and asserts an active-low open-drain RESET signal when voltage falls below 1.575V (±2.5% over temperature). It features capacitor-adjustable reset timeout (275µs base + 2.73s/F × CSRT), guaranteed operation down to VCC = 1V, and consumes only 1.6µA typical quiescent current. It is used in battery-powered controllers and portable medical instruments for reliable power-on reset and brownout protection.

For engineers reviewing the MAX6425UK16 datasheet, MAX6425UK16 pinout, MAX6425UK16 application, or MAX6425UK16 equivalent, key selection criteria include its 1.575V reset threshold, SOT23-5 open-drain output, capacitor-programmable timeout, immunity to short VCC transients, and guaranteed reset validity at VCC ≥ 1V.

Technical Context

The MAX6425UK16 implements a precision voltage monitor with laser-trimmed resistors to set its 1.575V reset threshold (suffix "16" per Table 1), and uses an internal 240nA current source charging an external capacitor on the SRT pin to generate the reset timeout delay. Its open-drain RESET output requires an external pullup and supports logic-level interfacing across supplies up to 5.5V.

It operates across –40°C to +125°C, maintains ±2.5% reset threshold accuracy over full temperature range, and provides 80µs VCC-to-RESET delay during falling VCC. The device is immune to negative-going VCC transients ≤50µs when overdriven by 100mV below VTH, enabling robust operation in noisy power environments.

Key Specifications

Pinout & Package

MAX6425UK16 is housed in a 5-pin SOT23-5 package with exposed pad (not electrically connected), measuring 2.9mm × 1.6mm × 1.1mm. Pin 3 is internally unconnected (N.C.) and may be tied to GND for mechanical stability.

Key Features

Applications

Equivalent & Alternatives

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

Compared with NCP302LSN16T1G and TLV803EB16DBZR, the MAX6425UK16 uniquely combines capacitor-adjustable timeout, 1.6µA quiescent current, and guaranteed 1V operation - making it optimal for long-life, field-deployed systems requiring precise, configurable reset timing under brownout conditions.

Availability

MAX6425UK16 is available at Aetrix Electronics and suitable for battery-powered medical sensors, automotive body control modules, and portable industrial data loggers requiring stable component supply, long-term lifecycle support, and guaranteed parametric performance across –40°C to +125°C.

Supply support for MAX6425UK16 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.

The MAX6425UK16 belongs to the MAX6340/MAX6421–MAX6426 family of low-power µP supervisors, engineered specifically for reliable reset generation in space-constrained, battery-operated, and high-temperature embedded systems.

FAQ

What is the exact reset threshold voltage of MAX6425UK16 and how stable is it over temperature?

The MAX6425UK16 has a nominal reset threshold of 1.575V, with ±2.5% accuracy over the full –40°C to +125°C operating range. This is achieved via laser-trimmed internal resistors and is specified in the Electrical Characteristics table. The device exhibits excellent thermal stability, with normalized threshold variation less than ±0.5% across temperature (per Figure toc08), ensuring consistent brownout detection in extreme environments.

How do I calculate the external capacitor value for a desired reset timeout period with MAX6425UK16?

Use the formula CSRT = (tRP – 275µs) / 2.73×10⁶, where tRP is the desired timeout in seconds and CSRT is in farads. For example, a 100ms timeout requires CSRT = (0.1 – 0.000275) / 2.73×10⁶ ≈ 36.5nF. Ceramic capacitors with <10nA leakage are recommended; avoid electrolytics or high-leakage dielectrics to maintain timing accuracy.

Can MAX6425UK16 drive a reset input directly, or does it require external components?

The MAX6425UK16 has an open-drain RESET output and requires an external pullup resistor to function. A 10kΩ to 100kΩ resistor to any supply between 0V and 5.5V is sufficient. This configuration enables level-shifting and wired-OR capability. Without the pullup, RESET remains floating and cannot assert a valid logic high; the device itself only sinks current when active.

Is MAX6425UK16 compatible with microcontrollers that have Schmitt-trigger reset inputs?

Yes, MAX6425UK16 is fully compatible with Schmitt-trigger reset inputs. Its open-drain output cleanly transitions between near-0V (when asserted, VOL ≤ 0.3V at ISINK = 500µA) and the pullup-supply voltage (VOH = VPU), providing clean edges and sufficient noise margin. The 4mV hysteresis (VHYST = 4×VTH) built into the internal comparator further enhances noise immunity before assertion.

Does MAX6425UK16 provide any protection against ESD or electrical overstress on its pins?

The MAX6425UK16 includes standard IC-level ESD protection: ±2kV HBM on all pins per JEDEC JS-001. Absolute maximum ratings specify VCC, SRT, and RESET pins tolerate –0.3V to +6.0V, and RESET (open-drain) withstands up to +6.0V regardless of VCC. However, it is not designed as a front-end protector; external TVS diodes are recommended for harsh automotive or industrial surge environments.