Analog Devices Inc./Maxim Integrated MAX6426UK30+T

Overview

MAX6426UK30+T from Analog Devices is a low-power microprocessor supervisor IC with open-drain active-low reset output, 3.0V ±2.5% factory-trimmed reset threshold, capacitor-adjustable reset timeout (275µs to 5.75ms), and guaranteed operation down to VCC = 1V. It monitors supply voltage in battery-powered embedded controllers and portable equipment requiring precise brownout protection.

For engineers reviewing the MAX6426UK30+T datasheet, MAX6426UK30+T pinout, MAX6426UK30+T application, or MAX6426UK30+T equivalent, key selection criteria include its SOT23-5 open-drain RESET output, 1.6µA typical quiescent current, -40°C to +125°C operating range, and compatibility with multi-rail logic interfacing via external pullup.

Technical Context

The MAX6426UK30+T implements a precision voltage detector using laser-trimmed resistors to set its 3.0V reset threshold with ±2.5% accuracy over temperature. Its reset assertion is triggered by VCC falling below VTH, and deassertion is delayed by an internal 240nA current source charging an external capacitor (CSRT) to a 0.65V ramp threshold.

As an open-drain device, MAX6426UK30+T requires an external pullup resistor (10kΩ–100kΩ) to any supply up to 5.5V, enabling wired-OR reset capability and logic-level translation across mixed-voltage systems. It remains functional down to VCC = 1V, with RESET leakage <1.0µA when not asserted.

Key Specifications

Pinout & Package

MAX6426UK30+T is housed in a 5-pin SOT23-5 package (package code U5+2), RoHS-compliant, tape-and-reel format. Pin 1 is VCC, Pin 2 is GND, Pin 3 is SRT (reset timeout capacitor input), Pin 4 is RESET (open-drain output), and Pin 5 is NC (not internally connected).

Key Features

Applications

Equivalent & Alternatives

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

Compared with PST9230 and NCP302LSN30T1G, MAX6426UK30+T uniquely combines automotive-grade temperature range, capacitor-adjustable timeout, and ultra-low 1.6µA supply current-making it optimal for space-constrained, battery-sensitive, and safety-critical designs where timing flexibility and reliability are non-negotiable.

Availability

MAX6426UK30+T is available at Aetrix Electronics and suitable for battery-powered portable equipment, automotive body control modules, and industrial embedded controllers requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for MAX6426UK30+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

Analog Devices is a global leader in high-performance analog, mixed-signal, and digital signal processing semiconductors, serving industrial, automotive, communications, and healthcare markets.

The MAX6426UK30+T belongs to the MAX6340/MAX6421–MAX6426 family of low-power µP supervisors designed specifically for robust, capacitor-tunable reset functionality in space- and power-constrained embedded systems.

FAQ

What is the exact reset threshold voltage of MAX6426UK30+T and how accurate is it?

The MAX6426UK30+T has a nominal reset threshold of 3.00V, with ±1.5% accuracy at +25°C and ±2.5% over the full -40°C to +125°C operating range. This specification is laser-trimmed at wafer test and confirmed in the Electrical Characteristics table of the official Analog Devices datasheet (Rev 11, p.2). The threshold applies directly to the VCC pin and triggers reset assertion when VCC falls below this value.

Does MAX6426UK30+T require an external pullup resistor on the RESET pin?

Yes, MAX6426UK30+T features an open-drain RESET output and requires an external pullup resistor (typically 10kΩ–100kΩ) to a logic-compatible supply (0–5.5V). Without it, the RESET line cannot achieve a defined high state. The pullup value must balance leakage current tolerance and rise-time requirements-10kΩ ensures fast edges for high-speed µPs, while 100kΩ minimizes standby current in ultra-low-power designs.

Can MAX6426UK30+T operate reliably when VCC drops below 1.5V?

Yes, MAX6426UK30+T guarantees valid RESET output down to VCC = 1.0V. Its internal circuitry remains functional and the open-drain RESET output maintains specified VOL (<0.3V at ISINK = 500µA) and leakage (<1.0µA) even at 1.0V. However, below 1.0V, RESET behavior is not characterized-designs requiring reset assertion all the way to 0V should add a 100kΩ pulldown resistor per Analog Devices Application Note AN-712.

What capacitor value sets a 4.375ms reset timeout for MAX6426UK30+T?

A 1500pF capacitor (CSRT) between SRT and GND yields a nominal reset timeout of 4.375ms for MAX6426UK30+T, as specified in the Electrical Characteristics table (tRP = 4.375ms, CSRT = 1500pF). The relationship is linear: tRP = (2.73 × 10⁶ × CSRT) + 275µs. For precise timing, use a low-leakage ceramic capacitor (X7R/C0G) with <10nA leakage to avoid timeout drift.

Is MAX6426UK30+T pin-compatible with any other supervisor ICs?

Yes, MAX6426UK30+T is explicitly documented as pin-compatible with the PST92XX series (e.g., PST9230) per the "Benefits and Features" section of the datasheet. Both share identical 5-pin SOT23-5 pinout: VCC (1), GND (2), SRT (3), RESET (4), NC (5). However, electrical differences-including reset accuracy, supply current, and timeout adjustability-require verification before drop-in replacement in production designs.