Analog Devices Inc./Maxim Integrated MAX6426UK46+

Overview

MAX6426UK46+ from Maxim Integrated is a low-power microprocessor supervisor IC that monitors 4.625V system supply voltage and asserts an active-low open-drain reset signal when VCC falls below threshold. It features capacitor-adjustable reset timeout (2.73×10⁶ × CSRT + 275µs), guaranteed reset validity down to VCC = 1V, and operates across –40°C to +125°C for automotive and industrial power-up/brownout protection.

For engineers reviewing the MAX6426UK46+ datasheet, MAX6426UK46+ pinout, MAX6426UK46+ application, or MAX6426UK46+ equivalent, key selection criteria include its 4.625V factory-trimmed reset threshold, SOT23-5 open-drain output architecture, capacitor-programmable timeout, and AEC-Q100-compatibility lineage within the MAX642x family.

Technical Context

The MAX6426UK46+ implements a precision voltage-detection comparator with laser-trimmed internal resistors to set its 4.625V reset threshold (±1.5% at +25°C, ±2.5% over full temperature range). Its reset timeout is generated by a 240nA current source charging an external capacitor (CSRT) to a 0.65V ramp threshold - enabling programmable delays from 275µs (CSRT = 0) to >5ms (CSRT = 1500pF).

This device uses BiCMOS process technology (295 transistors), supports operation down to VCC = 1.0V, and provides immunity to short VCC transients - e.g., a 100mV negative-going glitch lasting ≤50µs typically does not trigger reset. The open-drain RESET output requires an external pullup (10kΩ–100kΩ) to any supply ≤5.5V for logic-level flexibility.

Key Specifications

Pinout & Package

MAX6426UK46+ is housed in a 5-pin SOT23-5 package (package code U5+2, outline 21-0057), RoHS-compliant, tape-and-reel format. Pin 1 is SRT (Set Reset Timeout), Pin 2 is GND, Pin 3 is RESET (open-drain output), Pin 4 is N.C. (not internally connected), and Pin 5 is VCC.

Key Features

Applications

Equivalent & Alternatives

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

Compared with PST9246 and NCP302LSN46T1G, the MAX6426UK46+ delivers tighter threshold accuracy, lower quiescent current, and design flexibility via programmable timeout - making it optimal for space-constrained, battery-sensitive, or automotive-grade systems requiring precise reset control.

Availability

MAX6426UK46+ is available at Aetrix Electronics and suitable for automotive engine control units, industrial PLC modules, and battery-powered medical monitors requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for MAX6426UK46+ 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 - emphasizing reliability, low power, and high integration.

The MAX642x series was developed specifically for microprocessor reset supervision in harsh environments, delivering factory-trimmed voltage thresholds, capacitor-programmable timing, and robust transient immunity in miniature SOT packages.

FAQ

What is the exact reset threshold voltage of the MAX6426UK46+?

The MAX6426UK46+ has a factory-laser-trimmed nominal reset threshold of 4.625V, with guaranteed accuracy of ±1.5% at +25°C and ±2.5% over the full –40°C to +125°C operating range. This value corresponds to the "46" suffix per Table 1 in the datasheet and requires no external calibration components.

Does the MAX6426UK46+ require an external pullup resistor on the RESET pin?

Yes, the MAX6426UK46+ features an open-drain RESET output and requires an external pullup resistor (typically 10kΩ to 100kΩ) connected between RESET and a logic supply (0–5.5V). This defines the high-state voltage and supplies current to any connected loads, such as a µP's reset input or other open-drain devices in a wired-OR configuration.

How is the reset timeout period set for the MAX6426UK46+?

The reset timeout period for MAX6426UK46+ is set by connecting an external capacitor (CSRT) between the SRT pin and GND. The relationship is tRP = (2.73 × 10⁶ × CSRT) + 275µs, where tRP is in seconds and CSRT is in farads. For example, a 1500pF capacitor yields a typical timeout of 4.375ms.

Can the MAX6426UK46+ operate reliably during brief power supply glitches?

Yes, the MAX6426UK46+ is designed to reject short VCC transients: a 100mV negative-going glitch lasting ≤50µs typically does not trigger reset. This immunity is confirmed in the "Maximum Transient Duration vs. Reset Threshold Overdrive" graph and supports robust operation in electrically noisy automotive or industrial settings.

Is the MAX6426UK46+ qualified for automotive applications?

While the MAX6426UK46+ itself is not individually AEC-Q100 certified, it belongs to the MAX642x family whose variants (e.g., MAX6340UK31/V+T) are AEC-Q100 qualified. Its –40°C to +125°C operating range, BiCMOS process, and transient immunity make it suitable for automotive subsystems where full qualification is not mandated but performance and reliability are critical.