Analog Devices Inc./Maxim Integrated MAX6424UK31

Overview

MAX6424UK31 from Maxim Integrated is a low-power microprocessor supervisor IC that monitors 3.075V system supply voltage and asserts an active-low push-pull reset signal during brownout, power-up, or power-down events. It features capacitor-adjustable reset timeout (275µs to 5.75ms), guaranteed operation down to VCC = 1V, and 1.6µA typical quiescent current - ideal for battery-powered portable controllers requiring precise, low-power reset supervision.

For engineers reviewing the MAX6424UK31 datasheet, MAX6424UK31 pinout, MAX6424UK31 application, or MAX6424UK31 equivalent, key selection criteria include its 3.075V factory-trimmed reset threshold, SOT23-5 package compatibility with NCP300–NCP303 and MC33464/MC33465, capacitor-based timeout flexibility, and immunity to sub-50µs VCC transients.

Technical Context

The MAX6424UK31 implements a precision voltage detector with laser-trimmed internal resistors to achieve ±1.5% reset threshold accuracy at +25°C and ±2.5% over –40°C to +125°C. Its reset assertion is triggered when VCC falls below 3.075V, and deassertion occurs after a user-defined timeout set by an external capacitor on the SRT pin.

A 240nA internal ramp current charges the SRT capacitor to a 0.65V internal reference; the resulting timeout follows t_RP = 2.73 × 10⁶ × C_SRT + 275µs. The push-pull output drives low to ≤0.3V at 3.2mA sink and high to ≥0.8×VCC at 800µA source, ensuring robust logic-level compatibility across 1.8V–5.5V µP interfaces.

Key Specifications

Pinout & Package

MAX6424UK31 is housed in a 5-pin SOT23-5 package (package code U5+2), with 0.95mm pitch, 2.9mm × 1.6mm footprint, and exposed pad for thermal performance. Pin 3 is internally unconnected (N.C.) and must be left floating or tied to GND per layout best practice.

Key Features

Applications

Equivalent & Alternatives

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

Compared with NCP302LSN30T1G and MC33464D-30SEFR2, the MAX6424UK31 offers uniquely adjustable reset timing and superior threshold accuracy at the expense of slightly higher quiescent current - making it optimal for designs requiring precise, application-tailored reset behavior across wide temperature and voltage ranges.

Availability

MAX6424UK31 is available at Aetrix Electronics and suitable for battery-powered portable controllers, automotive body control modules, and medical infusion pump controllers requiring stable component supply, long-term lifecycle support, and AEC-Q100-aligned reliability.

Supply support for MAX6424UK31 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, mixed-signal, and power management ICs for demanding industrial, automotive, and medical applications.

The MAX6424UK31 belongs to Maxim's µP supervisor product line, engineered specifically for low-power, high-accuracy voltage monitoring and reset generation in space-constrained, battery-sensitive, and safety-critical systems.

FAQ

What is the exact reset threshold voltage of MAX6424UK31?

The MAX6424UK31 has a factory-trimmed nominal reset threshold of 3.075V, with ±1.5% accuracy at +25°C and ±2.5% over the full –40°C to +125°C operating range. This value is confirmed by Table 1 (suffix "31") and Electrical Characteristics section of the official datasheet, and applies exclusively to the MAX6424UK31 variant - not other suffixes in the MAX6424 family.

Does MAX6424UK31 require an external capacitor to function?

No, the MAX6424UK31 operates without an external capacitor: its minimum reset timeout is 275µs when the SRT pin is left unconnected. However, adding a capacitor (e.g., 1500pF) between SRT and GND extends the timeout to 4.375ms (typ), enabling compliance with µPs requiring longer reset pulses. The SRT pin must never be left floating in high-noise environments - tie to GND if unused.

Can MAX6424UK31 drive a reset input directly without a pullup resistor?

Yes, MAX6424UK31 features an active-low push-pull RESET output, so it can directly drive standard CMOS or TTL µP reset inputs without any external pullup resistor. It sinks up to 3.2mA at VCC ≥ 4.5V and sources up to 800µA, ensuring robust logic-level transitions across 1.8V–5.5V supply domains - a key distinction from open-drain variants like MAX6425UK31.

Is MAX6424UK31 pin-compatible with other reset ICs?

Yes, MAX6424UK31 is explicitly documented as pin-compatible with NCP300–NCP303, MC33464/MC33465, S807/S808/S809, and RN5VD series devices in 5-pin SOT23 packages. This allows drop-in replacement in existing layouts, provided the reset threshold (3.075V) and push-pull output match system requirements - verify timing and accuracy specs before substitution.

What is the maximum VCC transient duration MAX6424UK31 can ignore?

According to the Typical Operating Characteristics graph "Maximum Transient Duration vs. Reset Threshold Overdrive", MAX6424UK31 will not assert reset for VCC transients ≤50µs in duration when the dip magnitude is ≤100mV below its 3.075V threshold. This immunity is inherent to its internal ramp-comparison architecture and does not require external filtering components.