Analog Devices Inc./Maxim Integrated MAX6424UK45+T

Overview

MAX6424UK45+T from Analog Devices is a low-power microprocessor supervisor IC with active-low push-pull reset output, 4.5V nominal reset threshold (±1.5% at +25°C), capacitor-adjustable reset timeout (3.0–5.75ms with 1500pF), and guaranteed operation down to VCC = 1V. It monitors supply voltage in portable and battery-powered systems to prevent erroneous code execution during power-up, brownout, or power-down.

For engineers reviewing the MAX6424UK45+T datasheet, MAX6424UK45+T pinout, MAX6424UK45+T application, or MAX6424UK45+T equivalent, key selection criteria include reset threshold accuracy, quiescent current (1.6µA typ at VCC ≤ 2.0V), SOT23-5 package compatibility, open-drain vs. push-pull output logic, and capacitor-based timeout flexibility for µP reset timing alignment.

Technical Context

The MAX6424UK45+T implements a precision voltage detector with laser-trimmed internal reference and hysteresis (4×VTH), using a 240nA constant-current source to charge an external capacitor on the SRT pin. Reset assertion occurs when VCC falls below 4.5V (±1.5% at +25°C), and deassertion follows after the capacitor ramps to 0.65V.

Its push-pull RESET output drives low to 0.3V at 50µA (VCC ≥ 1.0V) and high to 0.8×VCC (min) across 1.8–4.5V supply range, ensuring robust interface with CMOS µP reset inputs. The device operates over –40°C to +125°C and maintains valid reset signaling down to VCC = 1V.

Key Specifications

Pinout & Package

MAX6424UK45+T is housed in a 5-pin SOT23-5 package (package code U5+2), with exposed pad not electrically connected. Pin 1 is SRT (Set Reset Timeout), Pin 2 is GND, Pin 3 is RESET (active-low push-pull), Pin 4 is N.C., and Pin 5 is VCC.

Key Features

Applications

Equivalent & Alternatives

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

Compared with NCP302LSN45T1G and TLV809EC25DBVR, the MAX6424UK45+T uniquely combines push-pull output, capacitor-adjustable timeout (275µs–5.75ms), and guaranteed 1V operation-enabling precise, low-power, and flexible reset control in battery-critical and automotive systems where timing alignment and supply resilience are essential.

Availability

MAX6424UK45+T is available at Aetrix Electronics and suitable for portable medical sensors, automotive body control modules, and industrial PLC I/O submodules requiring stable component supply, long-term lifecycle support, and RoHS-compliant packaging.

Supply support for MAX6424UK45+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 MAX6424UK45+T belongs to the MAX6340/MAX6421–MAX6426 family of low-power µP supervisors, designed specifically for reliable power-on reset, brownout protection, and capacitor-tunable timeout in space- and energy-constrained embedded systems.

FAQ

What is the exact reset threshold voltage of the MAX6424UK45+T and how tightly is it specified?

The MAX6424UK45+T has a nominal reset threshold of 4.5V, specified as ±1.5% at +25°C and ±2.5% over the full –40°C to +125°C temperature range. This tight tolerance ensures consistent detection of 5V rail undervoltage across environmental conditions without requiring system-level calibration. The threshold is laser-trimmed during manufacturing and referenced to an internal 0.65V bandgap, making the MAX6424UK45+T suitable for applications demanding precise supply monitoring.

How does the capacitor on the SRT pin determine the reset timeout period for the MAX6424UK45+T?

The SRT pin of the MAX6424UK45+T sources a precise 240nA current into an external capacitor (CSRT) connected to ground. The reset timeout period (tRP) is calculated as tRP = 2.73 × 10⁶ × CSRT + 275µs, where tRP is in seconds and CSRT in farads. For example, a 1500pF capacitor yields a typical timeout of 4.375ms. Ceramic capacitors with leakage <10nA are recommended to maintain accuracy, and layout best practices require short, noise-isolated traces to SRT to avoid timing errors.

Is the MAX6424UK45+T compatible with microcontrollers that require a reset pulse longer than 5ms?

No-the MAX6424UK45+T's maximum reset timeout is 5.75ms (with 1500pF on SRT). For µPs requiring longer hold times (e.g., >6ms), the MAX6424UK45+T cannot meet that requirement natively. Engineers must either select a different supervisor with extended timeout capability or implement external timing circuitry. The datasheet confirms the upper limit under Electrical Characteristics: tRP = 5.75ms max at CSRT = 1500pF, and no higher values are supported by the internal ramp architecture of the MAX6424UK45+T.

Can the MAX6424UK45+T operate reliably when the supply voltage drops below 1.5V?

Yes-the MAX6424UK45+T guarantees functional reset assertion down to VCC = 1.0V, and its RESET output remains valid (VOL ≤ 0.3V, VOH ≥ 0.8×VCC) across the full 1.0V–5.5V supply range. This makes it suitable for deep brownout scenarios such as battery depletion in portable devices. However, below 1.0V, RESET output drive strength degrades significantly, so system design must ensure critical µP operations complete before VCC reaches 1.0V. The MAX6424UK45+T specification explicitly covers operation down to 1.0V, not just "down to 1V" as a limit.

Does the MAX6424UK45+T have AEC-Q100 qualification for automotive use?

No-the MAX6424UK45+T itself is not listed as AEC-Q100 qualified in the provided datasheet. Only the MAX6340UK31/V+T variant is explicitly noted as AEC-Q100 qualified. While the MAX6424UK45+T shares the same SOT23-5 package, –40°C to +125°C temperature rating, and automotive-grade process (BiCMOS), qualification requires formal test documentation per AEC-Q100 stress categories, which is not assigned to this specific part number. For automotive safety-critical applications, designers should verify qualification status directly with Analog Devices or select the certified MAX6340UK31/V+T alternative.