Analog Devices Inc./Maxim Integrated MAX6424UK22+T

Overview

MAX6424UK22+T from Analog Devices is a low-power microprocessor supervisor IC that monitors VCC supply voltage and asserts an active-low push-pull reset signal when voltage falls below 2.188V (typical), with capacitor-adjustable timeout (3.0–5.75ms at CSRT = 1500pF) and guaranteed operation down to VCC = 1V. It serves as a system-level power-on reset controller in battery-powered embedded controllers and portable instrumentation.

For engineers reviewing the MAX6424UK22+T datasheet, MAX6424UK22+T pinout, MAX6424UK22+T application, or MAX6424UK22+T equivalent, key selection criteria include its 2.188V reset threshold accuracy (±2.5% over temperature), 1.6µA typical quiescent current, SOT23-5 package compatibility with NCP300–NCP303 and MC33464/MC33465, and immunity to sub-50µs VCC transients.

Technical Context

The MAX6424UK22+T implements a precision voltage detector with laser-trimmed internal resistors defining a 2.188V nominal reset threshold, coupled to a 240nA current source charging an external SRT capacitor to generate a programmable reset timeout. Its push-pull output drives µP reset inputs directly without external pull-up components.

Reset assertion occurs within 80µs of VCC falling below threshold; deassertion requires both VCC rising above threshold and the SRT capacitor ramping to 0.65V. The device guarantees valid RESET output down to VCC = 1V and operates across –40°C to +125°C.

Key Specifications

Pinout & Package

MAX6424UK22+T is housed in a 5-pin SOT23-5 package (package code U5+2, outline 21-0057), with 0.95mm pitch, 2.9mm × 1.6mm footprint, and exposed pad for thermal enhancement.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX6424UK22+T, NCP302LSN22T1G adds design complexity with pull-up dependency and reduced noise immunity, while MC33464D-22 trades tighter threshold accuracy and lower quiescent current for broader qualification history in automotive Tier-1 systems.

Availability

MAX6424UK22+T is available at Aetrix Electronics and suitable for portable medical sensors, battery-powered industrial controllers, and automotive body control modules requiring stable component supply across extended temperature ranges and long product lifecycles.

Supply support for MAX6424UK22+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, Inc. is a global leader in high-performance analog, mixed-signal, and digital signal processing semiconductors, headquartered in Wilmington, MA.

The MAX6424UK22+T belongs to the MAX6340/MAX6421–MAX6426 family of ultra-low-power microprocessor supervisors, designed specifically for reliable power-on reset generation in space-constrained, battery-sensitive, and thermally demanding embedded systems.

FAQ

What is the exact reset threshold voltage of MAX6424UK22+T and how does it vary with temperature?

The MAX6424UK22+T has a nominal reset threshold of 2.188V, with ±1.5% accuracy at +25°C and ±2.5% over the full –40°C to +125°C operating range. This is confirmed by Table 1 (suffix "22") and Electrical Characteristics section, where VTH min/max values are 2.133V and 2.243V respectively at temperature extremes. The device uses laser-trimmed resistors to achieve this precision without external components.

Can MAX6424UK22+T operate with a 1.2V supply, and what is its behavior below 1.6V?

Yes, MAX6424UK22+T operates down to VCC = 1.0V per Absolute Maximum Ratings and Electrical Characteristics tables. At 1.2V, reset assertion remains functional, and RESET output is guaranteed valid (VOL ≤ 0.3V, VOH ≥ 0.8×VCC). Below 1.0V, operation is not specified; however, the device guarantees RESET validity down to VCC = 1V, making it suitable for ultra-low-voltage energy harvesting systems.

How do I calculate the SRT capacitor value for a 5ms reset timeout with MAX6424UK22+T?

Use the formula CSRT = (tRP − 275µs) / 2.735 × 10⁶, where tRP is in seconds. For 5ms (0.005s): CSRT = (0.005 − 0.000275) / 2,735,000 ≈ 1727pF. A standard 1800pF ceramic capacitor yields ~5.2ms timeout, verified in Typical Operating Characteristics figure toc04. Select X7R or C0G dielectric with leakage <10nA.

Is MAX6424UK22+T pin-compatible with NCP302LSN22T1G, and what are the critical interface differences?

Yes, MAX6424UK22+T and NCP302LSN22T1G share identical SOT23-5 pinout (GND, VCC, SRT, RESET, N.C.) and 2.2V reset threshold. Critical differences: MAX6424UK22+T uses push-pull RESET (no pull-up needed), while NCP302LSN22T1G uses open-drain RESET requiring external pull-up. Also, MAX6424UK22+T draws 1.6µA vs. 1.8µA, and offers tighter threshold accuracy (±2.5% vs. ±3%).

Does MAX6424UK22+T require special PCB layout considerations for the SRT pin?

Yes - the SRT pin connects to a precision 240nA current source, so layout must minimize stray capacitance and leakage. Keep SRT traces short (<5mm), avoid routing near high-speed signals or high-voltage nodes, and isolate from ground/power planes. Do not place test points or connectors on SRT; use guard rings if necessary. Ceramic capacitor should be placed adjacent to SRT pin with direct ground connection.