Analog Devices Inc./Maxim Integrated MAX6423XS46+T

Overview

MAX6423XS46+T from Analog Devices is a low-power microprocessor supervisor IC in SC70-4 package, providing active-low open-drain reset output with 4.625V ±2.5% factory-trimmed reset threshold and capacitor-adjustable timeout (275µs to 5.75ms). It monitors VCC from 1.0V to 5.5V, draws only 1.6µA typical supply current, and guarantees valid reset assertion down to VCC = 1V - used for brownout protection in battery-powered embedded controllers.

For engineers reviewing the MAX6423XS46+T datasheet, MAX6423XS46+T pinout, MAX6423XS46+T application, or MAX6423XS46+T equivalent, key selection criteria include its 4-pin SC70 footprint, open-drain logic compatibility with multiple supply rails, immunity to sub-50µs VCC transients, and guaranteed operation across –40°C to +125°C industrial temperature range.

Technical Context

The MAX6423XS46+T implements a precision voltage-detection architecture using laser-trimmed resistors to set its 4.625V reset threshold, with ±2.5% accuracy over full temperature range. Its SRT pin hosts a 240nA constant-current source that charges an external capacitor to generate the reset timeout delay, enabling programmable deassertion timing independent of VCC.

As an open-drain supervisor, it requires an external pullup resistor (10kΩ–100kΩ) to any logic rail up to 5.5V, allowing interoperability with µPs operating at different I/O voltages. The device asserts RESET low when VCC falls below threshold and holds it low for the capacitor-defined period after VCC recovers - ensuring reliable power-up sequencing without internal timing components.

Key Specifications

Pinout & Package

MAX6423XS46+T is housed in a 4-pin SC70 package (outline 21-0098), with 0.65mm pitch and exposed pad not connected. Pin 1 is SRT (Set Reset Timeout), Pin 2 is GND, Pin 3 is RESET (open-drain output), and Pin 4 is VCC.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX6423US46+T, the MAX6423XS46+T offers identical supervision performance in a smaller SC70 footprint ideal for ultra-compact designs; versus NCP302HS46T1G, it provides critical design flexibility through adjustable timeout and open-drain output - essential for multi-rail and fail-safe reset architectures.

Availability

MAX6423XS46+T is available at Aetrix Electronics and suitable for battery-powered medical monitors, automotive body control modules, and industrial PLC I/O modules requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for MAX6423XS46+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 since 1965.

The MAX6421–MAX6426 family delivers ultra-low-power, precision voltage supervision for mission-critical embedded systems where deterministic reset behavior, small size, and wide temperature operation are mandatory.

FAQ

What is the exact reset threshold voltage of MAX6423XS46+T and how is it trimmed?

The MAX6423XS46+T has a nominal reset threshold of 4.625V, with ±2.5% accuracy over –40°C to +125°C. This value is achieved via factory laser trimming of internal resistors during wafer sort, ensuring stable performance without external calibration. The "46" suffix in MAX6423XS46+T directly references this 4.625V threshold per Table 1 in the datasheet.

Can MAX6423XS46+T drive a reset input directly without an external pullup resistor?

No - MAX6423XS46+T features an open-drain RESET output and requires an external pullup resistor (typically 10kΩ–100kΩ) to a valid logic rail (0–5.5V) to establish the high state. Without it, RESET remains floating when deasserted, risking undefined µP behavior. The pullup defines both logic-high voltage and sink current capability.

How do I calculate the capacitor value needed for a 3.5ms reset timeout with MAX6423XS46+T?

Use the formula CSRT = (tRP – 275µs) / 2.735 × 10⁶, where tRP is in seconds. For 3.5ms: CSRT = (0.0035 – 0.000275) / 2,735,000 ≈ 1180pF. Select a low-leakage ceramic capacitor (X7R/C0G) rated ≥6.3V; tolerance impacts timeout accuracy (±10% cap → ±10% timeout).

Is MAX6423XS46+T qualified for automotive applications per AEC-Q100?

No - only the MAX6340UK31/V+T variant is explicitly AEC-Q100 qualified per the datasheet. MAX6423XS46+T is rated for –40°C to +125°C operation and widely used in automotive body electronics, but lacks formal AEC-Q100 stress testing documentation. For ASIL-B systems, verify qualification status with Analog Devices prior to design-in.

What is the maximum transient duration MAX6423XS46+T can ignore when VCC dips 100mV below its 4.625V threshold?

Per the "Maximum Transient Duration vs. Reset Threshold Overdrive" graph, MAX6423XS46+T tolerates negative VCC transients of ≤50µs duration when the dip magnitude is 100mV below threshold (i.e., to 4.525V). Longer transients at this overdrive level will trigger reset assertion, ensuring robustness against power rail noise.