Analog Devices Inc./Maxim Integrated MAX6385XS28D7-T

Overview

MAX6385XS28D7-T from Maxim Integrated is a low-power microprocessor supervisory circuit with active-high push-pull reset output, factory-set 2.80V reset threshold (±2.5% over –40°C to +125°C), 1200ms minimum VCC reset timeout, and debounced manual reset input (MR). It monitors single supply voltage in battery-powered embedded systems and guarantees valid reset state down to VCC = 1.0V.

For engineers reviewing the MAX6385XS28D7-T datasheet, MAX6385XS28D7-T pinout, MAX6385XS28D7-T application, or MAX6385XS28D7-T equivalent, key selection factors include its 2.80V threshold accuracy, 1200ms power-up reset hold time, MR input with internal 63kΩ pullup, 4-pin SC70 package, and compatibility with critical μP power sequencing in portable and industrial controllers.

Technical Context

The MAX6385XS28D7-T implements a precision bandgap-based reset comparator with ±2.5% threshold tolerance across –40°C to +125°C and 60ppm/°C tempco. Its internal timer enforces a guaranteed minimum 1200ms reset assertion after VCC rises above 2.80V.

It features a dedicated active-high push-pull RESET output capable of sourcing 800µA at VCC ≥ 4.5V (VOH ≥ 0.8×VCC) and sinking 3.2mA (VOL ≤ 0.4V), plus a debounced MR input with 1µs minimum pulse width support and 100ns glitch rejection.

Key Specifications

Pinout & Package

MAX6385XS28D7-T is housed in a RoHS-compliant 4-pin SC70 package (outline 21-0098, land pattern 90-0187), with 0.65mm pitch and thermal resistance θJA = 322.6°C/W on multilayer board.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX6385XS28D7-T, MAX6326XR28D7-T lacks MR and requires external pullup, while TPS3808G33DBVR shifts threshold by +130mV and alters MR pullup strength-both require schematic and timing validation before substitution.

Availability

MAX6385XS28D7-T is available at Aetrix Electronics and suitable for portable medical sensors, industrial PLC I/O modules, automotive body control units, and smart energy meters requiring stable component supply and long-term lifecycle support.

Supply support for MAX6385XS28D7-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

Maxim Integrated (now part of Analog Devices) designs precision analog, mixed-signal, and power management ICs for demanding industrial, automotive, and computing applications.

The MAX638x family delivers ultra-low-power, high-accuracy reset supervision for battery-operated and mission-critical embedded systems where deterministic power-on sequencing and brownout protection are essential.

FAQ

What is the exact reset threshold voltage of MAX6385XS28D7-T and how stable is it over temperature?

The MAX6385XS28D7-T has a factory-set nominal reset threshold of 2.80V, with guaranteed tolerance of ±2.5% over the full operating temperature range of –40°C to +125°C. Its temperature coefficient is 60ppm/°C, meaning threshold drift is limited to ±0.32mV/°C - ensuring consistent brownout detection across automotive and industrial environments without external calibration.

Does MAX6385XS28D7-T support manual reset, and what are the electrical requirements for the MR pin?

Yes, MAX6385XS28D7-T includes a debounced manual reset (MR) input with an internal 63kΩ pullup resistor to VCC. To assert reset, MR must be driven below 0.3×VCC (for VTH < 4V) for ≥1µs. The input rejects glitches <100ns and tolerates noise up to 100ns duration. Leaving MR unconnected defaults to high via the internal pullup, making external components unnecessary for basic operation.

What is the minimum supply voltage at which MAX6385XS28D7-T guarantees correct reset output behavior?

MAX6385XS28D7-T guarantees valid reset output logic states down to VCC = 1.0V. Below this level, the internal circuitry cannot maintain defined output behavior. This feature ensures reliable reset assertion during deep brownout conditions common in battery-powered systems, allowing safe shutdown or last-gasp data storage before complete power loss.

How does the 1200ms reset timeout of MAX6385XS28D7-T impact system startup timing?

The 1200ms minimum reset timeout of MAX6385XS28D7-T ensures the reset signal remains asserted for at least 1.2 seconds after VCC exceeds 2.80V. This accommodates slow-ramping power supplies, large decoupling capacitors, and complex μP initialization sequences - preventing premature code execution before clocks, PLLs, and peripherals stabilize. The timeout is monotonic and temperature-compensated per datasheet specifications.

Is MAX6385XS28D7-T pin-compatible with legacy Maxim reset ICs like MAX809 or MAX6326?

No, MAX6385XS28D7-T is not pin-compatible with MAX809 or MAX6326. While the datasheet notes functional compatibility with those families, MAX6385XS28D7-T uses a 4-pin SC70 package with pinout VCC–RESET–MR–GND, whereas MAX809 uses 3-pin SOT23 (VCC–GND–RESET) and MAX6326 uses 3-pin SC70 (VCC–GND–RESET). Direct replacement requires PCB layout revision to accommodate the additional MR pin and revised pin mapping.