Analog Devices Inc./Maxim Integrated MAX6385XS29D3+

Overview

MAX6385XS29D3+ from Maxim Integrated is a push-pull active-high microprocessor supervisory circuit with factory-set 2.93V reset threshold, 140ms minimum VCC reset timeout, and manual reset input. It monitors +1.8V to +5.0V supply rails in low-power embedded systems, consumes only 3μA at +1.8V, guarantees valid reset output down to VCC = 1V, and operates across -40°C to +125°C. Used in portable equipment and dual-voltage controllers for reliable power-up sequencing.

For engineers reviewing the MAX6385XS29D3+ datasheet, MAX6385XS29D3+ pinout, MAX6385XS29D3+ application, or MAX6385XS29D3+ equivalent, key selection criteria include its active-high push-pull reset output, ±2.5% threshold accuracy over temperature, 140ms VCC reset timeout, MR input with internal 63kΩ pullup, and 4-pin SC70 package compatibility with space-constrained PCB layouts.

Technical Context

The MAX6385XS29D3+ implements a precision voltage comparator with ±2.5% reset threshold accuracy over -40°C to +125°C and 60ppm/°C tempco, paired with a monolithic timer that enforces a guaranteed minimum 140ms reset assertion after VCC rises above 2.93V. Its active-high push-pull output drives directly into μP reset inputs without external pullups.

It integrates a debounced manual reset input (MR) with 1μs minimum pulse width support and 100ns glitch rejection, featuring an internal 63kΩ pullup resistor to VCC. The device guarantees correct logic state of RESET down to VCC = 1V, enabling robust operation during brownout conditions.

Key Specifications

Pinout & Package

MAX6385XS29D3+ uses a 4-pin SC70 package (outline 21-0098, land pattern 90-0187), optimized for high-density PCB layouts with 0.65mm pitch and 1.3mm × 1.7mm footprint.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX6385LT29D3+, the MAX6385XS29D3+ saves 0.4mm² PCB area and offers lower thermal resistance in compact layouts; versus TPS3808G33DBVR, it delivers tighter threshold tolerance, shorter timeout, and push-pull drive-eliminating external components and simplifying validation.

Availability

MAX6385XS29D3+ is available at Aetrix Electronics and suitable for portable instrumentation, automotive body electronics, industrial controllers, and battery-powered sensor nodes requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for MAX6385XS29D3+ 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 and mixed-signal ICs for demanding industrial, automotive, and communications applications, emphasizing low power, high reliability, and AEC-Q100 qualification.

The MAX6381–MAX6390 family delivers single/dual low-voltage μP reset circuits targeting space- and power-constrained embedded systems where guaranteed reset behavior across extreme temperatures is critical.

FAQ

What is the exact reset threshold voltage of the MAX6385XS29D3+ and how stable is it over temperature?

The MAX6385XS29D3+ has a factory-set nominal reset threshold of 2.93V, with guaranteed accuracy of ±2.5% over the full operating temperature range of -40°C to +125°C. This corresponds to a min/max threshold window of 2.85V to 3.00V at temperature extremes, ensuring reliable detection of 3.3V rail brownout without false triggering. The 60ppm/°C tempco further limits drift within this band.

Does the MAX6385XS29D3+ require external components for basic operation?

No, the MAX6385XS29D3+ requires no external components for core supervision functionality. Its 2.93V threshold is factory-trimmed, the MR input includes a 63kΩ internal pullup resistor, and the active-high push-pull RESET output drives directly into μP reset pins. Only a 0.1μF VCC bypass capacitor is recommended for transient immunity-no resistors, capacitors, or diodes are needed for reset generation.

How does the manual reset (MR) function interact with the VCC reset timeout in the MAX6385XS29D3+?

In the MAX6385XS29D3+, asserting MR low forces immediate reset assertion regardless of VCC level. After MR is released, the device enforces the same 140ms minimum timeout period before deasserting RESET-identical to the VCC-initiated timeout. This ensures consistent reset hold time whether triggered by supply fault or user action, simplifying system-level timing analysis and eliminating dual-timing paths.

Can the MAX6385XS29D3+ operate reliably at VCC = 1.2V, and what happens to the RESET output below that?

Yes, the MAX6385XS29D3+ guarantees correct RESET logic state down to VCC = 1V. At VCC = 1.2V, RESET remains fully functional: it asserts high when VCC falls below 2.93V and holds for 140ms after recovery. Below 1V, the internal circuitry ceases operation and RESET enters high-impedance-so systems requiring validity to 0V must add an external pullup (for active-high) or pulldown (for active-low variants), though MAX6385XS29D3+ does not support that mode.

Is the MAX6385XS29D3+ pin-compatible with legacy Maxim reset ICs like the MAX809?

Yes, the MAX6385XS29D3+ is pin-compatible with MAX809/MAX810/MAX803 and other members of the MAX6326–MAX6348 series in the same 4-pin SC70 package. Pin 1 is VCC, Pin 2 is RESET, Pin 3 is GND, and Pin 4 is MR-matching the physical layout and signal mapping of those predecessors. This allows drop-in replacement in existing designs without PCB modification, provided the active-high output and 2.93V threshold meet system requirements.