Analog Devices Inc./Maxim Integrated MAX6368PKA44-T

Overview

MAX6368PKA44-T from Maxim Integrated is a low-power microprocessor supervisory circuit with auxiliary user-adjustable reset input, battery-backup switchover, and chip-enable gating. It monitors VCC supply (1.2V–5.5V), asserts active-low open-drain RESET upon VCC brownout or RESET IN falling below 1.235V, maintains CMOS RAM during power failure via BATT-to-OUT switching, and provides 150ms guaranteed reset timeout. Used in portable POS terminals and industrial controllers requiring reliable power-fail response.

For engineers reviewing the MAX6368PKA44-T datasheet, MAX6368PKA44-T pinout, MAX6368PKA44-T application, or MAX6368PKA44-T equivalent, key selection criteria include its 4.38V factory-set reset threshold (±0.13V), 10µA quiescent current at VCC > VTH, 1.5ns CE IN-to-CE OUT propagation delay, and support for battery-backed SRAM write protection in space-constrained SOT23-8 designs.

Technical Context

The MAX6368PKA44-T integrates a precision voltage comparator for VCC monitoring and a separate 1.235V reference-based comparator for the auxiliary RESET IN input, enabling dual-supply fault detection. Its internal MOSFET switch routes power from VCC or BATT to OUT based on VCC–VBATT differential (±20mV hysteresis) and VCC–VTH relationship.

Chip-enable gating uses a series transmission gate between CE IN and CE OUT, disabled during reset assertion to block spurious memory writes; CE OUT is actively pulled up to OUT when disconnected. The open-drain RESET output requires external pull-up and remains asserted for ≥150ms after VCC recovery or RESET IN deassertion.

Key Specifications

Pinout & Package

MAX6368PKA44-T is housed in an 8-pin SOT23 package (2.9mm × 1.6mm × 1.1mm), optimized for PCB area-constrained applications such as handheld instrumentation and embedded controllers.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX6368PKA44-T, MAX6367PKA44-T adds BATT ON status signaling but removes RESET IN capability, while TPS3808G33DBVR offers lower quiescent current but omits battery switchover, CE gating, and auxiliary reset functionality-making it suitable only for basic power monitoring.

Availability

MAX6368PKA44-T is available at Aetrix Electronics and suitable for portable POS terminals, industrial PLC controllers, medical handheld monitors, and smart energy meters requiring stable component supply with long-term lifecycle support.

Supply support for MAX6368PKA44-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 and mixed-signal ICs for power management, sensing, and connectivity in demanding industrial and embedded environments.

The MAX6365–MAX6368 family delivers integrated power-supply supervision, battery backup control, and memory write protection in ultra-small SOT23 packages for space- and power-constrained µP systems.

FAQ

What is the factory-set reset threshold voltage for MAX6368PKA44-T?

The MAX6368PKA44-T has a factory-set VCC reset threshold of 4.38V (typical), with a guaranteed range of 4.25V to 4.50V across temperature (−40°C to +85°C). This value is laser-trimmed during production and applies specifically to the "KA44" suffix variant, enabling precise brownout detection for +5V systems without external components.

How does the RESET IN function work on MAX6368PKA44-T?

The RESET IN pin on MAX6368PKA44-T compares an external voltage against an internal 1.235V reference. When the voltage at RESET IN falls below 1.235V (±0.05V), the device asserts the active-low RESET output. This allows monitoring of a secondary supply (e.g., 3.3V or 2.5V rail) using a simple resistor divider, with propagation delay of 1.5µs (typ) from RESET IN transition to RESET assertion.

Does MAX6368PKA44-T support battery-backup operation, and what are the switchover conditions?

Yes, MAX6368PKA44-T supports automatic battery-backup operation. Switchover from VCC to BATT occurs only when both conditions are met: (1) VCC falls below the 4.38V reset threshold, and (2) VCC is at least 20mV lower than VBATT. A 40mV hysteresis prevents oscillation during slow VCC decay, and the internal MOSFET delivers up to 150mA from VCC or 20mA from BATT to the OUT pin.

What is the purpose of CE IN and CE OUT on MAX6368PKA44-T?

CE IN and CE OUT implement chip-enable signal gating to prevent erroneous memory writes during power faults. During normal operation, CE IN passes directly to CE OUT with 1.5ns delay. When RESET asserts, the path is disabled: if CE IN is low at reset assertion, CE OUT stays low for 12µs (typ) to complete ongoing memory access; otherwise, CE OUT is pulled high to OUT, blocking further writes until reset deasserts.

What package type and pin count does MAX6368PKA44-T use?

MAX6368PKA44-T uses an 8-pin SOT23 package (2.9mm × 1.6mm × 1.1mm body size), with standard SOT23 pinout and lead (Pb)-free construction. The "-T" suffix indicates tape-and-reel packaging, and the device is rated for operation from −40°C to +85°C ambient temperature.