Analog Devices Inc./Maxim Integrated MAX6365HKA44+

Overview

The MAX6365HKA44+ from Maxim Integrated is a low-power microprocessor supervisory circuit with battery backup, chip-enable gating, and manual reset input. It monitors VCC supply voltage (reset threshold 4.38V), provides active-low open-drain RESET output, switches CMOS RAM power between VCC and backup battery, and guarantees RESET assertion down to 1.2V supply. It is used in portable equipment requiring reliable power-fail detection and data retention during brownout.

For engineers reviewing the MAX6365HKA44+ datasheet, MAX6365HKA44+ pinout, MAX6365HKA44+ application, or MAX6365HKA44+ equivalent, key selection criteria include its 4.38V factory-set reset threshold, 150ms minimum reset timeout, 10µA quiescent current, 8-pin SOT23 package, and integrated CE signal gating for SRAM write protection.

Technical Context

The MAX6365HKA44+ implements a precision voltage monitor with ±1.5% threshold accuracy over temperature, internal 20kΩ MR pullup, and debounced manual reset input. Its battery switchover logic enforces dual conditions: VCC must fall below 4.38V *and* drop at least 20mV below VBATT before engaging backup mode.

Chip-enable gating uses a transmission gate with 1.5ns typical propagation delay and <100Ω on-resistance when enabled; CE OUT is actively pulled up to OUT during reset assertion, holding low for 12µs if CE IN is low at reset onset.

Key Specifications

Pinout & Package

MAX6365HKA44+ is housed in an 8-pin SOT23 package (2.9mm × 1.6mm × 1.1mm), optimized for space-constrained portable designs. Pin numbering follows standard SOT23 top-view orientation.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX6365PKA44+, the MAX6365HKA44+ offers open-drain flexibility for shared reset buses; compared with TPS3808G33DBVR, it uniquely integrates battery switchover, CE gating, and 4.38V precision monitoring - making it irreplaceable in portable SRAM-retention designs.

Availability

MAX6365HKA44+ is available at Aetrix Electronics and suitable for portable medical monitors, industrial PLC modules, retail POS terminals, and smart energy meters requiring stable component supply across extended product lifecycles.

Supply support for MAX6365HKA44+ 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, sensing, and connectivity applications in industrial, automotive, and computing markets.

The MAX6365–MAX6368 family was engineered specifically for µP system reliability - integrating reset generation, battery backup control, and SRAM write protection into ultra-small SOT23 packages for space- and power-constrained embedded devices.

FAQ

What is the factory-set reset threshold voltage for the MAX6365HKA44+?

The MAX6365HKA44+ has a factory-trimmed reset threshold of 4.38V (typical), with guaranteed range 4.25V to 4.50V over -40°C to +85°C. This value is laser-trimmed during production and does not require external components. The '44' suffix in MAX6365HKA44+ explicitly denotes this 4.38V threshold variant, confirmed in Maxim's Reset Threshold Ranges table and Device Marking Codes.

Does the MAX6365HKA44+ support battery backup functionality, and how does switchover work?

Yes, the MAX6365HKA44+ fully supports battery backup. Switchover activates only when two conditions are met simultaneously: VCC falls below the 4.38V reset threshold *and* VCC drops at least 20mV below VBATT. Once engaged, OUT connects to BATT, supplying up to 20mA while drawing <1µA standby current. The 40mV total hysteresis prevents oscillation during slow VCC decay, as documented in the Absolute Maximum Ratings and Electrical Characteristics sections.

What type of RESET output does the MAX6365HKA44+ provide, and what are its drive capabilities?

The MAX6365HKA44+ provides an active-low open-drain RESET output (pin 1). When asserted, it sinks up to 1.6mA with VOL ≤ 0.3V at VCC > 2.1V; when deasserted, it presents high-impedance and requires an external pullup. This configuration enables wired-OR reset bus architectures. The 'H' in MAX6365HKA44+ denotes the open-drain active-high variant - however, per the Pin Description and Selector Guide, MAX6365 variants use active-low RESET, and the 'H' here specifies the output structure as open-drain active-low.

How does the manual reset (MR) input function on the MAX6365HKA44+?

The MR input (pin 4) on MAX6365HKA44+ is a debounced, internally pulled-up (20kΩ to VCC) logic input. Driving MR low asserts RESET continuously; RESET remains asserted for ≥150ms after MR returns high. No external debounce components are needed. The input accepts TTL/CMOS levels and tolerates glitches - validated by 100ns glitch immunity at 3.3V VCC, as specified in the Electrical Characteristics table under MANUAL RESET parameters.

Can the MAX6365HKA44+ be used without a backup battery, and what connections are required?

Yes, the MAX6365HKA44+ operates without a backup battery. In this configuration, connect BATT to GND and tie OUT directly to VCC. The device continues full supervisory function: monitoring VCC for 4.38V threshold violation, asserting RESET, and gating CE IN to CE OUT. All specifications - including 150ms reset timeout, 10µA supply current, and 1.5ns CE propagation delay - remain valid, as confirmed in the Applications Information section titled "Operation Without a Backup Power Source".