Analog Devices Inc./Maxim Integrated MAX6365PKA31+T

Overview

MAX6365PKA31+T from Maxim Integrated is a low-power microprocessor supervisory circuit with battery backup, chip-enable gating, and debounced manual reset input. It monitors VCC supply voltage (reset threshold = 3.08V typ), asserts active-low open-drain RESET during power-up/down/brownout, switches OUT between VCC and backup battery (VBATT), and gates CE signals with 1.5ns propagation delay. Used in portable equipment requiring reliable memory write protection and brownout recovery.

For engineers reviewing the MAX6365PKA31+T datasheet, MAX6365PKA31+T pinout, MAX6365PKA31+T application, or MAX6365PKA31+T equivalent, key selection criteria include its 3.08V factory-set reset threshold, 150ms minimum reset timeout, 10µA quiescent current, SOT23-8 package, and integrated CE signal gating for SRAM protection during supply faults.

Technical Context

The MAX6365PKA31+T implements a precision voltage monitor with ±1.5% threshold accuracy over temperature, coupled to an internal power-switching MOSFET that connects either VCC or VBATT to OUT based on VCC–VBATT differential (±20mV switchover hysteresis). Its manual reset input (MR) features internal 20kΩ pullup and 120ns MR-to-RESET delay at VCC = 3.3V.

Chip-enable gating uses a transmission gate architecture with 20–100Ω on-resistance (reset not asserted), enabling CE IN–CE OUT pass-through during normal operation and forcing CE OUT low for 12µs when CE IN is low at reset assertion. RESET remains asserted for ≥150ms after VCC rises above 3.08V.

Key Specifications

Pinout & Package

MAX6365PKA31+T 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 MAX6365PKA31+T, MAX6365LKA31+T offers identical monitoring but different output drive architecture, while TPS3808G33DBVR reduces feature set to basic reset generation-making it suitable only for simpler, non-backup applications.

Availability

MAX6365PKA31+T is available at Aetrix Electronics and suitable for portable medical monitors, industrial data loggers, retail point-of-sale terminals, smart energy meters, and battery-backed embedded controllers requiring stable component supply across extended product lifecycles.

Supply support for MAX6365PKA31+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 interface applications in industrial, automotive, and computing markets.

The MAX6365–MAX6368 family targets space-constrained, battery-sensitive µP systems needing integrated reset supervision, seamless battery backup, and hardware-enforced memory write protection-eliminating discrete diode-OR, reset generators, and external gating logic.

FAQ

What is the exact reset threshold voltage of the MAX6365PKA31+T?

The MAX6365PKA31+T has a factory-preset reset threshold of 3.00V (min), 3.08V (typ), and 3.15V (max) at TA = –40°C to +85°C. This value is laser-trimmed during production and specified in the Reset Threshold Ranges table of the datasheet. The "KA31" suffix explicitly denotes this 3.08V nominal threshold, making MAX6365PKA31+T suitable for 3.3V systems where brownout detection must occur before VCC drops below 3.1V.

Does the MAX6365PKA31+T support battery backup operation with lithium coin cells?

Yes, the MAX6365PKA31+T supports lithium coin cell backup (e.g., CR2032, 3V nominal) on the BATT pin. It automatically switches OUT from VCC to BATT when VCC falls below both the 3.08V reset threshold and VBATT minus 20mV. In backup mode, IBACK is ≤3µA over temperature, enabling multi-year operation from a typical 220mAh coin cell. The device requires VCC to be present at startup-BATT alone cannot power up the circuit.

How does the CE gating function protect memory in the MAX6365PKA31+T?

The MAX6365PKA31+T protects memory by inserting a transmission gate between CE IN and CE OUT. During normal operation, CE IN passes through to CE OUT with ≤9ns delay. When RESET asserts (due to VCC brownout, MR low, etc.), CE OUT is forced low for 12µs-even if CE IN remains high-blocking write cycles to SRAM or flash. This hardware-enforced gating prevents partial writes and data corruption without software intervention, a critical feature for fail-safe data logging.

What is the purpose of the MR pin on the MAX6365PKA31+T, and how is it used?

The MR (Manual Reset) pin on the MAX6365PKA31+T allows external initiation of a reset cycle. Driving MR low asserts RESET continuously; RESET remains asserted for ≥150ms after MR returns high. MR includes an internal 20kΩ pullup to VCC, so a simple momentary switch from MR to GND suffices-no external resistor or debounce circuitry is needed. This simplifies front-panel reset implementation in consumer and industrial equipment using MAX6365PKA31+T.

Can the MAX6365PKA31+T operate with a 1.8V main supply?

Yes, the MAX6365PKA31+T operates with VCC as low as 1.2V and guarantees RESET/RESET functionality down to 1.2V. At VCC = 1.8V, it continues monitoring, asserting RESET when VCC falls below 3.08V (which cannot occur), so the device remains in reset until VCC exceeds 3.08V. Thus, MAX6365PKA31+T is not suitable for 1.8V-only systems-it is designed for 3.3V or 5V rails where its 3.08V threshold provides meaningful brownout margin.