Analog Devices Inc./Maxim Integrated MAX6366PKA44+

Overview

The MAX6366PKA44+ from Maxim Integrated is a low-power microprocessor supervisory circuit with integrated watchdog timer, battery-backup switchover, and chip-enable gating. It monitors VCC supply voltage (reset threshold = 4.38V typ), asserts active-low open-drain RESET during power-up/down/brownout, provides 1.6s watchdog timeout, and switches OUT between VCC and backup battery with <1µA battery standby current. Used in portable POS terminals and industrial controllers requiring reliable power-fail response.

For engineers reviewing the MAX6366PKA44+ datasheet, MAX6366PKA44+ pinout, MAX6366PKA44+ application, or MAX6366PKA44+ equivalent, key selection criteria include reset threshold accuracy (±0.13V over temp), guaranteed RESET operation down to 1.2V VCC/VBATT, 150ms minimum reset timeout, and SOT23-8 package compatibility with space-constrained embedded designs.

Technical Context

The MAX6366PKA44+ implements a precision bandgap-based reset comparator with factory-trimmed 4.38V threshold (range 4.25V–4.50V), coupled to an internal watchdog timer that triggers RESET pulses upon WDI signal stall exceeding 1.6s. Its battery switchover logic enforces dual conditions: VCC must fall below VTH *and* be at least 20mV below VBATT before enabling BATT-to-OUT conduction via a low-on-resistance MOSFET (4.6Ω typ at 2.38V).

Chip-enable gating uses a transmission gate with 1.5ns propagation delay (typ) and 20–100Ω on-resistance, actively pulling CE OUT to OUT when disabled. RESET remains asserted for ≥150ms after VCC recovery, with 20µs fast response to VCC falling edge (10V/ms).

Key Specifications

Pinout & Package

MAX6366PKA44+ is housed in an 8-pin SOT23 package (2.9mm × 1.6mm × 1.1mm), optimized for PCB area-constrained applications including handheld instruments and IoT edge nodes.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX6366HKA44+, the MAX6366PKA44+ provides direct compatibility with standard active-low µP reset inputs; versus TPS3808G33DBVR, it delivers integrated battery switchover and watchdog functionality essential for data-critical portable systems.

Availability

MAX6366PKA44+ is available at Aetrix Electronics and suitable for portable medical monitors, industrial PLC I/O modules, smart energy meters, and POS terminal power management requiring stable component supply across extended temperature ranges.

Supply support for MAX6366PKA44+ 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 product line delivers integrated power-supply supervision, battery backup control, and memory write protection for microprocessor systems operating under harsh voltage conditions.

FAQ

What is the exact reset threshold voltage for MAX6366PKA44+?

The MAX6366PKA44+ features a factory-trimmed reset threshold of 4.38V typical, with a guaranteed range of 4.25V to 4.50V across -40°C to +85°C. This value is laser-trimmed during production and documented in the Reset Threshold Ranges table of the datasheet. The '44' suffix in MAX6366PKA44+ explicitly denotes this 4.38V threshold variant, making it suitable for monitoring nominal +5V rails with margin for tolerance and drift.

Does MAX6366PKA44+ support battery backup operation with lithium coin cells?

Yes, MAX6366PKA44+ supports lithium coin cell backup (e.g., CR2032) via its BATT pin. When VCC falls below 4.25V and drops at least 20mV below VBATT, the internal MOSFET connects the battery to OUT with 4.6Ω typical on-resistance. Battery standby current is limited to 3µA max, enabling >10-year operation on a standard 220mAh coin cell. The device requires no external diodes or FETs for switchover.

How does the watchdog function operate in MAX6366PKA44+?

The MAX6366PKA44+ watchdog monitors the WDI pin for edges: any rising or falling transition resets the 1.6s internal timer. If WDI remains static longer than 1.6s (1.00–2.25s range), a pulse is generated on the open-drain RESET output for ≥150ms. The timer clears on every edge or when RESET is asserted, enabling flexible software integration-such as toggling WDI at loop entry/exit points to detect hangs.

Can MAX6366PKA44+ be used without a backup battery?

Yes, MAX6366PKA44+ operates fully without a backup battery. In this configuration, connect BATT to GND and tie OUT directly to VCC. All supervision functions-including reset generation, watchdog monitoring, and CE gating-remain active. The device draws only 15µA typical supply current, making it viable for cost-sensitive applications where data retention during power loss is not required.

What is the purpose of the CE IN and CE OUT pins on MAX6366PKA44+?

The CE IN and CE OUT pins implement hardware write-protection for CMOS RAM or flash memory. During normal operation, CE IN passes directly to CE OUT with 1.5ns delay. When RESET asserts (due to brownout, watchdog timeout, or manual reset), CE OUT is immediately disabled-preventing erroneous writes during unstable power. If CE IN is low during reset, CE OUT stays low for 12µs to complete ongoing memory cycles before disconnecting.