Analog Devices Inc./Maxim Integrated MAX6366PKA26+

Overview

MAX6366PKA26+ 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 = 2.63 V), asserts an open-drain active-low RESET output during power-up/down/brownout, and triggers a 1.6 s watchdog timeout pulse upon µP inactivity. It operates from 1.2 V to 5.5 V and supports CMOS RAM backup in portable industrial controllers.

For engineers reviewing the MAX6366PKA26+ datasheet, MAX6366PKA26+ pinout, MAX6366PKA26+ application, or MAX6366PKA26+ equivalent, key selection criteria include its 2.63 V factory-set reset threshold, 1.6 s watchdog timeout, 10 µA quiescent current, open-drain active-low RESET output, and SOT23-8 package compatibility with space-constrained µP systems requiring reliable brownout detection and fail-safe memory protection.

Technical Context

The MAX6366PKA26+ integrates a precision voltage monitor with ±1.5% threshold accuracy over temperature, a monostable watchdog timer with 1.00–2.25 s timeout range (typ. 1.6 s), and bidirectional VCC/BATT switchover logic with 40 mV hysteresis. Its CE IN-to-CE OUT transmission gate provides 1.5 ns propagation delay and <100 Ω on-resistance when reset is deasserted.

It features a dedicated WDI input that clears the watchdog on any edge transition, guarantees RESET assertion down to 1.2 V VCC or VBATT, and maintains CE OUT low for 12 µs after CE IN goes low during reset to complete memory access. The device uses internal MOSFET switching for battery backup, with VCC-to-OUT R_ON ≤ 4.6 Ω at 2.38 V/25 mA.

Key Specifications

Pinout & Package

MAX6366PKA26+ is housed in an 8-pin SOT23 package (2.9 mm × 1.6 mm × 1.1 mm), optimized for high-density PCB layouts in portable and industrial control applications.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX6366HKA26+, the MAX6366PKA26+ offers flexible open-drain RESET for bus sharing but requires an external pull-up; compared with TPS3808G125DBVR, it delivers full supervisory functionality-including watchdog, CE gating, and battery switchover-at higher quiescent current, making it suitable for complex embedded systems demanding comprehensive power management.

Availability

MAX6366PKA26+ is available at Aetrix Electronics and suitable for industrial control, portable medical devices, smart energy meters, and point-of-sale terminals requiring stable component supply with long-term lifecycle support.

Supply support for MAX6366PKA26+ 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) is a semiconductor company specializing in high-performance analog, mixed-signal, and power management ICs for industrial, automotive, and computing applications.

The MAX6365–MAX6368 family was designed specifically for µP-based systems needing integrated reset supervision, battery backup, and memory write protection in ultra-small footprints-targeting portable, battery-powered, and space-constrained embedded platforms.

FAQ

What is the factory-set reset threshold voltage for MAX6366PKA26+?

The MAX6366PKA26+ has a factory-preset reset threshold of 2.63 V (minimum 2.55 V, maximum 2.70 V) across the full -40°C to +85°C operating temperature range. This value is laser-trimmed during production and does not require external resistors or configuration. The threshold is used to detect brownout conditions on the VCC supply and initiate the 150 ms reset timeout period. All electrical specifications for MAX6366PKA26+ assume this exact threshold setting.

Does MAX6366PKA26+ support battery-backup operation, and what are the key constraints?

Yes, MAX6366PKA26+ supports automatic battery-backup switchover when VCC falls below 2.63 V and VBATT exceeds VCC by at least 20 mV. In backup mode, OUT is sourced from BATT with ≤ 4.6 Ω on-resistance, delivering up to 20 mA while drawing only 3 µA from the battery (at VBATT = 2.8 V). The device requires VCC to be present at startup - it will not power up from BATT alone. MAX6366PKA26+ also guarantees RESET assertion down to 1.2 V VBATT, ensuring robust operation even as the backup cell discharges.

How does the watchdog timer in MAX6366PKA26+ function, and what is its timeout behavior?

The MAX6366PKA26+ watchdog timer has a typical timeout of 1.6 s (range 1.00–2.25 s) and is cleared on every rising or falling edge at the WDI pin. If WDI remains static longer than the timeout period, a pulse is generated on the open-drain RESET output for the full 150 ms reset timeout duration. The timer resets automatically whenever RESET is asserted (e.g., during power-up), eliminating spurious timeouts. No external components are needed - the MAX6366PKA26+ implements the entire watchdog function internally with edge-sensitive input logic.

What is the purpose and behavior of the CE IN and CE OUT pins on MAX6366PKA26+?

The CE IN and CE OUT pins implement chip-enable signal gating to prevent memory corruption during power faults. When reset is inactive, CE IN passes directly to CE OUT with 1.5 ns propagation delay and <100 Ω on-resistance. When reset asserts, CE OUT is immediately disabled; if CE IN is low at reset assertion, CE OUT stays low for 12 µs (typical) to allow completion of ongoing memory access before disconnecting. This behavior is intrinsic to MAX6366PKA26+ and requires no external logic - it is fully integrated into the supervisory function.

Can MAX6366PKA26+ operate with a 1.2 V supply, and how does it affect RESET output validity?

Yes, MAX6366PKA26+ operates from 1.2 V to 5.5 V, and both RESET and RESET outputs are guaranteed functional down to 1.2 V VCC or VBATT. At 1.2 V, the open-drain RESET output can sink ≥1.6 mA while maintaining VOL ≤ 0.4 V, ensuring compatible logic-level signaling with modern ultra-low-voltage µPs and FPGAs. This capability is explicitly tested and specified in the MAX6366PKA26+ datasheet - no derating or external level shifting is required for 1.2 V system integration.