Analog Devices Inc./Maxim Integrated MAX6366PKA29+

Overview

MAX6366PKA29+ from Maxim Integrated is a low-power microprocessor supervisory circuit with integrated watchdog timer, battery-backup switchover, and chip-enable gating. It monitors VCC (1.2V–5.5V), asserts active-high open-drain RESET on power-up/down/brownout or watchdog timeout, features 2.93V factory-set reset threshold, 1.6s watchdog timeout, and 150ms minimum reset timeout period. It is used in portable equipment requiring reliable power monitoring and data retention during main supply failure.

For engineers reviewing the MAX6366PKA29+ datasheet, MAX6366PKA29+ pinout, MAX6366PKA29+ application, or MAX6366PKA29+ equivalent, key selection criteria include its 2.93V reset threshold, 1.6s watchdog timeout, open-drain active-high RESET output, SOT23-8 package compatibility, and support for battery-backed CMOS RAM protection in space-constrained embedded systems.

Technical Context

The MAX6366PKA29+ implements a precision voltage monitor with ±1.5% threshold accuracy over temperature, a monostable watchdog timer triggered by WDI edge transitions, and a bidirectional analog switch for VCC/BATT switchover with 40mV hysteresis. Its CE IN-to-CE OUT transmission gate provides 1.5ns propagation delay and <100Ω on-resistance when not in reset.

It operates down to 1.2V on either VCC or VBATT, guarantees RESET/RESET validity at 1.2V, and maintains <3µA quiescent current in battery-backup mode. The internal 20kΩ MR pullup (not used here) and 1.235V reference for RESET IN are absent-this variant uses WDI instead of MR or RESET IN.

Key Specifications

Pinout & Package

MAX6366PKA29+ is housed in an 8-pin SOT23-8 package (2.9mm × 1.6mm × 1.1mm), surface-mount, RoHS-compliant, lead-free (+ suffix).

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX6366PKA29+, MAX6366HKA29+ eliminates external pullup dependency but increases output drive strength, while TPS3808G33DBVR reduces cost and current draw but removes critical battery-backup and memory protection capabilities essential for data-integrity-critical applications.

Availability

MAX6366PKA29+ is available at Aetrix Electronics and suitable for portable medical devices, industrial I/O modules, POS terminals, and smart energy meters requiring stable component supply, long-term lifecycle support, and guaranteed traceable sourcing.

Supply support for MAX6366PKA29+ 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, mixed-signal, and power-management ICs for demanding industrial, automotive, and computing applications.

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

FAQ

What is the reset threshold voltage of the MAX6366PKA29+?

The MAX6366PKA29+ has a factory-preset reset threshold of 2.93V (typical), with a guaranteed range of 2.85V to 3.00V over the full -40°C to +85°C operating temperature range. This threshold is laser-trimmed during production and applies to VCC monitoring for power-up, power-down, and brownout detection. The MAX6366PKA29+ does not use an adjustable reset input - its threshold is fixed and cannot be modified externally.

Does the MAX6366PKA29+ support battery backup for SRAM?

Yes, the MAX6366PKA29+ supports automatic battery backup for SRAM. When VCC falls below the 2.93V reset threshold and drops at least 20mV below VBATT, the internal switch connects BATT to OUT, powering the SRAM from the backup source. In this mode, quiescent current drops to under 3µA, enabling multi-year data retention from a standard coin cell. The device also provides CE OUT gating to prevent write corruption during switchover.

What is the function of the WDI pin on the MAX6366PKA29+?

The WDI (Watchdog Input) pin on the MAX6366PKA29+ resets the internal 1.6s watchdog timer on every rising or falling edge. If WDI remains static (high or low) for longer than 1.6s, the timer expires and triggers a RESET pulse for the full 150ms timeout period. This mechanism detects firmware lockups - the host µP must periodically toggle WDI within the timeout window to maintain normal operation.

Is the RESET output of the MAX6366PKA29+ push-pull or open-drain?

The RESET output of the MAX6366PKA29+ is open-drain and active-high. It requires an external pullup resistor to define the high-state voltage level, which may be VCC, OUT, or another system rail. This configuration allows multiple devices to share a common reset bus and supports level translation. Unlike push-pull variants (e.g., MAX6366HKA29+), it cannot actively drive high - only pull low or float.

Can the MAX6366PKA29+ operate with a 1.2V supply?

Yes, the MAX6366PKA29+ is fully specified to operate with VCC or VBATT as low as 1.2V. Its internal circuitry, including the voltage monitor, watchdog timer, and CE gating, remains functional and guaranteed across the entire 1.2V–5.5V range. RESET/RESET outputs remain valid down to 1.2V, and the device draws only ~15µA at 5.5V - making it ideal for ultra-low-power, single-cell battery applications.