Analog Devices Inc./Maxim Integrated MAX6368HKA26-T

Overview

MAX6368HKA26-T from Maxim Integrated is a low-power microprocessor supervisory circuit with auxiliary user-adjustable reset input, battery-backup switchover, and chip-enable gating. It monitors VCC (1.2V–5.5V), asserts active-low open-drain RESET when VCC drops below 2.63V or RESET IN falls below 1.235V, and switches OUT to BATT during brownout to preserve CMOS RAM data in portable equipment.

For engineers reviewing the MAX6368HKA26-T datasheet, MAX6368HKA26-T pinout, MAX6368HKA26-T application, or MAX6368HKA26-T equivalent, key selection criteria include its 2.63V factory-set VTH, 1.235V auxiliary RESET IN threshold, 150ms minimum reset timeout, 10µA quiescent current, and SOT23-8 package compatibility with space-constrained µP systems requiring dual-supply monitoring and write protection.

Technical Context

The MAX6368HKA26-T integrates a precision voltage comparator for VCC monitoring (±1.5% VTH tolerance over temperature), a dedicated 1.235V reference-based RESET IN comparator for secondary supply supervision, and a bidirectional MOSFET-based power switch that routes either VCC or BATT to OUT based on voltage comparison with 40mV hysteresis. Its CE gating path uses a transmission gate with 1.5ns propagation delay and 20Ω on-resistance when enabled.

RESET assertion is triggered by three independent conditions: VCC falling below 2.63V, RESET IN falling below 1.235V, or manual intervention via external circuitry - all resulting in an open-drain active-low output held for ≥150ms after fault clearance. The device operates down to 1.2V on either VCC or VBATT and guarantees RESET/RESET validity across that full range.

Key Specifications

Pinout & Package

MAX6368HKA26-T is housed in an 8-pin SOT23 package (2.9mm × 1.6mm × 1.1mm), 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 MAX6368PKA26-T, the MAX6368HKA26-T's open-drain RESET offers flexible voltage-level translation and wired-OR capability, while TPS3808G33DBVR trades away critical battery-switchover and CE gating to achieve lower quiescent current - making it unsuitable for RAM-retention-critical designs.

Availability

MAX6368HKA26-T is available at Aetrix Electronics and suitable for portable medical monitors, industrial PLC I/O modules, smart energy meters, and ruggedized handheld terminals requiring stable component supply, long-term lifecycle support, and guaranteed traceable sourcing.

Supply support for MAX6368HKA26-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) 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 systems needing integrated power supervision, battery switchover, and memory write protection in minimal footprint - targeting portable, battery-backed, and reliability-critical embedded devices.

FAQ

What is the factory-set reset threshold voltage for MAX6368HKA26-T?

The MAX6368HKA26-T has a factory-trimmed reset threshold (VTH) of 2.63V (min 2.55V, max 2.70V) for monitoring +3.3V or +2.5V power rails. This value is laser-trimmed during production and specified over the full -40°C to +85°C operating temperature range with ±1.5% tolerance. The '26' suffix in MAX6368HKA26-T directly encodes this 2.63V nominal threshold per Maxim's ordering guide.

How does the RESET IN function work on MAX6368HKA26-T?

The RESET IN pin on MAX6368HKA26-T compares an external voltage against an internal 1.235V reference. When the voltage at RESET IN falls below 1.235V (min 1.185V, max 1.285V), the device asserts the open-drain RESET output low - identical in timing and behavior to a VCC brownout event. This enables monitoring of secondary supplies like analog rails or isolated DC-DC outputs using a simple resistor divider.

Does MAX6368HKA26-T support battery-backup operation, and what are the switchover conditions?

Yes, MAX6368HKA26-T supports automatic battery-backup operation. Switchover to BATT occurs only when both conditions are met: (1) VCC falls below the 2.63V reset threshold, and (2) VCC is at least 20mV lower than VBATT. A 40mV hysteresis prevents oscillation during slow VCC decay. During backup mode, OUT is sourced from BATT, and CE OUT is gated to protect memory writes - all while drawing just 3µA from the backup cell.

What is the purpose of the CE IN and CE OUT pins on MAX6368HKA26-T?

CE IN and CE OUT provide hardware-enforced chip-enable gating to prevent corrupted memory writes during power faults. When CE IN is driven low, CE OUT follows immediately (1.5ns delay) during normal operation. Upon reset assertion, CE OUT is held low for 12µs to complete any in-progress memory access, then actively pulled up to OUT. This ensures SRAM write cycles finish before µP reset halts execution.

What package type and pin count does MAX6368HKA26-T use?

MAX6368HKA26-T is supplied in an 8-pin SOT23 package (2.9mm × 1.6mm × 1.1mm body size), with standard JEDEC MO-178AC footprint. Pinout is fixed across the MAX6365–MAX6368 family: RESET (1), CE IN (2), GND (3), RESET IN (4), VCC (5), OUT (6), BATT (7), CE OUT (8). This compact package enables high-density placement in space-constrained portable and industrial PCBs.