Analog Devices Inc./Maxim Integrated MAX6747KA45

Overview

The MAX6747KA45 from Maxim Integrated is a low-power microprocessor supervisory circuit with factory-trimmed 4.5V reset threshold, manual reset input (MR), capacitor-adjustable reset and watchdog timeout, push-pull active-low RESET output, and automotive-grade operation (-40°C to +125°C). It monitors VCC supply voltage and supports manual reset initiation for embedded controllers in battery-powered and critical power-up sequencing applications.

For engineers reviewing the MAX6747KA45 datasheet, MAX6747KA45 pinout, MAX6747KA45 application, or MAX6747KA45 equivalent, this device delivers precise 4.5V ±2% reset detection, guaranteed RESET validity down to VCC ≥1V, 3.7µA supply current at VCC ≤2.0V, and immunity to sub-50µs power-supply transients - key selection criteria for automotive and portable equipment designs.

Technical Context

The MAX6747KA45 implements dual-reset assertion logic: it triggers RESET when VCC falls below its 4.5V factory-trimmed threshold (±2%) or when the manual reset input (MR) is pulled low. The reset timeout period (tRP) is set externally via capacitor CSRT on SRT pin using tRP = 5.06 × 10⁶ × CSRT (seconds).

It features a standard watchdog timer (not windowed) with timeout adjustable via CSWT on SWT pin, and includes WDS input to extend watchdog timeout by 128×. Unlike MAX6752/MAX6753, it lacks SET0/SET1 pins and does not support min/max (window) watchdog functionality.

Key Specifications

Pinout & Package

MAX6747KA45 is housed in an 8-pin SOT23 package (JEDEC MO-178AA), surface-mount, lead-free compatible (suffix +T), with 1.27mm pitch and 2.9mm × 1.6mm footprint.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX6746KA45, the MAX6747KA45 adds MR functionality without altering reset threshold, timing adjustability, or package - making it the preferred choice when field-service or diagnostic reset is required. Compared with TLV809E45DBZR, it provides full watchdog supervision and manual reset at higher component count and cost, but delivers essential system-level reliability for mission-critical embedded control.

Availability

MAX6747KA45 is available at Aetrix Electronics and suitable for automotive engine control units, portable medical monitors, industrial PLC I/O modules, and smart energy meters requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for MAX6747KA45 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 demanding industrial, automotive, and computing applications, with emphasis on power efficiency, reliability, and integration.

The MAX6747KA45 belongs to the MAX6746–MAX6753 family of µP supervisory circuits engineered specifically for robust reset and watchdog supervision in automotive and industrial embedded systems where voltage monitoring accuracy and transient immunity are critical.

FAQ

What is the exact reset threshold voltage of the MAX6747KA45?

The MAX6747KA45 has a factory-trimmed reset threshold voltage of 4.5V with ±2% tolerance over the full automotive temperature range (-40°C to +125°C). This value is fixed and corresponds directly to the "45" suffix in the part number, per Maxim's ordering table. No external resistors are needed to set this threshold, as it applies to the VCC supply monitoring function.

Does the MAX6747KA45 support windowed watchdog functionality?

No, the MAX6747KA45 does not support windowed (min/max) watchdog functionality. It implements a standard single-timeout watchdog timer with normal and extended (128×) modes controlled by the WDS pin. Windowed watchdog capability is exclusive to the MAX6752 and MAX6753 variants, which include SET0/SET1 pins and different internal timing architecture.

Can the MAX6747KA45 monitor a voltage other than VCC?

No - the MAX6747KA45 monitors only the VCC supply voltage using its internal 4.5V comparator. It does not feature a dedicated RESET IN pin for external voltage monitoring. For dual-voltage or adjustable-threshold monitoring, consider the MAX6748–MAX6751 series, which include the RESET IN input and resistor-divider interface.

What is the minimum pulse width required on the MR pin to assert RESET?

The MR pin of the MAX6747KA45 requires a minimum low pulse width of 1µs to reliably assert the RESET output. The pin includes built-in 100ns glitch rejection, ensuring noise immunity, and features an internal 20kΩ pull-up resistor to VCC - allowing direct connection to a momentary switch without external components.

Is the MAX6747KA45 pin-compatible with other devices in the MAX6746–MAX6753 family?

The MAX6747KA45 shares the same 8-pin SOT23 package and pinout as MAX6746, MAX6748–MAX6751, and MAX6752/MAX6753. However, pin functionality differs: MAX6747 uses Pin 1 as MR, whereas MAX6748–MAX6751 use Pin 1 as RESET IN, and MAX6752/MAX6753 use Pins 5 and 6 as SET1 and SET0. PCB layout reuse requires verification of signal mapping per variant.