Analog Devices Inc./Maxim Integrated MAX6688AU40H

Overview

MAX6688AU40H from Maxim Integrated is a dual local/remote temperature switch IC with push-pull active-high outputs, factory-programmed +125°C remote trip threshold, pin-selectable local trip threshold in the +40°C to +80°C range (S1/S2 floating), ±1.5°C accuracy, and 215µA average supply current. It monitors CPU/FPGA die temperature via external P-N junction and board temperature simultaneously for thermal shutdown in high-reliability embedded systems.

For engineers reviewing the MAX6688AU40H datasheet, MAX6688AU40H pinout, MAX6688AU40H application, or MAX6688AU40H equivalent, key selection criteria include its +125°C factory-set remote trip point, 5°C-step local threshold programmability, 8-pin µMAX package footprint, push-pull output drive capability, and immunity to power-on transients.

Technical Context

The MAX6688AU40H integrates two independent thermal comparators: one dedicated to remote diode sensing (using DXP/DXN with 8–12µA bias current) and one for local die temperature monitoring. Both feature 5°C hysteresis and noise-immune oversampling at 2Hz sampling rate.

Its digital output stage uses CMOS push-pull drivers (TREMOTE and TLOCAL), eliminating external pull-up resistors required by open-drain variants like the MAX6687. The S1/S2 configuration is latched at power-on reset, ensuring stable threshold selection without runtime reconfiguration.

Key Specifications

Pinout & Package

Package: 8-pin µMAX (3mm × 3mm, 0.5mm pitch), RoHS-compliant, surface-mount, thermally enhanced leadframe.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar local/remote temperature switch applications.

Compared with MAX6687AU40H, the MAX6688AU40H eliminates pull-up components and simplifies GPIO interfacing, while LM95235CIMM/NOPB trades autonomous switching for programmable telemetry-making MAX6688AU40H optimal for deterministic, low-latency thermal safety where MCU involvement is undesirable or unavailable.

Availability

MAX6688AU40H is available at Aetrix Electronics and suitable for CPU thermal protection, FPGA die monitoring, and industrial fan control applications requiring stable component supply across extended temperature ranges (-40°C to +125°C).

Supply support for MAX6688AU40H 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 industrial, communications, and computing applications, emphasizing reliability, integration, and low-power operation.

The MAX6688AU40H belongs to Maxim's thermal management product line, engineered specifically for autonomous, hardware-based temperature monitoring and shutdown in high-performance digital systems where firmware intervention is unsafe or impractical.

FAQ

What is the remote temperature trip threshold for MAX6688AU40H?

The MAX6688AU40H has a factory-programmed remote temperature trip threshold of +125°C, as indicated by the "H" suffix in its part number. This value is laser-trimmed during manufacturing and cannot be adjusted. It triggers the TREMOTE output high when the external P-N junction (e.g., CPU die diode) exceeds +125°C, providing a fixed, reliable overtemperature cutoff point for critical system protection.

How do I configure the local temperature trip threshold on MAX6688AU40H?

The local temperature trip threshold of MAX6688AU40H is set by connecting pins S1 and S2 to VDD, GND, or leaving them floating before applying power to VDD. With both pins floating, the local threshold defaults to +60°C within the +40°C to +80°C range. Table 1 in the datasheet defines all 9 combinations; the setting is latched at power-on and remains fixed until the next power cycle.

Does MAX6688AU40H require external pull-up resistors on its outputs?

No, MAX6688AU40H does not require external pull-up resistors because it features CMOS push-pull, active-high outputs on both TREMOTE and TLOCAL. Unlike the open-drain MAX6687 variants, the MAX6688AU40H drives logic-high and logic-low states actively, enabling direct connection to microcontroller GPIOs, CPLDs, or other digital inputs without additional components.

What is the recommended capacitor value for DXP/DXN filtering on MAX6688AU40H?

The MAX6688AU40H requires a 2200pF ceramic capacitor connected between DXP and DXN pins to maintain temperature measurement accuracy and suppress noise coupling. This capacitor must be placed physically close to the IC pins. Deviations beyond ±50% of this value (i.e., <1100pF or >3300pF) may introduce up to ±1°C error in trip threshold due to altered RC time constants affecting diode voltage sampling.

Can MAX6688AU40H monitor both local and remote temperatures simultaneously?

Yes, MAX6688AU40H continuously monitors both local die temperature and remote P-N junction temperature in parallel. Its internal architecture includes separate sensing channels and comparators for each domain, with independent outputs (TLOCAL and TREMOTE) that assert independently based on their respective thresholds. This dual-monitoring capability enables layered thermal protection strategies-for example, fan activation at +75°C (local) and forced shutdown at +125°C (remote).