Analog Devices Inc./Maxim Integrated MAX6688AU75H

Overview

MAX6688AU75H from Maxim Integrated is a dual local/remote temperature switch IC with factory-programmed +125°C remote trip threshold and pin-selectable local threshold ranging from +75°C to +115°C in 5°C increments. It features CMOS push-pull active-high outputs, ±1.5°C accuracy over -40°C to +125°C, 215µA average supply current, and operates from 3.0V to 5.5V. It is used for CPU/FPGA thermal shutdown and fan control in embedded computing systems.

For engineers reviewing the MAX6688AU75H datasheet, MAX6688AU75H pinout, MAX6688AU75H application, or MAX6688AU75H equivalent, key selection criteria include remote diode interface compatibility, local threshold configurability via S1/S2 pins, push-pull output drive capability, µMAX package thermal performance, and hysteresis stability during power-up transients.

Technical Context

The MAX6688AU75H integrates two independent temperature sensing channels: a remote junction converter measuring external PNP substrate diodes (e.g., on CPU/FPGA dies) and an internal die temperature sensor. Remote trip is fixed at +125°C (H suffix), while local trip is set by S1/S2 logic states before power-on and remains latched.

It employs oversampling and integrated noise filtering on DXP/DXN inputs, supports 2200pF noise-reduction capacitor, and uses BiCMOS process for stable 2Hz sampling rate and 5°C hysteresis on both thresholds. Outputs assert only after confirmed temperature exceedance-not on single-sample faults or power-on reset.

Key Specifications

Pinout & Package

Package: 8-pin µMAX (3mm × 3mm, 0.5mm pitch, exposed pad), RoHS-compliant, thermal performance optimized for PCB-mounted die temperature sensing.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX6687AU75H, the MAX6688AU75H simplifies interface design with push-pull outputs but sacrifices bus-sharing capability; versus LM95235CIMM/NOPB, it delivers faster, deterministic hardware-triggered response without software overhead-ideal for safety-critical shutdown paths.

Availability

MAX6688AU75H is available at Aetrix Electronics and suitable for CPU thermal protection, FPGA board monitoring, and industrial fan control applications requiring stable component supply, long-term lifecycle assurance, and RoHS-compliant packaging.

Supply support for MAX6688AU75H 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, computing, and communications applications.

The MAX6688AU75H belongs to Maxim's thermal management product line, engineered specifically for hardware-based, fail-safe temperature monitoring in high-reliability embedded systems where deterministic response and minimal firmware dependency are critical.

FAQ

What is the remote temperature sensing method supported by the MAX6688AU75H?

The MAX6688AU75H uses an external P-N junction-typically the base-emitter junction of a substrate PNP transistor on a CPU, ASIC, or FPGA die-as its remote sensing element. It sources 8–12µA from DXP and sinks matching current at DXN to measure forward voltage drop, converting it to temperature with factory-trimmed +125°C trip threshold. Discrete diodes are not supported; only transistor-based junctions meet accuracy specifications.

How do I configure the local temperature trip threshold on the MAX6688AU75H?

The local trip threshold of the MAX6688AU75H is set by connecting pins S1 and S2 to VDD, GND, or leaving them floating *before* applying power to VDD. For example, S1=VDD and S2=GND configures +75°C; S1=VDD and S2=FLOAT configures +110°C. The setting is latched at power-on and cannot be changed dynamically-reconfiguration requires power cycle.

Does the MAX6688AU75H require external pull-up resistors on its outputs?

No. The MAX6688AU75H features CMOS push-pull, active-high outputs (TREMOTE and TLOCAL), eliminating the need for external pull-up resistors. Each output can source up to 1mA at VDD – 0.2V, enabling direct connection to logic inputs, LED anodes, or fan enable lines without additional components.

What is the recommended noise-filtering capacitor for the DXP/DXN inputs of the MAX6688AU75H?

A 2200pF ceramic capacitor must be placed directly across DXP and DXN, as close as possible to the MAX6688AU75H package. This capacitor filters high-frequency noise on the remote diode sense lines. Deviations exceeding ±50% from 2200pF may introduce up to ±1°C trip threshold error, per Maxim's characterization data.

Can the MAX6688AU75H be used to monitor ambient air temperature?

The MAX6688AU75H measures its own die temperature (local), which closely tracks PCB temperature due to low thermal resistance through its µMAX leads. While not ideal for direct ambient air sensing, it can reliably respond to ambient conditions if mounted on a thermally coupled copper plane designed to track ambient-e.g., via large ground pour and minimal airflow shielding.