Analog Devices Inc./Maxim Integrated MAX6687AU40H+

Overview

MAX6687AU40H+ from Maxim Integrated is a dual local/remote temperature switch IC in an 8-pin µMAX package, featuring factory-programmed +125°C remote trip threshold and pin-selectable local threshold ranging from +40°C to +80°C in 5°C steps. It delivers ±1.5°C accuracy, 2Hz sampling rate, and open-drain active-low outputs for CPU/FPGA thermal shutdown and fan control applications.

For engineers reviewing the MAX6687AU40H+ datasheet, MAX6687AU40H+ pinout, MAX6687AU40H+ application, or MAX6687AU40H+ equivalent, key selection considerations include remote diode interface compatibility, S1/S2 pin configuration for local threshold selection, open-drain output drive requirements, and 3.0V–5.5V supply operation in space-constrained thermal monitoring designs.

Technical Context

The MAX6687AU40H+ integrates two independent temperature switches: one monitors an external P-N junction (e.g., CPU die's substrate PNP) via DXP/DXN with fixed +125°C trip, while the other senses its own die temperature using a pin-programmable local threshold set by S1/S2 logic states. Both thresholds feature 5°C hysteresis to prevent oscillation near trip points.

It employs BiCMOS process technology with 7765 transistors, uses oversampling and integrated noise filtering on the remote diode path, and incorporates power-on reset (POR) circuitry that prevents false triggering during startup. The device asserts TREMOTE and TLOCAL only after confirmed temperature exceedance-not on transient single-sample faults.

Key Specifications

Pinout & Package

Package: 8-pin µMAX (3.05mm × 3.05mm × 0.8mm), surface-mount, lead-free, RoHS-compliant.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX6688AU40H+ and LM95235CIMM/NOPB, the MAX6687AU40H+ provides hardware-deadline thermal protection without software dependency, open-drain flexibility for mixed-voltage systems, and dual-sensing capability-making it optimal for safety-critical embedded shutdown where latency and autonomy are mandatory.

Availability

MAX6687AU40H+ is available at Aetrix Electronics and suitable for CPU thermal protection, FPGA die monitoring, and industrial temperature alarm systems requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for MAX6687AU40H+ 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 U.S.-based semiconductor company specializing in precision analog, mixed-signal, and power management ICs for industrial, computing, and communications markets.

The MAX6687/MAX6688 product line was designed specifically for autonomous, hardware-based thermal safety in high-performance digital systems-delivering deterministic shutdown without firmware intervention or communication bus reliance.

FAQ

What is the remote temperature trip threshold for MAX6687AU40H+?

The MAX6687AU40H+ has a factory-programmed remote temperature trip threshold of +125°C, indicated by the "H" suffix in the part number. This threshold is laser-trimmed during manufacturing and applies to the external P-N junction sensed via DXP/DXN pins. It remains fixed and cannot be adjusted in-circuit.

How do I configure the local temperature trip threshold on MAX6687AU40H+?

The local trip threshold of MAX6687AU40H+ is set by connecting pins S1 and S2 to GND, VDD, or leaving them floating-before applying power to VDD. For example, S1 = GND and S2 = floating selects +45°C. The configuration is latched at power-on and remains unchanged until next power cycle.

Does MAX6687AU40H+ require external components for remote temperature sensing?

Yes, MAX6687AU40H+ requires a 2200pF ceramic capacitor connected directly between DXP and DXN pins to ensure accurate remote temperature measurement. This capacitor filters noise and stabilizes the diode voltage reading; deviation beyond ±50% causes up to ±1°C error in trip threshold.

What is the output behavior of MAX6687AU40H+ when temperature exceeds threshold?

MAX6687AU40H+ features two open-drain active-low outputs: TREMOTE goes low when remote temperature exceeds +125°C, and TLOCAL goes low when local die temperature exceeds the S1/S2-selected threshold. Both outputs require external pull-up resistors (typically 10kΩ) to function correctly.

Can MAX6687AU40H+ be used with discrete diodes for remote sensing?

No-MAX6687AU40H+ is optimized for P-N junctions with ideality factor ~1.008, such as substrate PNP transistors found in CPUs/FPGAs. Discrete diodes exhibit inconsistent V_BE characteristics and will cause significant trip temperature error; only diode-connected transistors (e.g., CMPT3904, SST3904) are recommended per Maxim's design guidelines.