The MAX6638 thermal-management sensor includes internal (local) and external (remote) digital temperature sensors and two independent SMBus™ serial ports. The remote temperature accuracy is ±1.0°C, and the local temperature accuracy is ±2°C. The MAX6638 also features extended temperature resolution data available in 0.125°C increments. The MAX6638 provides three system alarms: channel 1 alert (ALERT1), overtemperature (OVERT1), and channel 2 alert (ALERT2) that contain programmable thresholds set independently by each of the SMBus serial ports (SMBus1 and SMBus2). Each alert output asserts when any of four temperature conditions is violated: local overtemperature, remote overtemperature, local undertemperature, or remote undertemperature. The overtemperature signal asserts when the temperature rises above the value in the overtemperature limit register. Use the OVERT1 output to activate a cooling fan or trigger a system shutdown. Each of the 2-wire serial-interface ports accepts standard System Management Bus (SMBus) write byte, read byte, send byte, and receive byte commands independently of one another with total collision avoidance handled by the MAX6638. Each SMBus can operate its own unique serial-data rate to access any register in the MAX6638 for data reads or data writes. The MAX6638 manages all dual-port data register access functions providing a seamless, conflict-free integration into a multimaster architecture for thermal management.
The MAX6638 is a thermal‑management sensor that provides both local and remote digital temperature measurements. It features two independent SMBus/I²C‑compatible ports with collision‑avoidance logic, programmable alarms (ALERT1, OVERT1, ALERT2) and conversion rates that can be set per port. The device operates from –40 °C to +125 °C and can measure temperatures from 0 °C to +145 °C with 0.125 °C resolution.
Typical applications include graphics cards, notebook computers, motherboard systems, desktops and workstations. The datasheet includes electrical characteristics, pin descriptions, functional diagrams, conversion timing, standby mode behavior, and package information for the 16‑pin, 4 mm × 4 mm TQFN package.
| Operating Temperature Range | -40 °C to +125 °C |
|---|---|
| Temperature Measurement Range | 0 °C to +145 °C |
| Remote Temperature Accuracy | ±1.0 °C (85 °C‑100 °C) |
| Local Temperature Accuracy | ±2 °C |
| Supply Voltage (VCC) | 3.0 V to 5.5 V |
| ADC Resolution | 11‑bit |
The remote temperature accuracy is ±1.0 °C from +85 °C to +100 °C.
It provides two independent SMBus/I²C‑compatible serial ports.