Temperature Monitors and PWM Fan Controllers

The MAX6653/MAX6663/MAX6664 are ACPI-compliant local and remote-junction temperature sensors and fan controllers. These devices measure their own die temperature, as well as the temperature of a remote-PN junction and control the speed of a DC cooling fan based on the measured temperature. Remote temperature measurement accuracy is ±1°C from +60°C to +100°C. Temperature measurement resolution is 0.125°C for both local and remote temperatures.

Internal watchdog set points are provided for both local and remote temperatures. There are two comparison set points for local temperatures and two for remote temperatures. When a set point is crossed, the MAX6653/MAX6663/MAX6664 assert either the active-low INT or active-low THERM outputs. These outputs can be used as interrupts, clock throttle signals, or overtemperature shutdown signals. Two pins on the MAX6653 control the power-up values of the comparison set points, providing fail-safe protection even when the system is unable to program the trip temperatures. The MAX6653 has two additional shutdown outputs, active-low SDR and active-low SDL, that are triggered when the remote or local temperatures exceed the programmed shutdown set points. The active-low INT output for the MAX6653/MAX6663 and active-low THERM outputs for the MAX6653/MAX6663/MAX6664 can also function as inputs if either is pulled low to force the fan to full speed, unless this function is masked by the user.

The MAX6653/MAX6663/MAX6664 are available in 16-pin QSOP packages and operate over the -40°C to +125°C temperature range.

Applications

* Industrial Controls * Networking Equipment * Personal Computing * Servers * Telecom Equipment * Test Equipment * Workstations

* Remote-Junction Temperature Sensor Within ±1°C Accuracy (+60°C to +100°C)

* ACPI-Compatible Programmable Temperature Alarms

* 0.125°C Resolution Local and Remote-Junction Temperature Measurement

* Programmable Temperature Offset for System Calibration

* SMBus 2-Wire Serial Interface with Timeout

* Automatic or Manual Fan-Speed Control

* PWM Fan Control Output

* Fan-Speed Monitoring and Watchdog

* Fan Fault and Failure Indicators

* Compatible with 2-Wire or 3-Wire Fans (Tachometer Output)

* +3V to +5.5V Supply Range

* Additional Shutdown Set Point (MAX6653)

* Controlled PWM Rise/Fall Times