The AMC6821 is an intelligent temperature monitor and pulse-width modulation (PWM) fan controller. It is designed for noise-sensitive or power-sensitive applications that require active system cooling. Using either a low-frequency or a high-frequency PWM signal, this device can simultaneously drive a fan, monitor remote sensor diode temperatures, and measure and control the fan speed so that it operates with minimal acoustic noise at the lowest possible speed.
●The AMC6821 has three fan control modes: Auto Temperature-Fan mode, Software-RPM mode, and Software-DCY mode. Each mode controls the fan speed by changing the duty cycle of a PWM output. Auto Temperature-Fan mode is an intelligent, closed-loop control that optimizes fan speed according to user-defined parameters. This mode allows the AMC6821 to run as a stand-alone device without CPU intervention; the fan can continue to be controlled (based on temperature measurements) even if the CPU or system locks up. Software-RPM mode is a second closed-loop control. In this mode, the AMC6821 adjusts the PWM output to maintain a consistent fan speed at a user-specified target value; that is, the device functions as a fan speed regulator. Software-RPM mode can also be used to allow the AMC6821 to operate as a stand-alone device. The third mode, Software-DCY, is open-loop. In Software-DCY mode, the PWM duty cycle is set directly by the value written to the device.
●The AMC6821 has a programmable SMBALERT output to indicate error conditions and a dedicated FAN-FAULT output to indicate fan failure. The THERM pin is a fail-safe output for over-temperature conditions that can be used to throttle a CPU clock. Additionally, the OVR pin indicates the over-temperature limit as well. All of the alarm thresholds are set through the device registers. The AMC6821 is available in a QSOP-16 package.
● Remote Temperature Sensor:
●±2°C Accuracy, 0.125°C Resolution
● Local Temperature Sensor:
●±2°C Accuracy, 0.125°C Resolution
● PWM Controller
● PWM Frequency: 10Hz to 40kHz
●Duty Cycle: 0% to 100%, 8 Bits
● Automatic Fan Speed Control Loops
● SMBus Interface
● Power: 2.7V to 5.5V
● Package (Green): QSOP-16 (4mm × 5mm)
● RoHS Compliant
● APPLICATIONS
● Notebook and Desktop PCs
● Network Servers
● Telecommunications Equipment
● PC-Based Equipment
● DLP and LCD Projectors
●DLP is a trademark of Texas Instruments.
●Pentium M, Pentium-IV are trademarks of Intel.
●JMC is a trademark of JMC Products.
●I2C is a trademark of Philips International, Inc.
●All other trademarks are the property of their respective owners.
