2.3.1 PWM Output Signal The Hardware Monitor Devise is required to provide an open-drain or open-collector type output for the PWM signal on pin 4 (see Table 1 and Figure 8) with the following properties: Frequency: 25kHz nominal, 21-28kHz is acceptable Current sink capability: 5mA required, 8mA recommended Maximum voltage capability: 5.25V Maximum VOL: 0.8V Signal is not inverted, 100% PWM results in Max fan speed