4-Wire Pulse Width Modulation (PWM) Controlled Fans Specification

Electrical Specifications
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2.2 Test Methodology
To measure the pull up and current sourced from the fan, power the fan to 13.2V and use a DMM
(Digital Muli-meter).
To verify the pull up value in the fan, measure the voltage between pin 4 (control) and pin 1
(ground).
To verify the current sourced by the fan, measure the current between pin 4 (control) and pin 1
(ground).
2.3 Hardware Monitor Device
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