AM4964

Document number: DS37241 Rev. 2 - 2

9 of 21

www.diodes.com

June 2014

© Diodes Incorporated

AM4964

A Product Line of

Diodes Incorporated

CF

–CF Capacitor Pin

A capacitor is connected to this pin as a filter to translate PWM signal to be stable voltage. The resistors R3 and R4 are connected to CF pin to

adjust the maximum speed at high temperature and low temperature corners.

Adjust the maximum speed vs. input duty to approximately match the target specification using R3 and R4 at low temperature (T<TL, V8<V7);

Measure the fan rotating speed vs. input duty. And draw a curve figure accordingly (Step=5%).

Output PWM Duty vs. R3 and R4 at Low Temperature

Adjust the maximum speed vs. input PWM duty to approximately match the target specification using R3 and R4 at high temperature (T>TH,

V8>V7+0.7V).

Output PWM Duty vs. R3 and R4 at High Temperature

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R3 open

Input Duty (%)

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R4 open

Input Duty (%)

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R3 open

Input Duty (%)

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R4 open

Input Duty (%)