PM8804 datasheet(23/27 Pages) STMICROELECTRONICS

Part #	PM8804

Description	PWM peak current mode controller for PoE and telecom systems

PDF	27 Pages

Scroll/Zoom	100%

Manufacturer	STMICROELECTRONICS [STMicroelectronics]

Direct Link	http://www.st.com

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23 / 27 page

DocID031629 Rev 1

23/27

PM8804

Layout guidelines

6.4

Component placement



Place the PM8804 and all the related components close to each other; use both sides



Place all the feedback components close to each other, use both sides



Place the sense resistors close to the power MOSFET, if possible on the same side



Place the input ceramic capacitors close to the input side of power transformer, if

possible on the same side



Place the primary snubber network close to the power transformer, on the bottom side



Place the rectifier diode or MOSFET close to the output side of the transformer, if

possible on the same side



Place the secondary snubber network close to the rectifier diode or MOSFET, bottom

side



Place the decoupling capacitors for VC close to the PM8804 pin 1



Place the components for FSW, DT and SS pins in a quiet area, separated as much as

possible from the other signals



Use interconnections of at least 20 mils for the following PM8804 pins: GAT1, GAT2,

VC.

PM8804 Datasheet(PDF) 23 Page - STMicroelectronics