A6986F datasheet(40/72 Pages) STMICROELECTRONICS

Part #	A6986F

Description	38 V 1.5 A synchronous step-down switching regulator

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Manufacturer	STMICROELECTRONICS [STMicroelectronics]

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A6986F

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DocID027739 Rev 1

Equation 26

whereas the zero is defined as:

Equation 27

6.3

Voltage divider

The contribution of the internal voltage divider for fixed output voltage devices is:

Equation 28

while adjustable output part number is:

Equation 29

A small signal capacitor in parallel to the upper resistor (see Figure 31) of the voltage divider

implements a leading network (fzero < fpole), sometimes necessary to improve the system

phase margin:

Figure 31. Leading network example

fPHF

 R

C0 Cp





--------------------------------------------------------

 R



-------------------------------------

GDIV s



R1 R2

--------------------

VFB

VOUT

--------------

0.85

3.3

-----------

0.2575

A6986F3V

0.85

-----------

0.17

A6986F5V

GDIV s



R1 R2

--------------------

A6986F

A6986F Datasheet(PDF) 40 Page - STMicroelectronics

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