MIC2103YML datasheet(28/38 Pages) MICREL

Part #	MIC2103YML

Description	75V, Synchronous Buck Controllers featuring Adaptive On-Time Control

PDF	38 Pages

Scroll/Zoom	100%

Manufacturer	MICREL [Micrel Semiconductor]

Direct Link	http://www.micrel.com

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28 / 38 page

Micrel, Inc.

MIC2103/04

November 26, 2013

Revision 2.0

If the voltage divider resistors R1 and R2 are in the kΩ

range, then a Cff of 1nF to 100nF can easily satisfy the

large

time

constant

requirements.

Also,

100nF

injection capacitor Cinj is used in order to be considered

as short for a wide range of the frequencies.

The process of sizing the ripple injection resistor and

capacitors is:

Step 1. Select Cff to feed all output ripples into the

feedback pin and make sure the large time constant

assumption is satisfied. Typical choice of Cff is 1nF to

100nF if R1 and R2 are in kΩ range.

Step 2. Select Rinj according to the expected feedback

voltage ripple using Equation 33:

ΔV

FB(pp)

div

−

Eq. 33

Then the value of Rinj is obtained as:

(

(R1//R2)

div

inj

−

Eq. 34

Step 3. Select Cinj as 100nF, which could be considered

as short for a wide range of the frequencies.

MIC2103YML Datasheet(PDF) 28 Page - Micrel Semiconductor