LM3753 datasheet(39/49 Pages) TI1

Part #	LM3753

Description	LM3753 Scalable 2-Phase Synchronous Buck Controller with Integrated FET Drivers and Linear Regulator Controller

PDF	49 Pages

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Manufacturer	TI1 [Texas Instruments]

Direct Link	http://www.ti.com

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39 / 49 page

fC =

öBW x Km x öP

0.5

(2 x S

) x 3

öZ

fC =

öBW x Km x öP

0.333

(2 x S

) x 3

öZB = öBW x Km x öP

0.333

LM3753

www.ti.com

SNVS614B – DECEMBER 2009 – REVISED MARCH 2013

ERROR AMPLIFIER BANDWIDTH LIMIT

When the ideal error amplifier gain reaches the open loop gain-bandwidth limit, the phase goes to zero. To

incorporate the amplifier bandwidth into the design procedure, determine the boundary limit with respect to the

ESR zero frequency:

(83)

Based on the relative ESR zero, the crossover frequency is set at 1/3 of the bandwidth limiting frequency.

ωZ > ωZB, calculate the optimal crossover frequency from:

(84)

ωZ < ωZB, calculate the optimal crossover frequency from:

(85)

Using this method, the maximum phase boost is achieved at the optimal crossover frequency.

In either case, the upper limit for fC is typically set at 1/5 of the switching frequency.

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LM3753 Datasheet(PDF) 39 Page - Texas Instruments