50

100

150

200

250

300

350

400

450

500

550

600

650

700

0.3

0.8

1.3

1.8

F (MHz)

R

k

f

) = 174

W

·

-1.122

TPS65252

www.ti.com

SLVSAM1B

– DECEMBER 2010 – REVISED FEBRUARY 2011

DETAILED DESCRIPTION

Adjustable Switching Frequency

To select the internal switching frequency connect a resistor from ROSC to ground. Figure 13 shows the required

resistance for a given switching frequency.

Figure 13. ROSC vs Switching Frequency

(1)

Out-of-Phase Operation

In order to reduce input ripple current, buck 1 and buck 2 operate 180

° out-of-phase. This enables the system

having less input ripple, then to lower component cost, save board space and reduce EMI.

Start-Up and Sequencing

Figure 14 shows the start-up sequencing and PGOOD signal generation.

© 2010–2011, Texas Instruments Incorporated

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