SP6656 Datasheet, PDF(13/17 Page) Sipex Corporation – High Efficiency 400mA Synchronous Buck Regulator with Bit Programmable Output

English

English German Russian Spanish Italian Polish Chinese Japanese Korean French Portuguese	Language :

SP6656 Datasheet, PDF (13/17 Pages) Sipex Corporation – High Efficiency 400mA Synchronous Buck Regulator with Bit Programmable Output

◁

APPLICATION INFORMATION

The output voltage is programmed by the external divider, as shown in the typical

application circuit on Page 1. Depending on the topology used, 1 or 2 output ,VOUT is

set as follows:

1) Single VOUT

First pick a value for RI that is no larger than 300K.

Too large a value of RI will reduce the AC voltage

seen by the loop comparator since the internal FB

pin capacitance can form a low pass filter with RF

in parallel with RI. The formula for RF with a given

RI and output voltage is:

VOUT

22pF

RF = (VOUT / 0.8V - 1) x (RI)

2) Dual VOUT (selectable)

First pick the lowest voltage that will be used and

utilize the same method as above.

RF = (VOUT_LOW/ 0.8V - 1) x (RI) RIâ¤ 300k

Then use the following equation to determine RS:

[RI//RS]

0.8 x RF

VOUT_HIGH

0.8

RS = [RI//RS]

1 [RI//RS]

VOUT

22pF

OVSO

Date: 7/9/04

SP6656 High Efficiency 400mA Synchronous Buck Regulator with Bit Programmable Output

▷