SC1403(2002) View Datasheet(PDF) - Semtech Corporation

Part Name

Description

Manufacturer

SC1403
(Rev.:2002)

Mobile Multi-Output PWM Controller with Virtual Current Sense

Semtech Corporation 

SC1403

POWER MANAGEMENT

Applications Information (Cont.)

Measured overall gain & phase response of the single-pole com-

pensation using SC1403 is plotter below.

60

PRELIMINARY

Table I. is useful only if the following ESR condition is satisfied.

fO

=

1

2 ⋅ π ⋅RESR

⋅CO

25

fo > 50KHz

where Resr is the equivalent ESR of the total output caps.

-10

Transient responses of the switcher using single-pole compensa-

tion are shown below. The load steps from 0A to 3A and 3A to 6A.

The applied di/dt is 2.5A/usec

-45

-80

1.00E+02

180

160

140

120

100

80

60

40

20

0

-20

1.00E+02

1.00E+03

f (Hz)

1.00E+04

1.00E+03

f (Hz)

1.00E+04

1.00E+05

1.00E+05

Table I. Recommended compensation cap for different output

capacitance.

Output Cap

< = 180µF

> 180µF & <1000µF

>1000µF

Recommended Compensation

Cap Value

100pF

200pF

330pF

 2002 Semtech Corp.

15

www.semtech.com

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