PROGRAMMABLE SYNCHRONOUS DC/DC

CONVERTER, DUAL LOW DROPOUT

REGULATOR CONTROLLER

© 1999 SEMTECH CORP.

October 25, 1999

652 MITCHELL ROAD NEWBURY PARK CA 91320

SC1164/5

6

MATERIALS LIST

Qty. Reference

Part/Description

Vendor

Notes

4

C1,C5,C13,C

18

0.1µF Ceramic

Various

6

C2,C3,C14-

C17

1500µF/6.3V

SANYO

MV-GX or equiv. Low ESR

6

C9-C12,

C21, C22

330µF/6.3V

Various

1

L1

4µH

8 Turns 16AWG on MICROMETALS T50-52D core

4

Q1,Q2,Q3,

Q4

See notes

See notes

FET selection requires trade-off between efficiency and

cost. Absolute maximum R

1R4

5m

Ω

IRC

OAR-1 Series

1R5

2.32k

Ω, 1%, 1/8W Various

1R6

1k

Ω, 1%, 1/8W

Various

1R1

10

Ω, 5%, 1/8W

Various

1

R12

1%, 1/8W

Various

See Table Below (Not required for SC1164)

1

R13

1%, 1/8W

Various

See Table Below (Not required for SC1164)

1

R14

1%, 1/8W

Various

See Table Below (Not required for SC1164)

1

R15

1%, 1/8W

Various

See Table Below (Not required for SC1164)

2

R17,R18

100k

Ω, 5%,1/8W

Various

Required if Voltage is applied to the linear FET(s) without

12V applied to SC1164/5

1

U1

SC1164/5CSW

SEMTECH

SETTING LDO OUTPUT VOLTAGE

error

t

significan

cause

not

does

term

)

R

I

(

the

that

so

enough

low

be

must

R

and

R

ion

clarificat

for

diagram

layout

See

resistor

feedback

Bottom

R

resistor

feedback

Top

R

current

bias

pin

Feedback

I

:

Where

)

R

I

(

R

)

R

R

(

265

.

1

V

A

FB

B

A

B

A

FB

A

FB

B

B

A

OUT

⋅

=

=

=

⋅

+

+

⋅

=

R

B

R

A

VOUT LDO1 (LDO2)

R12 (R14)

R13 (R15)

3.45V

105

Ω

182

Ω

3.30V

105

Ω

169

Ω

3.10V

102

Ω

147

Ω

2.90V

100

Ω

130

Ω

2.80V

100

Ω

121

Ω

2.50V

100

Ω

97.6

Ω

1.50V

100

Ω

18.7

Ω