US3036

4-4

Rev. 1.1

12/4/98

Figure 2- The circuit in figure 2 is the application of the US3036 providing a low cost solution for a 2.5V/2A supply from

the 5V dual supply. This circuit uses current sense resistor to set the current limiting.

TYPICAL APPLICATION

TYPICAL APPLICATION

5V to 2.5V for RDRAM Supply

Ref Desig

Description

Qty

Part #

Manufacturer

U1

LDO/Switcher IC

1

US3036CS ( 8 pin SOIC)

Unisem

Q2

MOSFET

1

IRF7204 (8 pin SOIC) or IRF7406 for 4A

IR

P Ch

SI9435DY (8 pin SOIC) or SI4431 for 4A

Temic

D1

Schottky Diode

1

SK33DICT (SMC)

Lite on

L2

Inductor

1

Core:T44-52,L=6 uH

Micro Metal

Turns: 15T, 20 AWG

(core)

L1

Inductor

1

L=1 uH

R1

Resistor

1

10 ohm,5%, SMT 1206 size

R2

Resistor

1

10 ohm, 5%, SMT 1206 size

R3

Resistor

1

200 kohm,1%, SMT 0805 size

R4

Resistor

1

1 kohm,1%, SMT 0805 size

R5

Resistor

1

1 kohm,1%, SMT 0805 size

R6

Resistor

1

5 miliohm,5%, 2W

Ohmite

R7,8

Resistor

2

3.57 kohm,1%, SMT 0805 size

C1

Capacitor

1

470uF,10V, Elect

Sanyo

C2

Capacitor

1

10CV1000DX, 1000uF,10V, Elect ,ESR=0.07 Ohm

Sanyo

C3

Capacitor

1

1 uF,Ceramic, SMT 0805 size

C4

Capacitor

1

470 pF,Ceramic, SMT 0805 size

Sanyo

C5

Capacitor

1

10 pF,Ceramic, SMT 0805 size

Sanyo

C6

Capacitor

1

4700pF

C7

Capacitor

1

10CV1000DX, 1000uF,10V, Elect ,ESR=0.07 Ohm

Sanyo

C8

Capacitor

1

0.15 uF

3036app1-1.3

Vout

C1

L1

C3

Q2

C2

L2

R4

C7

D1

R2

C4

R5

R1

R3

C5

C8

US3036

R8

R6

C6

R7

1

2 3

4

5

6

7

8

Drv Vcc

Vfb

NC

Gnd

CS-

CS+

SS

ATX

P.S.

5V

5V(S.B.)