Tracking, Sinking and Sourcing, Synchronous Buck

Controller for DDR Memory and Termination Supplies

______________________________________________________________________________________

13

POK

V+

DDR

EN/HSD

REF

GND

ILIM

VTT

VTTR

PGND

VL

BST

DH

LX

DL

FSEL

2.5V

C2

2 x 330

µF

6V

C1

1

µF

6.3V

C8

0.47

µF/10V

V+

PGND

C3

4.7

µF

10V

C4

0.47

µF

10V

C7

1

µF/6.3V

C9

0.47

µF/25V

2.5V

5.5V TO 14V

1.25V AT 7A

L1

0.68

µH/9A

Q2

IRF7463

Q1

IRF7463

D1

CMPSH-3

Q3

2N7002K

R3

20k

Ω

R2

5.1k

Ω

VL

VL

SHDN

POK

VL

OUTPUT CAPACITORS ARE SELECTED TO COMPLY WITH JEDEC SPECIFICATIONS

C6

4 x 270

µF

2V

VTTR

MAX1917

2m

Ω

3

10

2

1

7

5

6

8

11

14

15

16

12

13

4

9

Typical Application Circuits (continued)

POK

V+

DDR

EN/HSD

REF

GND

ILIM

VTT

VTTR

PGND

VL

BST

DH

LX

DL

FSEL

2.5V

C2

330

µF

6V

C1

1

µF

6.3V

C8

0.47

µF/10V

V+

PGND

C3

2.2

µF

10V

C4

0.22

µF

10V

C7

1

µF/6.3V

C9

0.47

µF/25V

2.5V

5.5V TO 14V

1.25V AT 3.5A

L1

1.0

µH/5A

Q2

IRF7811W

Q1

IRF7811W

D1

CMPSH-3

Q3

2N7002K

R3

20k

Ω

R2

5.1k

Ω

VL

VL

SHDN

POK

VL

OUTPUT CAPACITORS ARE SELECTED TO COMPLY WITH JEDEC SPECIFICATIONS.

C6

3 x 270

µF

2V

C5

10

µF

6.3V

VTTR

MAX1917

3

10

2

1

7

5

6

8

11

14

15

16

12

13

4

9

Figure 5. Typical Application Circuit for 1.25V at 3.5A Output

Figure 4. Typical Application Circuit for 1.25V at 7A Output Using Voltage Positioning