L6911C

16/20

Inductor selection

Since the maximum output current is equal to 14A, to have a 30% ripple (4A) in worst case a 3

µH inductor has

In worst case the peak is equal to 18.1A.

Output Capacitor

In the demo ten Sanyo capacitors, model 6MV1000GX are used, with a maximum ESR equal to 69m

Ω. There-

fore, the resultant ESR is 69m

Ω/10 = 1.9mΩ. For a load transient of 14A in worst case the drop results:

∆Vout = 14 * 0.00069 = 96.6mV

The voltage drop due to the capacitor discharge during load transient, considering that the maximum duty cycle

is equal to 100% results in 13mV with 2.5V of programmed output.

Input Capacitor

capacitors 25MV330GX, with a maximum ESR equal to 69m

Ω, are chosen to sustain the ripple. Therefore, the

resultant ESR is equal to 69m

Ω/5 = 13.8mΩ. So the losses in worst case are:

Over-Current Protection

Part List

R2

499k

1%

SMD 0805

R3, R7

1k

1%

SMD 0805

R4

20

SMD 0805

R5, R8

20k

SMD 0805

R9

15k

SMD 0805

R12

1K

SMD 0805

R13, R14

0

SMD 0805

C1, C2…C5

330

µ

SANYO – 25MV330GX

Radial 8x20mm

C6, C7…C15

1000

µ

SANYO – 6MV1000GX

Radial 8x20mm

C16, C17, C24, C25

100n

Ceramic

SMD 0805

C18

2.2n

Ceramic

SMD 0805

C19

8.2n

Ceramic

SMD 0805

C20

82n

Ceramic

SMD 0805

C21, C22

1

µ

Ceramic

SMD 1206

C23

1n

Ceramic

SMD 0805

L1

1.5

µ

T44-52 Core, 7T-18AWG

L2

3

µ

T50-52B Core, 10T-16AWG

U1

L6911C

STMicroelectronics

SO20

Q1, Q2…Q6

STS12NF30L

STMicroelectronics

SO8

D1

1N4148

STMicroelectronics

SOT23

D2

STPS3L25U

STMicroelectronics

SMB

F1

251015A-15°

Littlefuse

AXIAL

P

ESR I

rm s

2

⋅

670 mW

==