SiC401, SiC402, SiC403

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Vishay Siliconix

Revision: 17-Nov-14

2

Document Number: 62923

THIS DOCUMENT IS SUBJECT TO CHANGE WITHOUT NOTICE. THE PRODUCTS DESCRIBED HEREIN AND THIS DOCUMENT

SPECIFICATIONS

This reference board allows the end user to evaluate the

SiC401, SiC402, or the SiC403 chip for its features and all

functionalities.

It can also be a reference design for a user’s application.

CONNECTION AND SIGNAL / TEST POINTS

Power Sockets

Connect to a voltage source:

- SiC401A/BCD - 3 V to 17 V

- SiC402A/BCD - 3 V to 28 V

- SiC403A/BCD - 3 V to 28 V

Connect to a load that draws no more than:

• SiC401A/BCD - 15 A

• SiC402A/BCD - 10 A

• SiC403A/BCD - 6 A

5 V, GND (P5): External 5 V voltage source with 5 V to be

positive. Connect to a 5 V source when this option is

selected.

SELECTION JUMPERS

Mode Select

P7: This is a 2 way header which allows the user to select

SHORT - power save mode, the pin is at 5 V

A third option is available whereby pin 2 is shorted to 0 V to

disable the part.

UVLO Option

P8: This is a 2 way header that will enable the UVLO function

when selected. The divider resistors R1 and R2 can be

changed depending on the required turn on voltage level,

the pin requires a voltage greater than 3 V to enable.

OPEN - UVLO disabled

SHORT - UVLO enabled

P6: This is a 3 way header that will enable the user to select

between internal LDO and an external 5 V supply.

Position 1 - SHORT PIN 1-2 - internal LDO

Position 2 - SHORT PIN 2-3 - external 5 V

SIGNALS AND TEST LEADS

Input Voltage Sense

measure the voltage at the input of the regulator and remove

any losses generated due to the, connections from the

measurement. This can also be used by a power source with

sense capability.

Output Voltage Sense

measure the voltage at the output of the regulator and

remove any losses generated due to the connections, from

the measurement. This can also be used by an active load

with sense capability.

PGD (P9): Is an open drain output and is pulled up with a

10 k

+20 % percent of the set voltage this pin will go HI to

indicate the output is okay. The pin will also follow EN/PSV

condition switching LO if the IC is disabled.

POWER UP PROCEDURE

P6 jumper is in Position 1. If the P7 jumper is in place the

board will come up in power save mode, if not in place then

When applying higher than 12 V to the input it is reasonable

to install a RC snubber from LX to GND. There are place

holders on the reference board R9 and C11 for the snubber.

Values of 10

Ω and 1 nF are a reasonable starting point.

ADJUSTMENTS TO THE REFERENCE BOARD

OUTPUT VOLTAGE ADJUSTMENT

If a different output voltage is needed, simply change the

formula:

CHANGING SWITCHING FREQUENCY

The following equation illustrates the relationship between

k is shown by the following equation:

R

V

V

FB

-----------------------------

R

k

25 pF x F

SW

---------------------------------

k =

V

() x 10

V

IN

----------------------------------------------------

R

V

IN min.

15 μA

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