12

 2005 Semtech Corp.

www.semtech.com

POWER MANAGEMENT

SC900

r

e

t

s

i

g

e

R

e

m

a

N

r

e

t

s

i

g

e

R

s

s

e

r

d

d

A

7

t

i

B6

t

i

B5

t

i

B4

t

i

B3

t

i

B2

t

i

B1

t

i

B0

t

i

B

A

O

D

L0

0

x

0X

X

e

v

it

c

A

n

w

o

d

t

u

h

S

N

O

=

1

F

F

O

=

0

s

e

d

o

C

e

g

a

tl

o

V

t

u

p

t

u

O

O

D

L

A

e

l

b

a

T

B

O

D

L1

0

x

0

C

O

D

L2

0

x

0

D

O

D

L3

0

x

0

E

O

D

L4

0

x

0

t

e

s

e

R

O

D

L

l

o

r

t

n

o

C

5

0

x

0n

i

P

D

G

P

O

D

L

ti

B

y

ti

r

a

l

o

P

t

e

s

e

R

n

i

P

T

S

R

A

ti

B

y

ti

r

a

l

o

P

t

e

s

e

R

s

ti

B

c

i

g

o

L

r

o

ti

n

o

M

D

G

P

O

D

Ls

ti

B

y

a

l

e

D

D

G

P

O

D

Ls

ti

B

y

a

l

e

D

t

e

s

e

R

)

A

(

O

D

L

l

o

r

t

n

o

C

ff

O

/

n

O

r

e

t

s

i

g

e

R

6

0

x

0X

X

X

l

o

r

t

n

o

C

F

F

O

/

N

O

E

O

D

L

l

o

r

t

n

o

C

F

F

O

/

N

O

D

O

D

L

l

o

r

t

n

o

C

F

F

O

/

N

O

C

O

D

L

l

o

r

t

n

o

C

F

F

O

/

N

O

B

O

D

L

l

o

r

t

n

o

C

F

F

O

/

N

O

A

O

D

L

1

0

10

10

10

1

0

N

O

F

F

O

N

O

F

F

ON

O

F

F

O

N

O

F

F

O

N

O

F

F

O

7

t

i

Bt

l

u

s

e

R6

t

i

Bt

l

u

s

e

R5

t

i

B4

t

i

Bt

l

u

s

e

R3

t

i

B2

t

i

Bt

l

u

s

e

R1

t

i

B0

t

i

Bt

l

u

s

e

R

y

ti

r

a

l

o

P

n

i

P

D

G

P

O

D

Ly

ti

r

a

l

o

P

n

i

P

T

S

R

Ac

i

g

o

L

r

o

ti

n

o

M

D

G

P

O

D

Ly

a

l

e

D

D

G

P

O

D

Ly

a

l

e

D

T

S

R

A

0li

a

F

r

e

w

o

P

:

h

g

i

H

d

o

o

G

r

e

w

o

P

:

w

o

L

0t

e

s

e

R

:

h

g

i

H

d

o

o

G

r

e

w

o

P

:

w

o

L

00

s

O

D

L

E

&

D

,

C

,

A

d

o

o

G

00

s

m

0

5

10

0

s

m

0

5

1

1

d

o

o

G

r

e

w

o

P

:

h

g

i

H

li

a

F

r

e

w

o

P

:

w

o

L

1

d

o

o

G

r

e

w

o

P

:

h

g

i

H

t

e

s

e

R

:

w

o

L

01

d

o

o

G

E

O

D

L0

1

s

m

0

0

1

01

s

m

0

5

10

d

o

o

G

C

O

D

L1

0

s

m

0

5

10

s

m

0

0

1

11

d

o

o

G

D

O

D

L1

1

s

m

01

1

s

m

0

SC900 Slave Address:

R

E

I

F

I

T

N

E

D

I

E

P

Y

T

E

C

I

V

E

DE

C

I

V

E

D

S

S

E

R

D

D

A

W

/

R

000

1

0

0

0

A

X

Applications Information (Cont.)

LDO Reset Control Logic Table (Defaults are in Bold)

LDO Reset Control Logic Table (Defaults are in Bold)

Layout Considerations

Layout is straightforward if you use the Gerber files on

page 21 as a reference. Notice that the input voltage

feed to the SC900 is on the bottom of the board and

vias connect this voltage track to the top of the board

and then to the SC900 itself. The input bypass can be

one 4.7µF capacitor, two 3.3µF capacitors, three 2.2µF

capacitors or five 1µF capacitors. The determining fac-

tor is how much copper is available on the input voltage

feed track and how much room is available. If the input

Notes:

Digital outputs are powered from INB, additionally LDOB must be on for operation of LDOPGD and ARST.

voltage track is very thin, then use five 1µF capacitors

placed very close to the input pins of the SC900. If the

input track is fairly thick, then you can use a single 4.7µF

capacitor at the beginning of the voltage feed track since

a wider track has less inductance per inch. The

SC900EVB has five 1µF capacitors, but these can be

replaced with one 4.7µF in place of C1 and opens in

place of C9, C14, C15, and C16 (see page 20 for de-

tails).