SC4501STDEVB Semtech, SC4501STDEVB Datasheet - Page 14
SC4501STDEVB
Manufacturer Part Number
SC4501STDEVB
Description
EVALUATION BOARD
Manufacturer
Semtech
Datasheet
1.SC4501MLTRT.pdf
(21 pages)
Specifications of SC4501STDEVB
Silicon Manufacturer
Semtech
Application Sub Type
Step Up Switching Regulator
Kit Application Type
Power Management - Voltage Regulator
Silicon Core Number
SC4501
Lead Free Status / RoHS Status
Lead free / RoHS Compliant
Therefore
and
The spacing between p
converter is delivering the maximum output current from
the lowest V
condition. Ignoring C
low frequency pole with the equivalent output resistance
R
Application Information
POWER MANAGEMENT
O
2005 Semtech Corp.
D
R
of the error amplifier:
O
Z
p
2
2
1
1
Amplifier
6
6
8 .
12
12
Transcondu
IN
8 .
SHDN
SHDN
SHDN
. This represents the worst-case compensation
0
5
3 .
4
0
0
7 .
2
1
5 .
5 .
Open
10
H
. 0
5
. 0
and C
62
c
F
Loop
Figure 9. Suggested PCB Layout for the SC4501. Notice that there is no via
GND
GND
VOUT
VOUT
62
2
tan
and z
2
29
ce
6
C4
C4
Gain
for the moment, C
209
4 .
2
R1
R1
Krads
directly under the device. All vias are 12mil in diameter.
is the closest when the
Krads
60
49
R3
R3
C6
C6
R2
R2
1
C5
C5
dB
1
1
. 4
33
68
4
3 .
KHz
7 .
4
KHz
forms a
M
C2
C2
U1
U1
U1
U1
14
C3
C3
C
The poles p
shift in the loop response. For stable operation, the overall
loop gain should cross 0dB with -20dB/decade slope. Due
to the presence of the RHP zero, the 0dB crossover frequency
should not be higher than
effect and maximizes loop bandwidth. Thus
R
Increasing R
4
3
R
and R
determines the mid-band loop gain of the converter.
p
3
Z
1
C
1
4
R4
R4
C1
C1
3
260
39
I 2
R
also forms a zero with angular frequency:
R
V
3
1
O
3
OUT
1
D1
D1
1
, p
OUT
5 .
C
increases the mid-band gain and the crossover
C
4
4
rads
(
Krads
MAX
2
C
2
and the RHP zero z
)
4
1
30
7 .
1
9 .
M
41
K
6
1
z
Hz
3
1
L1
L1
2
3 .
820
820
. Placing z
KHz
VIN
VIN
pF
pF
2
all increase phase
1
near p
www.semtech.com
SC4501
2
nulls its
(15)