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PRODUCT SPECIFICATION
RC5053
15
P
Figure 11. Single Supply RC5053 5V to 1.8V-3.5V Application with Thermal Monitor
PWRGD
FAULT
OT
VID0 TO VID4
OUTEN
COMP
SS
SGND
SENSE
Q1*
Q2*
V
CC
PV
CC
V
IN
5V
L
O
2
μ
H
18A
RC5053
G1
I
FB
G2
0.1
μ
F
5V
1.8k
C
C
2200pF
R
C
15k
5.6k
5.6k
5.6k
C
SS
0.01
μ
F
0.1
μ
F
0.1
μ
F
0.1
μ
F
4.7
56
56
4.7
1N5817
10
μ
F
GND
I
MAX
1.8k
C
**
1200
μ
F
×
4
V
OUT
C
OUT
330
μ
F
×
7
+
+
C1
100pF
+
5
PENTIUM II
SYSTEM
DALE
NTHS-1206N02
MOUNT THERMISTER
IN CLOSE THERMAL
PROXIMITY TO Q1
* FAIRCHILD NDB6030L
** SANYO 10MV1200GX
COILTRONICS CTX02-13198 OR
PANASONIC 12TS-2R5SP
AVX TPSE337M006R0100
in the circuit such as close to the output capacitors. This
is not always practical, however, due to physical con-
straints. Another reasonably good point to make this
connection is between the output capacitors and the
source connection of the lowside FET Q2. Do not tie this
single point ground in the trace run between the low side
FET source and the input capacitor ground, as this area
of the ground plane will be very noisy.
3.
The small signal resistors and capacitors for frequency
compensation and soft start should be located very close
to their respective pins and the ground ends connected to
the signal ground pin through a separate trace. Do not
connect these parts to the ground plane!
4.
The V
CC
and PV
CC
decoupling capacitors should be as
close to the RC5053 as possible. The 10
μ
F bypass
capacitors for V
CC
and a 1
μ
F bypass capacitor for PV
CC
will help provide optimum regulation performance.
5.
The (+) plate of C
IN
should be connected as close as
possible to the drain of the upper MOSFET. An addi-
tional 1
μ
F ceramic capacitor between V
IN
and power
ground is recommended.
6.
The SENSE pin is very sensitive to pickup from the
switching node. Care should be taken to isolate SENSE
from possible capacitive coupling to the inductor switch-
ing signal. A 0.1
μ
F is required between the SENSE pin
and the SGND pin next to the RC5053.
7.
OUTEN is a high impedance input and should be exter-
nally pulled up to a logic HIGH for normal operation.
8.
Kelvin sense I
MAX
and I
FB
at Q1 drain and source pins.