NCP3065, NCV3065
http://onsemi.com
14
Figure 25. Buck Demoboard with External Switch Application Schematic
J1
1
15 k
1.8 nF
C2
C1
C4
R13
U1
NCP3065
5
36
4
8
7
1
2
COMP
TCAP
GND
N.C. SWC
SWE
R10
D1
MBRS140LT3G
J3
GND
1
J2
1
L1
0.1 mF
220 mF / 50 V
+
0.1 mF
V
CC
I
PK
PF0504.223NL
+
J5
1
J7
1
J6
ON/OFF
1
1
R1 R2 R3 R4 R5 R6 R7
R11
Q1 Q2
10 k
R9
J4
+VAUX
+VIN
BC807−LT1G BC817−LT1G
6x 1R0 ±1%R
0R04
C6
+LED
−LED
GND
R16
NU
R14
NU
1 k0805
0R15 ±1%
C5 100 pF
R8
C3
SOIC8
CT
1206
D2
R15
1 k
Q5
Q4
MMBT3904LT1G
MTB30P06V
MMSD4148
+
1206 1206 1206 1206 1206 1206
1k2
0805
0805
220 mF /
50 V
R12
0R15 ±1%
C7
1 mF / 50 V
C8
0.1 mF
J6
1
R11
1k2
0805
ON/OFF
Value of Components
Name Value
C1
100 mF, 50 V, Electrolytic Capacitor
C1, C4, C8 100 nF, Ceramic Capacitor, 1206
C2, C6
220 mF, 50 V, Electrolytic Capacitor
C3 2.2 nF, Ceramic Capacitor, 0805
C5 100 pF, Ceramic Capacitor, 0805
C7
1 mF / 50 V, Ceramic Capacitor, 1206
D1 MBRS540LT3G, Schottky Diode
D2 MMSD4148T1G, Diode
L1
22 mH
Q2 BC817−LT1G, SOT23
Name Value
Q4 MTB30P06V, P−MOS transistor
Q5 MMBT3904LT1G
R1
40 mW, Resistor 0.5 W
R8 6k8, Resistor 0805
R9 10k, Resistor 0805
R10 1k, Resistor 0805
R11 1k2, Resistor 0805
R12, R16
150 mW, Resistor 0.5 W
U1 NCP3065, SOIC8
Test Results
Test Condition Results
Line Regulation V
in
= 8 V to 35 V, I
o
= 3000 mA < 6%
Output Ripple V
in
= 12 V, I
o
= 3000 mA < 6%
Efficiency V
in
= 12 V, I
o
= 3000 mA > 78%
Short Circuit Current
V
in
= 12 V, Rload = 0.15 W
