Datasheet

LT3483/LT3483A
8
3483fc
Suggested Layout (DFN)
for Inverting Charge Pump
APPLICATIONS INFORMATION
Board Layout Considerations
As with all switching regulators, careful attention must
be given to the PCB board layout and component place-
ment. Proper layout of the high frequency switching path
is essential. The voltage signals of the SW and D pins
have sharp rising and falling edges. Minimize the length
and area of all traces connected to the SW and D pins.
In particular, it is desirable to minimize the trace length
to and from the flying capacitor, since current in this ca-
pacitor switches directions within a cycle. Always use a
ground plane under the switching regulator to minimize
interplane coupling.
Suggested Layout (SOT-23)
for Inverting Charge Pump
1
2
3
6
5
4
+
V
IN
GND
SHDN
C
F LY
C
OUT
3483 AI01
R1
L1
C
IN
V
OUT
V
IN
GND
SHDN
A
K
C
OUT
C
IN
C
F LY
3483 AI02
L1
R1
V
OUT
9
4
1
2
3
6
5
7
8
TYPICAL APPLICATIONS
3.6V to –22V DC/DC Converter 3.6V to –22V Converter Efficiency and Power Loss
SW
L1
10µH
D
LT3483
FB
C1
4.7µF
C2
0.1µF
D1
V
IN
R
S
30Ω
R1
2.2M
C1: TAIYO YUDEN LMK316BJ475MD
C2: TAIYO YUDEN TMK107BJ104 (X5R)
C3: TAIYO YUDEN TMK316BJ105MD
D1: PHILIPS PMEG3002AEB
L1: MURATA LQH2MCN100K02L
C3
1µF
5pF
3483 TA02a
V
OUT
–22V
8mA
V
IN
3.6V
SHDN
GND
LOAD CURRENT (mA)
0.1
EFFICIENCY (%)
POWER LOSS (mW)
65
70
EFFICIENCY
10
3483 TA02b
60
55
1
75
10
100
POWER
LOSS
1
0.1
1000