Datasheet

LT3420/LT3420-1
15
3420fb
BOARD LAYOUT
The high voltage operation of the LT3420/LT3420-1
demands careful attention to board layout. You will not
get advertised performance with careless layout. Fig-
ures 11 and 12 show the recommended component
placement. Keep the area for the high voltage end of the
secondary as small as possible. Note the larger than
minimum spacing for all high voltage nodes. This is
necessary to meet the breakdown specifications for the
circuit board. If the Photoflash capacitor is placed far
from the LT3420/LT3420-1 circuit, place a small (20nF-
50nF) ceramic capacitor with sufficient voltage rating
close to the part. This insures adequate bypassing.
Remember that LETHAL VOLTAGES ARE PRESENT in
this circuit. Use caution when working with the circuit.
Figure 11. Suggested Layout (MS10 Package)
3420 F11
CHARGE DONE
C3
C1
C2
+
–
R2
R1
D1A
D1B
PHOTOFLASH
CAPACITOR
V
OUT
V
BAT
V
CC
GND
T1
APPLICATIO S I FOR ATIO
WUUU
Figure 12. Suggested Layout (DD Package)
3420 F12
CHARGE DONE
C3
C1
C2
+
–
R2
R1
D1A
D1B
PHOTOFLASH
CAPACITOR
V
OUT
V
BAT
V
CC
GND
T1