Datasheet

L6920
8/13
Figure 12. Demoboard Circuit
Table 6.
R4, R5 should be selected in the range of 100k Ω - 10M Ω to minimize consumption and error due to current sunk
by FB pin (few nA).
5.2 Output capacitor selection
The output capacitor affects both efficiency and output ripple so its choice has to be considered with particular
care.
The capacitance value should be in the range of about 10
µ F-100 µ F.
An additional, smaller, low ESR capacitor can be in parallel for high frequency filtering. A typical value can be
around 1
µ F.
If very high performances, in terms of efficiency and output voltage ripple, are required, a very low ESR capac-
itor has to be chosen.
Ceramic capacitors are the lowest ESR but they are very expensive.
Other possibilities are low-ESR tantalum capacitors, available from KEMET, AVX and other sources. POSCAP
capacitors from SANYO and polymeric capacitors from PANASONIC are also good.
Below there is a list of some capacitors suppliers. The cap values and rated voltages are only a suggested pos-
sibility
Jumper Position Function
J1
1-2 Device enabled
2-3 Device disabled
J2
None Adjustable using R4 and R5 [not mounted]
1-2 3.3V output voltage
2-3 5V output voltage
L1 10µH
+VBATT
+VBATT
VBATT
F.B.
VOUT
7
1
8
GND
Panasonic
ELL6RH100M
Panasonic
EEFCDJ470R
Panasonic
EEFCDJ470R
C2
47µF
C3
N.C.
C1
47µF
C4
100nF
R1
N.C.
R3
N.C.
R2
N.C.
not mounted components
R4 N.C.
R5 N.C.
VOUT
GND
1
2
3
3
2
J2
J1
1
LBO
3
SHDN
5
VREF
GND
4
6
LBI
2
LBO
SHDN
L6920
D01IN1310