l6920 STMicroelectronics, l6920 Datasheet - Page 8

• Manufacturer Part Number: l6920
• Description: 1v High Efficiency Syncronous Step Up Converter
• Manufacturer: STMicroelectronics

L6920
Figure 12. Demoboard Circuit
Table 6.
R4, R5 should be selected in the range of 100kΩ - 10MΩ 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 10µF-100µF.
An additional, smaller, low ESR capacitor can be in parallel for high frequency filtering. A typical value can be
around 1µF.
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
8/13
Jumper
J1
J2
100nF
C4
N.C.
N.C.
R1
R2
+VBATT
not mounted components
VREF
GND
LBI
2
4
6
VBATT
Position
L6920
F.B.
None
1-2
2-3
1-2
2-3
7
1
8
3
5
VOUT
LBO
SHDN
N.C.
R3
ELL6RH100M
Panasonic
L1 10µH
J1
Device enabled
Device disabled
Adjustable using R4 and R5 [not mounted]
3.3V output voltage
5V output voltage
J2
1
2
3
2
N.C.
1
3
C3
R4 N.C.
R5 N.C.
47µF
47µF
C2
C1
D01IN1310
Function
EEFCDJ470R
EEFCDJ470R
Panasonic
Panasonic
+VBATT
GND
VOUT
GND
LBO
SHDN