LT1308BCF View Datasheet(PDF) - Linear Technology
Part Name
Description
MFG CO.
'LT1308BCF' PDF : 20 Pages View PDF
APPLICATIONS INFORMATION
VOUT
500mV/DIV
IL1
1A/DIV
LOAD 500mA
CURRENT 50mA
200μs/DIV
1308 F23
Figure 23. Load Step Response with 10μF X5R
Ceramic Output Capacitor and CPL
GSM AND CDMA PHONES
The LT1308A/LT1308B are suitable for converting a single
Li-Ion cell to 5V for powering RF power stages in GSM or
CDMA phones. Improvements in the LT1308A/LT1308B
error amplifiers allow external compensation values to be
reduced, resulting in faster transient response compared
to the LT1308. The circuit of Figure 24 (same as Figure 1,
printed again for convenience) provides a 5V, 1A output
from a Li-Ion cell. Figure 25 details transient response at
the LT1308A operating at a VIN of 4.2V, 3.6V and 3V. Ripple
voltage in Burst Mode operation can be seen at 10mA
load. Figure 26 shows transient response of the LT1308B
under the same conditions. Note the lack of Burst Mode
ripple at 10mA load.
+
Li-Ion
CELL
C1
47μF
SHUTDOWN
L1
4.7μH
D1
VIN
SW
LT1308B
SHDN
FB
VC
GND
47k
100pF
5V
1A
R1
309k +
R2
100k
C2
220μF
C1: AVX TAJC476M010
C2: AVX TPSD227M006
D1: IR 10BQ015
L1: MURATA LQH6N4R7
1308A/B F24
Figure 24. Li-Ion to 5V Boost Converter Delivers 1A
LT1308A/LT1308B
VOUT
VIN = 4.2V
VOUT
VIN = 3.6V
VOUT
VIN = 3V
ILOAD
1A
1mA
VOUT TRACES =
200mV/DIV
200μs/DIV
1308 F25
Figure 25. LT1308A Li-Ion to 5V Boost Converter
Transient Response to 1A Load Step
VOUT
VIN = 4.2V
VOUT
VIN = 3.6V
VOUT
VIN = 3V
ILOAD
1A
10mA
VOUT TRACES =
200mV/DIV
100μs/DIV
1308 F26
Figure 26. LT1308B Li-Ion to 5V Boost
Converter Transient Response to 1A Load Step
1308abfb
15
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