LT1301I LINER [Linear Technology], LT1301I Datasheet - Page 8

• Manufacturer Part Number: LT1301I
• Description: Micropower High Efficiency 5V/12V Step-Up DC/DC Converter for Flash Memory
• Manufacturer: LINER [Linear Technology]

LT1301
Capacitor Selection
Low ESR capacitors are required for both input and output
of the LT1301. ESR directly affects ripple voltage and
efficiency. For surface mount applications AVX TPS series
tantalum capacitors are recommended. These have been
specially designed for SMPS and have low ESR along with
high surge current ratings. For through-hole applications
Sanyo OS-CON capacitors offer extremely low ESR in a
small size. Again, if peak switch current is reduced using
the I
smaller, higher ESR units can be used. Suggested capaci-
tor sources are listed in Table 2.
8
TYPICAL APPLICATIONS
APPLICATIONS
LIM
pin, capacitor requirements can be relaxed and
U
INFORMATION
U
*SUMIDA CD54-100LC
COILCRAFT DO3316-223
2
AA
CELL
4 CELLS
+
U
Step-Up Converter with Automatic Output Disconnect
W
100µF
SHUTDOWN
+
N
C1
100µF
SHUTDOWN
NC
NC
U
Four-Cell to 5V Converter
SHDN
SELECT
I
SHDN
I
GND
LIM
LIM
GND
V
NC
IN
LT1301
LT1301
33µH
L1
SELECT
SENSE
SENSE
PGND
PGND
Diode Selection
Best performance is obtained with a Schottky rectifier
diode such as the 1N5817. Phillips Components makes
this in surface mount as the PRLL5817. Motorola makes
the MBRS130LT3 which is slightly better and also in
surface mount. For lower output power a 1N4148 can be
used although efficiency will suffer substantially.
Layout Considerations
The LT1301 is a high speed, high current device. The input
capacitor must be no more than 0.2˝ from V
ground. Connect the PGND and GND (pins 8 and 1)
together under the package. Place the inductor adjacent to
SW (pin 7) and make the switch pin trace as short as
possible. This keeps radiated noise to a minimum.
V
SW
SW
IN
10µH
L1*
+
100µF
C2
0.1µF
1N5817
+
470
L2
33µH
1N5817
100µF
2N4403
LT1301 TAO3
LT1301 TA4
+
5V, 200mA
0.1µF
C3
100µF
5V OUTPUT
200mA
80 to 83% EFFICIENT
AT I
LOAD
10mA
IN
(pin 6) and