LTC3539-2 Linear Technology, LTC3539-2 Datasheet - Page 10

• Manufacturer Part Number: LTC3539-2
• Description: 1MHz/2MHz Synchronous Step-Up DC/DC Converters
• Manufacturer: Linear Technology

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APPLICATIONS INFORMATION
LTC3539/LTC3539-2
Table 1. Representative Inductors
VENDOR
Coilcraft
[phone]
www.coilcraft.com
Murata
www.murata.com
Sumida
[phone]
www.sumida.com
TDK
[phone]
www.component.tdk.com
Toko
[phone]
www.tokoam.com
Wurth
[phone]
www.we-online.com
Output and Input Capacitor Selection
The internal loop compensation of the LTC3539 is designed
to be stable with output capacitor values of 10μF or greater.
Although ceramic capacitors are recommended, low ESR
(equivalent series resistance) tantalum capacitors may be
used as well.
Low ESR capacitors should be used to minimize the
output voltage ripple. Multilayer ceramic capacitors are
an excellent choice as they have extremely low ESR and
are available in small footprints. A 22μF to 47μF output
capacitor is suffi cient for output voltages of 3V or greater.
TYPICAL APPLICATIONS
1V TO 1.6V
*AT HIGH LOAD CURRENTS, A
TANTALUM CAPACITOR WILL
IMPROVE PERFORMANCE.
10
V
IN
PWM
OFF
BURST
2.2μF
ON
1 Cell to 1.8V
V
MODE
SHDN
GND
IN
LTC3539
2.2μH
PGND
V
SW
OUT
FB
1M
1.91M
PART/STYLE
MSS5131
LPS4018-222
MSS6132
MOS6020
LQH55D
LQH66S
CDRH4D22
CDRH4D28C
CDRH5D28
CDR6D23
VLF5014ST
D53LC
D63LCB
WE-TPC Type LH, X
WE-PD Type XS
22pF
3539 TA02
22μF*
x5
0.9V TO 1.6V
V
1.8V
500mA
OUT
V
IN
PWM
OFF
BURST
2.2μF
ON
1 Cell to 3.3V
V
MODE
SHDN
GND
IN
LTC3539
2.2μH
PGND
V
OUT
SW
FB
An output capacitor of up to 100μF is required at lower
output voltages. Even with V
values up to 100μF may be used to obtain extremely low
output voltage ripple and improve transient response. X5R
and X7R dielectric materials are preferred for their ability
to maintain capacitance over wide voltage and temperature
ranges. Y5V types should not be used.
A small ceramic capacitor in parallel with a larger tantalum
capacitor may be used in demanding applications which
have large load transients. A feedforward capacitor across
the top resistor of the feedback divider (from V
is usually required to improve transient response. A typical
value of 22pF will generally suffi ce.
Low ESR input capacitors reduce input switching noise and
reduce the peak current drawn from the battery. It follows
that ceramic capacitors are also a good choice for input
decoupling and should be located as close as possible to
the device. A 2.2μF input capacitor is suffi cient for most
applications. Larger values may be used without limita-
tions. Table 2 shows a list of several ceramic capacitor
manufacturers. Consult the manufacturers directly for
detailed information on their selection of ceramic parts.
Table 2. Capacitor Vendor Information
SUPPLIER
AVX
Murata
Taiyo-Yuden
TDK
1M
562k
22pF
3539 TA03
PHONE
[phone]
[phone]
[phone]
[phone]
22μF
x2
3V TO 4.5V
V
3.3V
350mA
OUT
V
IN
PWM
OFF
BURST
2.2μF
ON
Li-Ion Cell to 5V
OUT
V
MODE
SHDN
GND
IN
LTC3539-2
2.2μH
greater than 3V, larger
WEBSITE
www.avxcorp.com
www.murata.com
www.t-yuden.com
www.component.tdk.com
PGND
V
OUT
SW
FB
1M
309k
OUT
22pF
3539 TA04
to FB)
22μF
V
5V
750mA
3539f
OUT