LTC3528-2
13
35282fb
APPLICATIONS INFORMATION
Table 1. Recommended Inductors
VENDOR PART/STYLE
Coilcraft
(847) 639-6400
www.coilcraft.com
DO1606T, MSS5131, MSS5121
MSS6122, MOS6020
ME3220, DO1608C
1812PS
Coiltronics SD12, SD14, SD20
SD25, SD52
Sumida
(847) 956-0666
www.sumida.com
CD43
CDC5D23B
CDRH5D18
TDK VLP, VLF
VLCF, SLF, VLS
Toko
(408) 432-8282
www.tokoam.com
D53, D62, D63
D73, D75
Wurth
(201) 785-8800
www.we-online.com
WE-TPC type M, MH
Output and Input Capacitor Selection
Low
ESR (equivalent series resistance) 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 10µF to 22µF output capacitor is sufficient for most ap-
plications. Values larger than 22µF may be used to obtain
extremely low output voltage ripple and improve transient
response. X5R and X
7R dielectric materials are preferred
for their ability to maintain capacitance over wide voltage
and temperature ranges. Y5V types should not be used.
The internal loop compensation of the LTC3528-2 is de-
signed to be stable with output capacitor values of 10µF or
greater. Although ceramic capacitors are recommended,
low ESR tantalum capacitors may be used as well.
A small ceramic capacitor in parallel with
a larger tantalum
capacitor may be used in demanding applications which
have large load transients. Another method of improving the
transient response is to add a small feed-forward capaci-
tor across the top resistor of the feedback divider (from
V
OUT
to FB). A typical value of 68pF will generally suffice.
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 10µF input capacitor is sufficient
for most applications. Larger values may be used without
limitations. Table 2 shows a list of several ceramic capaci-
tor manufacturers. Consult the manufacturers directly for
detailed information on their selection of ceramic parts.
Table 2. Capacitor Vendor Information
SUPPLIER PHONE WEBSITE
AVX (803) 448-9411 www.avxcorp.com
Murata (714) 852-2001 www.murata.com
Taiyo-Yuden (408) 573-4150 www.t-yuden.com
TDK (847) 803-6100 www.component.tdk.com
TYPICAL APPLICATIONS
1 Cell to 1.8V
SW
V
IN
499k
2.2µH
1M
4.7µF
10µF
68pF
35282 TA02a
LTC3528-2
SHDN
PGOOD
V
OUT
FB
V
IN
0.88V TO 1.6V
V
OUT
1.8V
250mA
OFF ON
GND
Efficiency
LOAD CURRENT (mA)
0.01
80
90
100
100
35282 TA02b
70
60
0.1 1 10 1000
50
40
30
EFFICIENCY (%)
V
IN
= 0.9V
V
IN
= 1.2V
V
IN
= 1.5V
