LTC3558_15 Datasheet, PDF (24/32 Pages) Linear Technology – Linear USB Battery Charger with Buck and Buck-Boost Regulators

LTC3558
APPLICATIONS INFORMATION
Table 2 shows several inductors that work well with the
LTC3558 buck switching regulator. These inductors offer
a good compromise in current rating, DCR and physical
size. Consult each manufacturer for detailed information
on their entire selection of inductors.
Buck Switching Regulator
Input/Output Capacitor Selection
Low ESR (equivalent series resistance) ceramic capacitors
should be used at switching regulator outputs as well as
the switching regulator input supply. Ceramic capacitor
dielectrics are a compromise between high dielectric
constant and stability versus temperature and versus
DC bias voltage. The X5R/X7R dielectrics offer the best
compromise with high dielectric constant and acceptable
performance over temperature and under bias. Do not
use Y5V dielectrics. A 10μF output capacitor is sufficient
for most applications. For good transient response and
stability the output capacitor should retain at least 4μF
of capacitance over operating temperature and bias volt-
age. The buck switching regulator input supply should be
bypassed with a 10μF capacitor. Consult manufacturer
for detailed information on their selection and specifica-
tions of ceramic capacitors. Many manufacturers now
offer very thin (< 1mm tall) ceramic capacitors ideal for
use in height-restricted designs. Table 3 shows a list of
several ceramic capacitor manufacturers.
Table 3: Recommended Ceramic Capacitor Manufacturers
AVX
[phone]
www.avxcorp.com
Murata
[phone]
www.murata.com
Taiyo Yuden
[phone]
www.t-yuden.com
TDK
[phone]
www.tdk.com
Table 2. Recommended Inductors for Buck Switching Regulators
L
MAX I_DC
INDUCTOR TYPE
(μH)
(A)
DE2818C
DE2812C
4.7
1.25
4.7
1.15
CDRH3D16
4.7
0.9
SD3118
SD3112
LPS3015
4.7
1.3
4.7
0.8
4.7
1.1
*Typical DCR
MAX DCR
(mΩ)
72*
130*
110
162
246
200
SIZE IN mm
(L × W × H)
3 × 2.8 × 1.8
3 × 2.8 × 1.2
4 × 4 × 1.8
3.1 × 3.1 × 1.8
3.1 × 3.1 × 1.2
3 × 3 × 1.5
MANUFACTURER
Toko
www.toko.com
Sumida
www.sumida.com
Cooper
www.cooperet.com
Coilcraft
www.coilcraft.com
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