LTC3557EUF-1#TRPBF Linear Technology, LTC3557EUF-1#TRPBF Datasheet - Page 20

• Manufacturer Part Number: LTC3557EUF-1#TRPBF
• Description: IC USB POWER MANAGE 28-QFN
• Manufacturer: Linear Technology

Specifications of LTC3557EUF-1#TRPBF

• Applications: Handheld/Mobile Devices
• Voltage - Supply: 4.35 V ~ 5.5 V
• Operating Temperature: -40°C ~ 85°C
• Mounting Type: Surface Mount
• Package / Case: 28-QFN
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Current - Supply: -

LTC3557/LTC3557-1
The inductor value also has an effect on Burst Mode
operation. Lower inductor values will cause Burst Mode
switching frequency to increase.
Table 3 shows several inductors that work well with the
step-down switching regulators. 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.
Step-Down Switching Regulator Input/Output
Capacitor Selection
Low ESR (equivalent series resistance) ceramic capacitors
should be used at both step-down switching regulator
outputs as well as at each step-down switching regulator
input supply. Only X5R or X7R ceramic capacitors should
be used because they retain their capacitance over wider
voltage and temperature ranges than other ceramic types.
A 10μF output capacitor is suffi cient for the step-down
OPERATION
Table 3. Recommended Inductors for Step-Down Switching Regulators
INDUCTOR TYPE
DE2818C
D312C
DE2812C
CDRH3D16
CDRH2D11
CLS4D09
SD3118
SD3112
SD12
SD10
LPS3015
*Typical DCR
20
L (μH)
4.7
3.3
4.7
3.3
4.7
3.3
4.7
3.3
4.7
3.3
4.7
4.7
3.3
4.7
3.3
4.7
3.3
4.7
3.3
4.7
3.3
MAX I
1.25
1.45
0.79
0.90
0.75
1.59
0.97
1.29
1.42
1.08
1.31
1.2
1.4
0.9
1.1
0.5
0.6
1.3
0.8
1.1
1.3
DC
(A)
switching regulator outputs. For good transient response
and stability the output capacitor for step-down switching
regulators should retain at least 4μF of capacitance over
operating temperature and bias voltage. Each switching
regulator input supply should be bypassed with a 2.2μF
capacitor. Consult with capacitor manufacturers for
detailed information on their selection and specifi cations
of ceramic capacitors. Many manufacturers now offer
very thin (<1mm tall) ceramic capacitors ideal for use in
height-restricted designs. Table 4 shows a list of several
ceramic capacitor manufacturers.
Table 4. Ceramic Capacitor Manufacturers
AVX
Murata
Taiyo Yuden
Vishay Siliconix
TDK
MAX DCR (Ω)
0.105*
0.117*
0.104*
0.153*
0.108*
0.072
0.053
0.13*
0.085
0.123
0.162
0.113
0.246
0.165
0.24
0.20
0.11
0.17
0.19
0.13
0.2
3.0 × 2.8 × 1.8
3.0 × 2.8 × 1.8
3.6 × 3.6 × 1.2
3.6 × 3.6 × 1.2
3.0 × 2.8 × 1.2
3.0 × 2.8 × 1.2
4.0 × 4.0 × 1.8
4.0 × 4.0 × 1.8
3.2 × 3.2 × 1.2
3.2 × 3.2 × 1.2
4.9 × 4.9 × 1.0
3.1 × 3.1 × 1.8
3.1 × 3.1 × 1.8
3.1 × 3.1 × 1.2
3.1 × 3.1 × 1.2
5.2 × 5.2 × 1.2
5.2 × 5.2 × 1.2
5.2 × 5.2 × 1.0
5.2 × 5.2 × 1.0
3.0 × 3.0 × 1.5
3.0 × 3.0 × 1.5
SIZE in mm
(L × W × H)
www.avxcorp.com
www.murata.com
www.t-yuden.com
www.vishay.com
www.tdk.com
www.cooperet.com
www.coilcraft.com
www.sumida.com
MANUFACTURER
www.toko.com
Coil Craft
Sumida
Cooper
Toko
35571fc