STW41412 ST-Ericsson Inc, STW41412 Datasheet - Page 22

• Manufacturer Part Number: STW41412
• Description: IC CONV DC/DC DUAL STDN 16-TFBGA
• Manufacturer: ST-Ericsson Inc
• Type: Step-Down (Buck)r

Specifications of STW41412

• Internal Switch(s): Yes
• Synchronous Rectifier: Yes
• Number Of Outputs: 2
• Voltage - Output: 1.3V, 1.8V
• Current - Output: 200mA, 400mA
• Frequency - Switching: 900kHz
• Voltage - Input: 2.7 ~ 5.5 V
• Operating Temperature: -40°C ~ 85°C
• Mounting Type: Surface Mount
• Package / Case: 16-TFBGA
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Power - Output: -

STw4141
4.4
4.5
4.6
4.6.1
External clock synchronization
Figure 14. Application using external clock synchronization
Checking transient response versus external components
The regulator loop response can be checked by looking at the load transient response.
Switching regulators take several cycles to respond to a step in load current. When a load
step occurs, V
the equivalent series resistance of C
generating a feedback error signal used by the regulator to return V
value. In order to improve the transient response, it is better to use two 10 µF ceramic
capacitors on each output to reduce ESR.
Bill of Material
Inductor selection
The choice of which inductor to use depends on the price and size versus performance
required with the STw4141 application.
that work well in STw4141 applications.
Table 8.
VFL4012A-4R7M1R1
VFL3012A-4R7MR74
744031004
V
V
IN
IN
=2.7V to 5.5V
=2.7V to 5.5V
Part number
C
C
10 µF
10 µF
6.3 V
6.3 V
IN
IN
MODE/SYNC
MODE/SYNC
Bill of material: inductor selection
OUT
PVDD
PVDD
VDD
VDD
EN
EN
AUTO
AUTO
VSEL
VSEL
is immediately shifted by an amount equal to I
B1
B1
D3
D3
D4
D4
C2
C2
C3
C3
C1
C1
TDK
TDK
WUERTH
A2
A2
A1
A1
VLX1
VLX1
PGND
PGND
STw4141
STw4141
L 4.7 µH
L 4.7 µH
Supplier
C4
C4
GND
GND
OUT
B3
B3
A3
A3
T_MODE
T_MODE
VLX2
VLX2
Table 7
. I
D1
D1
D2
D2
A4
A4
B4
B4
B2
B2
LOAD
VOUT1
VOUT1
FB1
FB1
VOUT2
VOUT2
FB2
FB2
STATE
STATE
Value
(µH)
4.7
4.7
4.7
shows some typical surface mount inductors
also begins to charge or discharge C
C
C
22 µF
22 µF
6.3 V
6.3 V
C
C
22 µF
22 µF
6.3 V
6.3 V
OUT1
OUT1
OUT2
OUT2
0.085
R
0.14
0.16
(Ω)
DC
C
C
100 nF
100 nF
C
C
100 nF
100 nF
LOAD
1
1
2
2
Max DC
current
(mA)
Application information
1100
740
900
OUT
MODE_INFO
MODE_INFO
CLK
CLK
SLEEP
SLEEP
APE I/O
APE I/O
APE CORE
APE CORE
x ESR, where ESR is
to its steady-state
APPLICATION
APPLICATION
PROCESSOR
PROCESSOR
3.5 x 3.7 x 1.2
2.6 x 2.8 x 1.2
3.8 x 3.8 x 1.8
GND
GND
Size (mm)
W x L x H
OUT
21/30