LTC3406ES5#TR Linear Technology, LTC3406ES5#TR Datasheet - Page 12

• Manufacturer Part Number: LTC3406ES5#TR
• Description: IC REG SYNC SDWN 1.5MHZ TSOT23-5
• Manufacturer: Linear Technology
• Type: Step-Down (Buck)r

Specifications of LTC3406ES5#TR

• Internal Switch(s): Yes
• Synchronous Rectifier: Yes
• Number Of Outputs: 1
• Voltage - Output: 0.6 ~ 5.5 V
• Current - Output: 600mA
• Frequency - Switching: 1.5MHz
• Voltage - Input: 2.5 ~ 5.5 V
• Operating Temperature: -40°C ~ 85°C
• Mounting Type: Surface Mount
• Package / Case: TSOT-23-5, TSOT-5, TSOP-5
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant
• Power - Output: -
• Other names: LTC3406ES5TR

APPLICATIO S I FOR ATIO
LTC3406
LTC3406-1.5/LTC3406-1.8
12
Design Example
As a design example, assume the LTC3406 is used in a
single lithium-ion battery-powered cellular phone
application. The V
4.2V down to about 2.7V. The load current requirement
is a maximum of 0.6A but most of the time it will be in
standby mode, requiring only 2mA. Efficiency at both low
and high load currents is important. Output voltage is
2.5V. With this information we can calculate L using
equation (1),
V
OUT
L
=
( )
f
V
L1
( )
OUT
BOLD LINES INDICATE HIGH CURRENT PATHS
1
∆
Figure 6a. LTC3406 Suggested Layout
Figure 5a. LTC3406 Layout Diagram
–
+
I
L
SW
PIN 1
V
C
OUT
OUT
IN
L1
C
U
OUT
will be operating from a maximum of
⎛
⎜
⎝
1
1
2
3
−
LTC3406
RUN
SW
GND
VIA TO V
U
GND
V
LTC3406
V
OUT
IN
IN
V
V
C
⎞
⎟
⎠
FB
IN
IN
C
IN
5
4
W
C
R1
R2
FWD
R2
VIA TO GND
C
U
3406 F05a
FWD
R1
V
3406 F06a
IN
V
IN
(3)
VIA TO V
Substituting V
f = 1.5MHz in equation (3) gives:
A 2.2µH inductor works well for this application. For best
efficiency choose a 720mA or greater inductor with less
than 0.2Ω series resistance.
C
I
of less than 0.25Ω. In most cases, a ceramic capacitor will
satisfy this requirement.
LOAD(MAX)
IN
OUT
L
will require an RMS current rating of at least 0.3A ≅
=
1 5
.
V
Figure 6b. LTC3406-1.8 Suggested Layout
MHz
OUT
/2 at temperature and C
Figure 5b. LTC3406-1.8 Layout Diagram
V
OUT
2 5
OUT
.
–
+
(
240
V
BOLD LINES INDICATE HIGH CURRENT PATHS
= 2.5V, V
L1
C
mA
OUT
L1
)
SW
⎛
⎜
⎝
PIN 1
1
2
3
1
−
RUN
SW
C
LTC3406-1.8
IN
GND
OUT
2 5
4 2
= 4.2V, ∆I
.
.
V
LTC3406-1.8
V
V
OUT
V
C
OUT
IN
IN
⎞
⎟ =
⎠
GND
VIA TO V
5
4
will require an ESR
2 81
.
IN
VIA TO V
L
3406 F05b
C
= 240mA and
µ
IN
H
V
IN
OUT
V
3406fa
3406 F06b
IN