LTC3728LEGN Linear Technology, LTC3728LEGN Datasheet - Page 30

• Manufacturer Part Number: LTC3728LEGN
• Description: IC REG SW DUAL 2PH STPDWN 28SSOP
• Manufacturer: Linear Technology
• Series: PolyPhase®r
• Type: Step-Down (Buck)r

Specifications of LTC3728LEGN

• Internal Switch(s): No
• Synchronous Rectifier: Yes
• Number Of Outputs: 2
• Voltage - Output: 0.8 ~ 7 V
• Current - Output: 3A
• Frequency - Switching: 250kHz ~ 550kHz
• Voltage - Input: 4.5 ~ 28 V
• Operating Temperature: -40°C ~ 85°C
• Mounting Type: Surface Mount
• Package / Case: 28-SSOP
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant
• Power - Output: -

APPLICATIONS INFORMATION
LTC3728L/LTC3728LX
4. Are the SENSE
5. Is the INTV
6. Keep the switching nodes (SW1, SW2), top gate nodes
30
with minimum PC trace spacing? The fi lter capacitor
between SENSE
possible to the IC. Ensure accurate current sensing
with Kelvin connections at the SENSE resistor.
the IC, between the INTV
This capacitor carries the MOSFET drivers current peaks.
An additional 1μF ceramic capacitor placed immediately
next to the INTV
noise performance substantially.
(TG1, TG2), and boost nodes (BOOST1, BOOST2) away
R
IN
CC
V
decoupling capacitor connected close to
IN
C
–
+
CC
IN
BOLD LINES INDICATE
HIGH SWITCHING
CURRENT. KEEP LINES
TO A MINIMUM LENGTH.
and SENSE
and SENSE
+
and PGND pins can help improve
CC
and the power ground pins?
–
+
should be as close as
leads routed together
Figure 11. Branch Current Waveforms
CERAMIC
CERAMIC
SW1
SW2
D1
D2
7. Use a modifi ed “star ground” technique: a low imped-
L1
L2
from sensitive small-signal nodes, especially from the
opposites channel’s voltage and current sensing feed-
back pins. All of these nodes have very large and fast
moving signals and therefore should be kept on the
output side of the LTC3728L/LTC3728LX and occupy
minimum PC trace area.
ance, large copper area central grounding point on
the same side of the PC board as the input and output
capacitors with tie-ins for the bottom of the INTV
decoupling capacitor, the bottom of the voltage feedback
resistive divider and the SGND pin of the IC.
R
R
SENSE1
SENSE2
C
C
OUT1
OUT2
V
V
+
+
OUT1
OUT2
3728 F11
R
R
L1
L2
3728lxfe
CC