LTC3858 Linear Technology, LTC3858 Datasheet - Page 29

• Manufacturer Part Number: LTC3858
• Description: Synchronous Step-Down Controller
• Manufacturer: Linear Technology

applicaTions inForMaTion
MOSFET components to the sensitive current and voltage
sensing traces. In addition, investigate common ground
path voltage pickup between these components and the
SGND pin of the IC.
An embarrassing problem, which can be missed in an
otherwise properly working switching regulator, results
when the current sensing leads are hooked up backwards.
R
IN
V
IN
C
IN
BOLD LINES INDICATE
HIGH SWITCHING
CURRENT. KEEP LINES
TO A MINIMUM LENGTH.
Figure 11. Branch Current Waveforms
SW1
SW2
D1
D2
The output voltage under this improper hookup will still
be maintained but the advantages of current mode control
will not be realized. Compensation of the voltage loop will
be much more sensitive to component selection. This
behavior can be investigated by temporarily shorting out
the current sensing resistor—don’t worry, the regulator
will still maintain control of the output voltage.
L1
L2
R
R
SENSE1
SENSE2
C
C
OUT1
OUT2
V
V
OUT1
OUT2
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3858 F11
LTC3858
R
R
L1
L2

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