LTC3835 Linear Technology, LTC3835 Datasheet - Page 24

• Manufacturer Part Number: LTC3835
• Description: Low IQ Synchronous Step-Down Controller
• Manufacturer: Linear Technology

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LTC3835
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.
24
V
IN
R
IN
BOLD LINES INDICATE HIGH SWITCHING
CURRENT. KEEP LINES TO A MINIMUM LENGTH.
1nF
C1
C
IN
Figure 9. LTC3835 Recommended Printed Circuit Layout Diagram
Figure 10. Branch Current Waveforms
D1
SW
D
C
B
B
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
C
IN
R
SENSE
C
OUT
M1
M2
V
OUT
D1
OPTIONAL
L1
3835 F10
C
3835 F09
OUT
R
L1
V
V
IN
OUT
3835fc