Datasheet

LMP8646EB User’s Guide
November 2011 Page 7 of 20 SNOU010
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 
 
 
     
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ohmRFB
kk
mOhm
ROUT
RFBT
VV
RFBB
V
VGRI
ROUT
RFBT
VV
RFBB
V
ROUT
VGRI
ROUT
VGRI
RFBT
VV
RFBB
V
ROUT
VV
RFBT
VV
RFBB
V
III
FBO
FB
FBainSENSE
FBO
FBFBainSENSE
FBainSENSE
FBO
FB
FBOFBO
FB
ROUTRFBTRFBB
16074.1573
10
8.06.0
2
8.0
8.01055575.1
min_3102_
max
min_3102_
max
max
min_3102_
8646_min_3102_






















This equation provides an initial value for ROUT. To get the desired results, ROUT should be
adjusted. We recommend having an ROUT value of at least 50 ohm.
6. Step 6: Adjusting Components – capture the output current and output voltage plots and adjust the
components as necessary. The most common components to adjust are Cg to minimize the current
ripple and ROUT to decrease the current error.
A plot for the load current (black), output voltage of the LM3102 (blue), voltage the feedback pin of
the LM3102 (red), and switch frequency of the LM3102 (green), can be seen in figure 3.
Figure 3 – Plot for the SuperCap Application