Datasheet

LMP8646EB User’s Guide
November 2011 Page 9 of 20 SNOU010
Figure 5 – Recommended Components for the LM3102
3. Step 2: Choose the gain resistor, Rg, for LMP8646
If Rsense = 55 mOhm, then use the equation below to calculate for the appropriate gain resistor, Rg,
for a close-loop output current of 1A.






  
  
  
  
 
OhmkRg
mOhmA
kV
Rg
RI
kVFB
Rg
kOhm
Rg
RIVFB
kOhm
R
VA
R
cectranscondu
R
Gainwhere
GainRIVFB
SENSELIMIT
SENSELIMIT
GGG
LMPSENSELIMIT
73
55)1(
58.0
5
5
5/200/1tan/1
8646













4. Step 3: Choose the Bandwidth Capacitance, Cg.
The product of Cg and Rg determines the bandwidth for the LMP8646. Because each application is
very unique, the LMP8646 gain capacitance, Cg, needs to be adjusted to fit the appropriate
application.
Bench data has been collected for the resistive load application. We found that this application works
best for a bandwidth between 2 kHz to 30 kHz. If the bandwidth is not large enough, the LMP8646
will take a longer time to limit the output current.