Hi,
I’m confused about the usage of C1 and C4. Can the C1 and C4 positions on the CW308 be used to solder a shunt resistor instead of capacitors? I’m considering these positions for power analysis purposes and want to confirm if they are suitable for this modification.
Also, What is the voltage source connected with SHUNTL/SHUNTH If I use 0.9V voltage for core voltage and 2.5V for IO voltage?
Lastly, What is the maximum frequency that the CLKIN input on the ChipWhisperer-Lite HS1/IN can handle? I’m looking for the upper limit in terms of MHz that this input can reliably accept.
I’m not sure if you’re talking about a target board or the main CW308, but no, you can’t solder a resistor in that position. Consider the inverse: if you put a capacitor in the position of a shunt resistor, you would AC couple the power supply to the target and you’d get 0V on the target side of the capacitor.
I’m not sure what the max frequency HS1 will support, but I’d guess up to 105MHz. I’d have to verify that though.
I’m just confused about the purpose of C1 and C4 on the CW308 board. It doesn’t seem to be connected to anything.
Could you also clarify the connections for SHUNTL/SHUNTH?
Thanks for your help.
ZT
C1 is bulk capacitance on the 5V jack. C4 I believe is also for adding additional capacitance to the filter on the power line.
SHUNTL/SHUNTH should be at your core voltage. SHUNTH should be connected by your target board to FILT_HP/FILT_LP, while SHUNTL should be SHUNTH after being run through a shunt resistor.
