jianke
Member level 3
A question about a RF Differential RF Amplifier (AD8352)
Hi all,
My question is about the matching for a Differential RF Amplifier.
From the AD8352 datasheet, we can see that the input matching circuit is used to provide the input impedance match for a 50ohm system. I think the reason is for maxium power transfer for the amplifier input. When those energy meets the amplifier's high input resistance, the current will be changed to voltage.
But, when AD8352 is connected to a load, the output matching circuit can not be found between the load and amplifier's output impedance. I don't why. Without it, the energy will loss.
BTW, AD8352 input impedance is 3000ohm(+j0.9pF), output impedance is 100ohm(+3pF). The load is 200ohm or 1000ohm. If AD8325 drives AD9445 (a ADC), the AD9445 presents approximately 2 kΩ in parallel with 5 pF/differential load to the AD8352.
Hi all,
My question is about the matching for a Differential RF Amplifier.
From the AD8352 datasheet, we can see that the input matching circuit is used to provide the input impedance match for a 50ohm system. I think the reason is for maxium power transfer for the amplifier input. When those energy meets the amplifier's high input resistance, the current will be changed to voltage.
But, when AD8352 is connected to a load, the output matching circuit can not be found between the load and amplifier's output impedance. I don't why. Without it, the energy will loss.
BTW, AD8352 input impedance is 3000ohm(+j0.9pF), output impedance is 100ohm(+3pF). The load is 200ohm or 1000ohm. If AD8325 drives AD9445 (a ADC), the AD9445 presents approximately 2 kΩ in parallel with 5 pF/differential load to the AD8352.
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