AD8310 as photodiode log amplifier

we are planning to design a photo diode log amplifier using the AD8310 since our system needs to perform in the frequency range of 1 MHz to 100 MHz and we need to detect the optical signal in the range of -50 dBm power.

our requirements are as follows

1.     frequency range 1MHz to 100 MHz

2.     minimum input power : -50 dBm

       maximum input power : 0 dBm

required maximum output ; 4V

required minimum output : 1V

can we configure the AD8310 as a current to voltage converter as ADL5304????

if yes what are the design criterion has to be take care for the proper operation in the frequency range of 1 to 100 MHz

selected photodiode has a responsivity of 0.9 A/W and has a bandwidth of 2 GHz

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  • 0
    •  Analog Employees 
    on Apr 16, 2013 9:08 PM

    I think the AD8310 will suit your application as long as you get the biasing of the photodiode correct with those op-amps and the envelope bandwidth of the signal is less than 25 MHz.  Note the AD8310 is good to 440 MHz, but that is referring to a CW signal.  If the envelope of your signal is changing much faster than 25 MHz, the output of the AD8310 will not track the envelope well, due to the averaging capacitor that is on-chip. 

    Best Regards,

    Joel

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  • 0
    •  Analog Employees 
    on Apr 16, 2013 9:08 PM

    I think the AD8310 will suit your application as long as you get the biasing of the photodiode correct with those op-amps and the envelope bandwidth of the signal is less than 25 MHz.  Note the AD8310 is good to 440 MHz, but that is referring to a CW signal.  If the envelope of your signal is changing much faster than 25 MHz, the output of the AD8310 will not track the envelope well, due to the averaging capacitor that is on-chip. 

    Best Regards,

    Joel

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