8002

8002

8002

8002

Page 16 of 17

Once the power dissipation equations have been addressed, the required differential gain can be determined from

Equation 2.

From Equation 2, the minimum AVD is 2.83; use AVD = 3.Since the desired input impedance was 20k , and with a

AVD impedance of 2, a ratio of 1.5:1 of Rf to Ri results in an allocation of Ri = 20k

and Rf = 30k . The final design

step is to address the bandwidth requirements which must be stated as a pair of −3dB frequency points. Five times

away from a −3dB point is 0.17dB down from passband response which is better than the required ±0.25dB specified.

As stated in the External Components section, Ri in conjunction with Ci create a highpass filter.

Use 0.39uf.The high frequency pole is determined by the product of the desired frequency pole, fH, and the differential

gain, AVD. With a AVD = 3 and fH = 100kHz, the resulting GBWP = 300kHz which is much smaller than the 8002

GBWP of 2.5MHz. This figure displays that if a designer has a need to design an amplifier with a higher differential

gain, the 8002 can still be used without running into bandwidth limitations.