AD795

Rev. C | Page 11 of 20

MINIMIZING INPUT CURRENT

The AD795 is guaranteed to 1 pA maximum input current

with ±15 V supply voltage at room temperature. Careful atten-

tion to how the amplifier is used is necessary to maintain this

performance.

The amplifier’s operating temperature should be kept as low as

possible. Like other JFET input amplifiers, the AD795’s input

current doubles for every 10°C rise in junction temperature

(illustrated in Figure 9). On-chip power dissipation raises the

device operating temperature, causing an increase in input

current. Reducing supply voltage to cut power dissipation

reduces the AD795’s input current (see Figure 7). Heavy output

loads can also increase junction temperature; maintaining a

minimum load resistance of 10 kΩ is recommended.