LOG112 Datasheet, PDF (6/16 Pages) Texas Instruments – LOGARITHMIC AND LOG RATIO AMPLIFIERS

TYPICAL CHARACTERISTICS (Cont.)
At T_A = +25°C, V_S = ±5V, and R_L = 10kΩ, unless otherwise noted.
100M
10M
1M
100k
10k
1k
MINIMUM VALUE OF COMPENSATION CAPACITOR
Select C_C for I₁ min.
and I₂ max. Values
below 2pF may be ignored.
I₁ = 100pA
I₁ = 1nA
I₁ = 10nA
I₁ = 100nA
1µA
100
I₁ = 10µA
10
100µA
1mA
1
100pA 1nA 10nA 100nA 1µA 10µA 100µA 1mA 10mA
I₂
1M
100k
3dB FREQUENCY RESPONSE
10µA
1µA
10k
1k
100µA
1nA
= ^{10pF 100µA}
CC
10^{µA to 1µA}
10nA
10nA
100
I₁ = 1nA
10
1
= ^1000pF
CC
= ^1µF
CC
0.1
100pA 1nA 10nA 100nA 1µA 10µA 100µA
I₂
100µA
100µA
1mA
I₁ = 1mA
1µA
1mA
to 10µA
100nA
10nA
I₁ = 1nA
1mA
17
15
13
11
9
7
5
3
1
–1
100pA
LOG CONFORMITY vs INPUT CURRENT
+85°C
+75°C
–40°C to +25°C
1nA 10nA 100nA 1µA 10µA 100µA 1mA
Input Current (I₁ or I₂)
LOG CONFORMITY vs TEMPERATURE
700
600
7.5 Decade
500
400
7 Decade
300
6 Decade ^{5 Decade}
200
100
0
–40 –20
0
20
40
60
80
Temperature (°C)
6
LOG112, 2112
www.ti.com
SBOS246C