LOG114_12 Datasheet, PDF (7/29 Pages) Burr-Brown (TI) – Single-Supply, High-Speed, Precision LOGARITHMIC AMPLIFIER

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TYPICAL CHARACTERISTICS: V_S = +5V
All specifications at T_A = +25°C, R_VLOGOUT = 10kΩ, V_CM = GND, unless otherwise noted.
LOG114
SBOS301A − MAY 2004 − REVISED MARCH 2007
NORMALIZED TRANSFER FUNCTION
2.0
1.5
1.0
0.5
0
−0.5
−1.0
−1.5
−2.0
10^−4 10^−3 10^−2 10^−1
1
10¹ 10² 10³ 10⁴
Current Ratio (I₁/I₂)
ONE CYCLE OF NORMALIZED TRANSFER FUNCTION
0.40
0.35
0.30
0.25
0.20
0.15
0.10
0.05
0
1
10
Current Ratio (I₁/ I₂)
SCALING FACTOR ERROR (I₂ = reference 100pA to 10mA)
40
30
20
+70_ C
10
0_ C
+25_ C
0
−10
−10_ C
+80_ C
+90_ C
−20
100pA 1nA 10nA 100nA 1µA
10µA 100µA 1mA 10mA
Input Current (I₁)
2.5
2.0
1.5
1.0
0.5
0
−0.5
−1.0
−1.5
−2.0
−2.5
100pA 1nA
V_LOGOUT vs I₁ INPUT (I₂ = 1µA)
10nA 100nA 1µA 10µA 100µA 1mA 10mA
Input Current (I₁)
V_LOGOUT vs I₂ INPUT (I₁ = 1µA)
2.0
1.5
1.0
0.5
0
−0.5
−1.0
−1.5
−2.0
−2.5
100pA 1nA
10nA 100nA 1µA 10µA 100µA 1mA 10mA
Input Current (I₁)
V_LOGOUT vs I_REF
4
100pA
3
1nA
2
10nA
1µA ^100nA
1
0
−1
−2
−3
−4
100pA 1nA
10µA
1mA ^100µA
10mA
10nA 100nA 1µA 10µA 100µA 1mA 10mA
I_REF (I₂)
7