Datasheet

AD640–SPECIFICATIONS
DC SPECIFICATIONS
Model AD640J AD640B AD640T
Parameter Conditions Min Typ Max Min Typ Max Min Typ Max Units
TRANSFER FUNCTION
1
I
OUT
= I
Y
LOG |V
IN
/V
X
| for V
IN
= ± 0.75 mV to ±200 mV dc
SIGNAL INPUTS (Pins 1, 20)
Input Resistance Differential 500 500 500 kΩ
Input Offset Voltage Differential 50 500 50 200 50 200 µV
vs. Temperature 0.8 0.8 0.8 µV/°C
Over Temperature T
MIN
to T
MAX
300 µV
vs. Supply 2 2 2 µV/V
Input Bias Current 7 25 7 25 7 25 µA
Input Bias Offset 1 1 1 µA
Common-Mode Range –2 +0.3 –2 +0.3 –2 +0.3 V
INPUT ATTENUATOR
(Pins 2, 3, 4, 5 and 19)
Attenuation
2
Pin 5 to Pin 19 20 20 20 dB
Input Resistance Pins 5 to 3/4 300 300 300 Ω
SIGNAL OUTPUT (Pins 10, 11)
Small Signal Gain
3
50 50 50 dB
Peak Differential Output
4
±180 ±180 ± 180 mV
Output Resistance Either Pin to COM 75 75 75 Ω
Quiescent Output Voltage Either Pin to COM –90 –90 –90 mV
LOGARITHMIC OUTPUT
5
(Pin 14)
Voltage Compliance Range –0.3 +V
S
–1 –0.3 +V
S
–1 –0.3 V
S
–1 V
Slope Current, I
Y
0.95 1.00 1.05 0.98 1.00 1.02 0.98 1.00 1.02 mA
Accuracy vs. Temperature 0.002 0.002 0.002 %/°C
T
MIN
to T
MAX
0.98 1.02 mA
Accuracy vs. Supply +V
S
= 4.5 V to 7.5 V 0.08 1.0 0.08 0.4 0.08 0.4 %/V
Intercept Voltage
6
, V
X
0.85 1.00 1.15 0.95 1.00 1.05 0.95 1.00 1.05 mV
vs. Temperature 0.5 0.5 0.5 µV/°C
Over Temperature T
MIN
to T
MAX
0.90 1.10 mV
vs. Supply ±V
S
= 4.5 V to 7.5 V 2 2 2 µV/V
Logarithmic Offset
(Alt. Definition of V
X
) –61.5 –60.0 –58.7 –60.5 –60.0 –59.5 –60.5 –60.0 –59.5 dBV
vs. Temperature 0.004 0.004 0.004 dB/°C
Over Temperature T
MIN
to T
MAX
–60.9 –59.1 dB
vs. Supply ±V
S
= 4.5 V to 7.5 V 0.017 0.017 0.017 dB/V
Intercept Voltage Using Attenuator 8.25 10.0 11.75 9.0 10.0 11.0 9.0 10.0 11.0 mV
Zero Signal Output Current
7
–0.2 –0.2 –0.2 mA
ITC Disabled Pin 8 to COM –0.27 –0.27 –0.27 mA
Maximum Output Current 2.3 2.3 2.3 mA
APPLICATIONS RESISTORS
(Pins 15, 16, 17) 1.000 0.995 1.000 1.005 0.995 1.000 1.005 kΩ
DC LINEARITY
V
IN
±1 mV to ± 100 mV 0.35 1.2 0.35 0.6 0.35 0.6 dB
TOTAL ABSOLUTE DC
ACCURACY
V
IN
= ± 1 mV to ±100 mV
8
0.55 2 0.55 0.9 0.55 0.9 dB
Over Temperature T
MIN
to T
MAX
3 1.7 1.8 dB
Over Supply Range ±V
S
= 4.5 V to 7.5 V 2 1.0 1.0 dB
V
IN
= ± 0.75 mV to ±200 mV 1.0 3 1.0 2.0 1.0 2.0 dB
Using Attenuator
V
IN
= ± 10 mV to ±1 V 0.4 2.5 0.4 1.5 0.4 1.5 dB
Over Temperature T
MIN
to T
MAX
0.6 3 0.6 2.0 0.6 2.0 dB
V
IN
= ± 7.5 mV to 2 V 1.2 3.5 1.2 2.5 1.2 2.5 dB
POWER REQUIREMENTS
Voltage Supply Range
ⴞ 4.5 ⴞ 7.5 ⴞ 4.5 ⴞ 7.5 ⴞ 4.5 ⴞ 7.5 V
Quiescent Current
9
+V
S
(Pin 12) T
MIN
to T
MAX
915 9 15 9 15 mA
–V
S
(Pin 7) T
MIN
to T
MAX
35 60 35 60 35 60 mA
–2–
REV. C
(V
S
= ⴞ 5 V, T
A
= +25 ⴗ C, unless otherwise noted)