MAX4207 Maxim, MAX4207 Datasheet - Page 6

• Manufacturer Part Number: MAX4207
• Description: The MAX4207 logarithmic amplifier computes the log ratio of an input current relative to a reference current (externally or internally generated) and provides a corresponding voltage output with a default -0
• Manufacturer: Maxim

Precision Transimpedance Logarithmic
Amplifier with Over 5 Decades of Dynamic Range
(V
T
6
A
CC
= +25°C, unless otherwise noted.)
0.01
_______________________________________________________________________________________
0.1
30
25
20
15
10
10
5
0
1
= +5V, V
1.232
1
R
I
L
REF
V
= 100kΩ
1.234
LOGV2
10
= I
V
LOG
EE
REFVOUT
100
1.236
VOLTAGE-NOISE DENSITY
= -5V, GND = 0V, I
vs. FREQUENCY
1.30
1.29
1.28
1.27
1.26
1.25
1.24
1.23
1.22
1.21
1.20
FREQUENCY (Hz)
100nA
V
REFVOUT
1k
REFERENCE OUTPUT VOLTAGE (V
-50
DISTRIBUTION
1.238
10nA
10µA
10k
(V)
-25
1µA
1.240
100k
vs. TEMPERATURE
TEMPERATURE (°C)
1.242
0
1M
REF
25
1.246
10M
= 1µA, I
50
LOG
Typical Operating Characteristics (continued)
75
REFVOUT
25
20
15
10
5
4
3
2
1
0
5
0
10n
-1.0
INPUT OFFSET VOLTAGE DISTRIBUTION
= 10µA, LOGV2 = SCALE, LOGV1 = OSADJ, CMVIN = CMVOUT, R
100
INPUT OFFSET VOLTAGE = V
TOTAL WIDEBAND VOLTAGE NOISE
-0.5
)
100n
INPUT OFFSET VOLTAGE (mV)
0
AT V
0.5
1µ
LOGV2
I
LOG
1.0
(A)
vs. I
10µ
LOGIIN
1.5
f = 1Hz TO 1MHz
I
REF
LOG
- V
= I
2.0
CMVIN
100µ
LOG
1.30
1.29
1.28
1.27
1.26
1.25
1.24
1.23
1.22
1.21
1.20
2.5
REFERENCE OUTPUT VOLTAGE (V
-1.0
1m
3.0
-0.5
vs. LOAD CURRENT
LOAD CURRENT (mA)
-12
-16
-20
20
16
12
-4
-8
35
30
25
20
15
10
8
4
0
5
0
-50
240
LOGARITHMIC SLOPE DISTRIBUTION
I
I
REF
LOG
0
= 1µA
-25
= 1µA
245
vs. TEMPERATURE
OFFSET VOLTAGE
0.5
SLOPE (mV/DECADE)
TEMPERATURE (°C)
0
REFVOUT
250
25
1.0
)
50
SET
255
75
> 1MΩ,
100
260