LOG114EVM Datasheet, PDF (12/21 Pages) Texas Instruments – LOG114EVM User Guide

Verifying Results
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5 Verifying Results
Making measurements on the LOG114EVM is fast and easy. Connect a digital voltmeter or oscilloscope to
the terminal of interest and record the results. Included with the graph of measured results is a table of
results for common values of input currents. In Figure 13, two curves are shown. Both curves use a
resistor input and V_OUT is recorded as a function of input current. The compensated (red) curve connects
the resistor as shown in Figure 11 and uses the high-current linearity correction circuitry. The
uncompensated curve (blue) uses the resistor connected to I₁ and V_REF as shown in Figure 10.
3
Uncompensated Output
Compensated Output
2.5
2
1.5
1
10n 100n
1m
10m 100m
1m
10m
Input Current (A)
Figure 13. LOG114EVM Measured Results
Table 1 lists several typical results obtained with various input voltages.
Input
10 nA
100 nA
1 μA
10 μA
100 μA
1 mA
10 mA
Table 1. LOG114EVM Typical Results
Uncompensated
V_LOGOUT (V)
1.36
V_OUT (V)
1.15
1.74
1.38
2.11
1.60
2.49
1.83
2.87
2.06
3.29
2.31
4.11
2.82
Compensated
V_LOGOUT (V)
1.36
V_OUT (V)
1.15
1.74
1.38
2.11
1.60
2.49
1.83
2.87
2.06
3.29
2.30
4.11
2.67
12
LOG114EVM User Guide
Copyright © 2011, Texas Instruments Incorporated
SBOU110 – September 2011
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