Datasheet

100
1k 10k
0
2
4
6
8
10
12
14
16
FEEDBACK RESISTANCE, R
F
(:)
CURRENT NOISE DENSITY (pA/
Hz)
i
n
i
ni
i
t
e
n
/R
F
LMH6624
SNOSA42F –NOVEMBER 2002–REVISED MARCH 2013 www.ti.com
SINGLE SUPPLY OPERATION
The LMH6624/LMH6626 can be operated with single power supply as shown in Figure 55. Both the input and
output are capacitively coupled to set the DC operating point.
Figure 55. Single Supply Operation
LOW NOISE TRANSIMPEDANCE AMPLIFIER
Figure 56 implements a low-noise transimpedance amplifier commonly used with photo-diodes. The
transimpedance gain is set by R
f
. Equation 4 provides the total input current noise density (i
ni
) equation for the
basic transimpedance configuration and is plotted against feedback resistance (R
f
) showing all contributing noise
sources in Figure 57. This plot indicates the expected total equivalent input current noise density (i
ni
) for a given
feedback resistance (R
f
). The total equivalent output voltage noise density (e
no
) is i
ni
*R
f
.
Figure 56. Transimpedance Amplifier Configuration
Figure 57. Current Noise Density vs. Feedback Resistance
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