OPA2890 Datasheet, PDF (17/38 Pages) Texas Instruments – Low-Power, Wideband, Voltage-Feedback OPERATIONAL AMPLIFIER with Disable

OPA2890
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+5V
+V_S
698W
0.1mF
6.8mF
0.1mF
50W
DIS
V_I
698W
V_D
1/2
V_O 200W
59W
OPA2890
V_S/2
R_F
750W
R_G
750W
0.1mF
Figure 50. DC-Coupled, G = +2V/V, Single-Supply,
Specification and Test Circuit
Again, an additional resistor (50Ω in this case) is
included directly in series with the noninverting input.
This minimum recommended value provides part of
the dc source resistance matching for the
noninverting input bias current. It is also used to form
a simple parasitic pole to roll off the frequency
response at very high frequencies ( > 500MHz) using
the input parasitic capacitance. The gain resistor (R_G)
is AC-coupled, giving the circuit a dc gain of +1V/V,
which puts the input dc bias voltage (2.5V) on the
output as well. The output voltage can swing to within
1V of either supply pin while delivering greater than
40mA output current.
DIFFERENTIAL OPERATION
Figure 51 shows the inverting differential
configuration used as the basis for the ±5V and +5V
Typical Characteristics. This circuit offers a
combination of excellent distortion with low quiescent
current for frequencies below 100kHz.
The other possibility is to use the OPA2890 in a
differential configuration as shown in Figure 52. This
figure illustrates the differential noninverting
configuration that has the advantage of showing a
high input impedance to any prior stage.
SBOS364C – DECEMBER 2007 – REVISED DECEMBER 2009
R_G
V_IN
R_G
+5V
1/2
OPA2830
R_F
R_F
G_D =
R_F
R_G
R_L V_OUT
1/2
OPA2830
-5V
Figure 51. Differential Inverting Specification and
Test Circuit
+5V
1/2
OPA2830
G_D = 1 +
2R_F
R_G
R_F
V_IN
R_G
R_F
R_L
1/2
OPA2830
-5V
Figure 52. Differential Noninverting Specification
and Test Circuit
Copyright © 2007–2009, Texas Instruments Incorporated
Product Folder Link(s): OPA2890
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