OPA2695 Datasheet, PDF (21/40 Pages) Texas Instruments – Dual, Ultra-Wideband, Current-Feedback OPERATIONAL AMPLIFIER with Disable

OPA2695
www.ti.com..................................................................................................................................................................................................... SBOS354 – APRIL 2008
Figure 71 shows the ac-coupled, single +5V supply,
gain of –8V/V circuit configuration used as a basis for
the +5V only Typical Characteristics. In this case, the
midpoint dc bias on the noninverting input is also
decoupled with an additional 0.1µF decoupling
capacitor. This decoupling configuration reduces the
source impedance at higher frequencies for the
noninverting input bias current noise. This 2.5V bias
on the noninverting input pin appears on the inverting
input pin and, because R_G is dc blocked by the input
capacitor, also appears at the output pin. One
advantage to inverting operation is that because
there is no signal swing across the input stage, higher
slew rates and operation to even lower supply
voltages are possible. To retain a 1V_PP output
capability, operation down to a 3V supply is allowed.
At a +3V supply, the input common-mode range is
0V. However, for the inverting configuration of a
current-feedback amplifier, wideband operation is
retained even with the input stage saturated.
The single-supply test circuits of Figure 70 and
Figure 71 show +5V operation. These same circuits
can be used over a single-supply range of +5V to
+12V. Operating on a single +12V supply, with the
absolute maximum supply voltage specification of
+13V, gives adequate design margin for the typical
±5% supply tolerance.
+5V
+V_S
806W
20W
1000pF
0.1mF
806W
0.1mF
R_G
52.8W
V_I
1000pF
0.1mF
6.8mF
1/2
OPA2695
DIS
V_O ^0.1mF
50W Load
50W
R_F
422W
1000pF
Figure 71. AC-Coupled, G = –8V/V, Single-Supply Specifications and Test Circuit
Copyright © 2008, Texas Instruments Incorporated
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