OPA4684M Datasheet, PDF (15/32 Pages) Texas Instruments – QUAD LOW-POWER CURRENT-FEEDBACK OPERATIONAL AMPLIFIER

OPA4684M
QUAD LOWĆPOWER CURRENTĆFEEDBACK
OPERATIONAL AMPLIFIER
SGLS145B − AUGUST 2003 − REVISED FEBRUARY 2004
Figure 43. AC-Coupled, G = +2V/V, Single-Supply Specifications and Test Circuit
Figure 44 shows the AC-coupled, single +5-V supply, gain of −1V/V circuit configuration used as a basis for the
inverting +5 V only Typical Characteristics for each channel. In this case, the midpoint DC bias on the
noninverting input is also decoupled with an additional 0.1-µF capacitor. This reduces the source impedance
at higher frequencies for the noninverting input bias current noise. This 2.5-V bias on the noninverting input pin
appears on the inverting input pin and, since R_G is DC-blocked by the input capacitor, will also appear at the
output pin. One advantage to inverting operation is that since there is no signal swing across the input stage,
higher slew rates and operation to even lower supply voltages is possible. To retain a 1-Vp-p output capability,
operation down to a 3-V supply is allowed. At a +3-V supply, the input stage is saturated, but for the inverting
configuration of a current-feedback amplifier, wideband operation is retained even under this condition.
The circuits of Figures 43 and 44 show single-supply operation at +5 V. These same circuits may be used up
to single supplies of +12 V with minimal change in the performance of the OPA4684.
Figure 44. AC-Coupled, G = −1V/V, Single-Supply Specifications and Test Circuit
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