OPA2830_08 Datasheet, PDF (23/41 Pages) Burr-Brown (TI) – Dual, Low-Power, Single-Supply, Wideband OPERATIONAL AMPLIFIER

OPA2830
www.ti.com
SBOS309C – AUGUST 2004 – REVISED MARCH 2006
APPLICATIONS INFORMATION
WIDEBAND VOLTAGE-FEEDBACK
OPERATION
The OPA2830 is a unity-gain stable, very high-speed
voltage-feedback op amp designed for single-supply
operation (+3V to +10V). The input stage supports
input voltages below ground and to within 1.7V of the
positive supply. The complementary common-emitter
output stage provides an output swing to within
25mV of ground and the positive supply. The
OPA2830 is compensated to provide stable
operation with a wide range of resistive loads.
high frequencies is 150Ω || 1500Ω. The 1.13kΩ and
2.26kΩ resistors at the noninverting input provide the
common-mode bias voltage. Their parallel
combination equals the DC resistance at the
inverting input (R_F), reducing the DC output offset
due to input bias current.
V_S = +3V
6.8µF
+
2.26kΩ
0.1µF
Figure 70 shows the AC-coupled, gain of +2
configuration used for the +5V Specifications and
Typical Characteristic Curves. For test purposes, the
input impedance is set to 50Ω with a resistor to
ground. Voltage swings reported in the Electrical
Characteristics are taken directly at the input and
output pins. For the circuit of Figure 70, the total
effective load on the output at high frequencies is
150Ω || 1500Ω. The 1.5kΩ resistors at the
noninverting input provide the common-mode bias
voltage. Their parallel combination equals the DC
resistance at the inverting input (R_F), reducing the
DC output offset due to input bias current.
0.1µF _+1V
V_IN
53.6Ω
1.13kΩ
1/2
OPA2830
+V_S/3
R_G
750Ω
R_F
750Ω
V_OUT
R_L
150Ω
+V_S
3
Figure 71. AC-Coupled, G = +2, +3V
Single-Supply Specification and Test Circuit
V_S = +5V
6.8µF
+
1.5kΩ
0.1µF
0.1µF
2.5V
V_IN
53.6Ω
1/2
1.5kΩ _OPA2830
+V_S/2
R_G
750Ω
R_F
750Ω
V_OUT
R_L
150Ω
+V_S
2
Figure 70. AC-Coupled, G = +2, +5V
Single-Supply Specification and Test Circuit
Figure 71 shows the AC-coupled, gain of +2
configuration used for the +3V Specifications and
Typical Characteristic Curves. Voltage swings
reported in the Electrical Characteristics are taken
directly at the input and output pins. For the circuit of
Figure 71, the total effective load on the output at
Figure 72 shows the DC-coupled, gain of +2, dual
power-supply circuit configuration used as the basis
of the ±5V Electrical Characteristics and Typical
Characteristics. For test purposes, the input
impedance is set to 50Ω with a resistor to ground
and the output impedance is set to 150Ω with a
series output resistor. Voltage swings reported in the
specifications are taken directly at the input and
output pins. For the circuit of Figure 72, the total
effective load will be 150Ω || 1.5kΩ. Two optional
components are included in Figure 72. An additional
resistor (348Ω) is included in series with the
noninverting input. Combined with the 25Ω DC
source resistance looking back towards the signal
generator, this gives an input bias current cancelling
resistance that matches the 375Ω source resistance
seen at the inverting input (see the DC Accuracy and
Offset Control section). In addition to the usual
power-supply decoupling capacitors to ground, a
0.01µF capacitor is included between the two
power-supply pins. In practical PC board layouts, this
optional capacitor will typically improve the
2nd-harmonic distortion performance by 3dB to 6dB.
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