OPA4830 Datasheet, PDF (22/45 Pages) National Semiconductor (TI) – Quad, Low-Power, Single-Supply, Wideband Operational Amplifier

OPA4830
SBOS350A – DECEMBER 2006 – REVISED MAY 2008.................................................................................................................................................... www.ti.com
APPLICATION INFORMATION
WIDEBAND VOLTAGE-FEEDBACK
OPERATION
The OPA4830 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 OPA4830 is
compensated to provide stable operation with a wide
range of resistive loads.
Figure 72 shows the ac-coupled, gain of +2V/V
configuration used for the +5V Electrical
Characteristics and Typical Characteristics. 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 72, 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. This parallel combination equals the dc
resistance at the inverting input (R_F), reducing the dc
output offset because of input bias current.
V_S = +5V
6.8mF
+
1.50kW
0.1mF
0.1mF
2.5V
V_IN
53.6W
1.50kW
1/4
OPA4830
V_OUT
R_L
150W
R_G
750W
R_F
750W
+V_S
+V_S/2
2
Figure 72. AC-Coupled, G = +2V/V, +5V
Single-Supply Specification and Test Circuit
Figure 73 shows the ac-coupled, gain of +2V/V
configuration used for the +3V Electrical
Characteristics and Typical Characteristics. 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 73, the
total effective load on the output at high frequencies
is 150Ω || 1500Ω. The 1.13kΩ and 2.26kΩ resistors
at the noninverting input provide the common-mode
bias voltage. The parallel combination equals the dc
resistance at the inverting input (R_F), reducing the dc
output offset as a result of input bias current.
V_S = +3V
6.8mF
+
2.26kW
0.1mF
0.1mF _+1V
V_IN
53.6W
1/4
1.13kW _OPA4830
V_OUT
R_L
150W
R_G
750W
R_F
750W
+V_S
+V_S/3
3
Figure 73. AC-Coupled, G = +2V/V, +3V
Single-Supply Specification and Test Circuit
22
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