OPA830IDBVT datasheet(19/35 Pages) TI

19 / 35 page

OPA830

SBOS263F − AUGUST 2004 − REVISED AUGUST 2008

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APPLICATIONS INFORMATION

WIDEBAND VOLTAGE-FEEDBACK

OPERATION

The OPA830 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 OPA830 is compensated to provide

stable operation with a wide range of resistive loads.

Figure 1 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

Ω 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 1, the total

effective load on the output at high frequencies is

150

Ω || 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 (RF), reducing the DC output offset due to

input bias current.

OPA830

VS =+5V

OUT

53.6

Ω

1.50k

Ω

S/2

1.50k

Ω

150

Ω

6.8

µF

0.1

µF

0.1

µF

750

Ω

750

Ω

2.5V

Figure 1. AC-Coupled, G = +2, +5V Single-Supply

Specification and Test Circuit

Figure 2 shows the AC-coupled, gain of +2 configuration

used for the +3V Specifications and Typical Characteristic

Curves. For test purposes, the input impedance is set to

Ω 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 2, the total

effective load on the output at high frequencies is

150

Ω || 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 (RF), reducing the DC

output offset due to input bias current.

OPA830

S =+3V

OUT

53.6

Ω

2.26k

Ω

1.13k

Ω

150

Ω

6.8

µF

0.1

µF

0.1

µF

750

Ω

750

Ω

+1V

S/3

Figure 2. AC-Coupled, G = +2, +3V Single-Supply

Specification and Test Circuit

Figure 3 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 50

Ω with

a resistor to ground and the output impedance is set to

150

Ω 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 3, the total

effective load will be 150

Ω || 1.5kΩ. Two optional

components are included in Figure 3. An additional

resistor (348

Ω) is included in series with the noninverting

input. Combined with the 25

Ω DC source resistance

looking back towards the signal generator, this gives an

input bias current cancelling resistance that matches the

375

Ω 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 0.01

µF 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.

OPA830IDBVT Datasheet(PDF) 19 Page - Texas Instruments

OPA830IDBVT Datasheet(HTML) 19 Page - Texas Instruments

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