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APPLICATION INFORMATION

DUAL-SUPPLY, NON-INVERTING AMPLIFIER

OPA699

49.9

Ω

6

I

VH

V

O

V

IN

I

VL

-V

3

2

4

7

8

5

R

F

750

Ω

R

G

150

Ω

500

Ω

0.1

µF

0.1

µF

0.1

µF

100

Ω

3.01k

Ω 1.91kΩ

3.01k

Ω 1.91kΩ

0.1

µF

V

V

+

2.2

µF

+

2.2

µF

+V

S0035-02

SINGLE-SUPPLY, NON-INVERTING AMPLIFIER

OPA699M

SGLS289A – MAY 2005 – REVISED MARCH 2006

The OPA699 is a +4 V/V minimum gain voltage-feedback amplifier that combines features of a wideband, high

slew rate amplifier with output voltage limiters. Its output can swing up to 1 V from each rail and can deliver up to

120 mA. These capabilities make it an ideal interface to drive an ADC while adding overdrive protection for the

ADC inputs.

Figure 47 shows the ac-coupled, gain of +6 V/V, dual power-supply circuit configuration used as the basis of the

±5-V Electrical Characteristics and Typical Characteristics. For test purposes, the input impedance is set to 50

Ω

with a resistor to ground and the output is set to 500

Ω. Voltage swings reported in the specifications are taken

directly at the input and output pins. For the circuit of Figure 47, the total output load will be 500

Ω || 900 Ω =

321

Ω. The voltage limiting pins are set to ±2 V through a voltage divider network between +V

polarities shown. One additional component is included in Figure 47. An additional resistor (100

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-canceling resistance that matches the 125-

Ω source resistance seen

at the inverting input (see the dc accuracy and offset control section). The power-supply bypass for each supply

consists of two capacitors: one electrolytic 2.2 µF and one ceramic 0.1 µF. The power-supply bypass capacitors

are shown explicitly in Figure 47 and Figure 48, but will be assumed in the other figures. An additional 0.01-µF

power-supply decoupling capacitor (not shown here) can be included between the two power-supply pins. In

performance by 3 dB to 6 dB.

Figure 47. DC-Coupled, Dual Supply Amplifier

Figure 48 shows an ac-coupled, noninverting gain amplifier for single +5-V supply operation. This circuit was

used for ac characterization of the OPA699, with a 50-

Ω source (which it matches) and a 500-Ω load. The

mid-point reference on the noninverting input is set by two 1.5-k

Ω resistors. This gives an input bias

current-canceling resistance that matches the 750-

Ω dc source resistance seen at the inverting input (see the dc

accuracy and offset control section). The power-supply bypass for the supply consists of two capacitors: one

electrolytic 2.2 µF and one ceramic 0.1 µF. The power-supply bypass capacitors are shown explicitly in Figure 47

17

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