© 2014 Exar Corporation

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exar.com/XR1009

Rev 1B

XR1009, XR2009

Application Information

General Description

The XR1009 and XR2009 are a single supply, general

purpose, voltage-feedback ampli ers fabricated on a

complementary bipolar process. The XR1009 offers 35MHz

unity gain bandwidth, 27V/μs slew rate, and only 208μA

supply current. It features a rail-to-rail output stage and is

unity gain stable.

The design utilizes a patent pending topology that provides

increased slew rate performance. The common mode input

range extends to 300mV below ground and to 1.2V below

Vs. Exceeding these values will not cause phase reversal.

However, if the input voltage exceeds the rails by more than

0.5V, the input ESD devices will begin to conduct. The output

will stay at the rail during this overdrive condition.

The design uses a Darlington output stage. The output

stage is short circuit protected and offers “soft” saturation

protection that improves recovery time.

Figures 1, 2, and 3 illustrate typical circuit congurations for

non-inverting, inverting, and unity gain topologies for dual

supply applications. They show the recommended bypass

capacitor values and overall closed loop gain equations.

Figure 4 shows the typical non-inverting gain circuit for

single supply applications.

+

-

0.1μF

6.8μF

Output

Input

0.1μF

6.8μF

Figure 1: Typical Non-Inverting Gain Circuit

+

-

0.1μF

6.8μF

Output

For optimum input offset

Input

0.1μF

6.8μF

Figure 2: Typical Inverting Gain Circuit

+

-

0.1μF

6.8μF

Output

G = 1

Input

0.1μF

6.8μF

Figure 3: Unity Gain Circuit

+

-

0.1μF

6.8μF

Out

In

+

Figure 4: Single Supply Non-Inverting Gain Circuit