VOUT

+

-

VIN

+5V

-5V

CPOS

6.8 µF

RG

RF

0.01 µF

6.8 µF

CNEG

0.01 µF

RIN

0.1 µF

CSS

AV = 1 +RF/RG = VOUT/VIN

VOUT

+

-

VIN

+5V

-5V

CPOS

6.8 µF

RG

RF

0.01 µF

6.8 µF

CNEG

0.01 µF

RT

25:

0.1 µF

CSS

SELECT RT TO

YIELD DESIRED

RIN = RT||RG

AV =

VOUT

VIN

RF

RG

=

LMH6738

www.ti.com

SNOSAC1E – APRIL 2004 – REVISED MARCH 2013

APPLICATION INFORMATION

Figure 22. Recommended Non-Inverting Gain

Figure 23. Recommended Inverting Gain Circuit

Circuit

GENERAL INFORMATION

The LMH6738 is a high speed current feedback amplifier, optimized for very high speed and low distortion. The

LMH6738 has no internal ground reference so single or split supply configurations are both equally useful.

EVALUATION BOARDS

Texas Instruments provides the following evaluation boards as a guide for high frequency layout and as an aid in

device testing and characterization. Many of the data sheet plots were measured with these boards.

Device

Package

Evaluation Board

Part Number

LMH6738MQA

SSOP

LMH730275

FEEDBACK RESISTOR SELECTION

One of the key benefits of a current feedback operational amplifier is the ability to maintain optimum frequency

response independent of gain by using appropriate values for the feedback resistor (RF). The Electrical

Characteristics and Typical Performance plots specify an RF of 550Ω, a gain of +2 V/V and ±5V power supplies

(unless otherwise specified). Generally, lowering RF from it’s recommended value will peak the frequency

response and extend the bandwidth while increasing the value of RF will cause the frequency response to roll off

faster. Reducing the value of RF too far below it’s recommended value will cause overshoot, ringing and,

eventually, oscillation.

Copyright © 2004–2013, Texas Instruments Incorporated

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