LTC6405

13

6405fa

APPLICATIONS INFORMATION

Figure 1. DC Test Circuit

–

+

1

SHDN

5

6

–IN

7

+OUT

8

+OUTF

16

15

+IN

NC

14

–OUT

13

–OUTF

2

3

4

12

11

10

9

6405 F01

LTC6405

SHDN

0.1μF

0.01μF

100k

100k

+

–

–

+

0.1μF

0.1μF

0.1μF

0.1μF

1.25pF

1.25pF

1.25pF

0.1μF

0.01μF

50Ω

50Ω

*TO OPTIMIZE THE HIGH FREQUENCY PERFORMANCE FOR THE PIN CONFIGURATION OF THE LTC6405

IN THE SMALL MSOP PACKAGE, A FEEDBACK RESISTANCE OF AT LEAST 300Ω IS RECOMMENDED.

PACKAGE

MSOP*

QFN

DEFAULT VALUES

1.0pF

1.8pF

300Ω

200Ω

300Ω

200Ω

Functional Description

The LTC6405 is a small outline, wideband, low noise, and

low distortion fully-differential amplifier with accurate

output phase balancing. The LTC6405 is optimized to

drive low voltage, single-supply, differential input analog-

to-digital converters (ADCs). The LTC6405 input common

mode range is rail-to-rail, while the output common mode

voltage is independently adjustable by applying a voltage

near-ground to 4V, to be compatible with a wide range of

ADC converter input requirements. This makes the LTC6405

ideal for level shifting signals with a wide common mode

range for driving 12-bit to 16-bit single supply, differential

input ADCs. The differential output allows for twice the

signal swing in low voltage systems when compared to

single-ended output amplifiers. The balanced differential

nature of the amplifier also provides even-order harmonic

distortion cancellation, and less susceptibility to common

mode noise (like power supply noise). The LTC6405 can be

used as a single ended input to differential output amplifier,

or as a differential input to differential output amplifier.

The LTC6405 output common mode voltage, defined as the

average of the two output voltages, is independent of the

input common mode voltage, and is adjusted by applying

is an internal resistive voltage divider, which develops a

potential of 2.5V (if the supply is 5V). It is recommended

pin to a low impedance ground plane. The LTC6405’s

internal common mode feedback path forces accurate

output phase balancing to reduce even order harmonics,

and centers each individual output about the potential set

V

2