EL2140CS datasheet(7/12 Pages) ELANTEC

7 / 12 page

EL2140C2141C

150 MHz Differential Twisted Pair Driver

Applications Information

Contd

H3 The third harmonic should be the dominant

harmonic and is primarily affected by output

load current which of course is unavoidable

However this should encourage the user not to

waste current in the gain setting resistors and to

use values that consume only a small proportion

of the load current so long as peaking does not

occur The more load current the worse the dis-

tortion but depending on the frequency it may

be possible to reduce the amplifier gain so that

there is more internal gain left to cancel out any

distortion

H5 The fifth harmonic should always be below

the third and will not become significant until

heavy load currents are drawn

Generally

should respond to the same efforts applied to re-

ducing the third harmonic

H6 The sixth harmonic should not be a problem

and is the result of poor power supply decou-

pling While 100 nF chip capacitors may be suffi-

cient for some applications it would be insuffi-

cient for driving full signal swings into a twisted

pair line at 100 kHz Under these conditions the

addition of 47

mF tantalum capacitors would

cure the problem

Typical Applications Circuits

2140-15

Figure 1 Typical Twisted Pair Application

EL2140CS Datasheet(PDF) 7 Page - Elantec Semiconductor