Upgrading to a higher performance cable, such as a Belden
8281 or equivalent, is one solution to boosting system band-
width. There are at least two downsides to this option, how-
ever. The first is that it introduces significantly higher cable
costs. The second is problems presented to technicians who
have to work with more rigid cables.
A better solution may be to use a cable driving buffer such as
Intersil’s HFA1114. The driver’s frequency response is
tunable for a specific cable length via components
connected to the summing node (see Figure 3). By shunting
R
1
, R
C
acts to increase the amplifier’s gain while C
C
controls the cut-in frequency of the compensation.
These three components peak the amplifier’s frequency
response to counteract the cable’s roll-off characteristic. By
squeezing more bandwidth out of a given cable, higher-per-
formance cables aren’t needed.
An unexpected but welcome side effect of this particular
solution is that using the on-chip gain-setting resistors frees
up board space for the compensation components.
1
2
V
IN
3
4
R
1
300
300
8
7
R
T
6
5
SUMMING NODE
R
C
R
T
V
OUT
--
R
F
+
HFA1114
C
C
FIGURE 3. INSTEAD OF UPGRADING TO A HIGHER
PERFORMANCE CABLE TO INCREASE SYSTEM
BANDWIDTH, A CABLE DRIVER LIKE THE HFA1114
CAN BE EMPLOYED. THE DRIVER’S FREQUENCY
RESPONSE IS TUNABLE FOR A SPECIFIC CABLE
LENGTH VIA THE COMPONENTS CONNECTED TO
THE SUMMING NODE.
All Intersil semiconductor products are manufactured, assembled and tested under
ISO9000
quality systems certification.
Intersil semiconductor products are sold by description only. Intersil Corporation reserves the right to make changes in circuit design and/or specifications at any time with-
out notice. Accordingly, the reader is cautioned to verify that data sheets are current before placing orders. Information furnished by Intersil is believed to be accurate and
reliable. However, no responsibility is assumed by Intersil or its subsidiaries for its use; nor for any infringements of patents or other rights of third parties which may result
from its use. No license is granted by implication or otherwise under any patent or patent rights of Intersil or its subsidiaries.
For information regarding Intersil Corporation and its products, see web site
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