Datasheet

Block Diagram
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Device Operation
BLOCK DESCRIPTION
The Equalizer Filter block is a multi-stage adaptive filter. If
Bypass is high, the equalizer filter is disabled.
The DC Restoration / Level Control block receives the dif-
ferential signals from the equalizer filter block. This block
incorporates a self-biasing DC restoration circuit to fully DC
restore the signals. If Bypass is high, this function is disabled.
The signals before and after the DC Restoration / Level Con-
trol block are used to generate the Automatic Equalization
Control (AEC) signal. This control signal sets the gain and
bandwidth of the equalizer filter. The loop response in the
AEC block is controlled by an external 1µF capacitor placed
across the AEC+ and AEC- pins. Cable Length Indicator
(CLI) is derived from this block.
The Output Driver produces SDO and SDO
. SDO and
SDO may be forced to mute by activating MUTE.
CABLE LENGTH INDICATOR (CLI)
The cable length indicator provides a voltage to indicate the
length of cable being equalized. The CLI voltage decreases
as the cable length increases. Figure 1 shows the typical CLI
voltage vs. Belden 1694A cable length. Note: CLI is only valid
when an input signal is present.
0 50 100 150 200 250 300 350
1.8
1.9
2.0
2.1
2.2
2.3
2.4
2.5
2.6
CLI (V)
BELDEN 1694A CABLE LENGTH (m)
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FIGURE 1. CLI vs. Belden 1694A Cable Length
MUTE
MUTE can be used to manually mute or enable the LMH0024
outputs. MUTE must be tied to a low-level input or ground for
SDO and SDO
to be active. Applying a high input to MUTE
will mute the LMH0024 outputs.
INPUT INTERFACING
The LMH0024 accepts either differential or single-ended in-
put. The input must be AC coupled. Transformer coupling is
not supported.
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LMH0024