DVI/HDMI TMDS FR-4 and

Cable Equalizer/Driver

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7

DRIVER

EQUALIZER

LIMITING

AMPLIFIER

TERMINATED

DRIVER

EQUALIZER

LIMITING

AMPLIFIER

TERMINATED

DRIVER

EQUALIZER

EQUALIZER

LIMITING

AMPLIFIER

TERMINATED

DRIVER

LIMITING

AMPLIFIER

TERMINATED

OUTD+/-

LEVEL

OUTPUT LEVEL CONTROL

OUTC+/-

OUTB+/-

OUTA+/-

INA+/-

INB+/-

INC+/-

IND+/-

ENABLE

MAX3814

Detailed Description

The MAX3814 TMDS equalizer/driver accepts differential

CML input data rates from 250Mbps to 1.65Gbps. It con-

sists of four differential CML input buffers, four indepen-

dent fixed equalizers, four limiting amplifiers, and four

differential CML output buffers (Figure 1). The MAX3814

functions both as an equalizer and as a driver.

As an equalizer the MAX3814 automatically adjusts for

attenuation levels up to 16dB at 825MHz from either

dielectric board losses or skin-effect losses in copper

cable.

As a driver the MAX3814 provides CML outputs. The

CML output is normally open (i.e., no back termination)

and is DC-coupled by transmission line to a termination

at the far end per DVI/HDMI standards. The MAX3814

provides nominally 10mA output-switching currents.

However, with the MAX3814, there is a selectable higher

current drive to accommodate a differential 200

Ω back

termination resistor while maintaining the differential

Ω back termination resistor

serves to dampen signal reflections returning to the

device from discontinuities in the channel such as DVI or

HDMI connectors, providing a 10dB return loss. See the

CML Inputs and Outputs section for more information.

Figure 1. Functional Diagram