This section describes the changes that have been implemented in this document. The changes are listed by revision,
starting with the most current publication.
Revision 4.2 of this datasheet was published on April 26, 2005. In revision 4.2 of the document, the package drawing
for VSC7983CD was updated to include pre-dipped and solder-dipped specifications. For more information, see
“Package Drawing for VSC7983CD‚’’ page 20.
The advantages of the VSC7983 device are its excellent output match, data retiming, internal stabilization of offset
and modulation, and small package size. The VSC7983 device provides up to 3 V of output modulation swing and
1 V of voltage offset (or bias). The output compliance (the lowest achievable level of output swing) is better than
3.4 V for VCC – VEE > 4.9 V power supply.
The VSC7983 device has been characterized at 4.75 V to verify operation over power supply variations in 5 V
systems. This reduction in power supply only affects the output voltage compliance and modulation limits. The
reduced output voltage compliance (VOC) is 3.3 V for modulation voltages (VOM) of up to 2.8 V. The VSC7983
device is capable of moving the crossing point from the top to the bottom of the output eye. Specifications are
guaranteed over all conditions for crossing points from 25% to 80%. For a crossing point from 25% to 85% the
modulation voltage (VOM) limit is reduced to 2.8 V. See Table 2 for these limitations.
The VSC7983 device inputs are to be AC-coupled and the outputs are to be DC-coupled. Information on AC-coupling
the outputs is available. For assistance with this and other configurations, please contact your local Vitesse sales
representative. Evaluation boards for all configurations and detailed supplemental information are also available.
The VSC7983 device consumes 277 mA typical from a –5.2 V power supply and 300 mA maximum with a 2.5 V
output swing and 1 V offset voltage. The following equation provides an estimation of worst-case power dissipation:
PD = 5.5 V • (180 mA + VOM/25)
Output Bias Voltage (VBIAS)
Output Compliance Voltage (VOC)
Output HIGH Voltage (VOH)
Output Modulation Voltage (VOM)
Output LOW Voltage (VOL)
Figure 1. Output Voltage Range Specifications
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G52394 Revision 4.2
April 26, 2005