DS32EV400SQ/NOPB National Semiconductor, DS32EV400SQ/NOPB Datasheet - Page 14

• Manufacturer Part Number: DS32EV400SQ/NOPB
• Description: IC EQUALIZER QUAD 3.2GBPS 48LLP
• Manufacturer: National Semiconductor
• Series: PowerWise®r

Specifications of DS32EV400SQ/NOPB

• Applications: Signal Processing
• Interface: Serial
• Voltage - Supply: 2.5V, 3.3V
• Package / Case: 48-LLP
• Mounting Type: Surface Mount
• For Use With: DS32EV400-EVK - KIT EVALUATION
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Other names: DS32EV400SQTR

www.national.com
DS32EV400 Applications
Information
DisplayPort™ Application
The DS32EV400 maybe used to extend the reach of the cable
for DisplayPort applications. Typical DisplayPort cables are
in the 6 meter range. With the DS32EV400 Equalizer, nominal
cables may be doubled to 12 meters in length. The Quad de-
vices supports 1, 2, or 4 channel applications.
The DS32EV400 is compatible with the high speed video
channels of DisplayPort and can double the cable reach from
six meters nominal to twelve meters. The DS32EV400 pro-
vides 20 dB of equalization at 3 Gbps and is well suited for
the 2.7 Gbps DisplayPort application. Lengths up to 10 meters
of 28 AWG can be supported on the input and 2 meters on
the output for 12 meters total. The DisplayPort AUX channel
is a low speed line and can be typically extended without the
need of an equalizer. DisplayPort also provides 1.5W of pow-
er in the cable which can be used to power the DS32EV400.
A single Channel version is also available (DS32EV100).
UNUSED EQUALIZER CHANNELS
It is recommended to put all unused channels into standby
mode.
GENERAL RECOMMENDATIONS
The DS32EV400 is a high performance circuit capable of de-
livering excellent performance. Careful attention must be paid
to the details associated with high-speed design as well as
providing a clean power supply. Refer to the LVDS Owner's
Manual for more detailed information on high speed design
tips to address signal integrity design issues.
PCB LAYOUT CONSIDERATIONS FOR DIFFERENTIAL
PAIRS
The CML inputs and outputs must have a controlled differen-
tial impedance of 100Ω. It is preferable to route CML lines
exclusively on one layer of the board, particularly for the input
traces. The use of vias should be avoided if possible. If vias
must be used, they should be used sparingly and must be
FIGURE 9. Automatic Enable Configuration
14
placed symmetrically for each side of a given differential pair.
Route the CML signals away from other signals and noise
sources on the printed circuit board. See AN-1187 for addi-
tional information on LLP packages.
POWER SUPPLY BYPASSING
Two approaches are recommended to ensure that the
DS32EV400 is provided with an adequate power supply.
First, the supply (V
nected to power planes routed on adjacent layers of the
printed circuit board. The layer thickness of the dielectric
should be minimized so that the V
a low inductance supply with distributed capacitance. Sec-
ond, careful attention to supply bypassing through the proper
use of bypass capacitors is required. A 0.01μF bypass ca-
pacitor should be connected to each V
capacitor is placed as close as possible to the DS32EV400.
Smaller body size capacitors can help facilitate proper com-
ponent placement. Additionally, three capacitors with capac-
itance in the range of 2.2 μF to 10 μF should be incorporated
in the power supply bypassing design as well. These capac-
itors can be either tantalum or an ultra-low ESR ceramic and
should be placed as close as possible to the DS32EV400.
DC COUPLING
The DS32EV400 supports both AC coupling with external ac
coupling capacitor, and DC coupling to its upstream driver, or
downstream receiver. With DC coupling, users must ensure
the input signal common mode is within the range of the elec-
trical specification V
with 50 Ω to V
vice, both the DS32EV400 and the downstream receiver
should be power-up and power-down together. This is to
avoid the internal ESD structures at the output of the
DS32EV400 at power-down from being turned on by the
downstream receiver.
DD
. When power-up and power-down the de-
DD
ICMDC
) and ground (GND) pins should be con-
and the device output is terminated
DD
and GND planes create
DD
pin such that the
30031905