ds64ev400sqx National Semiconductor Corporation, ds64ev400sqx Datasheet - Page 11

• Manufacturer Part Number: ds64ev400sqx
• Description: Programmable Quad Equalizer
• Manufacturer: National Semiconductor Corporation

DS64EV400 Applications
Information
The DS64EV400 is a programmable quad equalizer opti-
mized for operation up to 10 Gbps for backplane and cable
applications.
EQUALIZER BOOST CONTROL
Each data channel support eight programmable levels of
equalization boost. The state of the FEB pin determines how
the boost settings are controlled. If the FEB pin is held High,
then the equalizer boost setting is controlled by the Boost Set
pins (BST_[2:0]) in accordance with Table 2. If this program-
ming method is chosen, then the boost setting selected on the
Boost Set pins is applied to all channels. When the FEB pin
is held Low, the equalizer boost level is controlled through the
SMBus. This programming method is accessed via the ap-
propriate SMBus registers (see Table 1). Using this approach,
equalizer boost settings can be programmed for each channel
individually. FEB is internally pulled High (default setting);
therefore if left unconnected, the boost settings are controlled
by the Boost Set pins (BST_[0:2]). The eight levels of boost
settings enables the DS64EV400 to address a wide range of
media loss and data rates.
Microstri
Length
p FR4
Trace
6 mil
(m)
10
15
20
25
30
40
0
5
TABLE 2. EQ Boost Control Table
length (m)
Twin-AX
24 AWG
cable
10
0
2
3
4
5
6
7
Channel
3.2 GHz
Loss at
(dB)
12.5
7.5
10
15
17
22
0
5
Loss at 5
GHz (dB)
Channel
10
14
18
21
24
30
0
6
FIGURE 6. Simplified Block Diagram
(Default)
[BST_2,
BST_0]
BST_1,
0 0 0
0 0 1
0 1 0
0 1 1
1 0 0
1 0 1
1 1 0
1 1 1
11
DATA CHANNELS
The DS64EV400 provides four data channels. Each data
channel consists of an equalizer stage, a limiting amplifier, a
DC offset correction block, and a CML driver as shown in Fig-
ure 6.
DEVICE STATE AND ENABLE CONTROL
The DS64EV400 has an Enable feature on each data channel
which provides the ability to control device power consump-
tion. This feature can be controlled either via each Enable Pin
(ENn Pin) or via the Enable Control Bit which is accessed
through the SMBus port (see Table 1 and Table 3). If the En-
able is activated, the corresponding data channel is placed in
the ACTIVE state and all device blocks function as described.
The DS64EV400 can also be placed in STANDBY mode to
save power. In this mode only the control interface including
the SMBus port, as well as the signal detection circuit remain
active.
SIGNAL DETECT
The DS64EV400 features a signal detect circuit on each data
channel. The status of the signal of each channel can be de-
termined by either reading the Signal Detect bit (SDn) in the
SMBus registers (see Table 1) or by the state of each SDn
pin. A logic High indicates the presence of a signal that has
exceeded a specified maximum threshold value (called
Register 07[0]
0 : Disable
0 : Disable
1 : Enable
1 : Enable
(SMBus)
TABLE 3. Controlling Device State
ENn Pin
(CMOS)
X
X
1
0
Register 03[3]
Register 03[7]
Register 04[3]
Register 04[7]
(EN Control)
Channel 0:
Channel 1:
Channel 2:
Channel 3:
(SMBus)
X
X
0
1
Device State
STANDBY
STANDBY
ACTIVE
ACTIVE
www.national.com
30032006