89HP0504PB Datasheet, PDF (8/26 Pages) Integrated Device Technology – 4 Channel 5Gbps PCIe® Signal Repeater

IDT 89HP0504PB Data Sheet
Mode
Control Inputs
[A,B]RXDETEN
RSTB
Tx Termina-
tions
Description
Channel
0
Enabled
Channel
1
Enabled but
inactive
Channel
1
Enabled and
active
1
50Ω
Rx signal detected.
Receiver detect disabled.
Receiver terminations set to 50Ω.
1
50Ω
TX output is squelched.
A valid receiver was detected.
Receiver terminations set to 50Ω.
Output common-mode is held at
its active value.
1
50Ω
TX output is active.
A valid receiver was detected.
Receiver terminations set to 50Ω.
Table 3 Transmitter Impedance (Part 2 of 2)
PCIe Receiver Detection Support
The P0504PB transmitter fully supports PCIe Receiver Detection requirements. Receiver detection is enabled for channels A0 and A1 by asserting
pin ARXDETEN and for channels B0 and B1 by asserting pin BRXDETEN. For receiver detection to occur, a low pulse (minimum 200ns) must be
applied at pin RSTB. The rising edge of the RSTB signal starts the receiver detection procedure. Neither ARXDETEN nor BRXDETEN can be toggled
during the receiver detection procedure, i.e., they must be kept high for at least 200ns before the RSTB rising edge and they cannot go to low sooner
than 2ms from the time the RSTB goes high. The receiver detection takes place once per RSTB pulse.
RXDETEN
T3 >0ns
T4 >= 2ms
RSTB
VCM
T0 >= 200 ns
VDD
T1 = 800us T2 = 1.5us
RxDetStat
(i t l)
Figure 5 Receiver Detection Timing
Modes of Operation
The device supports several data transfer modes, electrical idle mode, and several power reducing modes.
Electrical Idle Mode
In electrical idle mode, the transmitter stops toggling and maintains its common-mode voltage level. The device enters electrical idle mode when
the envelope of the incoming signal on a given channel has fallen below a programmable threshold level.
Power Reducing Modes
The Repeater supports five power-down states and one active state as shown in Table 4. The user can choose between full chip power-down,
channel based power-down, and electrical idle modes. Power reducing modes can be selected via PDB and RSTB.
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February 8, 2011