MAX14950A Datasheet, PDF (17/20 Pages) Maxim Integrated Products – Single-Lane PCIe Equalizer/Redriver

MAX14950A
Single-Lane PCIe Equalizer/Redriver
Programmable Output Deemphasis
Programmable output deemphasis/preshoot for channel
A is controlled by the three bits: OEQA2, OEQA1, OEQA0
and channel B is controlled by the three bits: OEQB2,
OEQB1, OEQB0 (Table 2.)
Receiver Detection
The device features receiver detection on each channel.
Upon initial power-up, if EN is high, receiver detection
initializes. Receiver detection can also be initiated on a
rising or falling edge of the RXDET input when EN is high.
During this time, the part remains in low-power standby
mode and the outputs are squelched, despite the logic-
high state of EN. Until a channel has detected a receiver,
the receiver detection repeats indefinitely on each chan-
nel. If a channel detects a receiver, the other channel is
limited to a few retries. Upon receiver detection, input
common-mode termination and electrical idle detection
are enabled (Table 3.)
Electrical Idle Detection
The device features electrical idle detection to prevent
unwanted noise from being redriven at the output. When
the device detects the differential input has fallen below
the electrical idle low threshold, it squelches the output.
For differential input signals that are above the electrical
idle high threshold, the device turns on the output and
redrives the signal.
Table 2. Output Deemphasis/Preshoot
OEQ_2
0
0
0
0
1
1
1
1
OEQ_1
0
0
1
1
0
0
1
1
OEQ_0
0
1
0
1
0
1
0
1
OUTPUT DEEMPHASIS
RATIO (dB)
0
3.5
6
6
3.5
6
9
9
PEAK-TO-PEAK
SWING (V)
1.0
1.0
1.0
1.2
1.0
1.0
0.9
1.0
PRESHOOT
No
No
No
No
Yes
Yes
Yes
Yes
Table 3. Receiver Detection Input Function
RXDET
X
EN
DESCRIPTION
0
Receiver detection is inactive
X
1
Following a rising edge of EN signal, indefinite retry until a receiver is detected for at
least one channel. Retries stop a few times after any channel is detected.
Rising/Falling Edge
1
Initiate receiver detection
X = Don’t care.
Maxim Integrated
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