MAX14955 Datasheet, PDF (17/19 Pages) Maxim Integrated Products – Computer on Modules

MAX14955
Single-Lane PCIe Gen III Redriver
with Equalization and Extended
Temperature Operation
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
1.0V
1.0V
1.0V
1.2V
1.0V
1.0V
0.9V
1.0V
PRESHOOT
No
No
No
No
Yes
Yes
Yes
Yes
Table 3. Receiver Detection Input Function
RXDET
X
X
Rising/falling edge
X = Don’t care.
EN
DESCRIPTION
0
Receiver detection is inactive.
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.
1
Initiate receiver detection.
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.
Applications Information
Layout
Circuit board layout and design can significantly affect
the performance of the device. Use good high-frequency
design techniques, including minimizing ground induc-
tance and using controlled-impedance transmission lines
on data signals. Power-supply decoupling capacitors must
be placed as close as possible to V_CC. Always connect
V_CC to a power plane. It is recommended to run receive
and transmit on different layers to minimize crosstalk.
Exposed-Pad Package
The exposed-pad, 40-pin TQFN package incorporates
features that provide a very low thermal resistance path
for heat removal from the IC. The exposed pad on the
device must be soldered to the circuit board ground plane
for proper thermal performance. For more information on
exposed-pad packages, refer to Maxim Application Note
HFAN-08.1: Thermal Considerations of QFN and Other
Exposed-Paddle Packages.
Power-Supply Sequencing
Caution: Do not exceed the absolute maximum rat-
ings because stresses beyond the listed ratings can
cause permanent damage to the device.
Proper power-supply sequencing is recommended for all
devices. Always apply GND then V_CC before applying
signals, especially if the signal is not current limited.
www.maximintegrated.com
Maxim Integrated │  17