XRT91L82ES Exar, XRT91L82ES Datasheet - Page 23

• Manufacturer Part Number: XRT91L82ES
• Description: Bus Transceivers Transceiver
• Manufacturer: Exar

Specifications of XRT91L82ES

• Product Category: Bus Transceivers
• Rohs: yes

xr
xr
xr
xr
REV. P1.0.5
XRT91L82 supports external Signal Detection (SDEXT). The external Signal Detect function is supported by
the SDEXT input. This input is coming from the optical module through an output usually called “SD” or “FLAG”
which indicates the lack or presence of optical power. Depending on the manufacturer of these devices, the
polarity of this signal can be either active "Low" or active "High." The SDEXT and POLARITY inputs are
Exclusive OR’ed to generate the internal Loss of Signal Detect (LOSD) declaration and Mute upon LOSD
control signal. Whenever an external SD is absent, the XRT91L82 will automatically force the receive parallel
data output to a logic state "0" for the entire duration that a LOSD condition is declared as well as update the
status registers whenever the host mode serial microprocessor interface feature is active. This acts as a
receive data mute upon LOSD function to prevent random noise from being misinterpreted as valid incoming
data. Table 6 specifies SDEXT declaration polarity settings.
REF
REF
OCLK
OCLK
TOL
OCLK
OCLK
2.4
SDEXT
JIT
Jitter specification is defined using a 12kHz to 20MHz appropriate SONET/SDH filter.
1
DUTY
TOL
N
Required to meet SONET output frequency stability requirements.
JIT
JIT
FREQ
DUTY
0
0
1
1
AME
External Signal Detection
POLARITY I
Reference clock duty cycle
Reference clock frequency tolerance
Clock output jitter generation with 155.52 MHz reference clock
Clock output jitter generation with 166.63 MHz reference clock
Input jitter tolerance with 1 MHz < f < 20 MHz PRBS pattern
Frequency output
Clock output duty cycle
0
1
0
1
Active Low. Optical signal presence indicated by
SDEXT logic 0 input from optical module.
LOSD not declared.
Active High. Optical signal presence indicated by
SDEXT logic 1 input from optical module.
LOSD declared.
Active Low. Optical signal presence indicated by
SDEXT logic 0 input from optical module.
LOSD declared.
Active High. Optical signal presence indicated by
SDEXT logic 1 input from optical module.
LOSD not declared.
NTERNAL
T
ABLE
T
ABLE
5: C
S
IGNAL
P
LOCK AND
ARAMETER
6: LOSD D
D
ETECT
2.488/2.666 GBPS STS-48/STM-16 SONET/SDH TRANSCEIVER
1
PRELIMINARY
D
ECLARATION
ATA
R
20
ECOVERY
P
OLARITY
U
NIT
R
P
RXDO[15:0]P/N
ECEIVE
ERFORMANCE
S
D
2.488
ATA
M
ETTING
-20
0.4
45
45
Not Muted
Not Muted
IN
Muted
Muted
O
P
UTPUT
ARALLEL
T
5
5
YP
Local Reference Clock
Local Reference Clock
Hi-Spd Received Data
Hi-Spd Received Data
R
C
R
EFERENCE
LOCK AND
2.667
ECOVERY
M
+20
0.7
55
55
7
7
AX
XRT91L82
D
PLL
L
mUI
mUI
U
OCK
GHz
ATA
ppm
NITS
%
UI
%
rms
rms