DS90CR287, DS90CR288A
www.ti.com
SNLS056G – OCTOBER 1999 – REVISED MARCH 2013
DS90CR287/DS90CR288A +3.3V Rising Edge Data Strobe LVDS
28-Bit Channel Link - 85MHz
Check for Samples: DS90CR287, DS90CR288A
FEATURES
DESCRIPTION
•
•
•
•
•
•
•
•
•
•
•
•
•
The DS90CR287 transmitter converts 28 bits of
LVCMOS/LVTTL data into four LVDS (Low Voltage
Differential Signaling) data streams. A phase-locked
transmit clock is transmitted in parallel with the data
streams over a fifth LVDS link. Every cycle of the
transmit clock 28 bits of input data are sampled and
transmitted.
1
20 to 85 MHz Shift Clock Support
50% Duty Cycle on Receiver Output Clock
2.5 / 0 ns Set & Hold Times on TxINPUTs
Low Power Consumption
±1V Common-Mode Range (around +1.2V)
Narrow Bus Reduces Cable Size and Cost
Up to 2.38 Gbps Throughput
Up to 297.5 Mbytes/sec Bandwidth
345 mV (typ) Swing LVDS Devices for Low EMI
PLL Requires no External Components
Rising Edge Data Strobe
Compatible with TIA/EIA-644 LVDS Standard
Low Profile 56-Lead TSSOP Package
The DS90CR288A receiver converts the four LVDS
data streams back into 28 bits of LVCMOS/LVTTL
data. At a transmit clock frequency of 85 MHz, 28 bits
of TTL data are transmitted at a rate of 595 Mbps per
LVDS data channel. Using a 85 MHz clock, the data
throughput is 2.38 Gbit/s (297.5 Mbytes/sec).
This chipset is an ideal means to solve EMI and
cable size problems associated with wide, high-speed
TTL interfaces.
Block Diagram
Figure 1. DS90CR287
See Package Number DGG-56 (TSSOP)
Figure 2. DS90CR288A
See Package Number DGG-56 (TSSOP)
1
Please be aware that an important notice concerning availability, standard warranty, and use in critical applications of
Texas Instruments semiconductor products and disclaimers thereto appears at the end of this data sheet.
PRODUCTION DATA information is current as of publication date.
Products conform to specifications per the terms of the Texas
Instruments standard warranty. Production processing does not
necessarily include testing of all parameters.
Copyright © 1999–2013, Texas Instruments Incorporated
DS90CR287, DS90CR288A
SNLS056G – OCTOBER 1999 – REVISED MARCH 2013
www.ti.com
Pin Diagram for TSSOP Packages
Figure 3. DS90CR287
Figure 4. DS90CR288A
Typical Application
Figure 5. DS90CR288A
These devices have limited built-in ESD protection. The leads should be shorted together or the device placed in conductive foam
during storage or handling to prevent electrostatic damage to the MOS gates.
2
Submit Documentation Feedback
Copyright © 1999–2013, Texas Instruments Incorporated
Product Folder Links: DS90CR287 DS90CR288A
DS90CR287, DS90CR288A
www.ti.com
SNLS056G – OCTOBER 1999 – REVISED MARCH 2013
Absolute Maximum Ratings (1) (2)
−0.3V to +4V
Supply Voltage (VCC)
CMOS/TTL Input Voltage
−0.5V to (VCC + 0.3V)
CMOS/TTL Output Voltage
−0.3V to (VCC + 0.3V)
LVDS Receiver Input Voltage
−0.3V to (VCC + 0.3V)
LVDS Driver Output Voltage
−0.3V to (VCC + 0.3V)
LVDS Output Short Circuit Duration
Continuous
Junction Temperature
+150°C
Storage Temperature
−65°C to +150°C
Lead Temperature (Soldering, 4 sec.)
+260°C
Solder Reflow Temperature
Maximum Package Power Dissipation @ +25°C
TSSOP Package
DS90CR287
1.63 W
DS90CR288A
Package Derating
ESD Rating
1.61 W
DS90CR287
12.5 mW/°C above +25°C
DS90CR288A
12.4 mW/°C above +25°C
(HBM, 1.5kΩ, 100pF)
> 7kV
(EIAJ, 0Ω, 200pF)
> 700V
Latch Up Tolerance @ +25°C
(1)
(2)
> ±300mA
“Absolute Maximum Ratings” are those values beyond which the safety of the device cannot be guaranteed. They are not meant to
imply that the device should be operated at these limits. “Electrical Characteristics” specify conditions for device operation.
If Military/Aerospace specified devices are required, please contact the Texas Instruments Sales Office/ Distributors for availability and
specifications.
Recommended Operating Conditions
Min
Nom
Max
Units
Supply Voltage (VCC)
3.0
3.3
3.6
V
Operating Free Air Temperature (TA)
−10
+25
+70
°C
2.4
V
100
mVPP
Receiver Input Range
0
Supply Noise Voltage (VCC)
Copyright © 1999–2013, Texas Instruments Incorporated
Product Folder Links: DS90CR287 DS90CR288A
Submit Documentation Feedback
3
DS90CR287, DS90CR288A
SNLS056G – OCTOBER 1999 – REVISED MARCH 2013
www.ti.com
Electrical Characteristics (1)
Over recommended operating supply and temperature ranges unless otherwise specified
Symbol
Parameter
Conditions
Min
Typ (2)
Max
Units
LVCMOS/LVTTL DC SPECIFICATIONS
VIH
High Level Input Voltage
2.0
VCC
V
VIL
Low Level Input Voltage
GND
0.8
V
VOH
High Level Output Voltage
IOH = −0.4 mA
VOL
Low Level Output Voltage
IOL = 2 mA
0.06
0.3
VCL
Input Clamp Voltage
ICL = −18 mA
−0.79
−1.5
V
IIN
Input Current
VIN = 0.4V, 2.5V or VCC
+1.8
+15
μA
IOS
Output Short Circuit Current
−60
−120
mA
290
450
mV
35
mV
1.375
V
35
mV
−3.5
−5
mA
±1
±10
μA
+100
mV
2.7
−10
VIN = GND
VOUT = 0V
3.3
V
V
μA
0
LVDS DRIVER DC SPECIFICATIONS
VOD
Differential Output Voltage
ΔVOD
Change in VOD between Complimentary
Output States
RL = 100Ω
250
VOS
Offset Voltage (3)
ΔVOS
Change in VOS between Complimentary
Output States
IOS
Output Short Circuit Current
VOUT = 0V, RL = 100Ω
IOZ
Output TRI-STATE Current
PWR DWN = 0V, VOUT = 0V or VCC
1.125
1.25
LVDS RECEIVER DC SPECIFICATIONS
VTH
Differential Input High Threshold
VTL
Differential Input Low Threshold
IIN
Input Current
VCM = +1.2V
−100
mV
VIN = +2.4V, VCC = 3.6V
±10
μA
VIN = 0V, VCC = 3.6V
±10
μA
TRANSMITTER SUPPLY CURRENT
ICCTW
ICCTZ
Transmitter Supply Current Worst Case
(with Loads) (4)
Transmitter Supply Current Power
Down (4)
RL = 100Ω,
CL = 5 pF,
Worst Case Pattern
Figure 6, Figure 7
f = 33 MHz
31
45
mA
f = 40 MHz
32
50
mA
f = 66 MHz
37
55
mA
f = 85 MHz
42
60
mA
10
55
μA
f = 33 MHz
49
70
mA
f = 40 MHz
53
75
mA
f = 66 MHz
81
114
mA
f = 85 MHz
96
135
mA
140
400
μA
PWR DWN = Low
Driver Outputs in TRI-STATE
under Powerdown Mode
RECEIVER SUPPLY CURRENT
ICCRW
ICCRZ
(1)
(2)
(3)
(4)
4
Receiver Supply Current Worst Case
Receiver Supply Current Power Down
CL = 8 pF,
Worst Case Pattern
Figure 6, Figure 8
PWR DWN = Low
Receiver Outputs Stay Low during
Powerdown Mode
“Absolute Maximum Ratings” are those values beyond which the safety of the device cannot be guaranteed. They are not meant to
imply that the device should be operated at these limits. “Electrical Characteristics” specify conditions for device operation.
Typical values are given for VCC = 3.3V and TA = +25°C.
VOS previously referred as VCM.
Current into device pins is defined as positive. Current out of device pins is defined as negative. Voltages are referenced to ground
unless otherwise specified (except VOD and ΔVOD).
Submit Documentation Feedback
Copyright © 1999–2013, Texas Instruments Incorporated
Product Folder Links: DS90CR287 DS90CR288A
DS90CR287, DS90CR288A
www.ti.com
SNLS056G – OCTOBER 1999 – REVISED MARCH 2013
Transmitter Switching Characteristics
Over recommended operating supply and temperature ranges unless otherwise specified
Symbol
Parameter
Min
Typ (1)
Max
Units
LLHT
LVDS Low-to-High Transition Time Figure 7
0.75
1.5
ns
LHLT
LVDS High-to-Low Transition Time Figure 7
0.75
1.5
ns
TCIT
TxCLK IN Transition Time Figure 9
6.0
ns
TPPos0
Transmitter Output Pulse Position for Bit0 Figure 19
TPPos1
TPPos2
1.0
−0.20
0
0.20
ns
Transmitter Output Pulse Position for Bit1
1.48
1.68
1.88
ns
Transmitter Output Pulse Position for Bit2
3.16
3.36
3.56
ns
TPPos3
Transmitter Output Pulse Position for Bit3
4.84
5.04
5.24
ns
TPPos4
Transmitter Output Pulse Position for Bit4
6.52
6.72
6.92
ns
TPPos5
Transmitter Output Pulse Position for Bit5
8.20
8.40
8.60
ns
TPPos6
Transmitter Output Pulse Position for Bit6
9.88
10.08
10.28
ns
TCIP
TxCLK IN Period Figure 10
11.76
T
50
ns
TCIH
TxCLK IN High Time Figure 10
0.35T
0.5T
0.65T
ns
TCIL
TxCLK IN Low Time Figure 10
0.35T
0.5T
0.65T
ns
TSTC
TxIN Setup to TxCLK IN Figure 10
THTC
TxIN Hold to TxCLK IN Figure 10
TCCD
TxCLK IN to TxCLK OUT Delay Figure 12
TPLLS
f = 85 MHz
f = 85 MHz
2.5
TA = 25°C, VCC = 3.3V
3.8
ns
0
ns
6.3
ns
Transmitter Phase Lock Loop Set Figure 14
10
ms
TPDD
Transmitter Powerdown Delay Figure 17
100
ns
TJIT
TxCLK IN Cycle-to-Cycle Jitter (Input clock requirement)
2
ns
(1)
Typical values are given for VCC = 3.3V and TA = +25°C.
Copyright © 1999–2013, Texas Instruments Incorporated
Product Folder Links: DS90CR287 DS90CR288A
Submit Documentation Feedback
5
DS90CR287, DS90CR288A
SNLS056G – OCTOBER 1999 – REVISED MARCH 2013
www.ti.com
Receiver Switching Characteristics
Over recommended operating supply and temperature ranges unless otherwise specified
Symbol
Parameter
Min
Typ (1)
Max
Units
CLHT
CMOS/TTL Low-to-High Transition Time Figure 8
2
3.5
ns
CHLT
CMOS/TTL High-to-Low Transition Time Figure 8
1.8
3.5
ns
RSPos0
Receiver Input Strobe Position for Bit 0 Figure 20
0.49
0.84
1.19
ns
RSPos1
Receiver Input Strobe Position for Bit 1
2.17
2.52
2.87
ns
RSPos2
Receiver Input Strobe Position for Bit 2
3.85
4.20
4.55
ns
RSPos3
Receiver Input Strobe Position for Bit 3
5.53
5.88
6.23
ns
RSPos4
Receiver Input Strobe Position for Bit 4
7.21
7.56
7.91
ns
RSPos5
Receiver Input Strobe Position for Bit 5
8.89
9.24
9.59
ns
RSPos6
Receiver Input Strobe Position for Bit 6
10.57
10.92
11.27
ns
RSKM
RxIN Skew Margin (2) Figure 21
RCOP
RxCLK OUT Period Figure 11
RCOH
RxCLK OUT High Time Figure 11
RCOL
f = 85 MHz
f = 85 MHz
290
ps
11.76
T
50
ns
4
5
6.5
ns
RxCLK OUT Low Time Figure 11
3.5
5
6
ns
RSRC
RxOUT Setup to RxCLK OUT Figure 11
3.5
RHRC
RxOUT Hold to RxCLK OUT Figure 11
3.5
RCCD
RxCLK IN to RxCLK OUT Delay @ 25°C, VCC = 3.3V (3) Figure 13
5.5
RPLLS
RPDD
(1)
(2)
(3)
6
f = 85 MHz
ns
ns
7
9.5
ns
Receiver Phase Lock Loop Set Figure 15
10
ms
Receiver Powerdown Delay Figure 18
1
μs
Typical values are given for VCC = 3.3V and TA = +25°C.
Receiver Skew Margin is defined as the valid data sampling region at the receiver inputs. This margin takes into account the transmitter
pulse positions (min and max) and the receiver input setup and hold time (internal data sampling window-RSPOS). This margin allows
LVDS interconnect skew, inter-symbol interference (both dependent on type/length of cable), and source clock (less than 150 ps).
Total latency for the channel link chipset is a function of clock period and gate delays through the transmitter (TCCD) and receiver
(RCCD). The total latency for the 217/287 transmitter and 218/288A receiver is: (T + TCCD) + (2*T + RCCD), where T = Clock period.
Submit Documentation Feedback
Copyright © 1999–2013, Texas Instruments Incorporated
Product Folder Links: DS90CR287 DS90CR288A
DS90CR287, DS90CR288A
www.ti.com
SNLS056G – OCTOBER 1999 – REVISED MARCH 2013
AC Timing Diagrams
Figure 6. “Worst Case” Test Pattern
Figure 7. DS90CR287 (Transmitter) LVDS Output Load and Transition Times
Figure 8. DS90CR288A (Receiver) CMOS/TTL Output Load and Transition Times
Figure 9. DS90CR287 (Transmitter) Input Clock Transition Time
Copyright © 1999–2013, Texas Instruments Incorporated
Product Folder Links: DS90CR287 DS90CR288A
Submit Documentation Feedback
7
DS90CR287, DS90CR288A
SNLS056G – OCTOBER 1999 – REVISED MARCH 2013
www.ti.com
Figure 10. DS90CR287 (Transmitter) Setup/Hold and High/Low Times
Figure 11. DS90CR288A (Receiver) Setup/Hold and High/Low Times
Figure 12. DS90CR287 (Transmitter) Clock In to Clock Out Delay
Figure 13. DS90CR288A (Receiver) Clock In to Clock Out Delay
8
Submit Documentation Feedback
Copyright © 1999–2013, Texas Instruments Incorporated
Product Folder Links: DS90CR287 DS90CR288A
DS90CR287, DS90CR288A
www.ti.com
SNLS056G – OCTOBER 1999 – REVISED MARCH 2013
Figure 14. DS90CR287 (Transmitter) Phase Lock Loop Set Time
Figure 15. DS90CR288A (Receiver) Phase Lock Loop Set Time
Figure 16. 28 Parallel TTL Data Inputs Mapped to LVDS Outputs
Copyright © 1999–2013, Texas Instruments Incorporated
Product Folder Links: DS90CR287 DS90CR288A
Submit Documentation Feedback
9
DS90CR287, DS90CR288A
SNLS056G – OCTOBER 1999 – REVISED MARCH 2013
www.ti.com
Figure 17. Transmitter Powerdown Delay
Figure 18. Receiver Powerdown Delay
Figure 19. Transmitter LVDS Output Pulse Position Measurement
10
Submit Documentation Feedback
Copyright © 1999–2013, Texas Instruments Incorporated
Product Folder Links: DS90CR287 DS90CR288A
DS90CR287, DS90CR288A
www.ti.com
SNLS056G – OCTOBER 1999 – REVISED MARCH 2013
Figure 20. Receiver LVDS Input Strobe Position
C—Setup and Hold Time (Internal data sampling window) defined by Rspos (receiver input strobe position) min and
max
Tppos—Transmitter output pulse position (min and max)
RSKM ≥ Cable Skew (type, length) + Source Clock Jitter (cycle to cycle)(1) + ISI (Inter-symbol interference)(2)
Cable Skew—typically 10 ps–40 ps per foot, media dependent
(1)
Cycle-to-cycle jitter is less than 150ps at 85MHz.
(2)
ISI is dependent on interconnect length; may be zero.
Figure 21. Receiver LVDS Input Skew Margin
Copyright © 1999–2013, Texas Instruments Incorporated
Product Folder Links: DS90CR287 DS90CR288A
Submit Documentation Feedback
11
DS90CR287, DS90CR288A
SNLS056G – OCTOBER 1999 – REVISED MARCH 2013
www.ti.com
DS90CR287 DGG (TSSOP) Package PIN DESCRIPTION — Channel Link Transmitter
Pin Name
I/O
No.
Description
TxIN
I
28
TTL level input.
TxOUT+
O
4
Positive LVDS differential data output.
TxOUT−
O
4
Negative LVDS differential data output.
TxCLK IN
I
1
TTL level clock input. The rising edge acts as data strobe. Pin name TxCLK IN. See APPLICATIONS
INFORMATION section.
TxCLK OUT+
O
1
Positive LVDS differential clock output.
TxCLK OUT−
O
1
Negative LVDS differential clock output.
PWR DOWN
I
1
TTL level input. Assertion (low input) TRI-STATES the outputs, ensuring low current at power down. See
APPLICATIONS INFORMATION section.
VCC
I
4
Power supply pins for TTL inputs.
GND
I
5
Ground pins for TTL inputs.
PLL VCC
I
1
Power supply pin for PLL.
PLL GND
I
2
Ground pins for PLL.
LVDS VCC
I
1
Power supply pin for LVDS outputs.
LVDS GND
I
3
Ground pins for LVDS outputs.
DS90CR288A DGG (TSSOP) Package PIN DESCRIPTION — Channel Link Receiver
Pin Name
I/O
No.
RxIN+
I
4
Positive LVDS differential data inputs.
RxIN−
I
4
Negative LVDS differential data inputs.
RxOUT
O
28
TTL level data outputs.
RxCLK IN+
I
1
Positive LVDS differential clock input.
RxCLK IN−
I
1
Negative LVDS differential clock input.
RxCLK OUT
O
1
TTL level clock output. The rising edge acts as data strobe. Pin name RxCLK OUT.
PWR DOWN
I
1
TTL level input. When asserted (low input) the receiver outputs are low.
VCC
I
4
Power supply pins for TTL outputs.
GND
I
5
Ground pins for TTL outputs.
PLL VCC
I
1
Power supply for PLL.
PLL GND
I
2
Ground pin for PLL.
LVDS VCC
I
1
Power supply pin for LVDS inputs.
LVDS GND
I
3
Ground pins for LVDS inputs.
12
Description
Submit Documentation Feedback
Copyright © 1999–2013, Texas Instruments Incorporated
Product Folder Links: DS90CR287 DS90CR288A
DS90CR287, DS90CR288A
www.ti.com
SNLS056G – OCTOBER 1999 – REVISED MARCH 2013
APPLICATIONS INFORMATION
The TSSOP version of the DS90CR287 and DS90CR288A are backward compatible with the existing 5V
Channel Link transmitter/receiver pair (DS90CR283, DS90CR284). To upgrade from a 5V to a 3.3V system the
following must be addressed:
1. Change 5V power supply to 3.3V. Provide this supply to the VCC, LVDS VCC and PLL VCC.
2. Transmitter input and control inputs except 3.3V TTL/CMOS levels. They are not 5V tolerant.
3. The receiver powerdown feature when enabled will lock receiver output to a logic low.
The Channel Link devices are intended to be used in a wide variety of data transmission applications. Depending
upon the application the interconnecting media may vary. For example, for lower data rate (clock rate) and
shorter cable lengths (< 2m), the media electrical performance is less critical. For higher speed/long distance
applications the media's performance becomes more critical. Certain cable constructions provide tighter skew
(matched electrical length between the conductors and pairs). Additional applications information can be found in
the following Interface Application Notes:
AN = ####
Topic
AN-1041 (SNLA218)
Introduction to Channel Link
AN-1108(SNLA008)
Channel Link PCB and Interconnect Design-In Guidelines
AN-806 (SNLA026)
Transmission Line Theory
AN-905 (SNLA035)
Transmission Line Calculations and Differential Impedance
AN-916 (SNLA219)
Cable Information
CABLES: A cable interface between the transmitter and receiver needs to support the differential LVDS pairs.
The 21-bit CHANNEL LINK chipset (DS90CR217/218A) requires four pairs of signal wires and the 28-bit
CHANNEL LINK chipset (DS90CR287/288A) requires five pairs of signal wires. The ideal cable/connector
interface would have a constant 100Ω differential impedance throughout the path. It is also recommended that
cable skew remain below 140ps (@ 85 MHz clock rate) to maintain a sufficient data sampling window at the
receiver.
In addition to the four or five cable pairs that carry data and clock, it is recommended to provide at least one
additional conductor (or pair) which connects ground between the transmitter and receiver. This low impedance
ground provides a common-mode return path for the two devices. Some of the more commonly used cable types
for point-to-point applications include flat ribbon, flex, twisted pair and Twin-Coax. All are available in a variety of
configurations and options. Flat ribbon cable, flex and twisted pair generally perform well in short point-to-point
applications while Twin-Coax is good for short and long applications. When using ribbon cable, it is
recommended to place a ground line between each differential pair to act as a barrier to noise coupling between
adjacent pairs. For Twin-Coax cable applications, it is recommended to utilize a shield on each cable pair. All
extended point-to-point applications should also employ an overall shield surrounding all cable pairs regardless
of the cable type. This overall shield results in improved transmission parameters such as faster attainable
speeds, longer distances between transmitter and receiver and reduced problems associated with EMS or EMI.
The high-speed transport of LVDS signals has been demonstrated on several types of cables with excellent
results. However, the best overall performance has been seen when using Twin-Coax cable. Twin-Coax has very
low cable skew and EMI due to its construction and double shielding. All of the design considerations discussed
here and listed in the supplemental application notes provide the subsystem communications designer with many
useful guidelines. It is recommended that the designer assess the tradeoffs of each application thoroughly to
arrive at a reliable and economical cable solution.
RECEIVER FAILSAFE FEATURE: These receivers have input failsafe bias circuitry to guarantee a stable
receiver output for floating or terminated receiver inputs. Under these conditions receiver inputs will be in a HIGH
state. If a clock signal is present, data outputs will all be HIGH; if the clock input is also floating/terminated, data
outputs will remain in the last valid state. A floating/terminated clock input will result in a HIGH clock output.
BOARD LAYOUT: To obtain the maximum benefit from the noise and EMI reductions of LVDS, attention should
be paid to the layout of differential lines. Lines of a differential pair should always be adjacent to eliminate noise
interference from other signals and take full advantage of the noise canceling of the differential signals. The
board designer should also try to maintain equal length on signal traces for a given differential pair. As with any
high-speed design, the impedance discontinuities should be limited (reduce the numbers of vias and no 90
degree angles on traces). Any discontinuities which do occur on one signal line should be mirrored in the other
Copyright © 1999–2013, Texas Instruments Incorporated
Product Folder Links: DS90CR287 DS90CR288A
Submit Documentation Feedback
13
DS90CR287, DS90CR288A
SNLS056G – OCTOBER 1999 – REVISED MARCH 2013
www.ti.com
line of the differential pair. Care should be taken to ensure that the differential trace impedance match the
differential impedance of the selected physical media (this impedance should also match the value of the
termination resistor that is connected across the differential pair at the receiver's input). Finally, the location of
the CHANNEL LINK TxOUT/RxIN pins should be as close as possible to the board edge so as to eliminate
excessive pcb runs. All of these considerations will limit reflections and crosstalk which adversely effect high
frequency performance and EMI.
INPUTS: The TxIN and control pin inputs are compatible with LVTTL and LVCMOS levels. This pins are not 5V
tolerant.
UNUSED INPUTS: All unused inputs at the TxIN inputs of the transmitter may be tied to ground or left no
connect. All unused outputs at the RxOUT outputs of the receiver must then be left floating.
TERMINATION: Use of current mode drivers requires a terminating resistor across the receiver inputs. The
CHANNEL LINK chipset will normally require a single 100Ω resistor between the true and complement lines on
each differential pair of the receiver input. The actual value of the termination resistor should be selected to
match the differential mode characteristic impedance (90Ω to 120Ω typical) of the cable. Figure 22 shows an
example. No additional pull-up or pull-down resistors are necessary as with some other differential technologies
such as PECL. Surface mount resistors are recommended to avoid the additional inductance that accompanies
leaded resistors. These resistors should be placed as close as possible to the receiver input pins to reduce stubs
and effectively terminate the differential lines.
DECOUPLING CAPACITORS: Bypassing capacitors are needed to reduce the impact of switching noise which
could limit performance. For a conservative approach three parallel-connected decoupling capacitors (MultiLayered Ceramic type in surface mount form factor) between each VCC and the ground plane(s) are
recommended. The three capacitor values are 0.1 μF, 0.01 μF and 0.001 μF. An example is shown in Figure 23.
The designer should employ wide traces for power and ground and ensure each capacitor has its own via to the
ground plane. If board space is limiting the number of bypass capacitors, the PLL VCC should receive the most
filtering/bypassing. Next would be the LVDS VCC pins and finally the logic VCC pins.
Figure 22. LVDS Serialized Link Termination
Figure 23. CHANNEL LINK
Decoupling Configuration
14
Submit Documentation Feedback
Copyright © 1999–2013, Texas Instruments Incorporated
Product Folder Links: DS90CR287 DS90CR288A
DS90CR287, DS90CR288A
www.ti.com
SNLS056G – OCTOBER 1999 – REVISED MARCH 2013
CLOCK JITTER: The CHANNEL LINK devices employ a PLL to generate and recover the clock transmitted
across the LVDS interface. The width of each bit in the serialized LVDS data stream is one-seventh the clock
period. For example, a 85 MHz clock has a period of 11.76 ns which results in a data bit width of 1.68 ns.
Differential skew (Δt within one differential pair), interconnect skew (Δt of one differential pair to another) and
clock jitter will all reduce the available window for sampling the LVDS serial data streams. Care must be taken to
ensure that the clock input to the transmitter be a clean low noise signal. Individual bypassing of each VCC to
ground will minimize the noise passed on to the PLL, thus creating a low jitter LVDS clock. These measures
provide more margin for channel-to-channel skew and interconnect skew as a part of the overall jitter/skew
budget.
INPUT CLOCK: The input clock should be present at all times when the part in enabled. If the clock is stopped,
the PWR DOWN pin should be asserted to disable the PLL. Once the clock is active again, the part can then be
enabled. Do not enable the part without a clock present.
COMMON-MODE vs. DIFFERENTIAL MODE NOISE MARGIN: The typical signal swing for LVDS is 300 mV
centered at +1.2V. The CHANNEL LINK receiver supports a 100 mV threshold therefore providing approximately
200 mV of differential noise margin. Common-mode protection is of more importance to the system's operation
due to the differential data transmission. LVDS supports an input voltage range of Ground to +2.4V. This allows
for a ±1.0V shifting of the center point due to ground potential differences and common-mode noise.
TRANSMITTER INPUT CLOCK: The transmitter input clock must always be present when the device is enabled
(PWR DOWN = HIGH). If the clock is stopped, the PWR DOWN pin must be used to disable the PLL. The PWR
DOWN pin must be held low until after the input clock signal has been reapplied. This will ensure a proper device
reset and PLL lock to occur.
POWER SEQUENCING AND POWERDOWN MODE: Outputs of the CHANNEL LINK transmitter remain in TRISTATE until the power supply reaches 2V. Clock and data outputs will begin to toggle 10 ms after VCC has
reached 3V and the Powerdown pin is above 1.5V. Either device may be placed into a powerdown mode at any
time by asserting the Powerdown pin (active low). Total power dissipation for each device will decrease to 5 μW
(typical).
The transmitter input clock may be applied prior to powering up and enabling the transmitter. The transmitter
input clock may also be applied after power up; however, the use of the PWR DOWN pin is required. Do not
power up and enable (PWR DOWN = HIGH) the transmitter without a valid clock signal applied to the TxCLK IN
pin.
The CHANNEL LINK chipset is designed to protect itself from accidental loss of power to either the transmitter or
receiver. If power to the transmit board is lost, the receiver clocks (input and output) stop. The data outputs
(RxOUT) retain the states they were in when the clocks stopped. When the receiver board loses power, the
receiver inputs are shorted to VCC through an internal diode. Current is limited (5 mA per input) by the fixed
current mode drivers, thus avoiding the potential for latchup when powering the device.
Copyright © 1999–2013, Texas Instruments Incorporated
Product Folder Links: DS90CR287 DS90CR288A
Submit Documentation Feedback
15
DS90CR287, DS90CR288A
SNLS056G – OCTOBER 1999 – REVISED MARCH 2013
www.ti.com
Figure 24. Single-Ended and Differential Waveforms
16
Submit Documentation Feedback
Copyright © 1999–2013, Texas Instruments Incorporated
Product Folder Links: DS90CR287 DS90CR288A
DS90CR287, DS90CR288A
www.ti.com
SNLS056G – OCTOBER 1999 – REVISED MARCH 2013
REVISION HISTORY
Changes from Revision F (March 2013) to Revision G
•
Page
Changed layout of National Data Sheet to TI format .......................................................................................................... 16
Copyright © 1999–2013, Texas Instruments Incorporated
Product Folder Links: DS90CR287 DS90CR288A
Submit Documentation Feedback
17
PACKAGE OPTION ADDENDUM
www.ti.com
30-Sep-2021
PACKAGING INFORMATION
Orderable Device
Status
(1)
Package Type Package Pins Package
Drawing
Qty
Eco Plan
(2)
Lead finish/
Ball material
MSL Peak Temp
Op Temp (°C)
(3)
Device Marking
(4/5)
(6)
DS90CR287MTD
NRND
TSSOP
DGG
56
34
Non-RoHS
& Green
Call TI
Level-2-235C-1 YEAR
-10 to 70
DS90CR287MTD
>B
DS90CR287MTD/NOPB
ACTIVE
TSSOP
DGG
56
34
RoHS & Green
SN
Level-2-260C-1 YEAR
-10 to 70
DS90CR287MTD
>B
DS90CR287MTDX/NOPB
ACTIVE
TSSOP
DGG
56
1000
RoHS & Green
SN
Level-2-260C-1 YEAR
-10 to 70
DS90CR287MTD
>B
DS90CR287SLC/NOPB
NRND
NFBGA
NZC
64
360
RoHS & Green
SNAGCU
Level-4-260C-72 HR
DS90CR288AMTD
NRND
TSSOP
DGG
56
34
Non-RoHS
& Green
Call TI
Level-2-235C-1 YEAR
-10 to 70
DS90CR288AMTD
>B
DS90CR288AMTD/NOPB
ACTIVE
TSSOP
DGG
56
34
RoHS & Green
SN
Level-2-260C-1 YEAR
-10 to 70
DS90CR288AMTD
>B
DS90CR288AMTDX/NOPB
ACTIVE
TSSOP
DGG
56
1000
RoHS & Green
SN
Level-2-260C-1 YEAR
-10 to 70
DS90CR288AMTD
>B
DS90CR287
SLC
>B
(1)
The marketing status values are defined as follows:
ACTIVE: Product device recommended for new designs.
LIFEBUY: TI has announced that the device will be discontinued, and a lifetime-buy period is in effect.
NRND: Not recommended for new designs. Device is in production to support existing customers, but TI does not recommend using this part in a new design.
PREVIEW: Device has been announced but is not in production. Samples may or may not be available.
OBSOLETE: TI has discontinued the production of the device.
(2)
RoHS: TI defines "RoHS" to mean semiconductor products that are compliant with the current EU RoHS requirements for all 10 RoHS substances, including the requirement that RoHS substance
do not exceed 0.1% by weight in homogeneous materials. Where designed to be soldered at high temperatures, "RoHS" products are suitable for use in specified lead-free processes. TI may
reference these types of products as "Pb-Free".
RoHS Exempt: TI defines "RoHS Exempt" to mean products that contain lead but are compliant with EU RoHS pursuant to a specific EU RoHS exemption.
Green: TI defines "Green" to mean the content of Chlorine (Cl) and Bromine (Br) based flame retardants meet JS709B low halogen requirements of
工商网监
湘ICP备2023018690号
