DS90CR213 [TI]

21-Bit Channel Link-66 MHz; 21位通道链接-66 MHz的
DS90CR213
型号: DS90CR213
厂家: TEXAS INSTRUMENTS    TEXAS INSTRUMENTS
描述:

21-Bit Channel Link-66 MHz
21位通道链接-66 MHz的

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中文:  中文翻译
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August 2005  
DS90CR213/DS90CR214  
21-Bit Channel Link—66 MHz  
General Description  
The DS90CR213 transmitter converts 21 bits of CMOS/TTL  
data into three LVDS (Low Voltage Differential Signaling)  
data streams. A phase-locked transmit clock is transmitted in  
parallel with the data streams over a fourth LVDS link. Every  
cycle of the transmit clock 21 bits of input data are sampled  
and transmitted. The DS90CR214 receiver converts the  
LVDS data streams back into 21 bits of CMOS/TTL data. At  
a transmit clock frequency of 66 MHz, 21 bits of TTL data are  
transmitted at a rate of 462 Mbps per LVDS data channel.  
Using a 66 MHz clock, the data throughput is 1.386 Gbit/s  
(173 Mbytes/s).  
width, which provides a system cost savings, reduces con-  
nector physical size and cost, and reduces shielding require-  
ments due to the cable’s smaller form factor.  
The 21 CMOS/TTL inputs can support a variety of signal  
combinations. For example, 5 4-bit nibbles (byte + parity) or  
2 9-bit (byte + 3 parity) and 1 control.  
Features  
n 66 MHz Clock Support  
n Up to 173 Mbytes/s bandwidth  
<
n Low power CMOS design ( 610 mW)  
<
n Power-down mode ( 0.5 mW total)  
The multiplexing of the data lines provides a substantial  
cable reduction. Long distance parallel single-ended buses  
typically require a ground wire per active signal (and have  
very limited noise rejection capability). Thus, for a 21-bit wide  
data and one clock, up to 44 conductors are required. With  
the Channel Link chipset as few as 9 conductors (3 data  
pairs, 1 clock pair and a minimum of one ground) are  
needed. This provides an 80% reduction in required cable  
n Up to 1.386 Gbit/s data throughput  
n Narrow bus reduces cable size and cost  
n 290 mV swing LVDS devices for low EMI  
n PLL requires no external components  
n Low profile 48-lead TSSOP package  
n Rising edge data strobe  
n Compatible with TIA/EIA-644 LVDS Standard  
Block Diagrams  
DS90CR213  
DS90CR214  
01288827  
Order Number DS90CR213MTD  
See NS Package Number MTD48  
01288801  
Order Number DS90CR214MTD  
See NS Package Number MTD48  
TRI-STATE® is a registered trademark of National Semiconductor Corporation.  
© 2005 National Semiconductor Corporation  
DS012888  
www.national.com  
Connection Diagrams  
DS90CR213  
DS90CR214  
01288821  
01288822  
Typical Application  
01288823  
www.national.com  
2
Absolute Maximum Ratings (Note 1)  
Package Derating:  
DS90CR213  
16 mW/˚C above +25˚C  
15 mW/˚C above +25˚C  
If Military/Aerospace specified devices are required,  
please contact the National Semiconductor Sales Office/  
Distributors for availability and specifications.  
DS90CR214  
ESD Rating (Note 4)  
This device does not meet 2000V  
Supply Voltage (VCC  
)
−0.3V to +6V  
−0.3V to (VCC + 0.3V)  
−0.3V to (VCC + 0.3V)  
−0.3V to (VCC + 0.3V)  
−0.3V to (VCC + 0.3V)  
CMOS/TTL Input Voltage  
CMOS/TTL Output Voltage  
LVDS Receiver Input Voltage  
LVDS Driver Output Voltage  
LVDS Output Short Circuit  
Duration  
Recommended Operating  
Conditions  
Min Nom Max Units  
Supply Voltage (VCC  
Operating Free Air  
Temperature (TA)  
)
4.75 5.0 5.25  
V
Continuous  
+150˚C  
Junction Temperature  
Storage Temperature  
Lead Temperature  
−10 +25 +70  
˚C  
V
−65˚C to +150˚C  
Receiver Input Range  
Supply Noise Voltage  
0
2.4  
(Soldering, 4 sec)  
+260˚C  
100  
mVP-P  
(VCC  
)
Maximum Package Power  
Dissipation Capacity  
MTD48 (TSSOP) Package:  
DS90CR213  
@
25˚C  
1.98W  
1.89W  
DS90CR214  
Electrical Characteristics  
Over recommended operating supply and temperature ranges unless otherwise specified.  
Symbol  
Parameter  
Conditions  
Min  
Typ  
Max  
Units  
CMOS/TTL DC SPECIFICATIONS  
VIH  
VIL  
High Level Input Voltage  
Low Level Input Voltage  
High Level Output Voltage  
Low Level Output Voltage  
Input Clamp Voltage  
2.0  
GND  
3.8  
VCC  
0.8  
V
V
VOH  
VOL  
VCL  
IIN  
IOH = −0.4 mA  
IOL = 2 mA  
4.9  
0.1  
V
0.3  
−1.5  
10  
V
ICL = −18 mA  
−0.79  
5.1  
V
Input Current  
VIN = VCC, GND, 2.5V or 0.4V  
VOUT = 0V  
µA  
mA  
IOS  
Output Short Circuit Current  
−120  
LVDS DRIVER DC SPECIFICATIONS  
VOD  
Differential Output Voltage  
Change in VOD between  
Complimentary Output States  
Offset Voltage  
RL = 100  
250  
1.1  
290  
450  
35  
mV  
mV  
VOD  
VOS  
1.25  
1.375  
35  
V
VOS  
Change in Magnitude of VOS  
between Complimentary Output  
States  
mV  
IOS  
IOZ  
Output Short Circuit Current  
Output TRI-STATE® Current  
VOUT = 0V, R = 100Ω  
−2.9  
1
−5  
10  
mA  
µA  
L
Powerdown = 0V, VOUT = 0V or VCC  
LVDS RECEIVER DC SPECIFICATIONS  
VTH  
VTL  
IIN  
Differential Input High Threshold  
Differential Input Low Threshold  
Input Current  
VCM = +1.2V  
+100  
mV  
mV  
µA  
−100  
VIN = +2.4V, VCC = 5.0V  
VIN = 0V, VCC = 5.0V  
10  
10  
µA  
TRANSMITTER SUPPLY CURRENT  
ICCTW  
Transmitter Supply Current  
Worst Case  
RL = 100, C = 5 pF,  
f = 32.5 MHz  
49  
51  
70  
63  
64  
84  
mA  
mA  
mA  
L
Worst Case Pattern  
(Figure 1 and Figure 2 )  
Powerdown = Low  
f = 37.5 MHz  
f = 66 MHz  
ICCTZ  
Transmitter Supply Current  
3
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Electrical Characteristics (Continued)  
Over recommended operating supply and temperature ranges unless otherwise specified.  
Symbol  
Parameter  
Conditions  
Min  
Typ  
Max  
Units  
TRANSMITTER SUPPLY CURRENT  
Power Down  
Driver Outputs in TRI-STATE under  
Powerdown Mode  
1
25  
µA  
RECEIVER SUPPLY CURRENT  
ICCRW  
Receiver Supply Current  
Worst Case  
CL = 8 pF,  
f = 32.5 MHz  
64  
70  
77  
85  
mA  
mA  
mA  
Worst Case Pattern  
(Figure 1 and Figure 3 )  
Powerdown = Low  
f = 37.5 MHz  
f = 66 MHz  
110  
140  
ICCRZ  
Receiver Supply Current  
Power Down  
Receiver Outputs in Previous State during  
Power Down Mode.  
1
10  
µA  
Note 1: “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. The tables of “Electrical Characteristics” specify conditions for device operation.  
Note 2: Typical values are given for V  
= 5.0V and T = +25˚C.  
A
CC  
Note 3: 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 V and V ).  
OD  
OD  
Note 4: ESD Rating: HBM (1.5 k, 100 pF)  
PLL V 1000V  
CC  
All Other Pins 2000V  
EIAJ (0, 200 pF) 150V  
Note 5: V  
previously referred as V  
.
CM  
OS  
Transmitter Switching Characteristics  
Over recommended operating supply and temperature ranges unless otherwise specified  
Symbol  
LLHT  
Parameter  
LVDS Low-to-High Transition Time (Figure 2 )  
LVDS High-to-Low Transition Time (Figure 2 )  
TxCLK IN Transition Time (Figure 4 )  
Min  
Typ  
0.75  
0.75  
Max  
1.5  
Units  
ns  
ns  
ns  
ps  
ns  
ns  
ns  
ns  
ns  
ns  
ns  
ns  
ns  
ns  
ns  
ns  
ns  
ms  
ns  
LHLT  
1.5  
TCIT  
8
TCCS  
TxOUT Channel-to-Channel Skew (Note 6) (Figure 5)  
350  
TPPos0 Transmitter Output Pulse Position for Bit 0 (Figure 16 )  
TPPos1 Transmitter Output Pulse Position for Bit 1  
TPPos2 Transmitter Output Pulse Position for Bit 2  
TPPos3 Transmitter Output Pulse Position for Bit 3  
TPPos4 Transmitter Output Pulse Position for Bit 4  
TPPos5 Transmitter Output Pulse Position for Bit 5  
TPPos6 Transmitter Output Pulse Position for Bit 6  
−0.30  
1.70  
3.60  
5.90  
8.30  
10.40  
12.70  
15  
0
0.30  
2.50  
4.50  
6.75  
9.00  
11.10  
13.40  
50  
(1/7)Tclk  
(2/7)Tclk  
(3/7)Tclk  
(4/7)Tclk  
(5/7)Tclk  
(6/7)Tclk  
T
f = 66 MHz  
TCIP  
TxCLK IN Period (Figure 6 )  
TCIH  
TxCLK IN High Time (Figure 6 )  
TxCLK IN Low Time (Figure 6 )  
TxIN Setup to TxCLK IN (Figure 6 )  
TxIN Hold to TxCLK IN (Figure 6 )  
0.35T  
0.35T  
5
0.5T  
0.65T  
0.65T  
TCIL  
0.5T  
TSTC  
THTC  
TCCD  
TPLLS  
TPDD  
3.5  
2.5  
1.5  
@
TxCLK IN to TxCLK OUT Delay 25˚C, VCC = 5.0V (Figure 8 )  
3.5  
8.5  
10  
Transmitter Phase Lock Loop Set (Figure 10 )  
Transmitter Powerdown Delay (Figure 14 )  
100  
Note 6: This limit based on bench characterization.  
Receiver Switching Characteristics  
Over recommended operating supply and temperature ranges unless otherwise specified  
Symbol  
CLHT  
Parameter  
CMOS/TTL Low-to-High Transition Time (Figure 3 )  
CMOS/TTL High-to-Low Transition Time (Figure 3 )  
Min  
Typ  
2.5  
2.0  
Max  
4.0  
Units  
ns  
CHLT  
4.0  
ns  
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4
Receiver Switching Characteristics (Continued)  
Over recommended operating supply and temperature ranges unless otherwise specified  
Symbol  
Parameter  
Min  
700  
600  
15  
Typ  
Max  
Units  
ps  
RSKM  
RxIN Skew Margin (Note 7) V  
= 5V,TA = 25˚C(Figure 17)  
f = 40 MHz  
f = 66 MHz  
CC  
ps  
RCOP  
RCOH  
RxCLK OUT Period (Figure 7 )  
T
5
50  
ns  
RxCLK OUT High Time (Figure 7 )  
f = 40 MHz  
f = 66 MHz  
f = 40 MHz  
f = 66 MHz  
f = 40 MHz  
f = 66 MHz  
f = 40 MHz  
f = 66 MHz  
6
ns  
4.3  
10.5  
7.0  
4.5  
2.5  
6.5  
4
ns  
RCOL  
RSRC  
RHRC  
RxCLK OUT Low Time (Figure 7 )  
ns  
9
ns  
RxOUT Setup to RxCLK OUT (Figure 7 )  
RxOUT Hold to RxCLK OUT (Figure 7 )  
ns  
4.2  
5.2  
ns  
ns  
ns  
@
RCCD  
RPLLS  
RPDD  
RxCLK IN to RxCLK OUT Delay 25˚C, VCC = 5.0V (Figure 9 )  
6.4  
10.7  
10  
1
ns  
Receiver Phase Lock Loop Set (Figure 11 )  
Receiver Powerdown Delay (Figure 15 )  
ms  
µs  
Note 7: Receiver Skew Margin is defined as the valid data sampling region at the receiver inputs. This margin takes into account for transmitter output skew (TCCS)  
and the setup and hold time (internal data sampling window), allowing LVDS cable skew dependent on type/length and source clock (TxCLK IN) jitter.  
RSKM cable skew (type, length) + source clock jitter (cycle to cycle)  
AC Timing Diagrams  
01288802  
FIGURE 1. “Worst Case” Test Pattern  
01288803  
01288804  
FIGURE 2. DS90CR213 (Transmitter) LVDS Output Load and Transition Times  
5
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AC Timing Diagrams (Continued)  
01288805  
01288806  
FIGURE 3. DS90CR214 (Receiver) CMOS/TTL Output Load and Transition Times  
01288807  
FIGURE 4. DS90CR213 (Transmitter) Input Clock Transition Time  
01288808  
Note 8: Measurements at V = 0V  
diff  
Note 9: TCSS measured between earliest and latest LVDS edges.  
Note 10: TxCLK Differential Low High Edge  
FIGURE 5. DS90CR213 (Transmitter) Channel-to-Channel Skew  
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6
AC Timing Diagrams (Continued)  
01288809  
FIGURE 6. DS90CR213 (Transmitter) Setup/Hold and High/Low Times  
01288810  
FIGURE 7. DS90CR214 (Receiver) Setup/Hold and High/Low Times  
01288811  
FIGURE 8. DS90CR213 (Transmitter) Clock In to Clock Out Delay  
01288812  
FIGURE 9. DS90CR214 (Receiver) Clock In to Clock Out Delay  
7
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AC Timing Diagrams (Continued)  
01288813  
FIGURE 10. DS90CR213 (Transmitter) Phase Lock Loop Set Time  
01288814  
FIGURE 11. DS90CR214 (Receiver) Phase Lock Loop Set Time  
01288815  
FIGURE 12. Seven Bits of LVDS in Once Clock Cycle  
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8
AC Timing Diagrams (Continued)  
01288816  
FIGURE 13. 21 Parallel TTL Data Inputs Mapped to LVDS Outputs  
01288817  
FIGURE 14. Transmitter Powerdown Delay  
01288818  
FIGURE 15. Receiver Powerdown Delay  
9
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AC Timing Diagrams (Continued)  
01288819  
FIGURE 16. Transmitter LVDS Output Pulse Position Measurement  
01288820  
SW — Setup and Hold Time (Internal Data Sampling Window)  
TCCS — Transmitter Output Skew  
RSKM Cable Skew (Type, Length) + Source Clock Jitter (Cycle to Cycle)  
Cable Skew — Typically 10 ps–40 ps per foot  
FIGURE 17. Receiver LVDS Input Skew Margin  
DS90CR213 Pin Description—Channel Link Transmitter  
Pin Name  
TxIN  
I/O  
I
No.  
21  
3
Description  
TTL level inputs.  
TxOUT+  
O
O
I
Positive LVDS differential data output.  
Negative LVDS differentiaI data output.  
TxOUT−  
3
TxCLK IN  
1
TTL level clock input. The rising edge acts as data strobe.  
Positive LVDS differential clock output.  
TxCLK OUT+  
TxCLK OUT−  
O
O
1
1
Negative LVDS differential clock output.  
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10  
DS90CR213 Pin Description—Channel Link Transmitter (Continued)  
Pin Name  
I/O  
No.  
Description  
TTL level input. Assertion (low input) TRI-STATES the outputs, ensuring low current at power  
down.  
PWR DOWN  
I
1
VCC  
I
I
I
I
I
I
4
5
1
2
1
3
Power supply pins for TTL inputs.  
Ground pins for TTL inputs.  
GND  
PLL VCC  
PLL GND  
LVDS VCC  
LVDS GND  
Power supply pin for PLL.  
Ground pins for PLL.  
Power supply pin for LVDS outputs.  
Ground pins for LVDS outputs.  
DS90CR214 Pin Description—Channel Link Receiver  
Pin Name  
RxIN+  
I/O  
No.  
3
Description  
I
I
Positive LVDS differential data inputs.  
Negative LVDS differential data inputs.  
TTL level outputs.  
RxIN−  
3
RxOUT  
O
I
21  
1
RxCLK IN+  
RxCLK IN−  
RxCLK OUT  
PWR DOWN  
VCC  
Positive LVDS differential clock input.  
Negative LVDS differentiaI clock input.  
I
1
O
I
1
TTL level clock output. The rising edge acts as data strobe.  
TTL Ievel input. Locks the previous receiver output state.  
Power supply pins for TTL outputs.  
Ground pins for TTL outputs.  
1
I
4
GND  
I
5
PLL VCC  
PLL GND  
LVDS VCC  
LVDS GND  
I
1
Power supply for PLL.  
I
2
Ground pin for PLL.  
I
1
Power supply pin for LVDS inputs.  
Ground pins for LVDS inputs.  
I
3
284) requires five pairs of signal wires. The ideal cable/  
connector interface would have a constant 100differential  
impedance throughout the path. It is also recommended that  
Applications Information  
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  
@
cable skew remain below 350 ps ( 66 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 pro-  
vides 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 ap-  
plications, 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.  
<
lengths ( 2m), the media electrical performance is less  
critical. For higher speed/long distance applications the me-  
dia’s performance becomes more critical. Certain cable con-  
structions provide tighter skew (matched electrical length  
between the conductors and pairs). Twin-coax for example,  
has been demonstrated at distances as great as 5 meters  
and with the maximum data transfer of 1.38 Gbit/s. Addi-  
tional applications information can be found in the following  
National Interface Application Notes:  
AN = ####  
AN-1041  
Topic  
Introduction to Channel Link  
PCB Design Guidelines for LVDS and  
Link Devices  
AN-1035  
AN-806  
AN-905  
Transmission Line Theory  
Transmission Line Calculations and  
Differential Impedance  
AN-916  
Cable Information  
The high-speed transport of LVDS signals has been demon-  
strated 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  
CABLES  
A cable interface between the transmitter and receiver needs  
to support the differential LVDS pairs. The 21-bit CHANNEL  
LINK chipset (DS90CR213/214) requires four pairs of signal  
wires and the 28-bit CHANNEL LINK chipset (DS90CR283/  
11  
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TERMINATION  
Applications Information (Continued)  
Use of current mode drivers requires a terminating resistor  
across the receiver inputs. The CHANNEL LINK chipset will  
normally require a single 100resistor 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 imped-  
ance (90to 120typical) of the cable. Figure 18 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.  
the design considerations discussed here and listed in the  
supplemental application notes provide the subsystem com-  
munications designer with many useful guidelines. It is rec-  
ommended that the designer assess the tradeoffs of each  
application thoroughly to arrive at a reliable and economical  
cable solution.  
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 differ-  
ential 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 line of the  
differential pair. Care should be taken to ensure that the  
differential trace impedance match the differential imped-  
ance of the selected physical media (this impedance should  
also match the value of the termination resistor that is con-  
nected 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.  
DECOUPLING CAPACITORS  
Bypassing capacitors are needed to reduce the impact of  
switching noise which could limit performance. For a conser-  
vative approach three parallel-connected decoupling capaci-  
tors (Multi-Layered Ceramic type in surface mount form fac-  
tor) between each VCC and the ground plane(s) are  
recommended. The three capacitor values are 0.1 µF,  
0.01µF and 0.001 µF. An example is shown in Figure 19. 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 ca-  
pacitors, the PLL VCC should receive the most filtering/  
bypassing. Next would be the LVDS VCC pins and finally the  
logic VCC pins.  
UNUSED INPUTS  
All unused inputs at the TxIN inputs of the transmitter must  
be tied to ground. All unused outputs at the RxOUT outputs  
of the receiver must then be left floating.  
01288824  
FIGURE 18. LVDS Serialized Link Termination  
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12  
COMMON MODE vs. DIFFERENTIAL MODE NOISE  
MARGIN  
Applications Information (Continued)  
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 dif-  
ferential 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.  
POWER SEQUENCING AND POWERDOWN MODE  
Outputs of the CHANNEL LINK transmitter remain in TRI-  
STATE until the power supply reaches 3V. Clock and data  
outputs will begin to toggle 10 ms after VCC has reached  
4.5V and the Powerdown pin is above 2V. 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).  
01288825  
FIGURE 19. CHANNEL LINK  
Decoupling Configuration  
CLOCK JITTER  
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  
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 66 MHz clock  
has a period of 15 ns which results in a data bit width of 2.16  
ns. Differential skew (t within one differential pair), intercon-  
nect skew (t 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.  
shorted to V  
through an internal diode. Current is limited  
CC  
(5 mA per input) by the fixed current mode drivers, thus  
avoiding the potential for latchup when powering the device.  
13  
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Applications Information (Continued)  
01288826  
FIGURE 20. Single-Ended and Differential Waveforms  
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14  
Physical Dimensions inches (millimeters) unless otherwise noted  
48-Lead Molded Thin Shrink Small Outline Package, JEDEC  
NS Package Number MTD48  
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