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DS90CR286AT-Q1
SNLS498A – NOVEMBER 2015 – REVISED DECEMBER 2015
DS90CR286AT-Q1 3.3 V Rising Edge Data Strobe
LVDS Receiver 28-Bit Channel Link 66 MHz
1 Features
3 Description
•
•
•
•
The DS90CR286AT-Q1 receiver converts four LVDS
(Low Voltage Differential Signaling) data streams
back into parallel 28 bits of LVCMOS data. The
receiver data outputs strobe on the output clock's
rising edge.
1
•
•
•
•
•
•
•
20 to 66 MHz Shift Clock Support
50% Duty Cycle on Receiver Output Clock
Best–in–Class Setup & Hold Times on Rx Outputs
Rx Power Consumption < 270 mW (typ) at 66
MHz Worst Case
Rx Power-down Mode < 200 μW (max)
ESD Rating: 4 kV (HBM), 1 kV (CDM)
PLL Requires No External Components
Compatible with TIA/EIA-644 LVDS Standard
Low Profile 56-Pin DGG (TSSOP) Package
Operating Temperature: −40°C to +105°C
Automotive AEC-Q100 Grade 2 Qualified
The receiver LVDS clock operates at rates from 20 to
66 MHz. The DS90CR286AT-Q1 phase-locks to the
input LVDS clock, samples the serial bit streams at
the LVDS data lines, and converts them into 28-bit
parallel output data. At an incoming clock rate of 66
MHz, each LVDS input line is running at a bit rate of
462 Mbps, resulting in a maximum throughput of
1.848 Gbps.
The DS90CR286AT-Q1 device is enhanced over
prior generation receivers due to a wider data valid
time on the receiver output. The DS90CR286AT-Q1
is designed for PCB board chip-to-chip OpenLDI-toRGB bridge conversion. LVDS data transmission over
cable interconnect is not recommended for this
device.
2 Applications
•
•
•
•
•
•
Video Displays
Automotive Infotainment
Industrial Printers and Imaging
Digital Video Transport
Machine Vision
OpenLDI-to-RGB Bridge
Users designing a sub-system with a compatible
OpenLDI transmitter and DS90CR286AT-Q1 receiver
must ensure an acceptable skew margin budget
(RSKM). Details regarding RSKM can be found in the
Application Information section.
Device Information(1)
PART NUMBER
PACKAGE
BODY SIZE (NOM)
DS90CR286AT-Q1
TSSOP (56)
14.00 mm × 6.10 mm
(1) For all available packages, see the orderable addendum at
the end of the data sheet.
Typical Application Block Diagram
PCB Trace
DS90CR286AT-Q1 28-Bit Rx
24-Bit RGB Display Unit
RxOUT[27:0]
100 Q
28-Bit Tx Data
(4 LVDS Data, 1 LVDS Clock)
100 Q
Graphics Processor Unit (GPU)
4 x LVDS-to- 28-Bit LVCMOS
100 Q
100 Q
LVDS Data
100 Q
LVDS Clock
RxCLK
PLL
1
An IMPORTANT NOTICE at the end of this data sheet addresses availability, warranty, changes, use in safety-critical applications,
intellectual property matters and other important disclaimers. PRODUCTION DATA.
DS90CR286AT-Q1
SNLS498A – NOVEMBER 2015 – REVISED DECEMBER 2015
www.ti.com
Table of Contents
1
2
3
4
5
6
Features ..................................................................
Applications ...........................................................
Description .............................................................
Revision History.....................................................
Pin Configuration and Functions .........................
Specifications.........................................................
6.1
6.2
6.3
6.4
6.5
6.6
6.7
7
1
1
1
2
3
4
Absolute Maximum Ratings ...................................... 4
ESD Ratings.............................................................. 4
Recommended Operating Conditions....................... 4
Thermal Information .................................................. 4
Electrical Characteristics........................................... 5
Switching Characteristics .......................................... 6
Typical Characteristics ............................................ 10
Detailed Description ............................................ 12
7.1 Overview ................................................................. 12
7.2 Functional Block Diagram ....................................... 12
7.3 Feature Description................................................. 12
7.4 Device Functional Modes........................................ 13
8
Application and Implementation ........................ 14
8.1 Application Information............................................ 14
8.2 Typical Application ................................................. 14
9 Power Supply Recommendations...................... 19
10 Layout................................................................... 19
10.1 Layout Guidelines ................................................. 19
10.2 Layout Example .................................................... 19
11 Device and Documentation Support ................. 21
11.1
11.2
11.3
11.4
11.5
Documentation Support .......................................
Community Resources..........................................
Trademarks ...........................................................
Electrostatic Discharge Caution ............................
Glossary ................................................................
21
21
21
21
21
12 Mechanical, Packaging, and Orderable
Information ........................................................... 21
4 Revision History
Changes from Original (November 2015) to Revision A
•
2
Page
Changed Product Preview to full datasheet Production Data release ................................................................................... 1
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SNLS498A – NOVEMBER 2015 – REVISED DECEMBER 2015
5 Pin Configuration and Functions
DGG Package
56-Pin TSSOP
Top View
Pin Functions
PIN
I/O , TYPE
PIN DESCRIPTION
10, 9,
12, 11,
16, 15,
20, 19
I, LVDS
Positive and negative LVDS differential data inputs. 100 Ω termination resistors
should be placed between RxIN+ and RxIN- receiver inputs as close as
possible to the receiver pins for proper signaling.
RxCLKIN+,
RxCLKIN-
18,
17
I, LVDS
Positive and negative LVDS differential clock input. 100 Ω termination resistor
should be placed between RxCLKIN+ and RxCLKIN- receiver inputs as close
as possible to the receiver pins for proper signaling.
RxOUT[27:0]
7, 6, 5, 3,
2, 1, 55, 54,
53, 51, 50, 49,
47, 46, 45, 43,
42, 41, 39, 38,
37, 35, 34, 33,
32, 30, 29, 27
O, LVCMOS
LVCMOS level data outputs.
RxCLK OUT
26
O, LVCMOS
LVCMOS Ievel clock output. The rising edge acts as the data strobe.
PWR DWN
25
I, LVCMOS
LVCMOS level input. When asserted low, the receiver outputs are low.
VCC
56, 48, 40, 31
Power
Power supply pins for LVCMOS outputs.
GND
52, 44, 36,
28, 4
Power
Ground pins for LVCMOS outputs.
PLL VCC
23
Power
Power supply for PLL.
PLL GND
24, 22
Power
Ground pin for PLL.
LVDS VCC
13
Power
Power supply pin for LVDS inputs.
LVDS GND
21, 14, 8
Power
Ground pins for LVDS inputs.
NAME
RxIN0+,
RxIN1+,
RxIN2+,
RxIN3+,
RxIN0-,
RxIN1-,
RxIN2-,
RxIN3-
NO.
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6 Specifications
6.1 Absolute Maximum Ratings
over operating free-air temperature range (unless otherwise noted)
(1)
MIN
MAX
UNIT
Supply Voltage (VCC)
−0.3
4
V
LVCMOS Output Voltage
−0.3
(VCC + 0.3)
V
LVDS Receiver Input Voltage
−0.3
(VCC + 0.3)
V
150
°C
260
°C
150
°C
Operating Junction Temperature
Lead Temperature (Soldering, 4 sec)
−65
Storage temperature, Tstg
(1)
Stresses beyond those listed under Absolute Maximum Ratings may cause permanent damage to the device. These are stress ratings
only, which do not imply functional operation of the device at these or any other conditions beyond those indicated under Recommended
Operating Conditions. Exposure to absolute-maximum-rated conditions for extended periods may affect device reliability.
6.2 ESD Ratings
VALUE
V(ESD)
(1)
Electrostatic discharge
Human-body model (HBM), per AEC Q100-002 (1)
±4000
Charged-device model (CDM), per AEC Q100-011
±1000
UNIT
V
AEC Q100-002 indicates that HBM stressing shall be in accordance with the ANSI/ESDA/JEDEC JS-001 specification.
6.3 Recommended Operating Conditions
over operating free-air temperature range (unless otherwise noted)
MIN
NOM
MAX
UNIT
Supply Voltage (VCC)
3.0
3.3
3.6
V
Operating Free Air Temperature (TA)
−40
25
105
°C
Receiver Input Range
0
Supply Noise Voltage (VNoise)
2.4
V
100
mVp-p
6.4 Thermal Information
DS90CR286AT-Q1
THERMAL METRIC
(1)
DGG (TSSOP)
UNIT
56 PINS
RθJA
Junction-to-ambient thermal resistance
64.6
RθJC(top)
Junction-to-case (top) thermal resistance
20.6
RθJB
Junction-to-board thermal resistance
33.3
ψJT
Junction-to-top characterization parameter
1.0
ψJB
Junction-to-board characterization parameter
33.0
(1)
4
°C/W
For more information about traditional and new thermal metrics, see the IC Package Thermal Metrics application report, SPRA953.
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6.5 Electrical Characteristics (1) (2)
over operating free-air temperature range (unless otherwise noted)
PARAMETER
TEST CONDITIONS
MIN
TYP
MAX
UNIT
LVCMOS DC SPECIFICATIONS (For PWR DWN Pin)
VIH
High Level Input Voltage
2.0
VCC
V
VIL
Low Level Input Voltage
GND
0.8
V
VCL
Input Clamp Voltage
−0.79
−1.5
V
IIN
Input Current
+1.8
+10
μA
ICL = −18 mA
VIN = 0.4 V, 2.5 V or VCC
V IN = GND
−10
2.7
μA
0
LVCMOS DC SPECIFICATIONS
VOH
High Level Output Voltage
IOH = −0.4 mA
VOL
Low Level Output Voltage
IOL = 2 mA
0.06
0.3
V
IOS
Output Short Circuit Current
VOUT = 0 V
−60
−120
mA
+100
mV
3.3
V
LVDS RECEIVER DC SPECIFICATIONS
VTH
Differential Input High
Threshold
VCM = 1.2 V
VTL
Differential Input Low
Threshold
VCM = 1.2 V
IIN
Input Current
ICCRW
Receiver Supply Current
Worst Case
ICCRZ
(1)
(2)
Receiver Supply Current
Power Down
−100
mV
VIN = 2.4 V, VCC = 3.6 V
±10
μA
VIN = 0V , VCC = 3.6 V
±10
μA
CL = 8 pF, Worst Case Pattern,
DS90CR286AT-Q1 (Figure 1
Figure 2), TA=−40°C to 105°C
f = 33 MHz
49
65
mA
f = 40 MHz
53
70
mA
f = 66 MHz
81
105
mA
10
55
μA
PWR DWN = Low; Receiver Outputs Stay Low
during Power Down Mode
Typical values are given for VCC = 3.3 V and TA = 25ºC.
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 ΔV OD).
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6.6 Switching Characteristics
over operating free-air temperature range (unless otherwise noted)
PARAMETER
TEST CONDITIONS
MIN
TYP
MAX
UNIT
CLHT
LVCMOS Low-to-High Transition Time
(Figure 2)
2
5
ns
CHLT
LVCMOS High-to-Low Transition Time
(Figure 2)
1.8
5
ns
RSPos0
Receiver Input Strobe Position for Bit 0
(Figure 8)
1.01
1.4
2.45
ns
RSPos1
Receiver Input Strobe Position for Bit 1
4.52
5.0
5.99
ns
RSPos2
Receiver Input Strobe Position for Bit 2
8.08
8.5
9.35
ns
f = 40 MHz, T = 25ºC
RSPos3
Receiver Input Strobe Position for Bit 3
11.59
11.9
12.89
ns
RSPos4
Receiver Input Strobe Position for Bit 4
15.15
15.6
16.53
ns
RSPos5
Receiver Input Strobe Position for Bit 5
18.86
19.2
20.20
ns
RSPos6
Receiver Input Strobe Position for Bit 6
22.34
22.9
23.91
ns
RSPos0
Receiver Input Strobe Position for Bit 0
(Figure 8)
0.58
1.1
1.55
ns
RSPos1
Receiver Input Strobe Position for Bit 1
2.77
3.3
3.80
ns
RSPos2
Receiver Input Strobe Position for Bit 2
5.01
5.4
5.77
ns
RSPos3
Receiver Input Strobe Position for Bit 3
7.11
7.5
7.88
ns
RSPos4
Receiver Input Strobe Position for Bit 4
9.24
9.7
10.12
ns
RSPos5
Receiver Input Strobe Position for Bit 5
11.44
11.9
12.32
ns
RSPos6
Receiver Input Strobe Position for Bit 6
13.62
14.1
14.50
ns
RSPos0
Receiver Input Strobe Position for Bit 0
(Figure 8)
0.68
1.2
1.64
ns
RSPos1
Receiver Input Strobe Position for Bit 1
2.88
3.4
3.88
ns
RSPos2
Receiver Input Strobe Position for Bit 2
5.08
5.5
5.87
ns
RSPos3
Receiver Input Strobe Position for Bit 3
7.20
7.6
7.98
ns
RSPos4
Receiver Input Strobe Position for Bit 4
9.30
9.7
10.24
ns
RSPos5
Receiver Input Strobe Position for Bit 5
11.50
12.0
12.40
ns
RSPos6
Receiver Input Strobe Position for Bit 6
13.70
14.2
14.57
ns
RSPos0
Receiver Input Strobe Position for Bit 0
(Figure 8)
0.84
1.3
1.74
ns
RSPos1
Receiver Input Strobe Position for Bit 1
3.00
3.6
4.05
ns
RSPos2
Receiver Input Strobe Position for Bit 2
5.14
5.6
6.02
ns
RSPos3
Receiver Input Strobe Position for Bit 3
7.30
7.8
8.14
ns
RSPos4
Receiver Input Strobe Position for Bit 4
9.42
9.9
10.40
ns
RSPos5
Receiver Input Strobe Position for Bit 5
11.59
12.1
12.57
ns
RSPos6
Receiver Input Strobe Position for Bit 6
13.83
14.3
14.73
ns
RCOP
RxCLK OUT Period (Figure 3)
50
ns
RCOH
RxCLK OUT High Time (Figure 3)
RCOL
RxCLK OUT Low Time (Figure 3)
RSRC
RxOUT Setup to RxCLK OUT (Figure 3)
RHRC
f = 66 MHz, T = -40ºC
f = 66 MHz, T = 25ºC
f = 66 MHz, T = 105ºC
15
10.0
12.2
ns
10.0
11.0
ns
6.5
11.6
ns
RxOUT Hold to RxCLK OUT (Figure 3)
6.0
11.6
ns
RCOH
RxCLK OUT High Time (Figure 3)
5.0
7.6
ns
RCOL
RxCLK OUT Low Time (Figure 3)
5.0
6.3
ns
RSRC
RxOUT Setup to RxCLK OUT (Figure 3)
4.5
7.3
ns
RHRC
RxOUT Hold to RxCLK OUT (Figure 3)
4.0
6.3
ns
6
f = 40 MHz
f = 66 MHz
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Switching Characteristics (continued)
over operating free-air temperature range (unless otherwise noted)
PARAMETER
TEST CONDITIONS
MIN
TYP
MAX
UNIT
3.5
5.0
7.5
ns
RCCD
RxCLK IN to RxCLK OUT Delay at 25°C,
VCC = 3.3V (1) (Figure 4)
RPLLS
Receiver Phase Lock Loop Set (Figure 5)
10
ms
RPDD
Receiver Power Down Delay (Figure 7)
1
μs
(1)
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 DS90CR285 transmitter and DS90CR286AT-Q1 receiver is: (T + TCCD) + (2*T + RCCD), where T =
Clock period. If another transmitter is used, the alternative transmitter's TCCD must be used to calculate total latency.
Figure 1. "Worst Case" Test Pattern
LVCMOS Output
Figure 2. LVCMOS Output Load and Transition Times
Figure 3. Setup/Hold and High/Low Times
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Figure 4. Clock In to Clock Out Delay
Figure 5. Phase Lock Loop Set Time
RxCLK IN
(Differential)
RxIN3
(Single-Ended)
RxOUT5-1
RxOUT27-1
RxOUT23
RxOUT17
RxOUT16
RxOUT11
RxOUT10
RxOUT5
RxOUT27
RxIN2
(Single-Ended)
RxOUT20-1
RxOUT19-1
RxOUT26
RxOUT25
RxOUT24
RxOUT22
RxOUT21
RxOUT20
RxOUT19
RxIN1
(Single-Ended)
RxOUT9-1
RxOUT8-1
RxOUT18
RxOUT15
RxOUT14
RxOUT13
RxOUT12
RxOUT9
RxOUT8
RxIN0
(Single-Ended)
RxOUT1-1
RxOUT0-1
RxOUT7
RxOUT6
RxOUT4
RxOUT3
RxOUT2
RxOUT1
RxOUT0
Figure 6. Mapping of 28 LVCMOS Parallel Data to 4D + C LVDS Serialized Data
8
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Figure 7. Power Down Delay
Figure 8. LVDS Input Strobe Position
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6.7 Typical Characteristics
2
4.5
4
Time (ns)
Time (ns)
1.5
1
3.5
3
Max
0.5
Max
2.5
Nominal
Nominal
Min
Min
0
2
±40
±10
20
50
80
110
Temperature (ƒC)
±40
20
50
80
C002
Figure 10. Rx Strobe Position 1 versus Temperature
Operating Frequency: 66 MHz
8.5
6.5
6
8
Time (ns)
5.5
5
Max
4.5
7.5
Max
7
Nominal
Nominal
Min
Min
4
6.5
±40
±10
20
50
80
110
Temperature (ƒC)
±40
20
50
80
110
Temperature (ƒC)
C004
Figure 12. Rx Strobe Position 3 versus Temperature
Operating Frequency: 66 MHz
10.5
13
12.5
Time (ns)
10
Time (ns)
±10
C003
Figure 11. Rx Strobe Position 2 versus Temperature
Operating Frequency: 66 MHz
9.5
12
11.5
Max
9
Max
11
Nominal
Nominal
Min
Min
8.5
10.5
±40
±10
20
50
Temperature (ƒC)
80
110
±40
±10
20
50
Temperature (ƒC)
C005
Figure 13. Rx Strobe Position 4 versus Temperature
Operating Frequency: 66 MHz
10
110
Temperature (ƒC)
Figure 9. Rx Strobe Position 0 versus Temperature
Operating Frequency: 66 MHz
Time (ns)
±10
C001
80
110
C006
Figure 14. Rx Strobe Position 5 versus Temperature
Operating Frequency: 66 MHz
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Typical Characteristics (continued)
15
Time (ns)
14.5
14
Max
13.5
Nominal
Min
13
±40
±10
20
50
80
Temperature (ƒC)
110
C007
LVCMOS Output Amplitude (2.0 V/DIV)
LVCMOS Output Amplitude (2.0 V/DIV)
Figure 15. Rx Strobe Position 6 versus Temperature
Operating Frequency: 66 MHz
Time (5.0 ns/DIV)
Time (20.0 ns/DIV)
Figure 17. Typical RxOUT Timing Diagram at 66 MHz
LVCMOS Output Amplitude (2.0 V/DIV)
LVCMOS Output Amplitude (2.0 V/DIV)
Figure 16. Parallel PRBS-7 on LVCMOS Outputs at 66 MHz
Time (5.0 ns/DIV)
Time (5.0 ns/DIV)
Figure 18. Typical RxOUT Setup Time at 66 MHz
(RSRC = 7.1 ns)
Figure 19. Typical RxOUT Hold Time at 66 MHz
(RHRC = 7.0 ns)
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7 Detailed Description
7.1 Overview
The DS90CR286AT-Q1 is an AEC-Q100 Grade 2 receiver that converts four LVDS (Low Voltage Differential
Signaling) data streams back into parallel 28 bits of LVCMOS data (24 bits of RGB and 4 bits of HSYNC,
VSYNC, DE, and CNTL). An internal PLL locks to the incoming LVDS clock ranging from 20 to 66 MHz. The
locked PLL then ensures a stable clock to sample the output LVCMOS data on the Receiver Clock Out rising
edge. The DS90CR286AT-Q1 features a PWR DWN pin to put the device into low power mode when there is no
active input data.
100 Q
4 x LVDS-to- 28-Bit LVCMOS
100 Q
7.2 Functional Block Diagram
28 x LVCMOS
Outputs
100 Q
100 Q
4 x LVDS Data
(140 to 462 Mbps on
Each LVDS Channel)
100 Q
LVDS Clock
(20 to 66 MHz)
Receiver Clock Out
PLL
PWR DWN
Figure 20. DS90CR286AT-Q1 Block Diagram
7.3 Feature Description
The DS90CR286AT-Q1 consists of several key blocks:
• LVDS Receivers
• Phase Locked Loop (PLL)
• Serial LVDS-to-Parallel LVCMOS Converter
• LVCMOS Drivers
7.3.1 LVDS Receivers
There are five differential LVDS inputs to the DS90CR286AT-Q1. Four of the LVDS inputs contain serialized data
originating from a 28-bit source transmitter. The remaining LVDS input contains the LVDS clock associated with
the data pairs.
12
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Feature Description (continued)
7.3.1.1 Input Termination
The DS90CR286AT-Q1 requires a single 100 Ω terminating resistor across the positive and negative lines on
each differential pair of the receiver input. To prevent reflections due to stubs, this resistor should be placed as
close to the device input pins as possible. Figure 21 shows an example.
RxIN+
TxOUT+
LVDS Interface
TxOUT-
100 Q
RxIN-
Figure 21. LVDS Serialized Link Termination
7.3.2 Phase Locked Loop (PLL)
The Channel Link I devices use an internal PLL to recover the clock transmitted across the LVDS interface. The
recovered clock is then used as a reference to determine the sampling position of the seven serial bits received
per clock cycle. The width of each bit in the serialized LVDS data stream is one-seventh the clock period.
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. Individual bypassing of
each VCC to ground will minimize the noise passed on to the PLL, thus creating a low jitter LVDS clock to
improve the overall jitter budget.
7.3.3 Serial LVDS-to-Parallel LVCMOS Converter
After the PLL locks to the incoming LVDS clock, the receiver deserializes each LVDS differential data pair into
seven parallel LVCMOS data outputs per clock cycle. For the DS90CR286AT-Q1, the LVDS data inputs map to
LVCMOS outputs according to Figure 6.
7.3.4 LVCMOS Drivers
The LVCMOS outputs from the DS90CR286AT-Q1 are the deserialized single-ended data from the serialized
LVDS data pairs. Each LVCMOS output is clocked by the PLL and should be strobed on the RxCLKOUT rising
edge by the endpoint device. All unused DS90CR286AT-Q1 RxOUT outputs can be left floating.
7.4 Device Functional Modes
7.4.1 Power Down Mode
The DS90CR286AT-Q1 receiver may be placed into a power down mode at any time by asserting the PWR
DWN pin (active low). The DS90CR286AT-Q1 is also designed to protect from accidental loss of power to either
the transmitter or receiver. If power to the transmitter 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 loses power, the
receiver inputs are shorted to VCC through an internal diode. Current is limited to 5 mA per input, thus avoiding
the potential for latch-up when powering the device.
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8 Application and Implementation
NOTE
Information in the following applications sections is not part of the TI component
specification, and TI does not warrant its accuracy or completeness. TI’s customers are
responsible for determining suitability of components for their purposes. Customers should
validate and test their design implementation to confirm system functionality.
8.1 Application Information
The DS90CR286AT-Q1 is designed for a wide variety of data transmission applications. The use of serialized
LVDS data lines in these applications allows for efficient signal transmission over a narrow bus width, thereby
reducing cost, power, and space. The DS90CR286AT-Q1 is designed for PCB board chip-to-chip OpenLDI-toRGB (LVDS-to-parallel) bridge conversion. LVDS data transmission over cable interconnect is not recommended
for this device. Users designing a sub-system with a compatible OpenLDI transmitter and DS90CR286AT-Q1
receiver must ensure an acceptable skew margin budget (RSKM).
8.2 Typical Application
PCB Trace
DS90CR286AT-Q1 28-Bit Rx
24-Bit RGB Display Unit
RxOUT[27:0]
100 Q
Graphics Processor Unit (GPU)
100 Q
28-Bit Tx Data
(4 LVDS Data, 1 LVDS Clock)
4 x LVDS-to- 28-Bit LVCMOS
100 Q
100 Q
LVDS Data
100 Q
LVDS Clock
RxCLK
PLL
Figure 22. Typical DS90CR286AT-Q1 Application Block Diagram
8.2.1 Design Requirements
For this design example, ensure that the following requirements are observed.
Table 1. DS90CR286AT-Q1 Design Parameters
DESIGN PARAMETER
Operating Frequency
Bit Resolution
Bit Data Mapping
RSKM (Receiver Skew Margin)
Input Termination for RxIN±
RxIN± Board Trace Impedance
14
DESIGN REQUIREMENTS
LVDS clock must be within 20-66 MHz.
No higher than 24 bpp. The maximum supported resolution is 8-bit RGB.
Determine the appropriate mapping required by the panel display following the
DS90CR286AT-Q1 outputs.
Ensure that there is acceptable margin between Tx pulse position and Rx
strobe position.
100 Ω ± 10% resistor across each LVDS differential pair. Place as close as
possible to IC input pins.
Design differential trace impedance with 100 Ω ± 5%.
LVCMOS Outputs
If unused, leave pins floating. Series resistance on each LVCMOS output
optional to reduce reflections from long board traces. If used, 33 Ω series
resistance is typical.
DC Power Supply Coupling Capacitors
Use a 0.1 µF capacitor to minimize power supply noise. Place as close as
possible to Vcc pins.
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8.2.2 Detailed Design Procedure
To begin the design process with the DS90CR286AT-Q1, determine the following:
•
•
•
•
Operating Frequency
Bit Resolution of the Panel
Bit Mapping from Receiver to Endpoint Panel Display
RSKM Interoperability with Transmitter Pulse Position Margin
8.2.2.1 Bit Resolution and Operating Frequency Compatibility
The bit resolution of the endpoint panel display reveals whether there are enough bits available in the
DS90CR286AT-Q1 to output the required data per pixel. The DS90CR286AT-Q1 has 28 parallel LVCMOS
outputs and can therefore provide a bit resolution up to 24 bpp (bits per pixel). In each clock cycle, the remaining
bits are the three control signals (HSync, VSync, DE) and one spare bit.
The number of pixels per frame and the refresh rate of the endpoint panel display indicate the required operating
frequency of the receiver clock. To determine the required clock frequency, refer to the following formula:
f_Clk = [H_Active + H_Blank] × [V_Active + V_Blank] × f_Vertical
where
•
•
•
•
•
•
H_Active = Active Display Horizontal Lines
H_Blank = Blanking Period Horizontal Lines
V_Active = Active Display Vertical Lines
V_Blank = Blanking Period Vertical Lines
f_Vertical = Refresh Rate (in Hz)
f_Clk = Operating Frequency of LVDS clock
(1)
In each frame, there is a blanking period associated with horizontal rows and vertical columns that are not
actively displayed on the panel. These blanking period pixels must be included to determine the required clock
frequency. Consider the following example to determine the required LVDS clock frequency:
• H_Active = 640
• H_Blank = 40
• V_Active = 480
• V_Blank = 41
• f_Vertical = 59.95 Hz
Thus, the required operating frequency is determined below:
[640 + 40] x [480 + 41] x 59.95 = 21239086 Hz ≈ 21.24 MHz
(2)
Since the operating frequency for the PLL in the DS90CR286AT-Q1 ranges from 20-66 MHz, the
DS90CR286AT-Q1 can support a panel display with the aforementioned requirements.
If the specific blanking interval is unknown, the number of pixels in the blanking interval can be approximated to
20% of the active pixels. The following formula can be used as a conservative approximation for the operating
LVDS clock frequency:
f_Clk ≈ H_Active x V_Active x f_Vertical x 1.2
(3)
Using this approximation, the operating frequency for the example in this section is estimated below:
640 x 480 x 59.95 x 1.2 = 22099968 Hz ≈ 22.10 MHz
(4)
8.2.2.2 Data Mapping between Receiver and Endpoint Panel Display
Ensure that the LVCMOS outputs are mapped to align with the endpoint display RGB mapping requirements
following the deserializer. Two popular mapping topologies for 8-bit RGB data are shown below:
1. LSBs are mapped to RxIN3±.
2. MSBs are mapped to RxIN3±.
The following tables depict how these two popular topologies can be mapped to the DS90CR286AT-Q1 outputs.
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Table 2. 8-Bit Color Mapping with LSBs on RxIN3±
LVDS INPUT
CHANNEL
RxIN0
RxIN1
RxIN2
RxIN3
LVDS BIT STREAM
POSITION
LVCMOS OUTPUT
CHANNEL
COLOR MAPPING
TxIN0
RxOUT0
R2
TxIN1
RxOUT1
R3
TxIN2
RxOUT2
R4
TxIN3
RxOUT3
R5
TxIN4
RxOUT4
R6
TxIN6
RxOUT6
R7
TxIN7
RxOUT7
G2
TxIN8
RxOUT8
G3
TxIN9
RxOUT9
G4
TxIN12
RxOUT12
G5
TxIN13
RxOUT13
G6
TxIN14
RxOUT14
G7
TxIN15
RxOUT15
B2
TxIN18
RxOUT18
B3
TxIN19
RxOUT19
B4
TxIN20
RxOUT20
B5
TxIN21
RxOUT21
B6
TxIN22
RxOUT22
B7
MSB
TxIN24
RxOUT24
HSYNC
Horizontal Sync
TxIN25
RxOUT25
VSYNC
Vertical Sync
TxIN26
RxOUT26
DE
Data Enable
TxIN27
RxOUT27
R0
LSB
TxIN5
RxOUT5
R1
TxIN10
RxOUT10
G0
TxIN11
RxOUT11
G1
TxIN16
RxOUT16
B0
TxIN17
RxOUT17
B1
TxIN23
RxOUT23
GP
COMMENTS
MSB
MSB
LSB
LSB
General Purpose
Table 3. 8-Bit Color Mapping with MSBs on RxIN3±
LVDS INPUT
CHANNEL
RxIN0
RxIN1
16
LVDS BIT STREAM
POSITION
LVCMOS OUTPUT
CHANNEL
COLOR MAPPING
COMMENTS
TxIN0
RxOUT0
R0
LSB
TxIN1
RxOUT1
R1
TxIN2
RxOUT2
R2
TxIN3
RxOUT3
R3
TxIN4
RxOUT4
R4
TxIN6
RxOUT6
R5
TxIN7
RxOUT7
G0
TxIN8
RxOUT8
G1
TxIN9
RxOUT9
G2
TxIN12
RxOUT12
G3
TxIN13
RxOUT13
G4
TxIN14
RxOUT14
G5
TxIN15
RxOUT15
B0
TxIN18
RxOUT18
B1
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LSB
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Table 3. 8-Bit Color Mapping with MSBs on RxIN3± (continued)
LVDS INPUT
CHANNEL
LVDS BIT STREAM
POSITION
LVCMOS OUTPUT
CHANNEL
COLOR MAPPING
TxIN19
RxOUT19
B2
TxIN20
RxOUT20
B3
TxIN21
RxOUT21
B4
TxIN22
RxOUT22
B5
TxIN24
RxOUT24
HSYNC
Horizontal Sync
TxIN25
RxOUT25
VSYNC
Vertical Sync
TxIN26
RxOUT26
DE
Data Enable
TxIN27
RxOUT27
R6
RxIN2
RxIN3
COMMENTS
TxIN5
RxOUT5
R7
TxIN10
RxOUT10
G6
MSB
TxIN11
RxOUT11
G7
TxIN16
RxOUT16
B6
TxIN17
RxOUT17
B7
MSB
TxIN23
RxOUT23
GP
General Purpose
MSB
In situations where the DS90CR286AT-Q1 must support 18 bpp, Table 2 is commonly used. With this mapping,
MSBs of RGB data are retained on RXIN0±, RXIN1±, and RXIN2± while the two LSBs for the original 8-bit RGB
resolution are ignored from RxIN3±.
8.2.2.3 RSKM Interoperability
One of the most important factors when designing the receiver into a system application is assessing how much
RSKM (Receiver Skew Margin) is available. In each LVDS clock cycle, the LVDS data stream carries seven
serialized data bits. Ideally, the Transmit Pulse Position for each bit will occur every (n x T)/7 seconds, where n =
Bit Position and T = LVDS Clock Period. Likewise, ideally the Receive Strobe Position for each bit will occur
every ((n + 0.5) x T)/7 seconds. However, due to the effects of clock jitter and ISI, both LVDS transmitter and
receiver in real systems will have a minimum and maximum pulse and strobe position, respectively, for each bit
position. This concept is illustrated in Figure 23:
Rspos0
min
Tppos0
min
max
Bit 0 Left Margin
Rspos1
max
Ideal Rx Strobe
Position
Tppos1
Bit 0 Right Margin
Bit 1 Left Margin
max
min
min
max
Ideal Rx Strobe
Position
Bit0
Bit 1 Right Margin
Tppos2
max
min
Bit1
Figure 23. RSKM Measurement Example
All left and right margins for Bits 0-6 must be considered in order to determine the absolute minimum for the
whole LVDS bit stream. This absolute minimum corresponds to the RSKM.
To improve RSKM performance between LVDS transmitter and receiver, designers may either advance or delay
the LVDS clock compared to the LVDS data. Moving the LVDS clock compared to the LVDS data can improve
the Rx strobe position compared to the Tx pulse position of the transmitter.
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If there is less left bit margin than right bit margin, the LVDS clock can be delayed so that the Rx strobe position
for incoming data appears to be delayed. If there is less right bit margin than left bit margin, all the LVDS data
pairs can be delayed uniformly so that the LVDS clock and Rx strobe position for incoming data appear to
advance. To delay an LVDS data or clock pair, designers can either add more PCB trace length or install a
capacitor between the LVDS transmitter and receiver. It is important to note that when using these techniques, all
serialized bit positions are shifted right or left uniformly.
When designing the DS90CR286AT-Q1 receiver with a third-party OpenLDI transmitter, users must calculate the
skew margin budget (RSKM) based on the Tx pulse position and the Rx strobe position to ensure error-free
transmission. For more information about calculating RSKM, refer to Application Note SNLA249.
8.2.3 Application Curves
TxIN7
TxIN6
TxIN4
TxIN3
TxIN2
TxIN1
LVDS Differential Clock
(500 mV/DIV)
LVDS Differential Input RxIN0±
(200 mV/DIV)
LVCMOS RXCLKOUT
(2 V/DIV)
LVCMOS RXCLKOUT
(2 V/DIV)
The following application curves are examples taken with a DS90C385 serializer interfacing to a DS90CR286ATQ1 deserializer in nominal temperature (25ºC) at an operating frequency of 66 MHz.
TxIN0
Time (5.0 ns/DIV)
Time (2.5 ns/DIV)
Figure 25. LVDS CLKIN aligned with LVCMOS RxCLKOUT
LVCMOS Amplitude (2 V/DIV)
LVCMOS Amplitude (2 V/DIV)
Figure 24. LVDS RxIN0± aligned with LVCMOS RxCLKOUT
Time (5.0 ns/DIV)
Time (20.0 ns/DIV)
Figure 26. RxOUT and RxCLKOUT Timing Diagram
18
Figure 27. PRBS-7 Output on RxOUT Channels
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9 Power Supply Recommendations
Proper power supply decoupling is important to ensure a stable power supply with minimal power supply noise.
Bypassing capacitors are needed to reduce the impact of switching noise which could limit performance. For a
conservative approach, three parallel-connected decoupling capacitors (Multi-Layered 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. The preferred capacitor size is 0402. An example is shown in Figure 28. The
designer should place bypass capacitors as close as possible to the VCC pins and ensure each capacitor has its
own via to connect the ground plane. If board space is limiting the number of bypass capacitors, the PLL VCC
should receive the most filtering or bypassing. Next would be the LVDS VCC pins and finally the logic VCC pins.
Figure 28. Recommended Bypass Capacitor Decoupling Configuration
10 Layout
10.1 Layout Guidelines
As with any high speed design, board designers must maximize signal integrity by limiting reflections and
crosstalk that can adversely affect high frequency and EMI performance. The following practices are
recommended layout guidelines to optimize device performance.
• Ensure that differential pair traces are always closely coupled to eliminate noise interference from other
signals and take full advantage of the common mode noise canceling effect of the differential signals.
• Maintain equal length on signal traces for a given differential pair.
• Limit impedance discontinuities by reducing the number of vias on signal traces.
• Eliminate any 90º angles on traces and use 45º bends instead.
• If a via must exist on one signal polarity, mirror the via implementation on the other polarity of the differential
pair.
• 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.
• When possible, use short traces for LVDS inputs.
10.2 Layout Example
The following images show an example layout of the DS90CR286AT-Q1. Traces in blue correspond to the top
layer and the traces in green correspond to the bottom layer. Note that differential pair inputs to the
DS90CR286AT-Q1 are tightly coupled and close to the connector pins. In addition, observe that the power
supply decoupling capacitors are placed as close as possible to the power supply pins with through vias in order
to minimize inductance.
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Layout Example (continued)
Figure 29. Example Layout with DS90CR286AT-Q1 (U1).
100-Q >s ^
Terminations close to
RxIN pins
33 Q ^ Œ] • Z •]•š}Œ•
occasionally used to
reduce reflections
Figure 30. Example Layout Close-up.
20
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11 Device and Documentation Support
11.1 Documentation Support
11.1.1 Related Documentation
IC Package Thermal Metrics application report, SPRA953
How to Calculate and Improve Receiver Skew Margin for Channel Link I Devices application note, SNLA249
11.2 Community Resources
The following links connect to TI community resources. Linked contents are provided "AS IS" by the respective
contributors. They do not constitute TI specifications and do not necessarily reflect TI's views; see TI's Terms of
Use.
TI E2E™ Online Community TI's Engineer-to-Engineer (E2E) Community. Created to foster collaboration
among engineers. At e2e.ti.com, you can ask questions, share knowledge, explore ideas and help
solve problems with fellow engineers.
Design Support TI's Design Support Quickly find helpful E2E forums along with design support tools and
contact information for technical support.
11.3 Trademarks
E2E is a trademark of Texas Instruments.
11.4 Electrostatic Discharge Caution
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.
11.5 Glossary
SLYZ022 — TI Glossary.
This glossary lists and explains terms, acronyms, and definitions.
12 Mechanical, Packaging, and Orderable Information
The following pages include mechanical, packaging, and orderable information. This information is the most
current data available for the designated devices. This data is subject to change without notice and revision of
this document. For browser-based versions of this data sheet, refer to the left-hand navigation.
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PACKAGE OPTION ADDENDUM
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10-Dec-2020
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)
DS90CR286ATDGGQ1
ACTIVE
TSSOP
DGG
56
34
RoHS & Green
SN
Level-2-260C-1 YEAR
-40 to 105
DS90CR286ATQ
DGG
DS90CR286ATDGGRQ1
ACTIVE
TSSOP
DGG
56
2000
RoHS & Green
SN
Level-2-260C-1 YEAR
-40 to 105
DS90CR286ATQ
DGG
(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
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