AD8197B [ADI]
4:1 HDMI/DVI Switch with Equalization; 4 : 1 HDMI / DVI开关,具有均衡型号: | AD8197B |
厂家: | ADI |
描述: | 4:1 HDMI/DVI Switch with Equalization |
文件: | 总28页 (文件大小:809K) |
中文: | 中文翻译 | 下载: | 下载PDF数据表文档文件 |
4:1 HDMI/DVI Switch with Equalization
AD8197B
FUNCTIONAL BLOCK DIAGRAM
FEATURES
4 inputs, 1 output HDMI/DVI links
Enables HDMI 1.3-compliant receiver
Pin-to-pin compatible with the AD8197A
4 TMDS channels per link
RESET
PARALLEL
SERIAL
AD8197B
2
2
Supports 250 Mbps to 2.25 Gbps data rates
Supports 25 MHz to 225 MHz pixel clocks
Equalized inputs allow use of long HDMI cables
(20 meters at 2.25 Gbps)
AVCC
DVCC
AMUXVCC
AVEE
DVEE
I2C_SDA
I2C_SCL
CONFIG
INTERFACE
CONTROL
LOGIC
3
I2C_ADDR[2:0]
VTTI
Fully buffered unidirectional inputs/outputs
Per input switchable, 50 Ω on-chip terminations
Switchable output 50 Ω on-chip terminations
Pre-emphasized outputs
Low added jitter
Single-supply operation (3.3 V)
VTTO
4
4
+
IP_A[3:0]
IN_A[3:0]
–
+
4
4
IP_B[3:0]
IN_B[3:0]
4
+
–
OP[3:0]
ON[3:0]
SWITCH
CORE
–
+
4
4
4
IP_C[3:0]
IN_C[3:0]
PE
EQ
–
+
4
4
IP_D[3:0]
IN_D[3:0]
–
HIGH SPEED
BUFFERED
4 auxiliary channels per link
Bidirectional unbuffered inputs/outputs
Flexible supply operation (3.3 V to 5 V)
HDCP standard compatible
VTTI
AUX_A[3:0]
AUX_B[3:0]
AUX_C[3:0]
AUX_D[3:0]
4
4
4
SWITCH
AUX_COM[3:0]
4
CORE
4
Allows switching of DDC bus and 2 additional signals
Output disable feature
LOW SPEED UNBUFFERED
BIDIRECTIONAL
Reduced power dissipation
Removable output termination
Figure 2.
GENERAL DESCRIPTION
Allows building of larger arrays
Two AD8197Bs support HDMI/DVI dual link
Standards compatible: HDMI receiver, HDCP, DVI
Serial (I2C slave) and parallel control interface
100-lead, 14 mm × 14 mm LQFP, Pb-free package
The AD8197B is an HDMI™/DVI switch featuring equalized
TMDS® inputs and pre-emphasized TMDS outputs, ideal for
systems with long cable runs. The AD8197B offers individual
control of the on/off state of the TMDS input termination
resistors via I2C® control. Outputs can be set to a high
APPLICATIONS
impedance state to reduce the power dissipation and/or to allow
the construction of larger arrays using the wire-OR technique.
Multiple input displays
Projectors
The AD8197B is provided in a 100-lead LQFP, Pb-free, surface-
mount package, specified to operate over the −40°C to +85°C
temperature range.
A/V receivers
Set-top boxes
Advanced television (HDTV) sets
PRODUCT HIGHLIGHTS
TYPICAL APPLICATION
GAME CONSOLE
MEDIA CENTER
SET-TOP BOX
1. Supports data rates up to 2.25 Gbps, enabling 1080p deep
color (12-bit color) HDMI formats and greater than UXGA
(1600 × 1200) DVI resolutions.
HDTV SET
HDMI
RECEIVER
DVD PLAYER
2. Input cable equalizer enables use of long cables at the input
(more than 20 meters of 24 AWG cable at 2.25 Gbps).
AD8197B
04:20
3. Auxiliary switch routes a DDC bus and two additional signals
for a single-chip, HDMI 1.3 receive-compliant solution.
Figure 1. Typical HDTV Application
Rev. 0
Information furnished by Analog Devices is believed to be accurate and reliable. However, no
responsibility is assumed by Analog Devices for its use, nor for any infringements of patents or other
rights of third parties that may result from its use. Specifications subject to change without notice. No
license is granted by implication or otherwise under any patent or patent rights of Analog Devices.
Trademarks and registeredtrademarks arethe property of their respective owners.
One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A.
Tel: 781.329.4700
Fax: 781.461.3113
www.analog.com
©2008 Analog Devices, Inc. All rights reserved.
AD8197B
TABLE OF CONTENTS
Features .............................................................................................. 1
Switching/Update Delay............................................................ 16
Parallel Control Interface .............................................................. 17
Serial Interface Configuration Registers ..................................... 18
High Speed Device Modes Register......................................... 19
Auxiliary Device Modes Register............................................. 19
Receiver Settings Register ......................................................... 19
Input Termination Select Register 1 and Register 2 .............. 19
Receive Equalizer Register 1 and Register 2 ........................... 19
Transmitter Settings Register.................................................... 20
Parallel Interface Configuration Registers .................................. 21
High Speed Device Modes Register......................................... 22
Auxiliary Device Modes Register............................................. 22
Applications....................................................................................... 1
Typical Application........................................................................... 1
Functional Block Diagram .............................................................. 1
General Description......................................................................... 1
Product Highlights ........................................................................... 1
Revision History ............................................................................... 2
Specifications..................................................................................... 3
Absolute Maximum Ratings............................................................ 5
Thermal Resistance ...................................................................... 5
Maximum Power Dissipation ..................................................... 5
ESD Caution.................................................................................. 5
Pin Configuration and Function Descriptions............................. 6
Typical Performance Characteristics ............................................. 9
Theory of Operation ...................................................................... 13
Introduction................................................................................ 13
Input Channels............................................................................ 13
Output Channels ........................................................................ 13
Auxiliary Switch.......................................................................... 14
Serial Control Interface.................................................................. 15
Reset ............................................................................................. 15
Write Procedure .......................................................................... 15
Read Procedure........................................................................... 16
Input Termination Resistor Control Register 1
and Register 2.............................................................................. 22
Receive Equalizer Register 1 and Register 2 ........................... 22
Transmitter Settings Register.................................................... 22
Application Information................................................................ 23
Pinout........................................................................................... 23
Cable Lengths and Equalization............................................... 23
PCB Layout Guidelines.............................................................. 24
Outline Dimensions....................................................................... 28
Ordering Guide .......................................................................... 28
REVISION HISTORY
1/08—Revision 0: Initial Version
Rev. 0 | Page 2 of 28
AD8197B
SPECIFICATIONS
TA = 27°C, AVCC = 3.3 V, VTTI = 3.3 V, VTTO = 3.3 V, DVCC = 3.3 V, AMUXVCC = 5 V, AVEE = 0 V, DVEE = 0 V, differential input
swing = 1000 mV, TMDS outputs terminated with external 50 Ω resistors to 3.3 V, unless otherwise noted.
Table 1.
Parameter
Conditions/Comments
Min
Typ Max
Unit
DYNAMIC PERFORMANCE
Maximum Data Rate (DR) per Channel
Bit Error Rate (BER)
Added Deterministic Jitter
Added Random Jitter
Differential Intrapair Skew
Differential Interpair Skew1
EQUALIZATION PERFORMANCE
Receiver (Highest Setting)2
Transmitter (Highest Setting)3
INPUT CHARACTERISTICS
Input Voltage Swing
NRZ
2.25
Gbps
PRBS 223 − 1
10−9
DR ≤ 2.25 Gbps, PRBS 27 − 1, EQ = 12 dB
25
1
1
ps (p-p)
ps (rms)
ps
At output
At output
40
ps
Boost frequency = 825 MHz
Boost frequency = 825 MHz
12
6
dB
dB
Differential
150
AVCC − 800
1200
AVCC
mV
mV
Input Common-Mode Voltage (VICM
OUTPUT CHARACTERISTICS
High Voltage Level
)
Single-ended high speed channel
Single-ended high speed channel
AVCC − 10
AVCC − 600
75
AVCC + 10
mV
Low Voltage Level
Rise/Fall Time (20% to 80%)
AVCC − 400 mV
135 200
ps
INPUT TERMINATION
Resistance
Single-ended
50
Ω
AUXILIARY CHANNELS
On Resistance, RAUX
On Capacitance, CAUX
Input/Output Voltage Range
POWER SUPPLY
AVCC
100
8
Ω
pF
V
DC bias = 2.5 V, ac voltage = 3.5 V, f = 100 kHz
Operating range
DVEE
3
AMUXVCC
3.6
3.3
V
QUIESCENT CURRENT
AVCC
Outputs disabled
30
52
95
5
40
60
44
66
mA
mA
mA
mA
mA
mA
mA
mA
Outputs enabled, no pre-emphasis
Outputs enabled, maximum pre-emphasis
Input termination on4
Output termination on, no pre-emphasis
Output termination on, maximum pre-emphasis 72
3.2
110 122
VTTI
VTTO
40
40
80
7
54
46
90
8
35
DVCC
AMUXVCC
0.01 0.1
POWER DISSIPATION
Outputs disabled
Outputs enabled, no pre-emphasis
Outputs enabled, maximum pre-emphasis
115
384
704
271 361
574 671
910 1050
mW
mW
mW
TIMING CHARACTERISTICS
Switching/Update Delay
High speed switching register: HS_CH
All other configuration registers
200
1.5
ms
ms
ns
RESET Pulse Width
50
Rev. 0 | Page 3 of 28
AD8197B
Parameter
Conditions/Comments
Min
2
Typ Max
Unit
SERIAL CONTROL INTERFACE5
Input High Voltage, VIH
Input Low Voltage, VIL
Output High Voltage, VOH
Output Low Voltage, VOL
PARALLEL CONTROL INTERFACE
Input High Voltage, VIH
Input Low Voltage, VIL
V
V
V
V
0.8
0.4
2.4
2
V
V
0.8
1 Differential interpair skew is measured between the TMDS pairs of a single link.
2 AD8197B output meets the transmitter eye diagram as defined in the DVI Standard Revision 1.0 and the HDMI Standard Revision 1.3.
3 Cable output meets the receiver eye diagram mask as defined in the DVI Standard Revision 1.0 and the HDMI Standard Revision 1.3.
4 Typical value assumes only the selected HDMI/DVI link is active with nominal signal swings and that the unselected HDMI/DVI links are deactivated. Minimum and
maximum limits are measured at the respective extremes of input termination resistance and input voltage swing.
5 The AD8197B is an I2C slave and its serial control interface is based on the 3.3 V I2C bus specification.
Rev. 0 | Page 4 of 28
AD8197B
ABSOLUTE MAXIMUM RATINGS
THERMAL RESISTANCE
Table 2.
θJA is specified for the worst-case conditions: a device soldered
in a 4-layer JEDEC circuit board for surface-mount packages.
θJC is specified for no airflow.
Parameter
Rating
3.7 V
3.7 V
AVCC to AVEE
DVCC to DVEE
DVEE to AVEE
VTTI
VTTO
AMUXVCC
0.3 V
Table 3. Thermal Resistance
AVCC + 0.6 V
AVCC + 0.6 V
5.5 V
Package Type
θJA
θJC
Unit
100-Lead LQFP
56
19
°C/W
Internal Power Dissipation
High Speed Input Voltage
2.2 W
AVCC − 1.4 V < VIN <
AVCC + 0.6 V
MAXIMUM POWER DISSIPATION
The maximum power that can be safely dissipated by the AD8197B
is limited by the associated rise in junction temperature. The
maximum safe junction temperature for plastic encapsulated
devices is determined by the glass transition temperature of the
plastic, approximately 150°C. Temporarily exceeding this limit
may cause a shift in parametric performance due to a change in
the stresses exerted on the die by the package.
High Speed Differential Input Voltage
Low Speed Input Voltage
2.0 V
DVEE − 0.3 V < VIN <
AMUXVCC + 0.6 V
DVEE − 0.3 V < VIN <
DVCC + 0.6 V
−65°C to +125°C
−40°C to +85°C
150°C
I2C and Parallel Logic Input Voltage
Storage Temperature Range
Operating Temperature Range
Junction Temperature
Exceeding a junction temperature of 175°C for an extended
period can result in device failure. To ensure proper operation, it
is necessary to observe the maximum power rating as determined
by the coefficients in Table 3.
Stresses above those listed under Absolute Maximum Ratings
may cause permanent damage to the device. This is a stress
rating only; functional operation of the device at these or any
other conditions above those indicated in the operational
section of this specification is not implied. Exposure to absolute
maximum rating conditions for extended periods may affect
device reliability.
ESD CAUTION
Rev. 0 | Page 5 of 28
AD8197B
PIN CONFIGURATION AND FUNCTION DESCRIPTIONS
1
75
74
73
72
71
70
69
68
67
66
65
64
63
62
61
60
59
58
57
56
55
54
53
52
51
AVCC
IP_C3
IN_C3
AVEE
IP_C2
IN_C2
VTTI
AVCC
PIN 1 INDICATOR
2
IN_B0
3
4
IP_B0
AVEE
IN_B1
IP_B1
VTTI
5
6
7
8
IN_B2
IP_B2
AVEE
IN_B3
IP_B3
AVCC
IN_A0
IP_A0
AVEE
IN_A1
IP_A1
VTTI
IP_C1
IN_C1
AVEE
IP_C0
IN_C0
AVCC
IP_D3
IN_D3
AVEE
IP_D2
IN_D2
VTTI
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
AD8197B
TOP VIEW
(Not to Scale)
IN_A2
IP_A2
AVCC
IN_A3
IP_A3
AVEE
IP_D1
IN_D1
AVCC
IP_D0
IN_D0
AVEE
Figure 3. Pin Configuration
Table 4. Pin Function Descriptions
Pin No.
Mnemonic
Type1
Power
HS I
HS I
Power
HS I
HS I
Power
HS I
HS I
HS I
HS I
HS I
HS I
HS I
HS I
HS I
HS I
Description
Positive Analog Supply. 3.3 V nominal.
1, 13, 22, 54, 63, 75
2
3
AVCC
IN_B0
IP_B0
AVEE
High Speed Input Complement.
High Speed Input.
Negative Analog Supply. 0 V nominal.
High Speed Input Complement.
High Speed Input.
Input Termination Supply. Nominally connected to AVCC.
High Speed Input Complement.
High Speed Input.
High Speed Input Complement.
High Speed Input.
High Speed Input Complement.
High Speed Input.
High Speed Input Complement.
High Speed Input.
High Speed Input Complement.
High Speed Input.
4, 10, 16, 25, 51, 60, 66, 72
5
6
IN_B1
IP_B1
VTTI
7, 19, 57, 69
8
9
IN_B2
IP_B2
IN_B3
IP_B3
IN_A0
IP_A0
IN_A1
IP_A1
IN_A2
IP_A2
11
12
14
15
17
18
20
21
Rev. 0 | Page 6 of 28
AD8197B
Pin No.
23
24
26
27
28
29, 95
30
31
32, 38, 47
33
Mnemonic
IN_A3
IP_A3
I2C_ADDR0
I2C_ADDR1
I2C_ADDR2
DVEE
PP_CH0
PP_CH1
DVCC
Type1
HS I
HS I
Description
High Speed Input Complement.
High Speed Input.
I2C Address 1st LSB.
I2C Address 2nd LSB.
I2C Address 3rd LSB.
Negative Digital and Auxiliary Multiplexer Power Supply. 0 V nominal.
High Speed Source Selection Parallel Interface LSB.
High Speed Source Selection Parallel Interface MSB.
Positive Digital Power Supply. 3.3 V nominal.
High Speed Output Complement.
High Speed Output.
Control
Control
Control
Power
Control
Control
Power
HS O
ON0
OP0
34
HS O
35, 41
36
37
VTTO
ON1
OP1
Power
HS O
HS O
Output Termination Supply. Nominally connected to AVCC.
High Speed Output Complement.
High Speed Output.
39
40
ON2
OP2
HS O
HS O
High Speed Output Complement.
High Speed Output.
42
43
ON3
OP3
HS O
HS O
High Speed Output Complement.
High Speed Output.
44
45
46
48
49
50
52
53
RESET
Control
Control
Control
Control
Control
Control
HS I
Configuration Registers Reset. Normally pulled up to AVCC.
High Speed Pre-Emphasis Selection Parallel Interface LSB.
High Speed Pre-Emphasis Selection Parallel Interface MSB.
High Speed Output Current Level Parallel Interface.
I2C Clock.
PP_PRE0
PP_PRE1
PP_OCL
I2C_SCL
I2C_SDA
IN_D0
I2C Data.
High Speed Input Complement.
High Speed Input.
IP_D0
HS I
55
56
IN_D1
IP_D1
HS I
HS I
High Speed Input Complement.
High Speed Input.
58
59
IN_D2
IP_D2
HS I
HS I
High Speed Input Complement.
High Speed Input.
61
62
IN_D3
IP_D3
HS I
HS I
High Speed Input Complement.
High Speed Input.
64
65
IN_C0
IP_C0
HS I
HS I
High Speed Input Complement.
High Speed Input.
67
68
IN_C1
IP_C1
HS I
HS I
High Speed Input Complement.
High Speed Input.
70
71
IN_C2
IP_C2
HS I
HS I
High Speed Input Complement.
High Speed Input.
73
74
IN_C3
IP_C3
HS I
HS I
High Speed Input Complement.
High Speed Input.
76
77
78
79
80
81
82
83
84
85
86
87
PP_EN
PP_EQ
AUX_D3
AUX_D2
AUX_D1
AUX_D0
AMUXVCC
AUX_C3
AUX_C2
AUX_C1
AUX_C0
AUX_COM3
AUX_COM2
Control
Control
LS I/O
LS I/O
LS I/O
LS I/O
Power
LS I/O
LS I/O
LS I/O
LS I/O
LS I/O
LS I/O
High Speed Output Enable Parallel Interface.
High Speed Equalization Selection Parallel Interface.
Low Speed Input/Output.
Low Speed Input/Output.
Low Speed Input/Output.
Low Speed Input/Output.
Positive Auxiliary Multiplexer Supply. 5 V typical.
Low Speed Input/Output.
Low Speed Input/Output.
Low Speed Input/Output.
Low Speed Input/Output.
Low Speed Common Input/Output.
Low Speed Common Input/Output.
88
Rev. 0 | Page 7 of 28
AD8197B
Pin No.
89
90
91
92
93
94
96
97
Mnemonic
AUX_COM1
AUX_COM0
AUX_B3
AUX_B2
AUX_B1
Type1
LS I/O
LS I/O
LS I/O
LS I/O
LS I/O
LS I/O
LS I/O
LS I/O
LS I/O
LS I/O
Control
Description
Low Speed Common Input/Output.
Low Speed Common Input/Output.
Low Speed Input/Output.
Low Speed Input/Output.
Low Speed Input/Output.
Low Speed Input/Output.
Low Speed Input/Output.
Low Speed Input/Output.
Low Speed Input/Output.
AUX_B0
AUX_A3
AUX_A2
AUX_A1
AUX_A0
PP_OTO
98
99
100
Low Speed Input/Output.
High Speed Output Termination Selection Parallel Interface.
1 HS = high speed, LS = low speed, I = input, O = output.
Rev. 0 | Page 8 of 28
AD8197B
TYPICAL PERFORMANCE CHARACTERISTICS
TA = 27°C, AVCC = 3.3 V, VTTI = 3.3 V, VTTO = 3.3 V, DVCC = 3.3 V, AMUXVCC = 5 V, AVEE = 0 V, DVEE = 0 V, differential input
swing = 1000 mV, TMDS outputs terminated with external 50 Ω resistors to 3.3 V, pattern = PRBS 27 − 1, data rate = 2.25 Gbps, unless
otherwise noted.
HDMI CABLE
AD8197B
DIGITAL
PATTERN
GENERATOR
SERIAL DATA
ANALYZER
EVALUATION
BOARD
SMA COAX CABLE
REFERENCE EYE DIAGRAM AT TP1
TP1
TP2
TP3
Figure 4. Test Circuit Diagram for Rx Eye Diagram
0.125UI/DIV AT 2.25Gbps
0.125UI/DIV AT 2.25Gbps
Figure 5. Rx Eye Diagram at TP2 (Cable = 2 meters, 30 AWG)
Figure 7. Rx Eye Diagram at TP3, EQ = 6 dB (Cable = 2 meters, 30 AWG)
0.125UI/DIV AT 2.25Gbps
0.125UI/DIV AT 2.25Gbps
Figure 6. Rx Eye Diagram at TP2 (Cable = 20 meters, 24 AWG)
Figure 8. Rx Eye Diagram at TP3, EQ = 12 dB (Cable = 20 meters, 24 AWG)
Rev. 0 | Page 9 of 28
AD8197B
TA = 27°C, AVCC = 3.3 V, VTTI = 3.3 V, VTTO = 3.3 V, DVCC = 3.3 V, AMUXVCC = 5 V, AVEE = 0 V, DVEE = 0 V, differential input
swing = 1000 mV, TMDS outputs terminated with external 50 Ω resistors to 3.3 V, pattern = PRBS 27 − 1, data rate = 2.25 Gbps, unless
otherwise noted.
HDMI CABLE
AD8197B
EVALUATION
BOARD
SERIAL DATA
ANALYZER
DIGITAL
PATTERN
GENERATOR
SMA COAX CABLE
REFERENCE EYE DIAGRAM AT TP1
TP1
TP2
TP3
Figure 9. Test Circuit Diagram for Tx Eye Diagrams
0.125UI/DIV AT 2.25Gbps
0.125UI/DIV AT 2.25Gbps
Figure 10. Tx Eye Diagram at TP2, PE = 2 dB
Figure 12. Tx Eye Diagram at TP3, PE = 2 dB (Cable = 2 meters, 30 AWG)
0.125UI/DIV AT 2.25Gbps
0.125UI/DIV AT 2.25Gbps
Figure 11. Tx Eye Diagram at TP2, PE = 6 dB
Figure 13. Tx Diagram at TP3, PE = 6 dB (Cable = 10 meters, 28 AWG)
Rev. 0 | Page 10 of 28
AD8197B
TA = 27°C, AVCC = 3.3 V, VTTI = 3.3 V, VTTO = 3.3 V, DVCC = 3.3 V, AMUXVCC = 5 V, AVEE = 0 V, DVEE = 0 V, differential input
swing = 1000 mV, TMDS outputs terminated with external 50 Ω resistors to 3.3 V, pattern = PRBS 27 − 1, data rate = 2.25 Gbps, unless
otherwise noted.
0.6
0.5
0.4
0.3
0.2
0.1
0
0.6
0.5
0.4
0.3
0.2
0.1
0
2m CABLE = 30AWG
2m CABLE = 30AWG
5m TO 20m CABLES = 24AWG
5m TO 20m CABLES = 24AWG
2.25Gbps
1.65Gbps, PE OFF
EQ = 12dB
1.65Gbps
EQ = 6dB
2.25Gbps, PE OFF
2.25Gbps, PE MAX
2.25Gbps
EQ = 6dB
1.65Gbps
EQ = 12dB
1.65Gbps, PE MAX
15 20
0
5
10
15
20
25
0
5
10
HDMI CABLE LENGTH (m)
HDMI CABLE LENGTH (m)
Figure 14. Jitter vs. Input Cable Length (See Figure 4 for Test Setup)
Figure 17. Jitter vs. Output Cable Length (See Figure 9 for Test Setup)
50
45
40
1200
1000
800
600
400
200
0
35
1080p
8-BIT
30
25
20
15
10
5
1080p
12-BIT
1.65Gbps
480p
480i
1080i/720p
DJ (p-p)
RJ (rms)
0
0
0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6 1.8 2.0 2.2 2.4
DATA RATE (Gbps)
0
0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6 1.8 2.0 2.2 2.4
DATA RATE (Gbps)
Figure 15. Jitter vs. Data Rate
Figure 18. Eye Height vs. Data Rate
50
800
700
600
500
400
300
200
100
0
45
40
35
30
25
20
15
10
5
DJ (p-p)
RJ (rms)
0
3.0
3.1
3.2
3.3
3.4
3.5
3.6
2.5 2.6 2.7 2.8 2.9 3.0 3.1 3.2 3.3 3.4 3.5 3.6
SUPPLY VOLTAGE (V)
SUPPLY VOLTAGE (V)
Figure 16. Jitter vs. Supply Voltage
Figure 19. Eye Height vs. Supply Voltage
Rev. 0 | Page 11 of 28
AD8197B
TA = 27°C, AVCC = 3.3 V, VTTI = 3.3 V, VTTO = 3.3 V, DVCC = 3.3 V, AMUXVCC = 5 V, AVEE = 0 V, DVEE = 0 V, differential input
swing = 1000 mV, TMDS outputs terminated with external 50 Ω resistors to 3.3 V, pattern = PRBS 27 − 1, data rate = 2.25 Gbps, unless
otherwise noted.
50
40
30
20
10
0
50
40
30
20
10
0
DJ (p-p)
DJ (p-p)
RJ (rms)
3.1
RJ (rms)
0.8
0
0.2
0.4
0.6
1.0
1.2
1.4
1.6
1.8
2.0
100
100
2.5
2.7
2.9
3.3
3.5
3.7
DIFFERENTIAL INPUT SWING (V)
INPUT COMMON-MODE VOLTAGE (V)
Figure 20. Jitter vs. Differential Input Swing
Figure 23. Jitter vs. Input Common-Mode Voltage
50
120
115
110
105
100
95
45
40
35
30
25
20
15
10
5
DJ (p-p)
90
85
RJ (rms)
0
–40
80
–40
–20
0
20
40
60
80
–20
0
20
40
60
80
100
TEMPERATURE (°C)
TEMPERATURE (°C)
Figure 21. Jitter vs. Temperature
Figure 24. Differential Input Termination Resistance vs. Temperature
160
140
120
100
80
FALL TIME
RISE TIME
60
40
20
0
–40
–20
0
20
40
60
80
TEMPERATURE (°C)
Figure 22. Rise and Fall Time vs. Temperature
Rev. 0 | Page 12 of 28
AD8197B
THEORY OF OPERATION
this operation, but it is not automatic. To obtain this functionality,
the channel selection and the input termination status must be
separately programmed via the I2C serial control interface.
VTTI
INTRODUCTION
The AD8197B is a pin-to-pin HDMI 1.3 receive-compliant
replacement for the AD8197A. The primary function of the
AD8197B is to switch one of four (HDMI or DVI) single link
sources to one output. Each HDMI/DVI link consists of four
differential, high speed channels and four auxiliary single-
ended, low speed control signals. The high speed channels
include a data-word clock and three transition minimized differ-
ential signaling (TMDS) data channels running at 10× the data-
word clock frequency for data rates up to 2.25 Gbps. The four
low speed control signals are 5 V tolerant bidirectional lines
that can carry configuration signals, HDCP encryption, and
other information, depending upon the specific application.
50Ω
50Ω
IP_xx
IN_xx
CABLE
EQ
AVEE
Figure 25. High Speed Input Simplified Schematic
The input equalizer can be manually configured to provide two
different levels of high frequency boost: 6 dB or 12 dB. The user
can individually control the equalization level of the eight high
speed input channels by selectively programming the associated
RX_EQ bits in the receive equalizer register through the serial
control interface. Alternately, the user can globally control the
equalization level of all eight high speed input channels by
setting the PP_EQ pin of the parallel control interface. No
specific cable length is suggested for a particular equalization
setting because cable performance varies widely between
manufacturers; however, in general, the equalization of the
AD8197B can be set to 12 dB without degrading the signal
integrity, even for short input cables. At the 12 dB setting, the
AD8197B can equalize more than 20 meters of 24 AWG cable at
2.25 Gbps.
All four high speed TMDS channels in a given link are identical;
that is, the pixel clock can be run on any of the four TMDS
channels. Transmit and receive channel compensation is
provided for the high speed channels where the user can
(manually) select among a number of fixed settings.
The AD8197B has two control interfaces. Users have the option
of controlling the part through either the parallel control
interface or the I2C serial control interface. However, the
parallel control interface is not able to control the switch status
of the input termination resistors and therefore has limited
usefulness in practical systems. Most systems use only the I2C
serial interface.
The AD8197B has eight user-programmable I2C slave addresses
to allow multiple AD8197Bs to be controlled by a single I2C bus.
RESET
A
pin is provided to restore the control registers of the
OUTPUT CHANNELS
AD8197B to the parallel control interface and some default
values. In all cases, serial programming values override any
prior parallel programming values, and any use of the serial
control interface disables the parallel control interface until the
AD8197B is reset.
Each high speed output differential pair is terminated to the
3.3 V VTTO power supply through two 50 Ω on-chip resistors
(see Figure 26). This termination is user-selectable; it can be
turned on or off by programming the TX_PTO bit of the
transmitter settings register through the serial control interface,
or by setting the PP_OTO pin of the parallel control interface.
INPUT CHANNELS
Each high speed input differential pair terminates to the 3.3 V
VTTI power supply through a pair of single-ended 50 Ω on-
chip resistors, as shown in Figure 25. The input termination
status for each individual high speed differential (TMDS) input
pair can be controlled by programming the appropriate RX_TO
bit in the receiver settings register. Refer to Table 5 and Table 12.
By default, the input terminations are disabled (switched open)
after reset. The input terminations cannot be switched when
programming the AD8197B through the parallel control
interface. This limits the usefulness of the parallel control
interface.
The output termination resistors of the AD8197B back-
terminate the output TMDS transmission lines. These back-
terminations, as recommended in the HDMI 1.3 specification,
act to absorb reflections from impedance discontinuities on the
output traces, improving the signal integrity of the output traces
and adding flexibility to how the output traces can be routed.
For example, interlayer vias can be used to route the AD8197B
TMDS outputs on multiple layers of the PCB without severely
degrading the quality of the output signal.
The AD8197B output has a disable feature that places the
outputs in a tristate mode. This mode is enabled by program-
ming the HS_EN bit of the high speed device modes register
through the serial control interface or by setting the PP_EN pin
of the parallel control interface. Larger wire-OR’ed arrays can be
constructed using the AD8197B in this mode.
Some systems require that the input terminations be switched
on only for the one selected HDMI source. The input termina-
tions for the three unselected HDMI sources require their input
termination switches to be open. The AD8197B can perform
Rev. 0 | Page 13 of 28
AD8197B
VTTO
When turning off the AD8197B, care needs to be taken with
the AMUXVCC supply to ensure that the auxiliary multiplexer
pins remain in a high impedance state. A scenario that illustrates
this requirement is one where the auxiliary multiplexer is used
to switch the display data channel (DDC) bus. In some applica-
tions, additional devices can be connected to the DDC bus
(such as an EEPROM with EDID information) upstream of the
AD8197B.
50Ω
50Ω
OPx
ONx
DISABLE
AVEE
I
OUT
Extended display identification data (EDID) is a VESA standard-
defined data format for conveying display configuration
information to sources to optimize display use. EDID devices
may need to be available via the DDC bus, regardless of the
state of the AD8197B and any downstream circuit. For this
configuration, the auxiliary inputs of the powered down
AD8197B need to be in a high impedance state to avoid pulling
down on the DDC lines and preventing these other devices
from using the bus.
Figure 26. High Speed Output Simplified Schematic
The AD8197B requires output termination resistors when the
high speed outputs are enabled. Termination can be internal
and/or external. The internal terminations of the AD8197B are
enabled by programming the TX_PTO bit of the transmitter
settings register or by setting the PP_OTO pin of the parallel
control interface. The internal terminations of the AD8197B
default to the setting indicated by PP_OTO upon reset. External
terminations can be provided either by on-board resistors or by
the input termination resistors of an HDMI/DVI receiver. If
both the internal terminations are enabled and external termi-
nations are present, set the output current level to 20 mA by
programming the TX_OCL bit of the transmitter settings
register through the serial control interface or by setting the
PP_OCL pin of the parallel control interface. The output
current level defaults to the level indicated by PP_OCL upon
reset. If only external terminations are provided (if the internal
terminations are disabled), set the output current level to 10 mA
by programming the TX_OCL bit of the transmitter settings
register or by setting the PP_OCL pin of the parallel control
interface. The high speed outputs must be disabled if there are
no output termination resistors present in the system.
The AD8197B requires +5 V on its supply pin, AMUXVCC, in
order for the AUXMUX channels to be high impedance. When
a TV is powered off, it cannot provide such a supply. However,
it can be provided from any HDMI source that is plugged into
it. A Schottky diode network, as shown in Figure 28, uses the
5 V supply (Pin 18) from any HDMI/DVI source to power
AMUXVCC and guarantee high impedance of the auxiliary
multiplexer pins. The AMUXVCC supply does not draw any
significant static current. The use of diodes ensures that
connected HDMI sources do not load this circuit if their +5 V
pin is low impedance when powered off. The 100 kꢀ resistor
ensures that a minimum of current flows through the diodes to
keep them forward biased.
This precaution does not need to be taken if the DDC
peripheral circuitry is connected to the bus downstream of
the AD8197B.
The output pre-emphasis can be manually configured to provide
one of four different levels of high frequency boost. The specific
boost level is selected by programming the TX_PE bits of the
transmitter settings register through the serial control interface,
or by setting the PP_PE bus of the parallel control interface. No
specific cable length is suggested for a particular pre-emphasis
setting because cable performance varies widely between
manufacturers.
+5V INTERNAL
(IF ANY)
PIN 18 HDMI CONNECTOR
PIN 14 DVI CONNECTOR
PIN 18 HDMI CONNECTOR
PIN 14 DVI CONNECTOR
BAT54L
BAT54L
BAT54L
SOURCE A +5V
+5V SOURCE C
I<50mA
I<50mA
AMUXVCC
AUXILIARY SWITCH
PERIPHERAL
CIRCUITRY
PERIPHERAL
CIRCUITRY
AD8197B
The auxiliary (low speed) lines have no amplification. They are
routed using a passive switch that is bandwidth compatible with
standard speed I2C. The schematic equivalent for this passive
connection is shown in Figure 27.
PERIPHERAL
CIRCUITRY
PERIPHERAL
CIRCUITRY
100kΩ
I<50mA
I<50mA
R
SOURCE B +5V
+5V SOURCE D
AUX
AUX_A0
½C
AUX_COM0
½C
BAT54L
BAT54L
PIN 18 HDMI CONNECTOR
PIN 14 DVI CONNECTOR
PIN 18 HDMI CONNECTOR
PIN 14 DVI CONNECTOR
AUX
AUX
Figure 28. Suggested AMUXVCC Power Scheme
Figure 27. Auxiliary Channel Simplified Schematic,
AUX_A0 to AUX_COM0 Routing Example
Rev. 0 | Page 14 of 28
AD8197B
SERIAL CONTROL INTERFACE
3. Send the write indicator bit (0).
RESET
4. Wait for the AD8197B to acknowledge the request.
On initial power-up, or at any point in operation, the AD8197B
register set can be restored to the status of the parallel control
interface pins and some preprogrammed default values by
5. Send the register address (eight bits) to which data is to be
written. This transfer should be MSB first.
RESET
pulling the
pin to low, in accordance with the specifica-
RESET
6. Wait for the AD8197B to acknowledge the request.
tions in Table 1. During normal operation, however, the
7. Send the data (eight bits) to be written to the register
whose address was set in Step 5. This transfer should be
MSB first.
pin must be pulled up to 3.3 V. Following a reset, the prepro-
grammed default values of the AD8197B register set correspond
to the state of the parallel interface configuration registers and
defaults, as listed in Table 18. The AD8197B can be controlled
through the parallel control interface until the first serial
control event occurs. As soon as any serial control event occurs,
the serial programming values, corresponding to the state of the
serial interface configuration registers (Table 5), override any
prior parallel programming values, and the parallel control
interface is disabled until the part is subsequently reset.
8. Wait for the AD8197B to acknowledge the request.
9. Perform one of the following:
9a. Send a stop condition (while holding the I2C_SCL
line high, pull the I2C_SDA line high) and release
control of the bus to end the transaction (shown in
Figure 29).
9b. Send a repeated start condition (while holding the
I2C_SCL line high, pull the I2C_SDA line low) and
continue with Step 2 in this procedure to perform
another write.
Note that the input termination resistor switch control is only
via I2C control. Therefore, any system that requires control of
these switches cannot operate in parallel control mode.
WRITE PROCEDURE
9c. Send a repeated start condition (while holding the
I2C_SCL line high, pull the I2C_SDA line low) and
continue with Step 2 of the read procedure (in the
Read Procedure section) to perform a read from
another address.
To write data to the AD8197B register set, an I2C master (such
as a microcontroller) needs to send the appropriate control
signals to the AD8197B slave device. The signals are controlled
by the I2C master, unless otherwise specified. For a diagram of
the procedure, see Figure 29. The steps for a write procedure are
as follows:
9d. Send a repeated start condition (while holding the
I2C_SCL line high, pull the I2C_SDA line low) and
continue with Step 8 of the read procedure (in the
Read Procedure section) to perform a read from the
same address set in Step 5.
1. Send a start condition (while holding the I2C_SCL line
high, pull the I2C_SDA line low).
2. Send the AD8197B part address (seven bits). The upper
four bits of the AD8197B part address are the static value
[1001] and the three LSBs are set by Input Pin I2C_ADDR2,
Input Pin I2C_ADDR1, and Input Pin I2C_ADDR0 (LSB).
This transfer should be MSB first.
*
I2C_SCL
R/W
GENERAL CASE
I2C_SDA
FIXED PART
ADDR
START
ADDR
REGISTER ADDR
DATA
STOP
ACK
ACK
ACK
EXAMPLE
I2C_SDA
1
2
3
4
5
6
7
8
9
*THE SWITCHING/UPDATE DELAY BEGINS AT THE FALLING EDGE OF THE
LAST DATA BIT; FOR EXAMPLE, THE FALLING EDGE JUST BEFORE STEP 8.
Figure 29. I2C Write Diagram
Rev. 0 | Page 15 of 28
AD8197B
I2C_SCL
R/W
R/W
FIXED PART
ADDR
FIXED PART
ADDR
GENERAL CASE
I2C_SDA
START
ADDR
REGISTER ADDR
SR
ADDR
DATA
STOP
ACK
ACK
6
ACK
ACK
12
EXAMPLE
I2C_SDA
1
2
3
4
5
7
8
9
10 11
13
Figure 30. I2C Read Diagram
13. Perform one of the following:
READ PROCEDURE
To read data from the AD8197B register set, an I2C master
(such as a microcontroller) needs to send the appropriate
control signals to the AD8197B slave device. The signals are
controlled by the I2C master, unless otherwise specified. For a
diagram of the procedure, see Figure 30. The steps for a read
procedure are as follows:
13a. Send a stop condition (while holding the I2C_SCL
line high, pull the SDA line high) and release control
of the bus to end the transaction (shown in Figure 30).
13b. Send a repeated start condition (while holding the
I2C_SCL line high, pull the I2C_SDA line low) and
continue with Step 2 of the write procedure (previous
Write Procedure section) to perform a write.
1. Send a start condition (while holding the I2C_SCL line
high, pull the I2C_SDA line low).
13c. Send a repeated start condition (while holding the
I2C_SCL line high, pull the I2C_SDA line low) and
continue with Step 2 of this procedure to perform a
read from another address.
2. Send the AD8197B part address (seven bits). The upper
four bits of the AD8197B part address are the static value
[1001] and the three LSBs are set by Input Pin
I2C_ADDR2, Input Pin I2C_ADDR1, and Input Pin
I2C_ADDR0 (LSB). This transfer should be MSB first.
13d. Send a repeated start condition (while holding the
I2C_SCL line high, pull the I2C_SDA line low) and
continue with Step 8 of this procedure to perform a
read from the same address.
3. Send the write indicator bit (0).
4. Wait for the AD8197B to acknowledge the request.
SWITCHING/UPDATE DELAY
5. Send the register address (eight bits) from which data is to
be read. This transfer should be MSB first.
There is a delay between when a user writes to the configura-
tion registers of the AD8197B and when that state change takes
physical effect. This update delay occurs regardless of whether
the user programs the AD8197B via the serial or the parallel
control interface. When using the serial control interface, the
update delay begins at the falling edge of I2C_SCL for the last
data bit transferred, as shown in Figure 29. When using the
parallel control interface, the update delay begins at the transition
edge of the relevant parallel interface pin. This update delay is
register-specific and the times are specified in Table 1.
6. Wait for the AD8197B to acknowledge the request.
7. Send a repeated start condition (Sr) by holding the
I2C_SCL line high and pulling the I2C_SDA line low.
8. Resend the AD8197B part address (seven bits) from Step 2.
The upper four bits of the AD8197B part address are the
static value [1001] and the three LSBs are set by the Input
Pin I2C_ADDR2, I2C_ADDR1 and Input Pin I2C_ADDR0
(LSB). This transfer should be MSB first.
9. Send the read indicator bit (1).
During a delay window, new values can be written to the
configuration registers, but the AD8197B does not physically
update until the end of that register’s delay window. Writing
new values during the delay window does not reset the window;
new values supersede the previously written values. At the end
of the delay window, the AD8197B physically assumes the state
indicated by the last set of values written to the configuration
registers. If the configuration registers are written after the delay
window ends, the AD8197B immediately updates and a new
delay window begins.
10. Wait for the AD8197B to acknowledge the request.
11. The AD8197B serially transfers the data (eight bits) held in
the register indicated by the address set in Step 5. This data
is sent MSB first.
12. Acknowledge the data from the AD8197B.
Rev. 0 | Page 16 of 28
AD8197B
PARALLEL CONTROL INTERFACE
The AD8197B can be partially controlled through the parallel
interface using the PP_EN, PP_CH[1:0], PP_EQ, PP_PRE[1:0],
PP_OTO, and PP_OCL pins. Logic levels for the parallel
interface pins are set in accordance with the specifications listed
in Table 1. Setting these pins updates the parallel control
interface registers, as listed in Table 18. Following a reset, the
AD8197B can be controlled through the parallel control
interface until the first serial control event occurs. As soon as
any serial control event occurs, the serial programming values
override any prior parallel programming values, and the parallel
control interface is disabled until the part is subsequently reset.
The default serial programming values correspond to the state
of the serial interface configuration registers, as listed in Table 5.
Note that after changing the status of the channel selection
(PP_CH[1:0]), it is necessary to assert a low logic level to
RESET
to ensure that the channel select status is properly
updated.
Note also that the input termination resistor switches can be
controlled only via serial programming. Therefore, as most
systems require controlling these resistors, serial control is
required and parallel control is of little use. However, the
parallel control pins determine the AD8197B status between
the time of the assertion of reset and the first serial program-
ming event.
Rev. 0 | Page 17 of 28
AD8197B
SERIAL INTERFACE CONFIGURATION REGISTERS
The serial interface configuration registers can be read and written using the I2C serial control interface, Pin I2C_SDA, and Pin I2C_SCL.
The least significant bits of the AD8197B I2C part address are set by tying the Pin I2C_ADDR2, Pin I2C_ADDR1, and Pin I2C_ADDR0
to 3.3 V (Logic 1) or 0 V (Logic 0). As soon as the serial control interface is used, the parallel control interface is disabled until the
AD8197B is reset as described in the Serial Control Interface section.
Table 5. Serial (I2C) Interface Register Map
Name
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
Addr. Default
High
High
High speed source select
0x00
0x40
Speed
Device
Modes
speed
switch
enable
HS_EN
0
0
0
0
0
0
0
0
HS_CH[1]
HS_CH[0]
Auxiliary
Device
Modes
Auxiliary
switch
enable
Auxiliary switch source
select
0x01
0x40
0x01
AUX_EN
AUX_CH[1]
AUX_CH[0]
Receiver
Settings
High speed 0x10
input
termination
resistor
select
RX_TS
0x11
Input
Term.
Resistor
Control 1
Source A and Source B: input termination select
RX_TO[6] RX_TO[5] RX_TO[4] RX_TO[3] RX_TO[2]
0x00
0x00
RX_TO[7]
RX_TO[1]
RX_TO[0]
Input
Source C and Source D: input termination select
0x12
Term.
Resistor
Control 2
RX_TO[15] RX_TO[14] RX_TO[13] RX_TO[12] RX_TO[11] RX_TO[10] RX_TO[9]
RX_TO[8]
Receive
Equalizer 1
Source A and Source B: input equalization level select
0x13
RX_EQ[0]
0x00
0x00
0x03
RX_EQ[7]
RX_EQ[6]
RX_EQ[5]
Source C and Source D: input equalization level select
RX_EQ[15] RX_EQ[14] RX_EQ[13] RX_EQ[12] RX_EQ[11] RX_EQ[10] RX_EQ[9]
RX_EQ[4]
RX_EQ[3]
RX_EQ[2]
RX_EQ[1]
Receive
Equalizer 2
0x14
RX_EQ[8]
Transmitter
Settings
High speed output
pre-emphasis level
select
High speed
output
termination current
High speed 0x20
output
select
level select
TX_PE[1]
TX_PE[0]
TX_PTO
TX_OCL
Rev. 0 | Page 18 of 28
AD8197B
HIGH SPEED DEVICE MODES REGISTER
HS_EN: High Speed (TMDS) Channels Enable Bit
INPUT TERMINATION SELECT REGISTER 1 AND
REGISTER 2
RX_TO[X]: High Speed (TMDS) Input Channel X
Termination Select Bit
Table 6. HS_EN Description
HS_EN Description
Table 11. RX_TO[X] Description
RX_TO[X] Description
0
1
High speed channels off, low power/standby mode
High speed channels on
0
1
Input termination for TMDS Channel X disconnected
Input termination for TMDS Channel X connected
HS_CH[1:0]: High Speed (TMDS) Switch Source Select Bus
Table 7. HS_CH Mapping
HS_CH[1:0] O[3:0] Description
Table 12. RX_TO[X] Mapping
RX_TO[X]
Corresponding Input TMDS Channel
00
01
10
11
A[3:0] High Speed Source A switched to output
Bit 0
Bit 1
Bit 2
Bit 3
Bit 4
Bit 5
Bit 6
Bit 7
B0
B1
B2
B3
A0
A1
A2
A3
C3
C2
C1
C0
D3
D2
D1
D0
B[3:0]
C[3:0]
High Speed Source B switched to output
High Speed Source C switched to output
D[3:0] High Speed Source D switched to output
AUXILIARY DEVICE MODES REGISTER
AUX_EN: Auxiliary (Low Speed) Switch Enable Bit
Table 8. AUX_EN Description
Bit 8
Bit 9
AUX_EN
Description
0
1
Auxiliary switch off
Auxiliary switch on
Bit 10
Bit 11
Bit 12
Bit 13
Bit 14
Bit 15
AUX_CH[1:0]: Auxiliary (Low Speed) Switch Source
Select Bus
Table 9. AUX_CH Mapping
AUX_CH[3:0] AUX_COM[3:0] Description
00
01
10
11
AUX_A[3:0]
AUX_B[3:0]
AUX_C[3:0]
AUX_D[3:0]
Auxiliary Source A switched
to output
Auxiliary Source B switched
to output
Auxiliary Source C switched
to output
Auxiliary Source D switched
to output
RECEIVE EQUALIZER REGISTER 1 AND REGISTER 2
RX_EQ[X]: High Speed (TMDS) Input X Equalization Level
Select Bit
Table 13. RX_EQ[X] Description
RX_EQ[X]
Description
0
1
Low equalization (6 dB)
High equalization (12 dB)
RECEIVER SETTINGS REGISTER
RX_TS: High Speed (TMDS) Channels Input Termination
On/Off Select Bit
Table 14. RX_EQ[X] Mapping
RX_EQ[X]
Corresponding Input TMDS Channel
Bit 0
Bit 1
Bit 2
Bit 3
Bit 4
Bit 5
Bit 6
Bit 7
B0
B1
B2
B3
A0
A1
A2
A3
C3
C2
C1
C0
D3
D2
D1
D0
Table 10. RX_TS Description
RX_TS
Description
0
1
All input terminations off (switches open)
Input termination resistor switch is controlled by
RX_TO[x] control bits from Input Term. Resistor
Control Registers 1 and 2.
Bit 8
Bit 9
Bit 10
Bit 11
Bit 12
Bit 13
Bit 14
Bit 15
Rev. 0 | Page 19 of 28
AD8197B
TX_PTO: High Speed (TMDS) Output Termination On/Off
Select Bit (For All Channels)
TRANSMITTER SETTINGS REGISTER
TX_PE[1:0]: High Speed (TMDS) Output Pre-Emphasis
Level Select Bus (For All TMDS Channels)
Table 16. TX_PTO Description
TX_PTO
Description
Table 15. TX_PE[1:0] Description
0
1
Output termination off
Output termination on
TX_PE[1:0]
Description
00
01
10
11
No pre-emphasis (0 dB)
Low pre-emphasis (2 dB)
Medium pre-emphasis (4 dB)
High pre-emphasis (6 dB)
TX_OCL: High Speed (TMDS) Output Current Level Select
Bit (For All Channels)
Table 17. TX_OCL Description
TX_OCL
Description
0
1
Output current set to 10 mA
Output current set to 20 mA
Rev. 0 | Page 20 of 28
AD8197B
PARALLEL INTERFACE CONFIGURATION REGISTERS
The parallel interface configuration registers can be directly set using the PP_EN, PP_CH[1:0], PP_EQ, PP_PRE[1:0], PP_OTO, and
PP_OCL pins. This interface is accessible only after the part is reset and before any registers are accessed using the serial control interface.
Because most systems use serial control for the input termination resistors, the parallel control interface is limited to controlling the
AD8197B status after reset and before serial logic control. The state of each pin is set by tying it to 3.3 V (Logic 1) or 0 V (Logic 0).
Table 18. Parallel Interface Register Map
Name
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
High Speed Device
Modes
High speed
switch enable
High speed source select
PP_EN
0
0
0
0
0
0
0
0
PP_CH[1]
PP_CH[0]
Auxiliary Device
Modes
Auxiliary switch
enable
Auxiliary switch source select
1
PP_CH[1]
PP_CH[0]
Receiver Settings
Input term.
select
(terminations
always open in
parallel control
mode)
1
Input Termination
Resistor Control.1
Source A and Source B input termination select (No parallel control termination, always open)
0
0
0
0
0
0
0
0
0
0
Input Termination
Resistor Control 2
Source C and Source D input termination select (No parallel control termination, always open)
0
0
0
0
0
0
Receive Equalizer 1
Receive Equalizer 2
Transmitter Settings
Source A and Source B input equalization level select
PP_EQ PP_EQ PP_EQ PP_EQ PP_EQ
Source C and Source D input equalization level select
PP_EQ PP_EQ PP_EQ PP_EQ PP_EQ
PP_EQ PP_EQ
PP_EQ PP_EQ
PP_EQ
PP_EQ
Output pre-emphasis
level select
Output termination Output current
on/off select
level select
PP_PE[1]
PP_PE[0]
PP_OTO
PP_OCL
Rev. 0 | Page 21 of 28
AD8197B
HIGH SPEED DEVICE MODES REGISTER
RECEIVE EQUALIZER REGISTER 1 AND REGISTER 2
PP_EN: High Speed (TMDS) Channels Enable Bit
PP_EQ: High Speed (TMDS) Inputs Equalization Level
Select Bit (For All TMDS Input Channels)
Table 19. PP_EN Description
PP_EN Description
The input equalization cannot be set individually (per channel)
when using the parallel interface; one equalization setting
affects all input channels.
0
1
High speed channels off, low power/standby mode
High speed channels on
Table 22. PP_EQ Description
PP_CH[1:0]: High Speed (TMDS) Switch Source Select Bus
PP_EQ
Description
Table 20. PP_CH Mapping
PP_CH[1:0] O[3:0] Description
0
1
Low equalization (6 dB)
High equalization (12 dB)
00
01
10
11
A[3:0]
B[3:0]
C[3:0]
D[3:0]
High Speed Source A switched to
output
High Speed Source B switched to
output
High Speed Source C switched to
output
High Speed Source D switched to
output
TRANSMITTER SETTINGS REGISTER
PP_PE[1:0]: High Speed (TMDS) Output Pre-Emphasis
Level Select Bus (For All TMDS Channels)
Table 23. PP_PE[1:0] Description
PP_PE[1:0]
Description
00
01
10
11
No pre-emphasis (0 dB)
Low pre-emphasis (2 dB)
Medium pre-emphasis (4 dB)
High pre-emphasis (6 dB)
Note that after changing the status of the channel selection
(PP_CH[1:0]0), it is necessary to assert a low logic level to
RESET to ensure that the channel select status is properly
updated.
PP_OTO: High Speed (TMDS) Output Termination On/Off
Select Bit (For All TMDS Channels)
AUXILIARY DEVICE MODES REGISTER
PP_CH[1:0]: Auxiliary Switch Source Select Bus
Table 24. PP_OTO Description
PP_OTO
Description
Table 21. PP_CH Mapping
PP_CH[1:0] AUX_COM[3:0] Description
0
1
Output termination off
Output termination on
00
01
10
11
AUX_A[3:0]
AUX_B[3:0]
AUX_C[3:0]
AUX_D[3:0]
Auxiliary Source A switched to
output
Auxiliary Source B switched to
output
Auxiliary Source C switched to
output
Auxiliary Source D switched to
output
PP_OCL: High Speed (TMDS) Output Current Level Select
Bit (For All TMDS Channels)
Table 25. TX_OCL Description
PP_OCL
Description
0
1
Output current set to 10 mA
Output current set to 20 mA
INPUT TERMINATION RESISTOR CONTROL
REGISTER 1 AND REGISTER 2
High speed input (TMDS) channels input terminations are off
when using the parallel interface. This can be changed only via
serial programming.
Rev. 0 | Page 22 of 28
AD8197B
APPLICATION INFORMATION
Figure 31. Layout of the TMDS Traces on the AD8197B Evaluation Board (Only Top Signal Routing Layer is Shown)
The AD8197B is an HDMI/DVI switch, featuring equalized
TMDS inputs and pre-emphasized TMDS outputs. It is in-
tended for use as a 4:1 switch in systems with long cable runs
on both the input and/or the output, and is fully HDMI 1.3
receive-compliant.
and transmit a full swing HDMI signal to an end receiver. More
information on the specific performance metrics of the AD8197B
can be found in the Typical Performance Characteristics
section.
The AD8197B also provides a distinct advantage in receive-type
applications because it is a fully buffered HDMI/DVI switch.
Although inverting the output pin order of the AD8197B on the
PCB requires a designer to place vias in the high speed signal
path, the AD8197B fully buffers and electrically decouples the
outputs from the inputs. Therefore, the effects of the vias placed
on the output signal lines are not seen at the input of the AD8197B.
The programmable output terminations also improve signal
quality at the output of the AD8197B. The PCB designer, there-
fore, has significantly improved flexibility in the placement and
routing of the output signal path with the AD8197B over other
solutions.
PINOUT
The AD8197B is designed to have an HDMI/DVI receiver
pinout at its input and a transmitter pinout at its output. This
makes the AD8197B ideal for use in AVR-type applications
where a designer routes both the inputs and the outputs directly
to HDMI/DVI connectors, as shown in Figure 31. When the
AD8197B is used in receiver type applications, it is necessary to
change the order of the output pins on the PCB to align with the
on-board receiver.
One advantage of the AD8197B in an AVR-type application
is that all of the high speed signals can be routed on one side
(the topside) of the board, as shown in Figure 31. In addition to
12 dB of input equalization, the AD8197B provides up to 6 dB
of output pre-emphasis that boosts the output TMDS signals
and allows the AD8197B to precompensate when driving long
PCB traces or output cables. The net effect of the input equali-
zation and output pre-emphasis of the AD8197B is that the
AD8197B can compensate for the signal degradation of both
input and output cables; it acts to reopen a closed input data eye
CABLE LENGTHS AND EQUALIZATION
The AD8197B offers two levels of programmable equalization
for the high speed inputs: 6 dB and 12 dB. The equalizer of
the AD8197B supports video data rates of up to 2.25 Gbps, and
as shown in Figure 14, it can equalize more than 20 meters of
24 AWG HDMI cable at 2.25 Gbps, which corresponds to the video
format 1080p with deep color.
Rev. 0 | Page 23 of 28
AD8197B
The length of cable that can be used in a typical HDMI/DVI
application depends on a large number of factors, including:
concern with laying out the auxiliary lines is ensuring that they
conform to the I2C bus standard and do not have excessive
capacitive loading.
•
Cable quality: the quality of the cable in terms of conductor
wire gauge and shielding. Thicker conductors have lower
signal degradation per unit length.
TMDS Signals
In the HDMI/DVI standard, four differential pairs carry the
TMDS signals. In DVI, three of these pairs are dedicated to
carrying RGB video and sync data. For HDMI, audio data is
interleaved with the video data; the DVI standard does not
incorporate audio information. The fourth high speed differ-
ential pair is used for the AV data-word clock and runs at
one-tenth the speed of the TMDS data channels.
•
•
Data rate: the data rate being sent over the cable. The signal
degradation of HDMI cables increases with data rate.
Edge rates: the edge rates of the source input. Slower input
edges result in more significant data eye closure at the end
of a cable.
•
Receiver sensitivity: the sensitivity of the terminating
receiver.
The four high speed channels of the AD8197B are identical.
No concession was made to lower the bandwidth of the fourth
channel for the pixel clock, so any channel can be used for any
TMDS signal. The user chooses which signal is routed over
which channel. Additionally, the TMDS channels are symmetrical;
therefore, the p and n of a given differential pair are inter-
changeable, provided the inversion is consistent across all inputs
and outputs of the AD8197B. However, the routing between
inputs and outputs through the AD8197B is fixed. For example,
Output Channel 0 always switches between Input A0, Input B0,
Input C0, Input D0, and so forth.
As such, specific cable types and lengths are not recommended
for use with a particular equalizer setting. In nearly all applica-
tions, the AD8197B equalization level can be set to high, or 12 dB,
for all input cable configurations at all data rates, without
degrading the signal integrity.
PCB LAYOUT GUIDELINES
The AD8197B is used to switch two distinctly different types of
signals, both of which are required for HDMI and DVI video.
These signal groups require different treatment when laying out
a PC board.
The AD8197B buffers the TMDS signals and the input traces
can be considered electrically independent of the output traces.
In most applications, the quality of the signal on the input
TMDS traces is more sensitive to the PCB layout. Regardless of
the data being carried on a specific TMDS channel, or whether
the TMDS line is at the input or the output of the AD8197B, all
four high speed signals should be routed on a PCB in accor-
dance with the same RF layout guidelines.
The first group of signals carries the audiovisual (AV) data.
HDMI/DVI video signals are differential, unidirectional, and
high speed (up to 2.25 Gbps). The channels that carry the video
data must be controlled impedance, terminated at the receiver,
and capable of operating at the maximum specified system data
rate. It is especially important to note that the differential traces
that carry the TMDS signals should be designed with a controlled
differential impedance of 100 Ω. The AD8197B provides single-
ended, 50 Ω terminations on-chip for both its inputs and outputs,
and both the input and output terminations can be enabled or
disabled through the serial control interface. The output termi-
nations can also be enabled or disabled through the parallel
control interface. Transmitter termination is not required by the
HDMI 1.3 standard, but its inclusion improves the overall system
signal integrity.
Layout for the TMDS Signals
The TMDS differential pairs can be either microstrip traces,
routed on the outer layer of a board, or stripline traces, routed
on an internal layer of the board. If microstrip traces are used,
there should be a continuous reference plane on the PCB layer
directly below the traces. If stripline traces are used, they must
be sandwiched between two continuous reference planes in the
PCB stack-up. Additionally, the p and n of each differential pair
must have a controlled differential impedance of 100 Ω. The
characteristic impedance of a differential pair is a function of
several variables including the trace width, the distance separating
the two traces, the spacing between the traces and the reference
plane, and the dielectric constant of the PC board binder material.
Interlayer vias introduce impedance discontinuities that can
cause reflections and jitter on the signal path, therefore, it is
preferable to route the TMDS lines exclusively on one layer of the
board, particularly for the input traces. In some applications, such
as using multiple AD8197Bs to construct large input arrays, the use
of interlayer vias becomes unavoidable. In these situations, the
input termination feature of the AD8197B improves system signal
integrity by absorbing reflections. Take care to use vias minimally
and to place vias symmetrically for each side of a given differential
pair. Furthermore, to prevent unwanted signal coupling and
The audiovisual (AV) data carried on these high speed channels
is encoded by a technique called transmission minimized differ-
ential signaling (TMDS) and in the case of HDMI, is also encrypted
according to the high bandwidth digital copy protection (HDCP)
standard.
The second group of signals consists of low speed auxiliary
control signals used for communication between a source and a
sink. Depending upon the application, these signals can include
the DDC bus (this is an I2C bus used to send EDID information
and HDCP encryption keys between the source and the sink),
the consumer electronics control (CEC) line, and the hot plug
detect (HPD) line. These auxiliary signals are bidirectional, low
speed, and transferred over a single-ended transmission line
that does not need to have controlled impedance. The primary
Rev. 0 | Page 24 of 28
AD8197B
interference, route the TMDS signals away from other signals
and noise sources on the PCB.
longer so strongly coupled, the width of the traces should be
increased to yield a differential impedance of 100 Ω in the new
configuration.
Both traces of a given differential pair must be equal in length
to minimize intrapair skew. Maintaining the physical symmetry
of a differential pair is integral to ensuring its signal integrity;
excessive intrapair skew can introduce jitter through duty cycle
distortion (DCD). The p and n of a given differential pair should
always be routed together to establish the required 100 Ω differ-
ential impedance. Enough space should be left between the
differential pairs of a given group so that the n of one pair does
not couple to the p of another pair. For example, one technique is
to make the interpair distance 4 to 10 times wider than the
intrapair spacing.
Ground Current Return
In some applications, it can be necessary to invert the output
pin order of the AD8197B. This requires a designer to route the
TMDS traces on multiple layers of the PCB. When routing
differential pairs on multiple layers, it is necessary to also
reroute the corresponding reference plane in order to provide
one continuous ground current return path for the differential
signals. Standard plated through-hole vias are acceptable for
both the TMDS traces and the reference plane. An example of
this is illustrated in Figure 32.
Any group of four TMDS channels (Input A, Input B, Input C,
Input D, or the output) should have closely matched trace
lengths to minimize interpair skew. Severe interpair skew can
cause the data on the four different channels of a group to arrive
out of alignment with one another. A good practice is to match
the trace lengths for a given group of four channels to within
0.05 inches on FR4 material.
THROUGH-HOLE VIAS
SILKSCREEN
LAYER 1: SIGNAL (MICROSTRIP)
PCB DIELECTRIC
LAYER 2: GND (REFERENCE PLANE)
PCB DIELECTRIC
Minimizing intrapair and interpair skew becomes increasingly
important as data rates increase. Any introduced skew consti-
tutes a correspondingly larger fraction of a bit period at higher
data rates.
LAYER 3: PWR
(REFERENCE PLANE)
PCB DIELECTRIC
Though the AD8197B features input equalization and output
pre-emphasis, the length of the TMDS traces should be
minimized to reduce overall signal degradation. Commonly
used PC board material such as FR4 is lossy at high frequencies;
therefore, long traces on the circuit board increase signal
attenuation resulting in decreased signal swing and increased
jitter through intersymbol interference (ISI).
LAYER 4: SIGNAL (MICROSTRIP)
SILKSCREEN
KEEP REFERENCE PLANE
ADJACENT TO SIGNAL ON ALL
LAYERS TO PROVIDE CONTINUOUS
GROUND CURRENT RETURN PATH.
Figure 32. Example Routing of Reference Plane
TMDS Terminations
Controlling the Characteristic Impedance of a TMDS
Differential Pair
The AD8197B provides internal, 50 Ω single-ended termina-
tions for all of its high speed inputs and outputs. It is not
necessary to include external termination resistors for the
TMDS differential pairs on the PCB.
The characteristic impedance of a differential pair depends
on a number of variables, including the trace width, the
distance between the two traces, the height of the dielectric
material between the trace and the reference plane below it,
and the dielectric constant of the PCB binder material. To
a lesser extent, the characteristic impedance also depends
upon the trace thickness and the presence of solder mask.
There are many combinations that can produce the correct
characteristic impedance. Generally, working with the PC board
fabricator is required to obtain a set of parameters to produce
the desired results.
The output termination resistors of the AD8197B back-terminate
the output TMDS transmission lines. These back-terminations
act to absorb reflections from impedance discontinuities on the
output traces, improving the signal integrity of the output traces
and adding flexibility to how the output traces can be routed.
For example, interlayer vias can be used to route the AD8197B
TMDS outputs on multiple layers of the PCB without severely
degrading the quality of the output signal.
Auxiliary Control Signals
One consideration is how to guarantee a differential pair with
a differential impedance of 100 Ω over the entire length of the
trace. One technique to accomplish this is to change the width
of the traces in a differential pair based on how closely one trace
is coupled to the other. When the two traces of a differential
pair are close and strongly coupled, they should have a width
that produces a 100 Ω differential impedance. When the traces
split apart, to go into a connector, for example, and are no
There are four single-ended control signals associated with each
source or sink in an HDMI/DVI application. These are hot plug
detect (HPD), consumer electronics control (CEC), and two
display data channel (DDC) lines. The two signals on the DDC
bus are SDA and SCL (serial data and serial clock, respectively).
These four signals can be switched through the auxiliary bus of
Rev. 0 | Page 25 of 28
AD8197B
the AD8197B and do not need to be routed with the same strict
considerations as the high speed TMDS signals.
HPD is a dc signal presented by a sink to a source to indicate
that the source EDID is available for reading. The placement
of this signal is not critical, but it should be routed as directly
as possible.
In general, it is sufficient to route each auxiliary signal as a
single-ended trace. These signals are not sensitive to impedance
discontinuities, do not require a reference plane, and can be
routed on multiple layers of the PCB. However, it is best to
follow strict layout practices whenever possible to prevent the
PCB design from affecting the overall application. The specific
routing of the HPD, CEC, and DDC lines depends upon the
application in which the AD8197B is being used.
When the AD8197B is powered up, one set of the auxiliary inputs
is passively routed to the outputs. In this state, the AD8197B
looks like a 100 Ω resistor between the selected auxiliary inputs
and the corresponding outputs as illustrated in Figure 27. The
AD8197B does not buffer the auxiliary signals; therefore, the
input traces, output traces, and the connection through the
AD8197B all must be considered when designing a PCB to meet
HDMI/DVI specifications. The unselected auxiliary inputs of
the AD8197B are placed into a high impedance mode when the
device is powered up. To ensure that all of the auxiliary inputs
of the AD8197B are in a high impedance mode when the device
is powered off, it is necessary to power the AMUXVCC supply
as illustrated in Figure 28.
For example, the maximum speed of signals present on the
auxiliary lines is 100 kHz I2C data on the DDC lines; therefore,
any layout that enables 100 kHz I2C to be passed over the DDC
bus should suffice. The HDMI 1.3 specification, however, places
a strict 50 pF limit on the amount of capacitance that can be
measured on either SDA or SCL at the HDMI input connector.
This 50 pF limit includes the HDMI connector, the PCB, and
whatever capacitance is seen at the input of the AD8197B, or an
equivalent receiver. There is a similar limit of 100 pF of input
capacitance for the CEC line.
In contrast to the auxiliary signals, the AD8197B buffers the
TMDS signals, allowing a PCB designer to layout the TMDS
inputs independently of the outputs.
The parasitic capacitance of traces on a PCB increases with
trace length. To help ensure that a design satisfies the HDMI
specification, the length of the CEC and DDC lines on the PCB
should be made as short as possible. Additionally, if there is a
reference plane in the layer adjacent to the auxiliary traces in
the PCB stack-up, relieving or clearing out this reference plane
immediately under the auxiliary traces significantly decreases
the amount of parasitic trace capacitance. An example of the
board stackup is shown in Figure 33.
Power Supplies
The AD8197B has five separate power supplies referenced to
two separate grounds. The supply/ground pairs are:
•
•
•
•
•
AVCC/AVEE
VTTI/AVEE
VTTO/AVEE
DVCC/DVEE
AMUXVCC/DVEE
3W
W
3W
The AVCC/AVEE (3.3 V) and DVCC/DVEE (3.3 V) supplies
power the core of the AD8197B. The VTTI/AVEE supply (3.3 V)
powers the input termination (see Figure 25). Similarly, the
VTTO/AVEE supply (3.3 V) powers the output termination
(see Figure 26). The AMUXVCC/DVEE supply (3.3 V to 5 V)
powers the auxiliary multiplexer core and determines the maxi-
mum allowed voltage on the auxiliary lines. For example, if the
DDC bus is using 5 V I2C, then AMUXVCC should be connected
to +5 V relative to DVEE.
SILKSCREEN
LAYER 1: SIGNAL (MICROSTRIP)
PCB DIELECTRIC
LAYER 2: GND (REFERENCE PLANE)
PCB DIELECTRIC
LAYER 3: PWR (REFERENCE PLANE)
PCB DIELECTRIC
In a typical application, all pins labeled AVEE or DVEE
should be connected directly to ground. All pins labeled AVCC,
DVCC, VTTI, or VTTO should be connected to 3.3 V, and
Pin AMUXVCC should be tied to 5 V. The supplies can also be
powered individually, but care must be taken to ensure that
each stage of the AD8197B is powered correctly.
LAYER 4: SIGNAL (MICROSTRIP)
SILKSCREEN
REFERENCE LAYER
RELIEVED UNDERNEATH
MICROSTRIP
Figure 33. Example Board Stackup
Rev. 0 | Page 26 of 28
AD8197B
Power Supply Bypassing
In applications where the AD8197B is powered by a single 3.3 V
supply, it is recommended to use two reference supply planes
and bypass the 3.3 V reference plane to the ground reference
plane with one 220 pF, one 1000 pF, two 0.01 μF, and one 4.7 μF
capacitors. The capacitors should via down directly to the
supply planes and be placed within a few centimeters of the
AD8197B. The AMUXVCC supply does not require additional
bypassing. This bypassing scheme is illustrated in Figure 35.
The AD8197B requires minimal supply bypassing. When
powering the supplies individually, place a 0.01 μF capacitor
between each 3.3 V supply pin (AVCC, DVCC, VTTI, and VTTO)
and ground to filter out supply noise. Generally, bypass capacitors
should be placed near the power pins and should connect directly
to the relevant supplies (without long intervening traces). For
example, to improve the parasitic inductance of the power supply
decoupling capacitors, minimize the trace length between
capacitor landing pads and the vias as shown in Figure 34.
RECOMMENDED
EXTRA ADDED INDUCTANCE
AD8197B
NOT RECOMMENDED
Figure 34. Recommended Pad Outline for Bypass Capacitors
Figure 35. Example Placement of Power Supply Decoupling Capacitors
Around the AD8197B
Rev. 0 | Page 27 of 28
AD8197B
OUTLINE DIMENSIONS
16.20
16.00 SQ
15.80
1.60 MAX
0.75
0.60
0.45
100
1
76
75
PIN 1
14.20
14.00 SQ
13.80
TOP VIEW
(PINS DOWN)
1.45
1.40
1.35
0.20
0.09
7°
3.5°
0°
0.08
COPLANARITY
51
50
25
0.15
0.05
26
SEATING
PLANE
0.27
0.22
0.17
VIEW A
0.50
BSC
LEAD PITCH
VIEW A
ROTATED 90° CCW
COMPLIANT TO JEDEC STANDARDS MS-026-BED
Figure 36. 100-Lead Low Profile Quad Flat Package [LQFP]
(ST-100)
Dimensions shown in millimeters
ORDERING GUIDE
Model
Temperature Range Package Description
Package Option Ordering Quantity
AD8197BASTZ1
AD8197BASTZ-RL1
AD8197B-EVALZ1
−40°C to +85°C
−40°C to +85°C
100-Lead Low Profile Quad Flat Package [LQFP]
100-Lead Low Profile Quad Flat Package [LQFP]
Evaluation Board
ST-100
ST-100
1,000
1 Z = RoHS Compliant Part.
©2008 Analog Devices, Inc. All rights reserved. Trademarks and
registered trademarks are the property of their respective owners.
D07015-0-1/08(0)
Rev. 0 | Page 28 of 28
相关型号:
AD8197BASTZ
SPECIALTY CONSUMER CIRCUIT, PQFP100, 14 X 14 MM, ROHS COMPLIANT, MS-026BED, LQFP-100
ROCHESTER
AD8197BASTZ-RL
SPECIALTY CONSUMER CIRCUIT, PQFP100, 14 X 14 MM, ROHS COMPLIANT, MS-026BED, LQFP-100
ROCHESTER
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