MAX3816A DS - Maxim Integrated

MAX3816A DS - Maxim Integrated
19-4109; Rev 0; 7/08
KIT
ATION
EVALU
E
L
B
AVAILA
I2C 2-Wire Extender for DDC in DVI,
HDMI, and VGA Interfaces
Features
♦ DDC or I2C Cable Extension Up to 60 Meters at
sates for excess load capacitance of long DVI™, HDMI™,
and VGA cables. A single MAX3816A placed at the display side of the link restores signal integrity bidirectionally
for both DDC clock and data over 0 to 60 meters of cable.
The MAX3816A features compensation for cable
capacitance with a guaranteed range up to 3000pF,
typically beyond 5000pF. The MAX3816A detects statechange assertion by the logical “AND” of the source
side and display side. It asserts the new state with a
rail-to-rail slew-rate-limited driver capable of meeting
I2C rise- and fall-time requirements under the full load
of the cable. After assertion of the new state, a holdoff
period of 2.5µs prevents a subsequent state change
while the cable channel settles.
100kbps for Both Clock and Data Channels
♦ Single-Sided Solution Requires Only One
MAX3816A at the Display Side
♦ Compensates for Cable Capacitance, 0 to 3000pF
Guaranteed (8x I2C Specification), or Beyond
5000pF Typical
♦ Parallel and Serial Operating Modes
♦ Prevents Ringing Due to Reflections by
Terminating Transmission Line Impedance After
Transitions
♦ Use with MAX3815 TMDS® Equalizer to Form a
Complete Digital Video Extension Solution
♦ 3.0V to 5.5V Power Supply
Under full load at 100kbps, the MAX3816A consumes
25mW, excluding pullup resistors. It is available in a
16-pin TSSOP package and operates from 0°C to +70°C.
♦ Optional Voltage Translation Between 5V Cable
DDC and 3.3V Display DDC Levels
Ordering Information
Applications
Front-Projector DVI/HDMI Inputs
PART
High-Definition Televisions, Displays, and
Computer Monitors
MAX3816ACUE+
TEMP RANGE
PIN-PACKAGE
0°C to +70°C
16 TSSOP
+Denotes a lead-free/RoHS-compliant package.
DVI/HDMI Cable-Extender Modules and Active
Cable Assemblies
Pin Configuration appears at end of data sheet.
Typical Application Circuit (Parallel Mode)
LONG CABLE FROM VIDEO SOURCE:
DVI, HDMI, OR CAT-5 CABLE UP TO 60m
(200ft)
CONNECTOR TO DISPLAY
DVI, HDMI, OR M1 CONNECTOR, < 3m
5V*
DDC +5V
DDC +5V
47kΩ
47kΩ
DDC SCL
DDC SCL
DDC SDA
DDC SDA
VCC
VDD
MAX3816A
CLOCK_C
DATA_C
VCC
CLOCK_D
DATA_D
MODE
DRVR_EN
10μF
DDC GND
GND_REF
VSS
VDD
VDD OR VSS (SEE DESCRIPTION)
DDC GND
10μF
SHIELD GNDS
SHIELD GNDS
CABLE HEAD OR EXTENDER BOX
*TO MEET DVI/HDMI SPECIFICATIONS FOR THE DDC +5V LINK, THE VDD SIDE OF THE MAX3816A MUST BE EXTERNALLY POWERED. IF NOT APPLICABLE, CONNECT TO DDC +5V.
*DDC (Display Data Channel) is part of the VESA Standard.
TMDS is a registered trademark of Silicon Image, Inc.
DVI is a trademark of Digital Display Working Group.
HDMI is a trademark of HDMI Licensing, LLC.
________________________________________________________________ Maxim Integrated Products
For pricing, delivery, and ordering information, please contact Maxim Direct at 1-888-629-4642,
or visit Maxim’s website at www.maxim-ic.com.
1
MAX3816A
General Description
The MAX3816A DDC*/I2C extender automatically compen-
MAX3816A
I2C 2-Wire Extender for DDC in DVI,
HDMI, and VGA Interfaces
ABSOLUTE MAXIMUM RATINGS
Voltage Range (relative to VSS) at VDD, VCC,
CLOCK_D, DATA_D, CLOCK_C, DATA_C,
DRVR_EN, MODE ..................................................-0.5V to +6.0V
Continuous Power Dissipation (TA = +70°C)
(derate 11.1mW/°C above +70°C) ..............................889mW
Voltage Range (relative to VSS) at GND_REF .......-0.5V to +0.5V
Operating Junction Temperature (TJ) Range ....-55°C to +150°C
Storage Ambient Temperature (TS) Range .......-40°C to +150°C
Electrostatic Discharge (ESD)
Human Body Model......................................................> ±3kV
Stresses beyond those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. These are stress ratings only, and functional
operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to
absolute maximum rating conditions for extended periods may affect device reliability.
ELECTRICAL CHARACTERISTICS
(VCC = +3.0V to +5.5V, VDD = +3.0V to +5.5V, TA = 0°C to +70°C. Typical values are at TA = +25°C, VCC = +5.0V, VDD = +3.3V,
unless otherwise noted.)
PARAMETER
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
5.5
V
POWER SUPPLY
Supply Voltage
VCC or VDD
See the Applications Information section
(Note 1)
3.0
ICC
VCC = 5.5V, VDD = 5.5V, 100kbps,
60pF load on cable, 10pF load on display,
current into VCC pin
1.3
IDD
VCC = 5.5V, VDD = 5.5V, 100kbps,
60pF load on cable, 10pF load on display,
current into VDD pin
4.3
DC to 500kHz
100
DC to 60Hz (series mode)
700
Supply Current
Supply Noise Tolerance
3.0
mA
7.0
mVP-P
CLOCK_C, DATA_C, CLOCK_D, DATA_D (Notes 2, 3)
Output-High Voltage
VOH
VOL
Output-Low Voltage
VHOLD
High-to-Low Threshold
Low-to-High Threshold
Output-High-State Current Limit
2
Cable side (CLOCK_C, DATA_C)
VCC - 0.1
VCC
Display side (CLOCK_D, DATA_D)
VDD - 0.1
VDD
VOL achieved within 1μs of negative
transition (see Figure 1a, State 2)
After VOL is achieved, VHOLD is
the most positive level allowed
if logic level is 0 and no other
driver is asserting low on the
same node (series mode)
0.2
Cable
side
15
Display
side
20
VTRIGIH
Threshold used to detect high-to-low
transition relative to supply (VCC for cable
side, VDD for display side)
VTRIGIL
Threshold used to detect low-tohigh transition relative to supply
(VCC for cable side, VDD for
display side)
0.4
V
% of
Supply
% of
Supply
75
Cable
side
12.5
Display
side
17.5
Output in ramp-up mode for DATA_C
V
5.0
_______________________________________________________________________________________
% of
Supply
16.5
mA
I2C 2-Wire Extender for DDC in DVI,
HDMI, and VGA Interfaces
(VCC = +3.0V to +5.5V, VDD = +3.0V to +5.5V, TA = 0°C to +70°C. Typical values are at TA = +25°C, VCC = +5.0V, VDD = +3.3V,
unless otherwise noted.)
PARAMETER
SYMBOL
TYP
MAX
3.0V to 3.6V supply
700
1000
4.5V to 5.5V supply
700
3.0V to 3.6V supply
200
4.5V to 5.5V supply
300
Driver On-Time
Driver asserting high or low
1750
ns
Driver Active Termination
Driver asserting high or low
60
Time to transition decision and assert
300
ns
Data/clock sensing off during this period
2.5
μs
Rise Time (Note 4)
tR
Fall Time (Note 4)
tF
CONDITIONS
MIN
300
UNITS
ns
ns
TRANSITION SENSING
Level-Sense Filter Delay
Holdoff Time
tHOLDOFF
LVTTL/LVCMOS CONTROL INPUTS (DRVR_EN, MODE)
Input-High Voltage
VIH
2.0
V
Input-Low Voltage
VIL
0.8
V
Input-High Current
IIH
VIH(MIN) < VIN
-1
+1
μA
Input-Low Current
I IL
VIN < VIL(MAX)
-1
+1
μA
Note 1: While the MAX3816A is operable over the continuous range of 3.0V to 5.5V, the DDC application requires VCC connection to
DDC +5V.
Note 2: All levels in the cable side clock and data I/O are referenced to GND_REF, unless otherwise noted.
Note 3: All levels in the display side clock and data I/O are referenced to VSS, unless otherwise noted.
Note 4: Rise time measured 30% to 70%; fall time measured 70% to 30%. Load range is 60pF to 3000pF on source side, and 10pF
to 400pF on display side. Pullup resistors are chosen to supply I2C maximum of 3mA when asserting low state.
Typical Operating Characteristics
(VCC = +5.0V, VDD = +3.3V, TA = +25°C, unless otherwise noted.)
4.0
8
2.5
2.0
100kbps DATA, 100kHz CLOCK, INCLUDES
3.3kΩ PULLUP RESISTORS FOR 5V SUPPLY
RANGE AND 2.2kΩ PULLUP RESISTORS FOR
3.3V SUPPLY RANGE
WITH
MAX3816A
7
CABLE CLOAD = 3000pF
3.0
IDD (mA)
ICC (mA)
3.5
9
6
DISPLAY CLOAD = 330pF
1V/div
100kbps DATA, 100kHz CLOCK,
INCLUDES 3.3kΩ PULLUP RESISTORS
MAX3816A toc01
4.5
10
MAX3816A toc02
IDD vs. VDD
5.0
MAX3816A toc03
ICC vs. VCC
CLOCK_C TRANSIENT RESPONSE
WITH AND WITHOUT MAX3816A, 30m CABLE LOAD
(2350pF)
5
WITHOUT
MAX3816A
4
CABLE CLOAD = 60pF
1.5
3
1.0
2
0.5
1
0
DISPLAY CLOAD = 10pF
0
4.50
4.75
5.00
VCC (V)
5.25
5.50
3.0
3.5
4.0
4.5
5.0
5.5
2μs/div
VDD (V)
3.3kΩ PULLUP RESISTOR AT EACH END OF CABLE.
PULLDOWN SOURCE: 25Ω CMOS SWITCH SIGNAL
INITIATED AND MEASURED AT REMOTE SOURCE.
_______________________________________________________________________________________
3
MAX3816A
ELECTRICAL CHARACTERISTICS (continued)
Typical Operating Characteristics (continued)
(VCC = +5.0V, VDD = +3.3V, TA = +25°C, unless otherwise noted.)
WITH
MAX3816A
1V/div
2μs/div
WITHOUT
MAX3816A
WITHOUT
MAX3816A
2μs/div
2μs/div
WITH
MAX3816A
CABLE SIDE TRANSITION TIME
vs. CABLE CAPACITANCE
1200
30% TO 70% RISE OR FALL (ns)
1V/div
MAX3816A toc07
CLOCK_C TRANSIENT RESPONSE
WITH AND WITHOUT MAX3816A, 62pF CABLE LOAD
WITHOUT
MAX3816A
3.3kΩ PULLUP RESISTOR AT EACH END OF CABLE.
PULLDOWN SOURCE: 25Ω CMOS SWITCH SIGNAL
INITIATED AND MEASURED AT REMOTE SOURCE.
3.3kΩ PULLUP RESISTOR AT EACH END OF CABLE.
PULLDOWN SOURCE: 25Ω CMOS SWITCH SIGNAL
INITIATED AND MEASURED AT REMOTE SOURCE.
VCC = 5V, 3.3kΩ PULLUP RESISTOR AT EACH
END OF CABLE
1000
MAX3816A toc08
WITHOUT
MAX3816A
3.3kΩ PULLUP RESISTOR AT EACH END OF CABLE.
PULLDOWN SOURCE: 25Ω CMOS SWITCH SIGNAL
INITIATED AND MEASURED AT REMOTE SOURCE.
MAX3816A toc06
WITH
MAX3816A
1V/div
WITH
MAX3816A
DATA_C TRANSIENT RESPONSE
WITH AND WITHOUT MAX3816A, 60m CABLE LOAD
(4700pF)
MAX3816A toc05
CLOCK_C TRANSIENT RESPONSE
WITH AND WITHOUT MAX3816A, 60m CABLE LOAD
(4700pF)
MAX3816A toc04
CLOCK_C TRANSIENT RESPONSE
WITH AND WITHOUT MAX3816A, 30m CABLE LOAD
(3100pF)
1V/div
MAX3816A
I2C 2-Wire Extender for DDC in DVI,
HDMI, and VGA Interfaces
800
600
RISE TIME
400
200
FALL TIME
0
2μs/div
PULLUP RESISTORS: TWO 3.3kΩ IN PARALLEL.
PULLDOWN SOURCE: 25Ω CMOS SWITCH.
4
0
1000
2000
3000
4000
5000
CAPACITANCE (pF)
_______________________________________________________________________________________
6000
I2C 2-Wire Extender for DDC in DVI,
HDMI, and VGA Interfaces
SERIES MODE TRANSIENT RESPONSE
(3000pF CABLE CAPACITANCE)
VIDEO SOURCE
CLOCK
5V/div
CLOCK_C AT
MAX3816A
2V/div
REFLECTION
ABERRATION AT
CLOCK_C PIN
NOT SEEN AT SOURCE
VIDEO SOURCE
DATA
5V/div
DISPLAY CLOCK
5V/div
MAX3816A toc10
MAX3816A toc09
REFLECTION ABSORBED BY MAX3816A
CLOCK_C AT
REMOTE CLIENT
2V/div
ACTUAL SIGNAL
AT VIDEO SOURCE
DISPLAY DATA
5V/div
2μs/div
1μs/div
50m CABLE ON SOURCE SIDE, 330pF CAPACITANCE
ON DISPLAY SIDE, VCC = 5V, VDD = 5V CLOCK AND
DATA INITIATED AT VIDEO SOURCE AND MEASURED
AT MAX3816A
60m CABLE, SIGNAL INITIATED AT DISPLAY SIDE
VTRIGIL vs. (VSS - GND_REF)
VHOLD vs. (VSS - GND_REF)
DISPLAY SIDE (REFERENCED
TO VDD RELATIVE TO VSS)
30
25
20
15
10
CABLE SIDE (REFERENCED
TO VDD RELATIVE TO GND_REF)
5
MAX3816A toc12
35
30
VTRIGIL (% OF SUPPLY VOLTAGE)
MAX3816A toc11
VHOLD (% OF SUPPLY VOLTAGE)
40
DISPLAY SIDE
(REFERENCED TO VDD)
25
20
15
10
CABLE SIDE
(REFERENCED TO VCC)
5
0
0
-0.6
-0.4
-0.2
0
0.2
VSS - GND_REF (V)
0.4
0.6
-0.6
-0.4
-0.2
0
0.2
0.4
0.6
VSS - GND_REF (V)
_______________________________________________________________________________________
5
MAX3816A
Typical Operating Characteristics (continued)
(VCC = +5.0V, VDD = +3.3V, TA = +25°C, unless otherwise noted.)
I2C 2-Wire Extender for DDC in DVI,
HDMI, and VGA Interfaces
MAX3816A
Pin Description
PIN
NAME
FUNCTION
1
DRVR_EN
2
VCC
3
CLOCK_C
I2C Cable-Side Clock with Cable Driver, CMOS Input/Output. Connect a 47k pullup resistor to VCC.
4
GND_REF
Cable-Side Ground Return. Connect directly to cable DDC ground wire. The MAX3816A circuitry uses
the video source DDC GND as a threshold reference. Also connect 10μF or larger bypass capacitors
as shown in Figure 6.
5
DATA_C
I2C Cable-Side Data with Cable Driver, CMOS Input/Output. Connect a 47k pullup resistor to VCC.
6
GND_REF
Cable-Side Ground Return (Alternate). Connected internally to pin 4 above.
Driver Enable Input, LVTTL/LVCMOS. Set high to enable all data and clock drivers for normal
operation. Set low to disable drivers, permitting isolation of cable bus from display bus.
Power Supply for Cable Side. In the DDC application, connect to DDC +5V. Connect 10μF or larger
bypass capacitor as shown in Figure 6.
7
VCC
Power Supply for Cable Side (Alternate). Connected internally to pin 2 above.
8, 9, 10
DNC
Do Not Connect
11
VDD
Power Supply for Display Side and Core Circuitry. Connect bypass capacitor as shown in Figure 6.
12
DATA_D
I2C Display-Side Data, CMOS Input/Output. Connect a 2.2k pullup resistor to VDD for VDD = 3.3V,
or a 3.3k pullup resistor to VDD for VDD = 5V.
13
VSS
14
CLOCK_D
15
VSS_T
Must Be Connected to V SS for Normal Operation
16
MODE
Mode Setting Input, LVTTL/LVCMOS. Force high for parallel mode (normal operation) and force low for
serial operation.
Ground for Display Side and Core Circuitry. Connect bypass capacitors as shown in Figure 6.
I2C Display-Side Clock, CMOS Input/Output. Connect a 2.2k pullup resistor to VDD for VDD = 3.3V,
or a 3.3k pullup resistor to VDD for VDD = 5V.
Theory of Operation
The MAX3816A has parallel and series modes. The
parallel mode is preferred for applications where high
tolerance to noncompliant source and sink devices is
desired (noncompliant VOL from displays and noncompliant VIH from sources are common). Further, the parallel mode can be operated with other speed-up
devices on the same bus, either active (DRVR_EN = HI)
or in bypass (DRVR_EN = LO).
Series mode is preferred for applications where high
tolerance to ground offset or noise between and source
and sink is needed. Series mode also isolates display
circuits from transmission line reflections in very long
cables, providing full isolation between cable and display buses. For in-display applications, series mode
can provide level shifting between the 5V cable DDC
and 3.3V display internal DDC.
A single MAX3816A is applied at the display side of the
video link to compensate for excessive cable capacitance. The overall operation of the MAX3816A, for
6
either the DATA or CLOCK signal, can be summarized
as follows (Figures 1a and 1b).
1) High state. Drivers off. Level sensing on.
If no client device is controlling the “wired-AND” bus
from either the source or display side, all device drivers are off and the bus (including the MAX3816A)
is waiting in the high state. The pullup resistors on
each side are holding the bus up to VCC on the
source side and VDD on the display side.
2) High-to-low transition. Drivers assert low. Level
sensing off (Holdoff).
A change of state is initiated by any device driver
pulling low. Once the signal transitions below 75%
of the power supply, the MAX3816A drives both the
source and display sides toward ground with a lowimpedance driver, level sensing is turned off, and
the holdoff timer is started. The source side is
pulled down to the level of the VSS. This is accomplished using a low-impedance n-channel buffer
that is designed to drive a 1 meter (60pF) to 60
_______________________________________________________________________________________
I2C 2-Wire Extender for DDC in DVI,
HDMI, and VGA Interfaces
3) Low state. Level sensing off (Holdoff).
Level sensing remains off until the completion of the
holdoff period, which is 2.5µs on both the clock and
data channels.
In series mode, drivers maintain low level (at or
below VHOLD). Either the client pulldowns sustain
the level below VOL, or the MAX3816A sustains the
level at VHOLD if no other driver on the same node
is pulling down. This action is in support of the
“wired-AND” function across source and display
sides.
4) Low state, drivers off. Level sensing on.
After the MAX3816A holdoff time completes, level
sensing resumes.
In series mode, the MAX3816A supports a “wiredAND” connection between source and display
sides; returning to the high state is supported only
when all client sources turn off. If either the source
or display side releases the bus, but not both, a
MAX3816A level-sensing buffer senses the transition at VTRIGIL, supporting the existing low state by
clamping the voltage to VHOLD and waiting for the
remaining side to release the bus.
5) Low-to-high transition. Drivers on. Level sensing
off (Holdoff).
A change of state is initiated when no device is
holding the bus low on both source and display
sides. When both sides exceed their respective
VTRIGIL levels, the source side turns on a slew-rate
controlled open-drain p-channel device, pulling up
to VCC for 1.75µs. Simultaneously, the display side
is released and the pullup resistors pull the displayside bus up to VDD, as per normal I2C operation.
6) High state. Drivers off. Level sensing off
(Holdoff).
During holdoff, no transitions are sensed. The high
state is maintained by external pullup resistors. Upon
the end of holdoff, when the cable and display levels
are above 85%, the state machine transitions to state
(1); otherwise, it waits until levels raise above 85% to
transition to state (1). Data, but not clock, has another exit from state (6) to (1) upon data source or data
display levels dropping below 60%.
I2C continuous clock applications are not recommended for the MAX3816A. The MAX3816A is optimized for
DDC applications with a noncontinuous clock.
Detailed Description
The MAX3816A DDC/I2C 2-wire extender consists of
two controllers with level-shifters, cable drivers, display
drivers, and level-sensing circuitry (Figure 2).
Controllers and Level Shifters
The MAX3816A functionality is governed by two controllers, one for CLOCK and one for DATA. Bidirectional
signaling is fully supported on both CLOCK and DATA.
The primary function of the controllers is to receive the
state-change information from the source- and displayside level-sense circuitry and support the “wired-AND”
function between the two. When the state changes, a
holdoff period is timed during which the source and
display drivers assert the next state, high or low, and all
input sensing is ignored while I/O transients settle
(Figure 3). The holdoff period is approximately 2.5µs.
The cable transmission-line termination feature is active
only during the first 1.75µs of holdoff, sufficiently long
enough to absorb roundtrip reflections from a 60m
cable.
In series mode, the CLOCK and DATA controllers isolate the source electronics from the display electronics.
The cable side of the MAX3816A is referenced to VCC
and GND_REF, and the display side is referenced to
VDD and VSS. This power scheme provides tolerance to
offset and noise between the source and display
devices.
Cable Drivers
The low-impedance cable drivers (Figure 10) can
charge and discharge at least 3000pF of capacitive
cable load within the I2C rise and fall time limits. The
drivers each incorporate a slew-rate limiter to control
the amount of high-frequency energy transmitted. The
cable drivers also provide a back termination impedance of approximately 60Ω to absorb transmission-line
reflections returning to the driver. The cable drivers
each include a high-state current-limiting feature to
clamp the output current to less than 16mA.
After 1.75µs of driver assertion, following a decision to
transition, the low-impedance drivers are turned off.
Subsequently, when another device asserts a new
state, it does not have to work against the low impedance of the MAX3816A.
_______________________________________________________________________________________
7
MAX3816A
meter (> 3000pF) cable with a controlled slew-rate.
Similarly, the display side is pulled down to VSS with
a controlled slew rate, open-drain n-channel MOS
device. These buffers stay on for 1.75µs.
MAX3816A
I2C 2-Wire Extender for DDC in DVI,
HDMI, and VGA Interfaces
Locally, connect a 47kΩ pullup resistor from CLOCK_C
and DATA_C to V CC . This assumes that a 1.65kΩ
pullup resistor resides at the opposite end of each
channel.
Locally, connect a 2.2kΩ pullup resistor from CLOCK_D
and DATA_D to VDD for VDD = 3.3V, or a 3.3kΩ pullup
resistor to VDD for VDD = 5V.
Display Drivers
The MAX3816A’s level-sensing circuitry monitors the
incoming data for state transitions. When the CLOCK or
DATA signal is high and drops below VTRIGIH, the controller ramps the outputs low. When the DATA and
CLOCK are low and both rise above VTRIGIL, referenced to GND_REF on the source side or VSS on the
display side, the output drives the level high.
The display drivers (Figure 11) are typical open-drain
pulldown devices capable of discharging up to 400pF
of capacitive load within the I2C fall-time limits.
HIGH
STATE
Level Sense
LOW
STATE
HOLDOFF TIMER = START
CLOCK_C “OR” CLOCK_D < 75%
1
2
SENSE ON
DRIVERS OFF
SENSE OFF
DRIVERS ON
HOLDOFF TIMER ≥ 2.5 μs
“AND”
CLOCK_C “AND” CLOCK_D > 85%
HOLDOFF TIMER = 1.75μs
6
3
SENSE OFF
DRIVERS OFF
SENSE OFF
(NOTE 3)
HOLDOFF TIMER = 2.5 μs
HOLDOFF TIMER = 1.75 μs
RAMP
UP
RAMP
DOWN
5
4
SENSE OFF
DRIVERS ON
SENSE ON
(NOTE 3)
HOLDOFF TIMER = START
CLOCK_D > 17.5% AND CLOCK_C > 12.5%
NOTES:
1) STATE CHANGE CONDITIONS ARE IN ITALICS. TRANSITION ACTIONS ARE UNDERLINED.
2) THE DATA CHANNEL STATE MACHINE IS IDENTICAL AND SYMMETRIC, EXCEPT THAT HOLDOFF TIME IS 2.0μs INSTEAD OF 2.5μs.
ALSO, IN ADDITION TO THE 85% CONDITION TO EXIT STATE 6, DATA HAS AN ADDITIONAL EXIT: DATA_C “OR” DATA_D < 60%.
3) DEPENDENT ON MODE PIN 16: MODE = LOW FOR SERIAL OPERATION (DRIVERS HOLD); MODE = HIGH FOR PARALLEL OPERATION (DRIVERS OFF).
Figure 1a. Clock State Machine Diagram
8
_______________________________________________________________________________________
I2C 2-Wire Extender for DDC in DVI,
HDMI, and VGA Interfaces
MAX3816A
VXX
CABLE/
SOURCE
SIDE
(NOTE 1)
DDC VIH = 70% VXX
VTRIGIH = 75% VXX
DDC VIL = 30% VXX
VTRIGIH = 12.5% VCC CLOCK_C,
17.5% VDD CLOCK_D
DDC VOL(max) = 0.4V
GND
3
STATE
NUMBER
1
2
6
4
5
1
VXX
DDC VIH = 70% VXX
DISPLAY
SIDE
(NOTE 1)
DDC VIL = 30% VXX
VHOLD = 15% VCC CLOCK_C,
20% VDD CLOCK_D
DDC VOL(max) = 0.4V
GND
HOLDOFF TIMER
0μs 1.75μs 2.5μs
0μs 1.75μs 2.5μs
NOTES:
1) THIS EXAMPLE APPLIES TO TRANSMISSION IN EITHER DIRECTION. SOURCE TO DISPLAY IS SHOWN.
2) VXX IS USED GENERICALLY FOR THE VOLTAGE AT THE VCC OR VDD PINS.
Figure 1b. Signal Waveform Example Showing States
_______________________________________________________________________________________
9
MAX3816A
I2C 2-Wire Extender for DDC in DVI,
HDMI, and VGA Interfaces
DRVR_EN
VDD
CMOS
VSS
MAX3816A
DRIVER ENABLE
VCC
CABLE DRIVER
VCC
VDD
DRIVER_ENABLE (INTERNAL)
DISPLAY
DRIVER
CABLE
TERMINATION
RESISTORS
CLOCK_C
CONTROLLER AND
LEVEL SHIFTER
CLOCK_D
VSS
GND_REF
VSS
VSS
VTRIGIH
LEVEL SENSE
LEVEL SENSE
VTRIGIH
LPF
LPF
VDD
VTRIGIL
VTRIGIL
DRIVER_ENABLE (INTERNAL)
CMOS
VCC
CABLE DRIVER
VCC
VDD
VSS
MODE
DRIVER_ENABLE (INTERNAL)
DISPLAY
DRIVER
CABLE
TERMINATION
RESISTORS
DATA_C
CONTROLLER AND
LEVEL SHIFTER
DATA_D
VSS
GND_REF
VSS
VSS
VTRIGIH
LEVEL SENSE
LEVEL SENSE
VTRIGIH
LPF
LPF
VTRIGIL
VTRIGIL
Figure 2. Functional Diagram
10
______________________________________________________________________________________
I2C 2-Wire Extender for DDC in DVI,
HDMI, and VGA Interfaces
tHOLDOFF
WITH
MAX3816A
VTRIGIH
CLOCK_C
OR
DATA_C
VTRIGIL
MAX3816A
tHOLDOFF
WITHOUT
MAX3816A
Figure 3. Holdoff Operation
tHOLDOFF_D
O = DECISION POINT
DATA
CLOCK
tHOLDOFF_C
Figure 4. Holdoff with Decision Points Shown
______________________________________________________________________________________
11
MAX3816A
I2C 2-Wire Extender for DDC in DVI,
HDMI, and VGA Interfaces
LONG CABLE FROM VIDEO SOURCE:
DVI, HDMI, OR M1 CONNECTOR
CABLE UP TO 60m (200ft)
DISPLAY I2C BUS
REFERENCE TO 3.3V
DISPLAY 3.3V
DDC +5V
VCC
47kΩ
VDD
47kΩ
2.2kΩ
2.2kΩ
MAX3816A
DDC SCL
CLOCK_C
DDC SDA
DATA_C
CLOCK_D
I2C SCL
DATA_D
I2C SDA
MODE
DRVR_EN
VCC
GND_REF
VSS
VDD OR VSS (SEE DESCRIPTION)
VSS
10μF
VDD
DDC GND
10μF
1μF
GROUND PLANE
SHIELD GNDS
DISPLAY GND
DISPLAY CIRCUIT BOARD
Figure 5. Typical In-Display Application Circuit
Applications Information
Use Single MAX3816A at Display Side
A single MAX3816A is designed to achieve full
100kbps operation over 60m (200ft) of cable.
•
•
In-Display Application, Series Mode
When inserted at the front-end of a display, the source
side of the MAX3816A should be powered by the
source VCC (typically 5V) and ground (GND_REF). The
display-side VDD should be powered by the local display supply (typically 3.3V) to level-shift and diminish
the effects of supply noise and offset between source
and display (Figure 5). Supply decoupling capacitors of
at least 10µF should be connected close to the
MAX3816A between GND_REF and V SS, as well as
between GND_REF and VCC.
12
•
•
MAX3816A In-Display, Series Mode Advantages
(See Figure 5)
Long cable reach.
The MAX3816A acts as a buffer between source and
display. Hence, source reflections are isolated to the
source side of the MAX3816A, protecting display circuits from reflections (stair-step waveforms).
The MAX3816A can be turned off (DRVR_EN asserted low) to isolate source and display buses. The display bus can then operate independently of
source-cable loading or malfunctions.
Multiple MAX3816As can be used in parallel as an
input mux to display, with only one “on” at a time.
Consideration
When using the level-shifter feature, as shown, and assuming the display 3.3V supply is off when the display is off,
the Display EDID Prom will not be able to communicate to
source DDC. If required, the solution is to either place a 5V
EDID Prom on the source side of the MAX3816A or derive
the 3.3V VDD from the DDC +5V supply.
______________________________________________________________________________________
I2C 2-Wire Extender for DDC in DVI,
HDMI, and VGA Interfaces
MAX3816A
LONG CABLE FROM VIDEO SOURCE:
DVI, HDMI, OR CAT-5 CABLE UP TO 60m
(200ft)
CONNECTOR TO DISPLAY
DVI, HDMI, OR M1 CONNECTOR, < 3m
5V*
DDC +5V
DDC +5V
47kΩ
VCC
47kΩ
VDD
3.3kΩ
3.3kΩ
MAX3816A
DDC SCL
CLOCK_C
DDC SDA
DATA_C
CLOCK_D
DDC SCL
DATA_D
DDC SDA
MODE
DRVR_EN
VCC
RETURN
VSS
VDD OR VSS (SEE DESCRIPTION)
VSS
10μF
DDC GND
DDC GND
10μF
GROUND PLANE
SHIELD GNDS
SHIELD GNDS
CABLE HEAD OR EXTENDER BOX
*TO MEET DVI/HDMI SPECIFICATIONS FOR THE DDC +5V LINK, THE VDD SIDE OF THE MAX3816A MUST BE EXTERNALLY POWERED.
IF NOT APPLICABLE, CONNECT TO DDC +5V.
Figure 6. External to Display, In Series
External Box or Cable Assembly
Applications
Three implementations external to the display such as
external box products or cable assemblies are shown
in Figures 6, 7, and 8.
MAX3816A External to Display, In Series
Advantages (See Figure 6)
• Long cable reach.
• The MAX3816A acts as a buffer between the source
and display. Hence, source reflections are isolated
to the source side of the MAX3816A, protecting display circuits from possible double clocking due to
stair-step waveforms caused by very long cables
with reflections.
• The MAX3816A can be turned off (DRVR_EN asserted low) to isolate source and display buses. The display bus can then operate independently of
source-cable loading or malfunctions. Also, multiple
MAX3816As can be used in parallel as an input mux
to display, with only one “on” at a time.
Consideration
Only one series-connected MAX3816A is allowed on a
bus. Two or more series-connected MAX3816A ICs will
not function. If multiple MAX3816A ICs are expected,
use the parallel applications in Figures 7 and 8.
______________________________________________________________________________________
13
MAX3816A
I2C 2-Wire Extender for DDC in DVI,
HDMI, and VGA Interfaces
+5V
+5V
3.3kΩ
SER
PAR
1
0
3.3kΩ
1
0
MAX4719
+5V
+5V
ENA
DRVR_EN
47kΩ
47kΩ
MODE
BYP
CLK_C
CLK_D
DATA_C
DATA_D
LONG CABLE
FROM SOURCE
CONNECTOR
TO DISPLAY
MAX3816A
SERIES MODE:
PARALLEL MODE:
BYPASS MODE:
ISOLATE MODE:
DRVR_EN = HI (ENA), MODE = LO (SER)
DRVR_EN = HI (ENA), MODE = HI (PAR)
DRVR_EN = LO (BYP), MODE = HI (PAR)
DRVR_EN = LO (BYP), MODE = LO (SER)
Figure 7. External to Display, Switchable Series and Parallel Mode
•
•
•
•
•
14
MAX3816A External to Display, Switchable Series
and Parallel Mode Advantages (See Figure 7)
Long cable reach.
In parallel mode, the MAX3816A is very tolerant of
noncompliant DDC sources and sinks.
The MAX3816A can be turned off and bypassed if
another MAX3816A or speed-up device is being
used on the same DDC.
In parallel mode, the MAX3816A can be used simultaneously with other I2C speed-up devices.
The MAX3816A acts as a buffer between source and
display. Hence, source reflections are isolated to the
source side of the MAX3816A, protecting display
circuits from possible double clocking due to stairstep waveforms caused by very long cables with
reflections.
• In series mode, the MAX3816A can be turned off
(DRVR_EN asserted low) to isolate between source
and display buses. The display bus can then operate independently of source-cable loading or malfunctions.
Consideration
Use a good quality CMOS switch with low resistance
(< 20Ω) and over/undervoltage tolerance.
______________________________________________________________________________________
I2C 2-Wire Extender for DDC in DVI,
HDMI, and VGA Interfaces
MAX3816A
LONG CABLE FROM VIDEO SOURCE:
DVI, HDMI, OR CAT-5 CABLE UP TO 60m
(200ft)
CONNECTOR TO DISPLAY
DVI, HDMI, OR M1 CONNECTOR, < 3m
5V*
DDC +5V
DDC +5V
47kΩ
47kΩ
DDC SCL
DDC SCL
DDC SDA
DDC SDA
VCC
VDD
MAX3816A
CLOCK_C
DATA_C
VCC
DATA_D
MODE
DRVR_EN
10μF
DDC GND
CLOCK_D
GND_REF
VSS
VDD
VDD OR VSS (SEE DESCRIPTION)
DDC GND
10μF
SHIELD GNDS
SHIELD GNDS
CABLE HEAD OR EXTENDER BOX
*TO MEET DVI/HDMI SPECIFICATIONS FOR THE DDC +5V LINK, THE VDD SIDE OF THE MAX3816A MUST BE EXTERNALLY POWERED. IF NOT APPLICABLE, CONNECT TO DDC +5V.
Figure 8. External to Display, In Parallel
MAX3816A External to Display, In Parallel
Advantages (See Figure 8)
• Medium-long cable reach.
• In parallel mode, the MAX3816A is very tolerant of
noncompliant DDC sources and sinks.
• The MAX3816A can be turned off if another
MAX3816A or speed-up device is being used on the
same DDC.
• The MAX3816A can be turned off without isolating
the display from the source side, letting DDC operate straight through unassisted or assisted.
Consideration
Long cable reflections can reach display circuits since
the MAX3816A is not used as a buffer between source
and display. Hence, very long cables could cause double-clocking at display circuits due to stair-step rise/fall
waveforms due to reflections.
______________________________________________________________________________________
15
I2C 2-Wire Extender for DDC in DVI,
HDMI, and VGA Interfaces
MAX3816A
Interface Schematics
VDD
VCC
MAX3816A
MAX3816A
SENSE
SENSE
VSS
RETURN
VCC
VSS
CLOCK_D
OR DATA_D
CLOCK_C
OR DATA_C
DRIVER
BACK
TERMINATION
VSS
DRIVERS
Figure 10. CLOCK_D/DATA_D Equivalent Interface Structure
RETURN
Figure 9. CLOCK_C/DATA_C Equivalent Interface Structure
VDD
MAX3816A
DRVR_EN
VSS
Figure 11. DRVR_EN Equivalent Interface Structure
16
______________________________________________________________________________________
I2C 2-Wire Extender for DDC in DVI,
HDMI, and VGA Interfaces
SOURCE CLIENT
DDC MASTER IN VIDEO SOURCE:
PC, DVD, STB
DDC +5V
RPULLUP
LONG CABLE
UP TO 60 METERS (200ft)
DVI OR HDMI CABLE, OR CAT-5
DDC+5V
DDC EXTENDER
ONE MAX3816A USED AT DISPLAY SIDE OF CABLE
IN CABLE HEAD, OR EXTENDER BOX, OR DISPLAY
DISPLAY CLIENT
CONNECTOR (OR SHORT CABLE < 3m)
TO PROJECTOR, LCD, PLASMA
RPULLUP
DDC +5V
FROM
SOURCE
DDC +5V
DDC+5V
47kΩ
VDD
VCC
47kΩ
3.3kΩ
RPULLUP
3.3kΩ
RPULLUP
MAX3816A
DDC SCL
DDC SCL
DDC SCL
CLOCK_C
DDC SDA
DDC SDA
DDC SDA
DATA_C
CLOCK_D
DDC SCL
DDC SCL
DATA_D
DDC SDA
DDC SDA
DDC GND
DRIVERS
INDISPLAY
MODE
DRVR_EN
VCC
GND_REF
VSS
VDD OR VSS
VSS
10μF
DDC GND
DRIVERS
INSOURCE
DDC GND
10μF
GROUND PLANE
SHIELDGNDS
SHIELDGNDS SHIELDGNDS
SOURCEGND
DISPLAYGND
VIDEO PROJECTOR
SELECT
RGB/HV
ADC/SYNC
VGA INPUT
MAX3816A
DDC EXTENDER
LAPTOP
HDMI/DVI-D
INPUT
IMAGE
SCALER AND
PROCESSOR
PANEL
INTERFACE
TIMING AND
DRIVERS
LCD,
DLP,
OR
LCOS
TMDS
DESERIALIZER
MAX3815
TMDS EQUALIZER
HDMI/DVI-D CABLE
UP TO 60m OR 200ft
______________________________________________________________________________________
17
MAX3816A
Typical In-Display Operating Circuits
MAX3816A
I2C 2-Wire Extender for DDC in DVI,
HDMI, and VGA Interfaces
Typical In-Display Operating Circuits (continued)
DVI-D EXTENDER BOX
UP TO 60m
DVI-D CABLE
MAX3816A
UP TO 3m
DVI-D CABLE
DDC EXTENDER
PC MONITOR
MAX3815
TMDS EQUALIZER
VIDEO SOURCE
DIGITAL CABLE
DIGITAL SATELLITE
DVD PC
Pin Configuration
Chip Information
TRANSISTOR COUNT: 5759
PROCESS: CMOS
TOP VIEW
+
DRVR_EN 1
16 MODE
VCC 2
15 VSS_T
14 CLOCK_D
CLOCK_C 3
GND_REF 4
MAX3816A
DATA_C 5
Package Information
For the latest package outline information and land patterns, go
to www.maxim-ic.com/packages.
13 VSS
12 DATA_D
GND_REF 6
11 VDD
VCC 7
10 DNC
DNC 8
9 DNC
PACKAGE TYPE
PACKAGE CODE
DOCUMENT NO.
16 TSSOP
U16+2
21-0066
TSSOP
Maxim cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim product. No circuit patent licenses are
implied. Maxim reserves the right to change the circuitry and specifications without notice at any time.
18 ____________________Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600
© 2008 Maxim Integrated Products
is a registered trademark of Maxim Integrated Products, Inc.
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