14
General Description The MAX3814 TMDS™ EQ/driver IC compensates for FR-4 and cable losses up to the DVI™/HDMI ® transmit connector and provides a fully compliant DVI/HDMI TMDS output. The device can also be used in DVI/HDMI cable applications to extend reach and improve jitter margin of cable channels at the receive-side connector. The on-chip TMDS drivers operate at a standard cur- rent level for implementing a typical DVI/HDMI non- back-terminated transmitter, as well as a 50% higher current mode for using a 200Ω back termination resis- tor (nonmatching) to achieve a 10dB return loss. Typical DVI/HDMI output drivers contribute to reflection problems between the connector and a typical high- impedance (open) DVI/HDMI Tx output. The selectable output current (LEVEL pin) gives the option of partial back termination (e.g., differentially connected 200Ω) to mitigate the reflection problem effectively while keeping common-mode offset to a minimum. The 4-channel implementation treats all channels identi- cally. To allow board layout flexibility for DVI and HDMI connectors, which have different channel order, the clock and data channels can be arbitrarily assigned. The MAX3814 operates from a 3.3V power supply, standard for DVI/HDMI applications, and is packaged in a 5mm x 5mm x 0.1mm, 32-pin TQFP package. Applications Laptop PC TMDS Equalizer and Driver Docking Station TMDS Equalizer and Driver Cable TMDS Equalizer Features Equalizes FR-4 Board Microstrip and Cable HF Losses Up to 15dB at 825MHz for Operation at 0.25Gbps to 1.65Gbps Compatible with HDMI 1.3 Less Than 0.2UI P-P Residual Jitter at 1.65Gbps for 0 to 15dB Channel Loss at 825MHz Input Terminations: 50Ω (Each Side to V CC ) ±10% Output of Driver is a Fully DVI/HDMI TMDS- Compatible Cable Driver Output Amplitude: 1.05V P-P Differential Enable Pin to Select Normal Operation or Power- Down Mode LEVEL Pin to Select Output Current for Use With or Without Back Termination 32-Pin TQFP for Four Channels; Any Channel Can Be Either a TMDS Data or Clock Signal V CC = 3.3V; Signal Pins Have Absolute Max Ratings of 5.5V (for Fault Conditions) MAX3814 DVI/HDMI TMDS FR-4 and Cable Equalizer/Driver ________________________________________________________________ Maxim Integrated Products 1 TERMINATED TO V CC IND+/- INC+/- INB+/- INA+/- OUTD+/- OUTC+/- OUTB+/- OUTA+/- ENABLE LEVEL OUTPUT LEVEL CONTROL MAX3814 4 3 2 EQUALIZER 1 4 3 2 LIMITING AMPLIFIER 1 4 3 2 DRIVER 1 Simplified Functional Diagram Ordering Information PART TEMP RANGE PIN-PACKAGE MAX3814CHJ+ 0°C to +70°C 32 TQFP 19-0813; Rev 2; 12/10 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. +Denotes a lead(Pb)-free/RoHS-compliant package. TMDS is a trademark of Silicon Image, Inc. DVI is a trademark of Digital Display Working Group. HDMI is a registered trademark and registered service mark of HDMI Licensing, LCC. EVALUATION KIT AVAILABLE Pin Configuration appears at end of data sheet.

EVALUATION KIT DVI/HDMI TMDS FR-4 and Cable Equalizer/Driver · MAX3814 DVI/HDMI TMDS FR-4 and Cable Equalizer/Driver 2 _____ ABSOLUTE MAXIMUM RATINGS

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General DescriptionThe MAX3814 TMDS™ EQ/driver IC compensates for FR-4 and cable losses up to the DVI™/HDMI® transmitconnector and provides a fully compliant DVI/HDMITMDS output. The device can also be used in DVI/HDMIcable applications to extend reach and improve jittermargin of cable channels at the receive-side connector.

The on-chip TMDS drivers operate at a standard cur-rent level for implementing a typical DVI/HDMI non-back-terminated transmitter, as well as a 50% highercurrent mode for using a 200Ω back termination resis-tor (nonmatching) to achieve a 10dB return loss.Typical DVI/HDMI output drivers contribute to reflectionproblems between the connector and a typical high-impedance (open) DVI/HDMI Tx output. The selectableoutput current (LEVEL pin) gives the option of partialback termination (e.g., differentially connected 200Ω) tomitigate the reflection problem effectively while keepingcommon-mode offset to a minimum.

The 4-channel implementation treats all channels identi-cally. To allow board layout flexibility for DVI and HDMIconnectors, which have different channel order, theclock and data channels can be arbitrarily assigned.

The MAX3814 operates from a 3.3V power supply,standard for DVI/HDMI applications, and is packagedin a 5mm x 5mm x 0.1mm, 32-pin TQFP package.

ApplicationsLaptop PC TMDS Equalizer and Driver

Docking Station TMDS Equalizer and Driver

Cable TMDS Equalizer

Features♦ Equalizes FR-4 Board Microstrip and Cable HF

Losses Up to 15dB at 825MHz for Operation at0.25Gbps to 1.65Gbps

♦ Compatible with HDMI 1.3

♦ Less Than 0.2UIP-P Residual Jitter at 1.65Gbps for0 to 15dB Channel Loss at 825MHz

♦ Input Terminations: 50Ω (Each Side to VCC) ±10%

♦ Output of Driver is a Fully DVI/HDMI TMDS-Compatible Cable Driver

♦ Output Amplitude: 1.05VP-P Differential

♦ Enable Pin to Select Normal Operation or Power-Down Mode

♦ LEVEL Pin to Select Output Current for Use Withor Without Back Termination

♦ 32-Pin TQFP for Four Channels; Any Channel CanBe Either a TMDS Data or Clock Signal

♦ VCC = 3.3V; Signal Pins Have Absolute MaxRatings of 5.5V (for Fault Conditions)

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DVI/HDMI TMDS FR-4 and Cable Equalizer/Driver

________________________________________________________________ Maxim Integrated Products 1

TERMINATED TO VCC

IND+/-

INC+/-

INB+/-

INA+/-

OUTD+/-

OUTC+/-

OUTB+/-

OUTA+/-

ENABLE

LEVELOUTPUT LEVEL CONTROLMAX3814

4

3

2EQUALIZER

1

4

3

2LIMITING

AMPLIFIER

1

4

3

2

DRIVER 1

Simplified Functional Diagram

Ordering InformationPART TEMP RANGE PIN-PACKAGE

MAX3814CHJ+ 0°C to +70°C 32 TQFP

19-0813; Rev 2; 12/10

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.

+Denotes a lead(Pb)-free/RoHS-compliant package.

TMDS is a trademark of Silicon Image, Inc.DVI is a trademark of Digital Display Working Group.HDMI is a registered trademark and registered service mark of HDMI Licensing, LCC.

EVALUATION KIT

AVAILABLE

Pin Configuration appears at end of data sheet.

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2 _______________________________________________________________________________________

ABSOLUTE MAXIMUM RATINGS

SPECIFICATION TABLES(Typical values measured at VCC = 3.3V, TA = +25°C; external terminations = 50Ω ±1%; min/max values valid over VCC = 3.3V±0.3V, TA = 0°C to +70°C; with external terminations = 50Ω ±1% to voltage = 3.3V ±0.7V. Tested at 1.65Gbps. AC parameters guar-anteed by design and characterization.)

POWER SUPPLY

Stresses beyond those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. These are stress ratings only, and functionaloperation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure toabsolute maximum rating conditions for extended periods may affect device reliability.

Termination-Supply Voltage Range.......................-0.5V to +4.0VSignal Voltage Range on Any One Signal Wire ....-0.5V to +4.0VCML Common-Mode Voltage Range on

Any I/O Pair (sustained) .....................................-0.5V to +5.5VCML Common-Mode Voltage Range on Any I/O Pair

(sustained, within VCC and GND) ...-3.3V to +3.3V, Differential

CML Output Loading (termination)............................0Ω to OpenOperating Ambient Temperature Range ................0°C to +70°CStorage Ambient Temperature Range...............-40°C to +150°CESD Human Body Model, Any Pin .....................................2000VLead Temperature (soldering, 10s) .................................+300°CSoldering Temperature (reflow) .......................................+260°C

PARAMETER CONDITIONS MIN TYP MAX UNITS

DC PARAMETERS

Supply Current 110 140 mA

OPERATING CONDITIONSPARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS

Supply Voltage VCC 3.0 3.3 3.6 V

Operating Ambient Temperature 0 25 70 °C

Data Rate 0.25 1.65 Gbps

Maximum Channel Loss At 825MHz, FR-4 microstrip compensate on curve

15 dB

Source Output Rise/Fall Time 20% to 80%, measured at source transmitter (input to channel)

240 ps

Differential Input-Voltage Swing Measured at source transmitter (input to channel)

700 1050 1400 mVP-P

Maximum Supply Noise Tolerance

DC-5000kHz, all specifications maintained 50 mVP-P

TMDS EQUALIZER PERFORMANCEPARAMETER CONDITIONS MIN TYP MAX UNITS

Residual Output Jitter (15 x RJRMS + DJ) from 0.25Gbps to 1.65Gbps

Subtract source jitter for DJ, 0 to 15dB FR4 loss at 825MHz (Note 1)

0.2 UIP-P

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_______________________________________________________________________________________ 3

SPECIFICATION TABLES (continued)(Typical values measured at VCC = 3.3V, TA = +25°C; external terminations = 50Ω ±1%; min/max values valid over VCC = 3.3V±0.3V, TA = 0°C to +70°C; with external terminations = 50Ω ±1% to voltage = 3.3V ±0.7V. Tested at 1.65Gbps. AC parameters guar-anteed by design and characterization.)

CML INPUTSPARAMETER CONDITIONS MIN TYP MAX UNITS

DC PARAMETERS

Common-Mode Input VoltageVCC -400

VCC +100

mV

Input Termination Voltage When disconnected from sourceVCC -

10VCC +

10mV

Single-Ended Input Termination With 50Ω load, each side to VCC 45 50 55 ΩAC PARAMETERS

Differential Input Return Loss < 1.6GHz 14 dB

CML OUTPUTSPARAMETER CONDITIONS MIN TYP MAX UNITS

DC PARAMETERS

With 50Ω load, each side to VCC;LEVEL = low

900 1050 1200

Differential Output-Voltage SwingWith 50Ω load, each side to VCC;LEVEL = high; 200Ω back termination

900 1050 1200

mVP-P

Single-Ended High OutputVoltage

LEVEL = lowVCC -

10VCC +

10mV

Single-Ended Low OutputVoltage

LEVEL = lowVCC -600

VCC -400

mV

Output Voltage When ENABLEDisabled

LEVEL = low, ENABLE = highVCC -

10VCC +

10mV

AC PARAMETERS

Output, Rise/Fall Time20% to 80%; with 50Ω load,each side to VCC

80 170 230 ps

Typical Operating Characteristics(VCC = +3.3V, TA = +25°C, unless otherwise noted. Residual jitter is measured directly from the eye diagram histogram after 5000 hits.)

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4 _______________________________________________________________________________________

Note 1: The specified FR-4 loss is from 12-mil traces, 7-mil spacing, and 6-mil depth (Prepreg) with no solder mask. The test patternis a 27 - 1, 20 zeros, inverted 27 - 1, and 20 ones.

LVTTL/LVCMOS AND OPEN-COLLECTOR LVTTL

PARAMETER CONDITIONS MIN TYP MAX UNITS

DC PARAMETERS

LVTTL Input High Voltage 2.0 V

LVTTL Input Low Voltage 0.8 V

LVTTL Input High Current -100 +100 μA

LVTTL Input Low Current -100 +100 μA

POWER-SUPPLY CURRENTvs. TEMPERATURE

MAX

3814

toc0

1

TEMPERATURE (°C)

POW

ER-S

UPPL

Y CU

RREN

T (m

A)

605040302010

50

100

150

00 70

LEVEL = HIGH

LEVEL = LOW

MAX3814 INPUT: EYE DIAGRAM OF 1.65Gbps DATA AFTER 80in OF FR-4

MAX3814 toc02

100ps/div

140m

V P-P

/div

MAX3814 toc03

MAX3814 OUTPUT: EYE DIAGRAM OF MAX3814 EQUALIZING 1.65Gbps DATA AFTER 80in OF FR-4

100ps/div

140m

V P-P

/div

SPECIFICATION TABLES (continued)(Typical values measured at VCC = 3.3V, TA = +25°C; external terminations = 50Ω ±1%; min/max values valid over VCC = 3.3V±0.3V, TA = 0°C to +70°C; with external terminations = 50Ω ±1% to voltage = 3.3V ±0.7V. Tested at 1.65Gbps. AC parameters guar-anteed by design and characterization.)

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_______________________________________________________________________________________ 5

MAX3814 toc04

MAX3814 OUTPUT: 1.65Gbps DATA AFTER30ft OF TENSOLITE 28 AWG CABLE

100ps/div

140m

V P-P

/div

MAX3814 toc05

MAX3814 OUTPUT: 250Mbps DATA AFTER 30ft OF TENSOLITE 28 AWG CABLE

100ps/div

140m

V P-P

/div

MAX3814 OUTPUT: 2.25Gbps DATA AFTER33ft OF 24 AWG SPECTRA STRIP CABLE

MAX3814 toc06

74ps/div

125m

V/di

v

Typical Operating Characteristics (continued)(VCC = +3.3V, TA = +25°C, unless otherwise noted. Residual jitter is measured directly from the eye diagram histogram after 5000 hits.)

SINGLE-ENDED/DIFFERENTIAL INPUT RETURN LOSS (S11/SDD11)

MAX

3814

toc0

7

FREQUENCY (MHz)

GAIN

(dB)

20001000

-25

-20

-15

-10

-5

0

-300 3000

(INPUT SIGNAL LEVEL = 0dBm)(OUTPUT DISABLED)

SDD11

S11

DETERMINISTIC JITTER vs.LENGTH OF FR-4 BOARD

MAX

3814

toc0

8

LENGTH OF FR-4 (in)

DJ (p

s)

908070605040302010

50

100

150

200

250

00 100

(SOURCE SIGNAL LEVEL = 700mVP-P/1200mVP-P,DATA RATE = 0.825Gbps AND 1.65Gbps,LOSS = 0.209dB/in AT 820MHz)

700mVP-P

1200mVP-P

1.65Gbps

825Mbps

700mVP-P

DETERMINISTIC JITTER vs.LENGTH OF 24 AWG CABLE

MAX

3814

toc0

9

LENGTH OF 24 AWG CABLE (ft)

DJ (p

s)

3530252015105

10

20

30

40

50

00 40

1.65Gbps

(SOURCE SIGNAL LEVEL = 700mVP-P,DATA RATE = 1.65Gbps AND 2.25Gbps,CABLE LOSS = 0.261dB/ft AT 1.12GHz)

2.25Gbps

DETERMINISTIC JITTER FOR 28 AWG TWIN AX CABLE

MAX

3814

toc1

0

LENGTH OF TWIN AX CABLE (ft)

DJ (p

s)

40302010

50

100

150

200

00 50

VIN = 700mVP-P

VIN = 1200mVP-P

(SOURCE SIGNAL LEVEL = 700mVP-P/1200mVP-P,DATA RATE = 1.65Gbps,LOSS = 0.358dB/ft AT 820MHz)

RESIDUAL JITTER DUE TO POWER-SUPPLYSINUSOIDAL NOISE

MAX

3814

toc1

1

NOISE FREQUENCY (MHz)

RESI

DUAL

JITT

ER (p

s)

1010.10.01

20

40

60

80

100

00.001 100

NO NOISE

50mV NOISE

(SOURCE SIGNAL LEVEL = 700mVP-P,NOISE SIGNAL LEVEL = 50mVP-P,

DATA RATE = 1.65Gbps, 60in FR-4)

RESIDUAL JITTERM

AX38

14 to

c12

INPUT SIGNAL LEVEL (mVP-P)

RESI

DUAL

JITT

ER (p

s)

15001100700

50

100

150

0300

(SOURCE SIGNAL LEVEL = 300mVP-P TO 1800mVP-P,DATA RATE = 1.65Gbps, 60in OF FR-4 BOARD,FR-4 LOSS = 12.61dB AT 820MHz)

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6 _______________________________________________________________________________________

Pin DescriptionPIN NAME FUNCTION

1, 8, 17, 24 N.C. No Connection. Not internally connected.

2 INB+ Positive TMDS Input, CML

3 INB- Negative TMDS Input, CML

4, 5, 9, 32 VCC Power Supply. All pins must be connected to VCC.

6 INC+ Positive TMDS Input, CML

7 INC- Negative TMDS Input, CML

10 IND+ Positive TMDS Input, CML

11 IND- Negative TMDS Input, CML

12 ENABLE Active-Low Enable Input, LVTTL. High to disable, outputs off. Low to enable, outputs on.

13, 16, 20, 21, 25, 28

VEE Negative Power Supply (Ground)

14 OUTD- Negative TMDS Output, CML

15 OUTD+ Positive TMDS Output, CML

18 OUTC- Negative TMDS Output, CML

19 OUTC+ Positive TMDS Output, CML

22 OUTB- Negative TMDS Output, CML

23 OUTB+ Positive TMDS Output, CML

26 OUTA- Negative TMDS Output, CML

27 OUTA+ Positive TMDS Output, CML

29 LEVEL Output Current Level Control, LVTTL. Low for 10mA output currents. High for 15mA currents. Used for 200 back differential termination resistors.

30 INA+ Positive TMDS Input, CML

31 INA- Negative TMDS Input, CML

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_______________________________________________________________________________________ 7

DRIVEREQUALIZER LIMITINGAMPLIFIER

TERMINATEDTO VCC

DRIVEREQUALIZER LIMITINGAMPLIFIER

TERMINATEDTO VCC

DRIVEREQUALIZER

EQUALIZER

LIMITINGAMPLIFIER

TERMINATEDTO VCC

DRIVERLIMITINGAMPLIFIER

TERMINATEDTO VCC

OUTD+/-

LEVELOUTPUT LEVEL CONTROL

OUTC+/-

OUTB+/-

OUTA+/-INA+/-

INB+/-

INC+/-

IND+/-

ENABLE

MAX3814

Detailed DescriptionThe MAX3814 TMDS equalizer/driver accepts differentialCML input data rates from 250Mbps to 1.65Gbps. It con-sists of four differential CML input buffers, four indepen-dent fixed equalizers, four limiting amplifiers, and fourdifferential CML output buffers (Figure 1). The MAX3814functions both as an equalizer and as a driver.

As an equalizer the MAX3814 automatically adjusts forattenuation levels up to 16dB at 825MHz from eitherdielectric board losses or skin-effect losses in coppercable.

As a driver the MAX3814 provides CML outputs. TheCML output is normally open (i.e., no back termination)and is DC-coupled by transmission line to a terminationat the far end per DVI/HDMI standards. The MAX3814provides nominally 10mA output-switching currents.However, with the MAX3814, there is a selectable highercurrent drive to accommodate a differential 200Ω backtermination resistor while maintaining the differentialswing of 1000mVP-P. This 200Ω back termination resistorserves to dampen signal reflections returning to thedevice from discontinuities in the channel such as DVI orHDMI connectors, providing a 10dB return loss. See theCML Inputs and Outputs section for more information.

Figure 1. Functional Diagram

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8 _______________________________________________________________________________________

CML Inputs and OutputsThe input buffers and the output drivers are current-mode logic (CML). See Figures 2, 3, and 4.

The input buffers consist of a 50Ω load resistor connectedto VCC and the input connected to a differential equalizer.

The output drivers are open-collector. The current inthese outputs can be adjusted to 10mA or 15mA withthe control pin LEVEL. For 10mA operation, each open-collector output drives through a transmission line to a50Ω pullup of the next stage, as shown in Figure 3. Forrecommended 15mA operation, the two outputs arebridged by an external 200Ω back termination resistor

that is subsequently pulled up by a 50Ω resistor of thenext stage, as shown in Figure 4. The ESD structure per-mits signals to achieve 5.5V absolute maximum ratings,high common-mode range, and compatibility to HDMItesting. The back termination resistor should be placedas close as possible to the MAX3814 in the layout.

The ESD protection for both the input and output cir-cuitry consists of diodes connected to a transient volt-age suppressor clamp shown as a Schottky diode inFigures 2, 3, and 4. For more information about thefunction of the suppressor clamp, refer to the DetailedDescription section of the MAX3208E data sheet(www.maxim-ic.com/MAX3208E).

EQUALIZERTRANSIENTSUPRESSORCLAMP

VCC

VCC

IN_+

IN_-

50Ω

50Ω

+

-

TRANSIENTSUPRESSORCLAMP

Figure 2. Simplified Input Circuit

5mA

50Ω50Ω

ENABLE = HIGH LEVEL = LOW

VT

TRANSIENTSUPRESSORCLAMP

10mA

OUT_+

OUT_-

Figure 3. Simplified Output Circuit Without Back TerminationResistor

Output Enable ControlThe ENABLE pin is an LVTTL input that allows the userto shut off the output-collector currents, thereby reduc-ing power consumption of the device. Forcing this pinhigh turns the output currents off; forcing this pin low(normal operation) turns the currents on.

Figure 5 shows a simplified circuit for both the outputand enable controls.

Applications InformationFigure 6a shows a typical TMDS channel from a graph-ics board of a laptop computer to a remote display.Maintaining a 100Ω differential impedance for thischannel has its challenges. Besides proper board lay-out of traces, there are multiple reflection points (A toH). For example, at interface F in Figure 6a, a circulararrow shows a reflection at the connector of a remotedisplay. When these reflections hit another interface,they reflect again and thus become echoes corruptingthe incident signal. In Figure 6b, the MAX3814 is usedto equalize losses, isolate reflections, and redrive thetransmission line with high fidelity.

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_______________________________________________________________________________________ 9

50Ω

200Ω

BACK TERMINATION

50Ω

VT

TRANSIENTSUPRESSORCLAMP

OUT_+

OUT_-

5mA

ENABLE = HIGH LEVEL = LOW

10mA

Figure 4. Simplified Output Circuit with Back TerminationResistor

TRANSIENTSUPRESSORCLAMP

50kΩ

44kΩ

VCC

44kΩ

88kΩ

LEVEL,ENABLEINPUTS

Figure 5. Simplified Input Circuitry for Output Level (LEVEL)and Enable (ENABLE) Control

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4 Laptop PC TMDS Equalizer and DriverAs shown at location XX in Figure 6b, the MAX3814equalizes trace losses and redrives the TMDS outputsat the docking connector. The 200Ω resistor at the out-put of the MAX3814 absorbs reflections from the dock-ing connector.

Dock or Port ExpanderThe MAX3814 can also be used on the dock or portexpander as it equalizes loss, isolates the connector,and redrives TMDS output signals at location YY asshown in Figure 6b. Similarly, with the previous applica-

tion, the 200Ω resistor at the output of the MAX3814absorbs reflections in this case from the DVI or theHDMI connector.

An optional 2dB to 6dB attenuator pad can be used toabsorb reflections between internal interface connec-tions. If used, the attenuator pad must be a matched Pior T attenuator network. The resulting flat through losscan be made by the excellent input sensitivity of theMAX3814 as shown in the Typical Application Circuits.The MAX3814’s excellent input sensitivity allows theattenuated signal to be restored.

DVI/HDMI TMDS FR-4 and Cable Equalizer/Driver

10 ______________________________________________________________________________________

LAPTOP

A

DOCKEXTERNAL DVI/HDMI

CABLE

DVI/HDMICONNECTOR

DVI/HDMICONNECTORMXM

CONNECTOR

REFLECTIONINTERFACES

DOCKINGCONNECTOR

INTERNALCONNECTOR

OR FLEX

REMOTE DISPLAY

GRAPHICSBOARD

ASIC ASIC

50Ω3.3V

50Ω3.3V

LAPTOP DOCK

EXTERNAL DVI/HDMICABLE

DVI/HDMICONNECTOR

DVI/HDMICONNECTORMXM

CONNECTORDOCKING

CONNECTOR

INTERNALCONNECTOR

OR FLEX

REMOTE DISPLAY

GRAPHICSBOARD

ASIC ASIC

200Ω50Ω3.3V

50Ω3.3V

50Ω3.3V

50Ω3.3V

50Ω3.3V

50Ω3.3V

200Ω50Ω3.3V

50Ω3.3V

200ΩPAD

B C D E F G H

MAX3814

XX

MAX3814

YY

MAX3814

ZZ

Figure 6a (top). Schematic Showing the TMDS Signal Channel from the Laptop Graphics Boards to the Remote Display. PossibleReflection Interfaces are Labeled A to H.

Figure 6b (bottom). Schematic Showing the Same Channel, with possible location of the MAX3814 to Equalize Losses, to AbsorbReflections, and to Redrive the Transmission Line.

Cable TMDS EqualizerThe MAX3814 is useful in providing equalization forcables losses at location ZZ, at the input DVI/HDMIconnector of the remote display. It can equalize cablelengths of 15 meters of 26 AWG wire and 12 meters of28 AWG wire. Again, the 200Ω resistor placed at theoutput of the MAX3814 absorbs reflections from theimperfect termination of the ASIC or imperfect transmis-sion-line interconnect.

Layout ConsiderationsThe TMDS CML inputs are the most critical paths forthe MAX3814 and great care should be taken to mini-mize discontinuities on these transmission linesbetween the connector and the IC. Here are some sug-gestions for maximizing the performance of theMAX3814.

• The data and clock inputs should be wired direct-ly between the cable connector and IC withoutstubs.

• The 4-channel implementation treats all channelsidentically. Input and output data channel designa-tions are only a guide. Polarity assignments can beswapped and channel paths can be interchanged.

• An uninterrupted ground plane should be posi-tioned beneath the high-speed I/Os.

• Ground-path vias should be placed close to theIC and the input/output interfaces to allow a returncurrent path to the IC and the DVI and HDMIinputs.

• Maintain a 100Ω differential transmission lineimpedance into and out of the MAX3814.

• To minimize possible reflections, choose the200Ω back termination option. Place this resistoras close to the MAX3814 as possible.

• Use good high-frequency layout techniques andmultilayer boards with an uninterrupted groundplane to minimize EMI and crosstalk. Refer to theschematic and board layers of the MAX3814EVKIT.

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______________________________________________________________________________________ 11

LAPTOP DOCKEXTERNAL DVI/HDMI

CABLE

DVI/HDMICONNECTOR

DVI/HDMICONNECTORMXM

CONNECTORDOCKING

CONNECTOR

REMOTE DISPLAY

GRAPHICSBOARD

ASIC ASIC

200Ω50Ω3.3V

50Ω3.3V

50Ω3.3V

50Ω3.3V

50Ω3.3V

50Ω3.3V

200Ω

CMOSROUTINGSWITCH

50Ω3.3V

50Ω3.3V

200Ω

MAX3814 MAX3814 MAX3814

Typical Application Circuits

MAX3814DRIVER/EQUALIZER

MAX3816DDC EXTENDER

MAX3815EQUALIZER

HDTV

UP TO 60mDVI-D OR

HDMI CABLE

STANDARDLENGTH DVI-D

OR HDMI CABLE

DIGITAL BROADCASTDIGITAL CABLE

DIGITAL SATELLITEDVD

Blu-ray™ DISCHD-DVD

Blu-ray is a trademark of Blu-ray Disc Association.

DVI-D OR HDMIEXTENDER BOX

VIDEO SOURCE

Typical Application Circuits (continued)

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12 ______________________________________________________________________________________

MAX3814

EQ/DRIVER

VCC

3.3V ±10%

VCC

VCC

LEVEL

50Ω0.1μF

0.1μF

0.1μF

0.1μFZ (DIFFERENTIAL) = 100Ω

AC-COUPLING APPLICATION:(NOT FOR A DC-COUPLED

DVI/HDMI TMDS LINK)

CONTROLLED IMPEDANCETRANSMISSION LINE OR CABLE

CONTROLLED IMPEDANCETRANSMISSION LINE OR CABLE

Z (DIFFERENTIAL) = 100Ω

50Ω

VCC

Rx

3.3V

50Ω

50Ω

3.3V

3.3V ±10%

100Ω

100Ω

3.3V ±10%

ENABLEGND

(1 OF 4)

MA

X3

81

4

DVI/HDMI TMDS FR-4 and Cable Equalizer/Driver

______________________________________________________________________________________ 13

Chip InformationPROCESS: SiGe BiPOLAR

Package InformationFor the latest package outline information and land patterns,go to www.maxim-ic.com/packages. Note that a “+”, “#”, or“-” in the package code indicates RoHS status only. Packagedrawings may show a different suffix character, but the drawingpertains to the package regardless of RoHS status.

MAX3814

TQFP(5mm × 5mm × 1.0mm)

TOP VIEW

29

30

28

27

12

11

13

INB+ V C

C

V CC

INC+

INC-

14

N.C.

OUTB

+

V EE

V EE

N.C.

OUTC

+

OUTC

-

1

+

2

VEE

4 5 6 7

2324 22 20 19 18

LEVEL

INA+

OUTD-

VEE

ENABLE

IND-

INB-

OUTB

-

3

21

31 10INA- IND+

32 9VCC VCC

OUTA+

26 15 OUTD+OUTA-

25 16 VEEN.

C.N.

C.

8

17

VEE

Pin Configuration

PACKAGETYPE

PACKAGECODE

OUTLINENO.

LANDPATTERN NO.

32 TQFP H32+1 21-0110 90-0149

MA

X3

81

4

DVI/HDMI TMDS FR-4 and Cable Equalizer/Driver

Maxim cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim product. No circuit patent licenses areimplied. Maxim reserves the right to change the circuitry and specifications without notice at any time.

14 ____________________Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600

© 2010 Maxim Integrated Products Maxim is a registered trademark of Maxim Integrated Products, Inc.

Revision HistoryREVISION NUMBER

REVISION DATE

DESCRIPTION PAGES

CHANGED

0 5/07 Initial release —

1 9/07 Corrected TA = 0°C to +85°C to TA = 0°C to +70°C in the Specification Tablesglobals; replaced the package outline drawing with the Package Information table

2, 3, 4, 13

2 12/10 Changed the operating ambient temperature max from 85°C (max) to 70°C (max) in the Operating Conditions table; added the package code and land pattern no. to the Package Information table

2, 13