MAXIM MAX4998ETI+T

19-5033; Rev 0; 10/09
Two-Lane and Four-Lane DisplayPort Passive
Switches with Separate AUX/HPD Control
Features
The MAX4998/MAX14998 high-speed passive switches
route DisplayPort™ between two possible destinations
or vice versa in laptops or desktop PCs. The MAX4998/
MAX14998 are intended to be used where ultra-highspeed performance and minimal input capacitance is
required.
S Single 3.3V Power-Supply Voltage
The MAX4998 has three double-pole/double-throw
(DPDT) switches and one single-pole/double-throw
(SPDT) switch. Two DPDT switches are for high-frequency switching, one DPDT switch is for AUX, and the one
SPDT switch is for HPD. The two high-frequency switches
are selected by SEL1, and the AUX and HPD are selected
by SEL2. This part is suitable for two-lane DisplayPort
switching.
S Designed for AC-Coupled Circuits
The MAX14998 has six double-pole/double-throw (DPDT)
switches. Four DPDT switches are for high-frequency
switching, and two DPDT switches are for AUX and HPD.
The four high-frequency switches are selected by SEL1,
and the AUX and HPD are selected by SEL2. This part is
suitable for four-lane DisplayPort switching.
The MAX4998/MAX14998 are fully specified to operate
from a single +3.3V (typ) power supply. The MAX4998
is available in a 3.5mm x 5.5mm, 28-pin TQFN package
with exposed pad, and the MAX14998 is available in a
3.5mm x 9mm, 42-pin TQFN package with exposed pad.
Both devices operate over the -40NC to +85NC extended
temperature range.
Applications
Notebook PCs
S 5GHz Bandwidth
S Support 1.6/2.7Gbps DisplayPort Signals
S Excellent Return Loss -14dB at 1.35GHz
S Independent High Frequency: AUX Select
S Pass Throughs Are Maintained
S Low 850µA (max) Supply Current
S Small Packages
3.5mm x 5.5mm, 28-Pin TQFN Package with
Exposed Pad
3.5mm x 9mm, 42-Pin TQFN Package with
Exposed Pad
S Flow-Through Layout for Easy Board Layout
S ESD Protection for All I/O Pins: Human Body
Model (HBM) Q4kV
Ordering Information
TEMP RANGE
PIN-PACKAGE
MAX4998ETI+T
PART
-40NC to +85NC
28 TQFN-EP**
MAX14998ETO+T*
-40NC to +85NC
42 TQFN-EP**
+Denotes a lead(Pb)-free/RoHS-compliant package.
T = Tape and reel.
*Future Product. Contact factory for availability.
**EP = Exposed Pad.
Typical Operating Circuit appears at end of data sheet.
Desktop PCs
DisplayPort is a trademark of Video Electronics Standards
Association (VESA).
________________________________________________________________ Maxim Integrated Products 1
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.
MAX4998/MAX14998
General Description
MAX4998/MAX14998
Two-Lane and Four-Lane DisplayPort Passive
Switches with Separate AUX/HPD Control
ABSOLUTE MAXIMUM RATINGS
(All voltages referenced to GND, unless otherwise noted.)
VDD. .........................................................................-0.3V to +4V
SEL1, SEL2, COM_, NO_, NC_ (Note 1)......-0.3V to +(VDD + 0.3)V
|VCOM_ - VNO_|, |VCOM_ - VNC_| (Note 1)...................... 0 to +2V
Continuous Current (COM_ to NO_/NC_)........................ Q70mA
Peak Current (COM_ to NO_/NC_)
(pulsed at 1ms, 10% duty cycle).................................. Q70mA
Continuous Current (SEL1, SEL2).................................... Q30mA
Peak Current (SEL1, SEL2)
(pulsed at 1ms, 10% duty cycle).................................. Q70mA
Continuous Power Dissipation (TA = +70NC)
28-Pin TQFN (derate 28.6mW/NC above +70NC)........2285mW
42-Pin TQFN (derate 34.5mW/NC above +70NC)........2758mW
Operating Temperature Range........................... -40NC to +85NC
Junction Temperature......................................................+150NC
Storage Temperature Range............................. -65NC to +150NC
Package Junction-to-Ambient Thermal Resistance (BJA) (Note 2)
28-Pin TQFN..................................................................35NC/W
42-Pin TQFN..................................................................29NC/W
Package Junction-to-Case Thermal Resistance (BJC) (Note 2)
28-Pin TQFN.................................................................2.7NC/W
42-Pin TQFN....................................................................2NC/W
Lead Temperature (soldering, 10s).................................+300NC
Note 1: Signals on COM_, NO_, NC_, SEL1, and SEL2 exceeding VDD or GND are clamped by internal diodes. Limit forwarddiode current to the maximum current rating.
Note 2: Package thermal resistances were obtained using the method described in JEDEC specification JESD51-7, using a
4-layer board. For detailed information on package thermal considerations, refer to www.maxim-ic.com/thermal-tutorial.
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
(VDD = +3.3V Q10%, TA = TMIN to TMAX, unless otherwise noted. Typical values are at VDD = +3.3V, TA = +25NC, unless otherwise
noted.) (Note 3)
PARAMETER
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
(VDD 1.8)
V
1.8
V
ANALOG SWITCH
Analog Signal Range
Voltage Between COM_ and
NO_/NC_
On-Resistance
VCOM_, VNO_,
VNC_
|VCOM_ - VNO_|,
|VCOM_ - VNC_|
RON
0
ICOM_ = 15mA;
VNO_, VNC_ = 0V, +1.2V
7
I
On-Resistance Match
Between Pairs of Same
Channel
DRON
VDD = +3.0V; ICOM_ = 15mA; VNO_,
VNC_ = 0V (Notes 4, 5)
0.1
2
I
On-Resistance Match
Between Channels
DRON
VDD = +3.0V; ICOM_ = 15mA; VNO_,
VNC_ = 0V (Notes 4, 5)
1.0
4
I
On-Resistance Flatness
RFLAT(ON)
VDD = +3.0V; ICOM_ = 15mA; VNO_,
VNC_ = 0V, +1.2V (Notes 5, 6)
0.3
1.5
I
NO_ or NC_ Off-Leakage
Current
INO_(OFF)
INC_(OFF)
VDD = +3.6V; VCOM_ = 0V, +1.2V;
VNO_ or VNC_ = +1.2V, 0V
-1
1
FA
COM_ On-Leakage
Current
ICOM_(ON)
VDD = +3.6V; VCOM_ = 0V, +1.2V;
VNO_ or VNC_ = VCOM_ or unconnected
-1
1
FA
120
ns
DIGITAL SIGNALS
SEL1 and SEL2 to Switch
Turn-On Time
tON_SEL
VNO_ or VNC_ = +1.0V, RL = 50I,
CL = 100pF (Figure 1)
45
2 _______________________________________________________________________________________
Two-Lane and Four-Lane DisplayPort Passive
Switches with Separate AUX/HPD Control
(VDD = +3.3V Q10%, TA = TMIN to TMAX, unless otherwise noted. Typical values are at VDD = +3.3V, TA = +25NC, unless otherwise
noted.) (Note 3)
PARAMETER
SYMBOL
SEL1 and SEL2 to Switch
Turn-Off Time
tOFF_SEL
Differential Insertion Loss
SDD21
Differential Crosstalk
CONDITIONS
SDD11
Signal Data Rate
BR
Differential -3dB Bandwidth
f-3BW
Differential Off-Isolation
TYP
MAX
UNITS
5
50
ns
VNO_ or VNC_ = +1.0V, RL = 50I,
CL = 100pF (Figure 1)
SDDCTK
Differential Return Loss
MIN
SDD21_OFF
f = 0.8GHz (Figure 2)
-0.67
f = 1.35GHz (Figure 2)
-0.95
f = 0.8GHz (Figure 2)
-37
f = 1.35GHz (Figure 2)
-34
f = 0.8GHz (Figure 2)
-20
f = 1.35GHz (Figure 2)
-14
RS = RL = 100I balanced
RS = RL = 100I balanced
17
Gbps
8.5
GHz
f = 1.35GHz (Figure 2)
-28
dB
dB
dB
dB
LOGIC INPUT (SEL1, SEL2)
Input Logic-High
VIH
Input Logic-Low
VIL
Input Logic Hysteresis
VHYST
Input Leakage Current
IIN
1.4
V
0.5
100
VSEL_ = 0V or VDD
V
mV
-1
+1
FA
3.0
3.6
V
850
FA
POWER SUPPLY
Power-Supply Range
VDD
VDD Supply Current
IDD
VSEL_ = 0V or VDD
500
Note 3: All units are 100% production tested at TA = +85NC. Limits over the operating temperature range are guaranteed by
design and characterization and are not production tested.
Note 4: DRON = RON(MAX) - RON(MIN).
Note 5: Guaranteed by design. Not production tested.
Note 6: Flatness is defined as the difference between the maximum and minimum value of on-resistance as measured over the
specified analog signal range.
Test Circuits/Timing Diagrams
+3.3V
LOGIC
INPUT
SEL_
VDD
t r < 5ns
t f < 5ns
VIH
VIL
50%
MAX4998/MAX14998
VN_
NO_ OR NC_
t OFF_SEL
COM_
VOUT
RL
SEL_
LOGIC
INPUT
SEL
CL
SWITCH
OUTPUT
COM_
VOUT
0.9 x VOUT
t ON_SEL
GND
t OFF_SEL
CL INCLUDES FIXTURE AND STRAY CAPACITANCE.
VOUT = VN_
0.9 x VOUT
0V
(
RL
RL + RON
)
SWITCH
OUTPUT
COM_
0.9 x VOUT
0.9 x VOUT
0V
t ON_SEL
Figure 1. Switching Time
_______________________________________________________________________________________ 3
MAX4998/MAX14998
ELECTRICAL CHARACTERISTICS (continued)
MAX4998/MAX14998
Two-Lane and Four-Lane DisplayPort Passive
Switches with Separate AUX/HPD Control
Test Circuits/Timing Diagrams (continued)
+3.3V
+3.3V
0.1µF
0.1µF
VDD
0V
0V
SEL1
SEL2
COM_+
MAX4998
MAX14998
50Ω
50Ω
COM_-
NC_+
NETWORK
ANALYZER
PORT 1
VIN+
50Ω
PORT 2
VIN-
50Ω
PORT 3
VOUT+
50Ω
VDD
NC_-
50Ω
COM_-
NC_+
50Ω
PORT 4
VOUT-
COM_+
MAX4998
MAX14998
NO_+
NO_-
SEL1
SEL2
VDD
VDD
NETWORK
ANALYZER
PORT 1
VIN+
50Ω
PORT 2
VIN-
50Ω
PORT 3
VOUT+
50Ω
PORT 4
VOUT-
50Ω
NO_+
50Ω
NO_-
NC_-
GND
GND
DIFFERENTIAL INSERTION LOSS/DIFFERENTIAL RETURN LOSS
DIFFERENTIAL INSERTION LOSS = 20log
(
VOUT+ - VOUTVIN+ - VIN-
DIFFERENTIAL OFF-ISOLATION
)
DIFFERENTIAL OFF-ISOLATION = 20log
(
+3.3V
0.1µF
VDD
0V OR VDD
0V OR VDD
SEL1
SEL2
COM_+
MAX4998
MAX14998
50Ω
50Ω
50Ω
50Ω
COM_-
NETWORK
ANALYZER
PORT 1
VIN+
50Ω
PORT 2
VIN-
50Ω
PORT 3
VOUT+
50Ω
PORT 4
VOUT-
50Ω
COM_+
COM_-
NO_+/NC_+
NO_+/NC_+
NO_-/NC_-
NO_-/NC_GND
DIFFERENTIAL CROSSTALK
DIFFERENTIAL CROSSTALK = 20log
(
VOUT+ - VOUTVIN+ - VIN-
)
MEASUREMENTS ARE STANDARDIZED AGAINST SHORTS AT IC TERMINALS.
DIFFERENTIAL OFF-ISOLATION IS MEASURED BETWEEN COM_ AND “OFF” NO_ OR NC_ TERMINAL ON EACH SWITCH.
DIFFERENTIAL ON-LOSS IS MEASURED BETWEEN COM_ AND “ON” NO_ OR NC_ TERMINAL ON EACH SWITCH.
DIFFERENTIAL CROSSTALK IS MEASURED BETWEEN ANY TWO PAIRS.
Figure 2. Differential On-Loss, Differential Off-Isolation, and Differential Crosstalk
4 _______________________________________________________________________________________
VOUT+ - VOUTVIN+ - VIN-
)
Two-Lane and Four-Lane DisplayPort Passive
Switches with Separate AUX/HPD Control
ON-RESISTANCE vs. COM_ VOLTAGE
6.0
5.5
TA = +25°C
7
TA = -40°C
6
5.0
-0.1 0.1
-0.1 0.1 0.3 0.5 0.7 0.9 1.1 1.3 1.5 1.7 1.9
0.3
0.5
1.1
1.3
0.9
VIL
3.5
tON_SEL
30
20
tOFF_SEL
3.6
3.0
3.1
3.2
3.3
3.4
-40
-50
-60
-70
3.5
-80
1000
FREQUENCY (MHz)
-5
-6
-7
-8
10
-20
-30
10,000
1000
10,000
DIFFERENTIAL RETURN LOSS
MAX4998/MAX14998 toc08
-10
100
FREQUENCY (MHz)
-40
-50
-60
0
-5
-10
-15
-20
-25
-30
-35
-80
100
-4
3.6
-70
10
-3
DIFFERENTIAL CROSSTALK
0
DIFFERENTIAL CROSSTALK (dB)
-30
-2
SUPPLY VOLTAGE (V)
MAX4998/MAX14998 toc07
-20
-1
-9
DIFFERENTIAL OFF-ISOLATION
-10
85
-10
SUPPLY VOLTAGE (V)
0
60
MAX4998/MAX14998 toc09
3.4
35
0
0
3.3
10
MAX4998/MAX14998 toc06
50
40
-15
DIFFERENTIAL INSERTION LOSS
TURN-ON/OFF TIME vs. SUPPLY VOLTAGE
0.5
3.2
200
TEMPERATURE (°C)
10
3.1
300
-40
DIFFERENTIAL INSERTION LOSS (dB)
VIH
1.1
3.0
400
0
1.5
DIFFERENTIAL RETURN LOSS (dB)
LOGIC THRESHOLD (V)
0.9
MAX4998/MAX14998 toc05
VDD = 3.3V
1.3
DIFFERENTIAL OFF-ISOLATION (dB)
0.7
60
TURN-ON/OFF TIME (ns)
MAX4998/MAX14998 toc04
LOGIC THRESHOLD vs. SUPPLY VOLTAGE
0.7
500
VCOM_ (V)
VCOM_ (V)
1.5
600
100
4
4.0
VDD = 3.3V
700
5
4.5
MAX4998/MAX14998 toc03
TA = +85°C
8
800
SUPPLY CURRENT (µA)
6.5
VDD = 3.3V
ICOM_ = 15mA
9
SUPPLY CURRENT vs. TEMPERATURE
MAX4998/MAX14998 toc02
7.0
10
ON-RESISTANCE (Ω)
VDD = 3.6V
ICOM_ = 15mA
7.5
ON-RESISTANCE (Ω)
MAX4998/MAX14998 toc01
ON-RESISTANCE vs. COM_ VOLTAGE
8.0
-40
10
100
1000
FREQUENCY (MHz)
10,000
10
100
1000
10,000
FREQUENCY (MHz)
_______________________________________________________________________________________ 5
MAX4998/MAX14998
Typical Operating Characteristics
(TA = +25°C, unless otherwise noted.)
Pin Configurations
NC5-
NC5+
NC4-
NC4+
VDD
NO3-
NO3+
NO2-
NO2+
NO1-
NO1+
NO0-
NO0+
NC3-
6
7
8
9
TQFN
18 NO5-
10 11 12 13 14 15 16 17
SEL2
5
SEL1
4
COM5-
3
COM5+
2
VDD
1
COM4-
10
COM4+
9
COM3-
8
COM3+
7
SEL1
COM1-
6
VDD
COM1+
5
COM3+
4
VDD
3
COM2-
2
COM2+
1
COM0-
+
19 NO5+
*EP
+
COM2-
NC0+ 42
*EP
COM2+
11 SEL2
NC0+ 28
20 NO4-
MAX14998
VDD
NC0- 41
COM1-
12 NO3+
21 NO4+
COM1+
NC1+ 40
COM0-
NC1- 39
13 NO2-
VDD
14 NO2+
COM0+
NC1- 25
NC1+ 26
MAX4998
NC3+
38 37 36 35 34 33 32 31 30 29 28 27 26 25 24 23 22
24 23 22 21 20 19 18 17 16 15
NC0- 27
NC2-
NC2+
VDD
NC3+
NC2-
NC2+
VDD
NO1-
NO1+
NO0-
GND
NO0+
TOP VIEWS
COM0+
MAX4998/MAX14998
Two-Lane and Four-Lane DisplayPort Passive
Switches with Separate AUX/HPD Control
TQFN
*CONNECT EXPOSED PAD TO GROUND.
Pin Description
PIN
NAME
FUNCTION
MAX4998
MAX14998
1
2
COM0+
Analog Switch 1. Common positive terminal.
2
3
COM0-
Analog Switch 1. Common negative terminal.
3
4
COM1+
Analog Switch 2. Common positive terminal.
4
5
COM1-
Analog Switch 2. Common negative terminal.
5
7
COM2+
Analog Switch 3. Common positive terminal.
6
8
COM2-
Analog Switch 3. Common negative terminal.
7, 9, 15, 19
1, 6, 13, 26
VDD
Positive Supply Voltage Input. Connect VDD to a +3.0V to +3.6V supply voltage.
Bypass VDD to GND with a 0.1FF ceramic capacitor placed as close to the device as
possible (see the Board Layout section).
8
9
COM3+
10
16
SEL1
Analog Switch 4. Common positive terminal.
Control Signal Input. Selects high-frequency switching.
11
17
SEL2
Control Signal Input. Selects AUX/HPD.
12
28
NO3+
Analog Switch 4. Normally Open positive terminal.
13
29
NO2-
Analog Switch 3. Normally Open negative terminal.
14
30
NO2+
Analog Switch 3. Normally Open positive terminal.
16
36
NC3+
Analog Switch 4. Normally Closed positive terminal.
17
37
NC2-
Analog Switch 3. Normally Closed negative terminal.
18
38
NC2+
Analog Switch 3. Normally Closed positive terminal.
20
31
NO1-
Analog Switch 2. Normally Open negative terminal.
21
32
NO1+
Analog Switch 2. Normally Open positive terminal.
22
33
NO0-
Analog Switch 1. Normally Open negative terminal.
6 _______________________________________________________________________________________
Two-Lane and Four-Lane DisplayPort Passive
Switches with Separate AUX/HPD Control
PIN
MAX4998
MAX14998
23
34
NAME
FUNCTION
NO0+
Analog Switch 1. Normally Open positive terminal.
24
—
GND
Ground
25
39
NC1-
Analog Switch 2. Normally Closed negative terminal.
26
40
NC1+
Analog Switch 2. Normally Closed positive terminal.
27
41
NC0-
Analog Switch 1. Normally Closed negative terminal.
28
42
NC0+
Analog Switch 1. Normally Closed positive terminal.
—
10
COM3-
Analog Switch 4. Common negative terminal.
—
11
COM4+
Analog Switch 5. Common positive terminal.
—
12
COM4-
Analog Switch 5. Common negative terminal.
—
14
COM5+
Analog Switch 6. Common positive terminal.
—
15
COM5-
Analog Switch 6. Common negative terminal.
—
18
NO5-
Analog Switch 6. Normally open negative terminal.
—
19
NO5+
Analog Switch 6. Normally open positive terminal.
—
20
NO4-
Analog Switch 5. Normally open negative terminal.
—
21
NO4+
Analog Switch 5. Normally open positive terminal.
—
22
NC5-
Analog Switch 6. Normally Closed negative terminal.
—
23
NC5+
Analog Switch 6. Normally Closed positive terminal.
—
24
NC4-
Analog Switch 5. Normally Closed negative terminal.
—
25
NC4+
Analog Switch 5. Normally Closed positive terminal.
—
27
NO3-
Analog Switch 4. Normally Open negative terminal.
—
35
NC3-
Analog Switch 4. Normally Closed negative terminal.
—
—
EP
Exposed Pad. Internally connected to GND. Connect to a large plane to maximize
thermal performance. Not intended as an electrical part.
Detailed Description
The MAX4998/MAX14998 high-speed passive switches
route one DisplayPort source between two possible
destinations or vice versa. The MAX4998 is used to
switch two-lanes plus AUX/HPD DisplayPort, and the
MAX14998 is used to switch four-lanes plus AUX/HPD
DisplayPort.
The MAX4998/MAX14998 feature two digital control
inputs (SEL1, SEL2) to switch signal paths.
Digital Control Inputs (SEL1, SEL2)
The MAX4998/MAX14998 provide two digital control
inputs (SEL1, SEL2) to select the signal path between
the COM_ and NO_/NC_ channels. SEL1 selects highfrequency switching, while SEL2 selects AUX/HPD. On
the MAX4998, switches 0 and 1 are high-frequency
switches and switches 2 and 3 are both low-frequency
switches. On the MAX14998, switches 0, 1, 2, and 3 are
high-frequency switches and switches 4 and 5 are lowfrequency switches. The truth tables for the MAX4998/
MAX14998 are depicted in the Functional Diagrams/
Truth Tables. Drive SEL_ 0V to VDD to minimize power
consumption.
Analog Signal Levels
The MAX4998/MAX14998 accept standard DisplayPort
signals to a maximum of (VDD - 1.8V). Signals on the
COM_+ channels are routed to either the NO_+ or NC_+
channels. Signals on the COM_- channels are routed
to either the NO_- or NC_- channels. The MAX4998/
MAX14998 are bidirectional switches, allowing COM_,
NO_, and NC_, to be used as either inputs or outputs.
_______________________________________________________________________________________ 7
MAX4998/MAX14998
Pin Description (continued)
MAX4998/MAX14998
Two-Lane and Four-Lane DisplayPort Passive
Switches with Separate AUX/HPD Control
Functional Diagrams/Truth Tables
VDD
MAX14998
COM0+
NC0+
COM0-
NC0NO0+
NO0-
COM1+
NC1+
COM1-
NC1VDD
NO1+
NO1COM2+
NC2+
COM2-
NC2-
MAX4998
NO2+
COM0+
NC0+
NO2-
COM0-
NC0-
COM3+
NC3+
NO0+
COM3-
NC3-
NO0-
NO3+
COM1+
NO3-
COM1-
NC1+
NC1NO1+
COM4+
NC4+
COM4-
NC4-
NO1-
NO4+
COM2+
NC2+
NO4-
COM2-
NC2-
COM5+
NC5+
COM5-
NC5NO5+
NO2+
NO2COM3+
NC3+
NO3+
NO5SEL1
SEL1
SEL2
SEL2
GND
GND
SEL1
0
1
EVENT
COM_ TO NC_
COM_ TO NO_
SWITCH
0, 1, 2, 3
0, 1, 2, 3
SEL1
0
1
EVENT
COM_ TO NC_
COM_ TO NO_
SWITCH
0, 1
0, 1
SEL2
0
1
EVENT
COM_ TO NC_
COM_ TO NO_
SWITCH
4, 5
4, 5
SEL2
0
1
EVENT
COM_ TO NC_
COM_ TO NO_
SWITCH
2, 3
2, 3
8 _______________________________________________________________________________________
Two-Lane and Four-Lane DisplayPort Passive
Switches with Separate AUX/HPD Control
VDD = +3.3V
DOCKING STATION
MAX4998
NO0+
NO0NO1+
NO1NO2+
NO2-
VCC = +1.1V
GRAPHICS AND MEMORY
CONTROLLER HUB
DP0
DP1
AUX
HPD
DP01
DP11
AUX1
+1.1V
10kΩ
COM0+
COM0COM1+
COM1COM2+
COM2COM3+
HPD1
NO3+
1
OF THE 7WZ07
2
DisplayPort
CONNECTOR
NC0+
NC0NC1+
NC1NC2+
NC2-
DP02
DP12
AUX2
+1.1V
10kΩ
CHANNEL SELECT
CHANNEL SELECT
SEL1
SEL2
HPD2
NC3+
1
OF THE 7WZ07
2
7WZ07 DUAL-GATE LOTIC OPERATES FROM +3.3V VCC
NOTE: THE APPLICATION SHOWN IS A TWO-LANE SWITCH BETWEEN THE DOCKING STATION AND DisplayPort CONNECTOR ON A LAPTOP. SEL2 NEEDS TO BE CHANGED FIRST
WHEN SWITCHING SO THAT THE AUX/HPD SIGNAL CAN ESTABLISH CONTACT AND SET PARAMETERS THROUGH DDC. THE HPD SIGNALS FROM THE DOCKING STATION AND DP
CONNECTOR NEED TO BE INPUT THROUGH A LEVEL TRANSLATOR, SUCH AS A 7WZ07 OR 742G07 NONINVERTING TO THE MAX4998. EACH OUTPUT IS PULLED UP TO MATCH THE
LOGIC LEVEL OF THE GMCH. THE COM SIDE OF THE MAX4998 NEEDS TO BE CONNECTED DIRECTLY TO THE GMCH, RUNNING AT LOW VOLTAGE (APPROXIMATELY 1.1V). THIS
ESTABLISHES THE COMMON-MODE VOLTAGE FOR THE SWITCH AND KEEPS THE SWITCH WITHIN ITS OPTIMAL RANGE. IF A FOUR-LANE DisplayPort SWITCH IS DESIRED, THE
MAX14998 SHOULD BE USED. THE CIRCUIT IS THE SAME EXCEPT THAT DP0 TO DP3 IS USED WITH AUX, AND THE HPD CIRCUITRY IS THE SAME.
_______________________________________________________________________________________ 9
MAX4998/MAX14998
Typical Operating Circuit
MAX4998/MAX14998
Two-Lane and Four-Lane DisplayPort Passive
Switches with Separate AUX/HPD Control
Applications Information
Package Information
Board Layout
For 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. Package drawings may show a different suffix character, but the drawing pertains to the package
regardless of RoHS status.
High-speed switches require proper layout and design
procedures for optimum performance. Keep designcontrolled impedance PCB traces as short as possible.
Ensure that power-supply bypass capacitors are placed
as close to the device as possible. Multiple bypass
capacitors are recommended. Connect all grounds and
the exposed pad to large ground planes.
Chip Information
PACKAGE TYPE
PACKAGE CODE
DOCUMENT NO.
28 TQFN-EP
T283555+1
21-0184
42 TQFN-EP
T423590+1
21-0181
PROCESS: CMOS
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.
10
© 2009
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Maxim Integrated Products Maxim is a registered trademark of Maxim Integrated Products, Inc.