19-4030; Rev 1; 8/08
DisplayPort/PCIe Passive Switches
General Description
The MAX4928A/MAX4928B high-speed passive switch-
es route PCI Express
®
(PCIe) data and/or DisplayPort™
signals between two possible destinations in desktop or
laptop PCs. The MAX4928A is intended to be used with
the ATX form factor desktop PCs, while the MAX4928B
is expected to be used in the BTX form factor.
The MAX4928A/MAX4928B are hex double-pole/dou-
ble-throw (6 x DPDT) switches. The MAX4928A/
MAX4928B feature a single digital control input (SEL) to
switch signal paths and a latch input (LE) that holds the
switches in a given state.
The MAX4928A/MAX4928B are fully specified to oper-
ate from a single +3.3V (typ) power supply. The
MAX4928A/MAX4928B are available in an industry
standard 5mm x 11mm, 56-pin TQFN package. Both
devices operate over the -40°C to +85°C extended
temperature range.
♦
Single +3.3V Power Supply Voltage
♦
Supports PCIe Gen I, Gen II, and DisplayPort
Data Rates > 5Gbps
♦
Excellent Return Loss > 12dB at 2.5GHz
♦
Six Bidirectional Pairs of Switches
All Switching in One Device
♦
Low 850µA (max) Supply Current
♦
Small 5mm x 11mm, 56-Pin TQFN Package
♦
Industry-Standard Pinouts
Features
MAX4928A/MAX4928B
Ordering Information
PART
MAX4928AETN+
MAX4928BETN+
TEMP RANGE
-40°C to +85°F
-40°C to +85°F
PIN-PACKAGE
56 TQFN-EP
56 TQFN-EP
Applications
Desktop PCs
Notebook PCs
PCI Express is a registered trademark of PCI-SIG.
DisplayPort is a trademark of Video Electronics Standards
Association (VESA).
+Denotes
a lead-free package/RoHS-Compliant package.
EP = Exposed paddle.
Typical Operating Circuit appears at end of data sheet.
Pin Configurations
TX1+
TX0+
TX1-
GND
TX0-
GND
V
DD
V
DD
D1+
V
DD
D0+
56 55 54 53 52 51 50 49
GND
IN0+
IN0-
IN1+
IN1-
V
DD
IN2+
IN2-
IN3+
1
2
3
4
5
6
7
8
9
48 GND
47 TX2+
46 TX2-
45 TX3+
44 TX3-
43 D0+
42 D0-
41 D1+
40 D1-
39 D2+
GND
SEL
LE
IN0+
IN0-
V
DD
IN1+
IN1-
IN2+
1
2
3
4
5
6
7
8
9
+
56 55 54 53 52 51 50 49
48 GND
47 D2+
46 D2-
45 D3+
44 D3-
43 TX0+
42 TX0-
41 TX1+
40 TX1-
39 TX2+
+
D0-
V
DD
D1-
TOP VIEW
GND
GND
38 TX2-
37 TX3+
36 TX3-
35 GND
34 V
DD
33 AUX+
32 AUX-
31 HPD1
*EP
21 22 23 24 25 26 27 28
V
DD
RX1-
RX0+
RX0-
RX1+
GND
GND
V
DD
30 HPD2
29 GND
IN3- 10
GND 11
OUT+ 12
OUT- 13
X+ 14
X- 15
GND 16
V
DD
17
SEL 18
LE 19
GND 20
21 22 23 24 25 26 27 28
HPD2
V
DD
AUX-
HPD1
AUX+
GND
GND
V
DD
*EP
IN2- 10
GND 11
IN3+ 12
IN3- 13
OUT+ 14
OUT- 15
GND 16
V
DD
17
X+ 18
X- 19
GND 20
MAX4928A
38 D2-
37 D3+
36 D3-
35 GND
34 V
DD
33 RX0+
32 RX0-
31 RX1+
30 RX1-
29 GND
MAX4928B
*CONNECT EXPOSED PADDLE TO GND.
TQFN
TQFN
________________________________________________________________
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.
DisplayPort/PCIe Passive Switches
MAX4928A/MAX4928B
ABSOLUTE MAXIMUM RATINGS
(All voltages referenced to GND, unless otherwise noted.)
V
DD
...........................................................................-0.3V to +4V
LE, SEL, IN_, X_, OUT_, D_, TX_, HPD_, RX_, AUX_
(Note 1) ...............................................-0.3V to + (V
DD
+ 0.3V)
|V
IN_
- V
TX_
|, |V
IN_
- V
D_
|, |V
X_
- V
HPD_
|, |V
X_
- V
RX1_
|,
|V
OUT_
- V
AUX_
|, |V
OUT_
- V
RX0_
| (Note 1) ...................0 to +2V
Continuous Current (IN_ to D_/TX_, X_ to HPD_/RX1_,
OUT_ to AUX_/RX0_ .....................................................±70mA
Peak Current (IN_ to D_/TX_, X_ to HPD_/RX1_, OUT_ to
AUX_/RX0_) (pulsed at 1ms, 10% duty cycle) .............±70mA
Continuous Current (LE, SEL)...........................................±30mA
Peak Current (LE, SEL)
(pulsed at 1ms, 10% duty cycle)..................................±70mA
Continuous Power Dissipation (T
A
= +70°C) for Multilayer Board
56-Pin TQFN (derate 41.0mW/°C above +70°C) .......3279mW
Operating Temperature Range ...........................-40°C to +85°C
Junction Temperature ......................................................+150°C
Storage Temperature Range .............................-65°C to +150°C
Package Junction-to-Ambient Thermal Resistance (θ
JA
)
(Note 2) .....................................................................24.4°C/W
Package Junction-to-Case Thermal Resistance (θ
JC
)
(Note 2) .......................................................................1.5°C/W
Lead Temperature (soldering) .........................................+300°C
Note 1:
Signals on IN_, X_, OUT_, D_, TX_, HPD_, RX_, or AUX_, LE, SEL exceeding V
DD
or GND are clamped by internal diodes.
Limit forward-diode current to 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, see 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
(V
DD
= +3.3V ±10%, T
A
=T
MIN
to T
MAX
, unless otherwise noted. Typical values are at V
DD
= +3.3V, T
A
= +25°C, unless otherwise
noted.) (Note 3)
PARAMETER
ANALOG SWITCH
Analog Signal Range
IN_, X_, OUT_,
D_, TX_, HPD_,
RX_, AUX_
|V
IN_
- V
TX_
|,
|V
IN_
- V
D_
|,
|V
X_
- V
HPD_
|,
|V
X_
- V
RX1_
|,
|V
OUT_
-
V
AUX_
|,
|V
OUT_
- V
RX0_
|
R
ON
ΔR
ON
I
IN_
= I
X_
= I
OUT_
= 15mA, V
D_
, V
TX_
,
V
HPD_
, V
AUX_
, or V
RX_
= 0V, +1.2V
V
DD
= +3.0V, I
IN_
= I
X_
= I
OUT_
= 15mA,
V
D_
, V
TX_
, V
HPD_
, V
AUX_
, or V
RX_
= 0V
(Notes 4, 5)
V
DD
= +3.0V, I
IN_
= I
X_
= I
OUT_
= 15mA,
V
D_
, V
TX_
, V
HPD_
, V
AUX_
, or V
RX_
= 0V
(Notes 4, 5)
V
DD
= +3.0V, I
IN_
= I
X_
= I
OUT_
= 15mA,
V
D_
, V
TX_
, V
HPD_
, V
AUX_
, or V
RX_
= 0V,
+1.2V (Notes 5, 6)
-0.1
(V
DD
-
1.8)
V
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
Voltage Between IN and D/TX, X
and HPD/RX1, and OUT and
AUX/RX0
0
1.8
V
On-Resistance
On-Resistance Match
Between Pairs of Same Channel
On-Resistance Match
Between Channels
8
Ω
0.1
2
Ω
ΔR
ON
1.5
4
On-Resistance Flatness
R
FLAT(ON)
0.3
1.5
Ω
2
_______________________________________________________________________________________
DisplayPort/PCIe Passive Switches
ELECTRICAL CHARACTERISTICS (continued)
(V
DD
= +3.3V ±10%, T
A
=T
MIN
to T
MAX
, unless otherwise noted. Typical values are at V
DD
= +3.3V, T
A
= +25°C, unless otherwise
noted.) (Note 3)
PARAMETER
D_ or TX_/
HPD_ or RX1_/
AUX_ or RX0_ Off-Leakage
Current
SYMBOL
I
D_ (OFF)
I
TX_ (OFF)
I
HPD_ (OFF)
I
RX1_ (OFF)
I
AUX_ (OFF)
I
RX0_ (OFF)
I
IN_ (ON)
I
X_ (ON)
I
OUT_ (ON)
CONDITIONS
MIN
TYP
MAX
UNITS
MAX4928A/MAX4928B
V
DD
= +3.6V , V
IN_
= V
X_
= V
OUT_
= 0V,
+1.2V; V
D_
or V
TX_
, V
HPD_
or V
RX1_
,
V
AUX_
or V
RX0_
= +1.2V, 0V
-1
+1
µA
V
DD
= +3.6V , V
IN_
= V
X_
= V
OUT_
= 0V,
+1.2V; V
D_
or V
TX_
= V
IN_
or
unconnected, V
HPD_
or V
RX1_
= V
X_
or
unconnected, V
AUX_
or V
RX0_
= V
OUT_
or unconnected
V
D_
or V
TX_
= +1.0V, R
L
= 50Ω,
V
HPD_
or V
RX1_
= +1.0V, R
L
= 50Ω,
V
AUX_
or V
RX0_
= +1.0V, R
L
= 50Ω,
LE = V
DD
, C
L
= 100pf (Figure 1)
V
D_
or V
TX_
= +1.0V, R
L
= 50Ω,
V
HPD_
or V
RX1_
= +1.0V, R
L
= 50Ω,
V
AUX_
or V
RX0_
= +1.0V, R
L
= 50Ω,
LE = V
DD
, C
L
= 100pf (Figure 1)
V
D_
or V
TX_
= +1.0V, R
L
= 50Ω,
V
HPD_
or V
RX1_
= +1.0V, R
L
= 50Ω,
V
AUX_
or V
RX0_
= +1.0V, R
L
= 50Ω
(Figure 1)
V
D_
or V
TX_
= +1.0V, R
L
= 50Ω,
V
HPD_
or V
RX1_
= +1.0V, R
L
= 50Ω,
V
AUX_
or V
RX0_
= +1.0V, R
L
= 50Ω,
(Figure 1)
V
D_
or V
TX_
= +1.0V, R
L
= 50Ω,
V
HPD_
or V
RX1_
= +1.0V, R
L
= 50Ω,
V
AUX_
or V
RX0_
= +1.0V, R
L
= 50Ω
(Figure 1)
f = 2.5GHz
f = 5.0GHz
f = 7.5GHz
f = 2.5GHz
IN_/X_/OUT_ On-Leakage
Current
-1
+1
DIGITAL SIGNALS
SEL to Switch Turn-On Time
t
ON_SEL
55
120
ns
SEL to Switch Turn-Off Time
t
OFF_SEL
8
50
ns
LE Setup Time
SEL to LE
t
SU
2
ns
LE Hold Time
SEL to LE
t
HOLD
2
ns
LE Minimum Pulse-Width Low
t
W
40
ns
-1.5
-3.3
-4.9
-40
-23
-28
-22
-21
-8
-7
dB
dB
dB
dB
Differential Insertion Loss
(Figure 2)
S
DD21
Differential Crosstalk (Figure 2)
Differential Off-Isolation
Differential Return Loss (Figure 2)
S
DDCTK
S
DD21_OFF
S
DD11
f = 5.0GHz
f = 7.5GHz
f = 3.0GHz
f = 2.8GHz
f = 5.0GHz
f = 7.5GHz
_______________________________________________________________________________________
3
DisplayPort/PCIe Passive Switches
MAX4928A/MAX4928B
ELECTRICAL CHARACTERISTICS (continued)
(V
DD
= +3.3V ±10%, T
A
=T
MIN
to T
MAX
, unless otherwise noted. Typical values are at V
DD
= +3.3V, T
A
= +25°C, unless otherwise
noted.) (Note 3)
PARAMETER
Signal Data Rate
Differential -3dB Bandwidth
LOGIC INPUT (LE, SEL)
Input Logic-High
Input Logic-Low
Input Logic Hysteresis
Input Leakage Current
POWER SUPPLY
Power Supply Range
V
DD
Supply Current
V
DD
I
DD
V
IN
= 0 or V
DD
3.0
3.6
850
V
µA
V
IH
V
IL
V
HYST
I
IN
V
IN
= 0 or V
DD
-1
100
+1
1.4
0.5
V
V
mV
µA
SYMBOL
BR
DBW
CONDITIONS
R
S
= R
L
= 100Ω balanced
R
S
= R
L
= 100Ω balanced
MIN
TYP
10
5
MAX
UNITS
Gbps
GHz
Note 3:
All units are 100% production tested at T
A
= +85°C. Limits over the operating temperature range are guaranteed by design
and characterization and are not production tested.
Note 4:
ΔR
ON
= R
ON (MAX)
- R
ON (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.
4
_______________________________________________________________________________________
DisplayPort/PCIe Passive Switches
Typical Operating Characteristics
(T
A
= +25°C, unless otherwise noted.)
MAX4928A/MAX4928B
ON-RESISTANCE vs. V
IN_
, V
X_
, V
OUT_
MAX4928A/B toc01
ON-RESISTANCE vs. V
IN_
, V
X_
, V
OUT_
MAX4928A/B toc02
SUPPLY CURRENT vs. TEMPERATURE
900
800
SUPPLY CURRENT (μA)
700
600
500
400
300
200
100
0
V
DD
= 3.3V
MAX4928A/B toc03
10.0
9.5
9.0
ON-RESISTANCE (Ω)
8.5
8.0
7.5
7.0
6.5
6.0
5.5
5.0
-0.1 0.1
0.3
0.5
0.7
0.9
1.1
1.3
V
DD
= 3.3V
10.0
9.5
9.0
ON-RESISTANCE (Ω)
8.5
8.0
7.5
7.0
6.5
6.0
5.5
5.0
V
DD
= 3.3V
-0.1 0.1
0.3
0.5
0.7
0.9
1.1
1.3
T
A
= -40°C
T
A
= +25°C
T
A
= +85°C
1000
1.5
1.5
-40
-15
10
35
60
85
V
IN_
,
V
X_
,
V
OUT_
(V)
V
IN_
,
V
X_
,
V
OUT_
(V)
TEMPERATURE (°C)
LOGIC THRESHOLD vs. SUPPLY VOLTAGE
MAX4928A/B toc04
TURN-ON/OFF TIME vs. SUPPLY VOLTAGE
MAX4928A/B toc05
DIFFERENTIAL INSERTION LOSS
MAX4928A/B toc06
1.5
V
DD
= 3.3V
100
0
DIFFERENTIAL INSERTION LOSS (dB)
-2
1.3
LOGIC THRESHOLD (V)
V
IH
1.1
80
TURN-ON/OFF TIME (ns)
60
t
ON_SEL
-4
0.9
V
IL
0. 7
40
t
OFF_SEL
-6
20
-8
0.5
3.0
3.1
3.2
3.3
3.4
3.5
3.6
SUPPLY VOLTAGE (V)
0
3.0
3.1
3.2
3.3
3.4
3.5
3.6
SUPPLY VOLTAGE (V)
-10
10
100
1,000
10,000
FREQUENCY (MHz)
DIFFERENTIAL OFF-ISOLATION
MAX4928A/B toc07
DIFFERENTIAL CROSSTALK
MAX4928A/B toc08
DIFFERENTIAL RETURN LOSS
MAX4928A/B toc09
0
DIFFERENTIAL OFF-ISOLATION (dB)
0
-20
0
DIFFERENTIAL RETURN LOSS (dB)
DIFFERENTIAL CROSSTALK (dB)
-20
-10
-40
-40
-20
-600
-60
-80
-30
-80
10
100
1,000
10,000
FREQUENCY (MHz)
-100
10
100
1,000
10,000
FREQUENCY (MHz)
-40
10
100
1,000
10,000
FREQUENCY (MHz)
_______________________________________________________________________________________
5
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