19-0770; Rev 2; 5/09
KIT
ATION
EVALU
BLE
AVAILA
5.0Gbps PCI Express Passive Switches
General Description
Features
♦
Single +3.0V to +3.6V Power-Supply Voltage
♦
Low Same-Pair Skew of 7ps
♦
Low 120µA (Max) Quiescent Current
♦
Supports PCIe Gen I and Gen || Data Rates
♦
Flow-Through Pin Configuration for Ease of
Layout
♦
Industry-Compatible Pinout
♦
Lead-Free Packaging
MAX4888A/MAX4889A
The MAX4888A/MAX4889A high-speed passive switches
route PCI Express
®
(PCIe) data between two possible
destinations. The MAX4888A is a quad single-pole/dou-
ble-throw (4 x SPDT) switch ideally suited for switching
two half lanes of PCIe data between two destinations. The
MAX4889A is an octal single-pole/double-throw (8 x
SPDT) switch ideal for switching four half lanes of PCIe
data between four destinations. The MAX4888A/
MAX4889A feature a single digital control input (SEL) to
switch signal paths.
The MAX4888A/MAX4889A are fully specified to oper-
ate from a single +3.0V to +3.6V power supply
††
. The
MAX4888A is available in a 3.5mm x 5.5mm, 28-pin
TQFN package. The MAX4889A is available in a 3.5mm
x 9.0mm, 42-pin TQFN package. Both devices operate
over the -40°C to +85°C temperature range.
Applications
Desktop Computers
Servers/Storage Area Networks
Laptops
Ordering Information/Selector Guide
PART
MAX4888AETI+
MAX4889AETO+
TEMP RANGE
-40°C to +85°C
-40°C to +85°C
PIN-PACKAGE
28 TQFN-EP*
42 TQFN-EP*
CONFIGURATION
Two Half Lanes
Four Half Lanes
+Denotes
lead(Pb)-free/RoHS-compliant package.
*EP
= Exposed paddle.
††
Contact factory if operating at +2.5V or +1.8V.
Typical Application Circuit appears at end of data sheet.
PCI Express is a registered trademark of PCI-SIG Corp.
Pin Configurations
TOP VIEW
NC1+
NC2+
NO1+
NO2+
NC3+
NC4+
NO3+
NO4+
COM4-
NC1-
NC2-
NO1-
NO2-
NC3-
NC4-
NO3-
NC1+
NC2+
NO1+
NO2+
NC1-
NC2-
NO1-
NO2-
GND
NO4-
21 GND
20 V+
19 GND
18 V+
3
COM1-
4
GND
5
V+
6
COM2+
7
COM2-
8
V+
9
SEL
10 11 12 13 14 15 16 17
COM3+
COM3-
COM4+
GND
V+
GND
GND
V+
24 23 22 21 20 19 18 17 16 15
GND 25
V+ 26
GND 27
V+ 28
1
GND
*EP
+
2
SEL
3
N.C.
4
COM1+
5
COM1-
6
COM2+
7
COM2-
8
V+
9
N.C.
10
GND
14 GND
13 V+
GND 39
V+ 40
GND 41
V+ 42
38 37 36 35 34 33 32 31 30 29 28 27 26 25 24 23 22
MAX4888A
12 GND
11 V+
MAX4889A
*EP
+
1
GND
2
COM1+
TQFN
*CONNECT EXPOSED PADDLE TO GROUND.
TQFN
________________________________________________________________
Maxim Integrated Products
V+
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.
5.0Gbps PCI Express Passive Switches
MAX4888A/MAX4889A
ABSOLUTE MAXIMUM RATINGS
(All voltages referenced to GND, unless otherwise noted.)
V+ .............................................................................-0.3V to +4V
SEL, COM__, NO__, NC__ (Note 1) .............-0.3V to (V+ + 0.3V)
| COM__ - NO__ |, | COM__ - NC__ | (Note 1).................0 to +2V
Continuous Current (COM_ to NO__/NC__) .....................±70mA
Peak Current (COM__ to NO__/NC__)
(pulsed at 1ms, 10% duty cycle)..................................±70mA
Continuous Current (SEL).................................................±30mA
Peak Current (SEL)
(pulsed at 1ms, 10% duty cycle)................................±150mA
Continuous Power Dissipation (T
A
= +70°C)
28-Pin TQFN (derate 20.8mW/°C above +70°C) ....1666.7mW
42-Pin TQFN (derate 35.7mW/°C above +70°C) ....2857.1mW
Operating Temperature Range ...........................-40°C to +85°C
Storage Temperature Range .............................-65°C to +150°C
Lead Temperature (soldering, 10s) .................................+300°C
Junction Temperature ......................................................+150°C
Note 1:
Signals on SEL, NO__, NC__ or COM__ exceeding V+ or GND are clamped by internal diodes. Limit forward-diode current
to maximum current rating.
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+ = +3.0V to +3.6V, T
A
= -40°C to +85°C, unless otherwise noted. Typical values are at V+ = +3.3V, T
A
= +25°C.) (Note 2)
PARAMETER
ANALOG SWITCH
Analog-Signal Range
V
COM_
,
V
NO_,
V
NC_
| V
COM_
-
V
NO_
| ,
| V
COM_
-
V
NC_
|
R
ON
R
ON
R
ON
R
FLAT(ON)
I
NO_(OFF)
I
NC_(OFF)
I
COM_(ON)
V+ = +3.0V, I
COM_
= 15mA,
V
NO_
or V
NC_
= 0V, +1.8V
V+ = +3.0V, I
COM_
= 15mA,
V
NO_
or V
NC_
= 0V (Notes 3, 4)
V+ = +3.0V, I
COM_
= 15mA,
V
NO_
or V
NC_
= 0V (Notes 3, 4)
V+ = +3.0V, I
COM_
= 15mA
V
NO_
or V
NC_
= 0V, +1.8V (Notes 4, 5)
V+ = +3.6V, V
COM_
= 0V, +1.8V,
V
NO_
or V
NC_
= +1.8V, 0V
V+ = +3.6V, V
COM_
= 0V, +1.8V,
V
NO_
or V
NC_
= V
COM_
or unconnected
-1
-1
(V+ - 1.2)
V
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
Voltage Between COM and
NO/NC
0
1.8
V
On-Resistance
On-Resistance Match Between
Pairs of Same Channel
On-Resistance Match
Between Channels
On-Resistance Flatness
NO_ or NC_ Off-Leakage
Current
COM_ On-Leakage
Current
7
0.1
0.6
0.06
1
2
2
+1
+1
μA
μA
2
_______________________________________________________________________________________
5.0Gbps PCI Express Passive Switches
MAX4888A/MAX4889A
ELECTRICAL CHARACTERISTICS (continued)
(V+ = +3.0V to +3.6V, T
A
= -40°C to +85°C, unless otherwise noted. Typical values are at V+ = +3.3V, T
A
= +25°C.) (Note 2)
PARAMETER
DYNAMIC
Turn-On Time
Turn-Off Time
Propagation Delay
Output Skew Between Pairs
Output Skew Between Same
Pair
On-Loss
SYMBOL
t
ON
t
OFF
t
PD
t
SK1
t
SK2
CONDITIONS
V
NO_
or V
NC_
= +1.0V, R
L
= 50 , Figure 1
V
NO_
or V
NC_
= +1.0V, R
L
= 50 , Figure 1
R
S
= R
L
= 50 , unbalanced, Figure 2
R
S
= R
L
= 50 , unbalanced; skew between
any two pairs, Figure 2
R
S
= R
L
= 50 , unbalanced; skew between
two lines on same pair, Figure 2
R
S
= R
L
= 50 ,
unbalanced,
Figure 3
1MHz < f < 100MHz
500MHz < f < 1.25GHz
MIN
TYP
90
10
50
50
10
-0.5
dB
-1.4
-53
dB
-32
5.0
f = 10MHz
f = 1.25GHz
-56
dB
-26
1
2
0.5
1.4
100
V
SEL
= 0V or V+
-1
1.65
V
SEL
= 0V or V+
V
SEL
= 0V or V+
Human Body Model
MAX4888A
MAX4889A
-1
±6
+1
3.60
60
120
+1
pF
pF
V
V
mV
μA
V
μA
μA
kV
Gbps
MAX
250
50
UNITS
ns
ns
ps
ps
ps
G
LOS
Crosstalk
V
CT1
Crosstalk between
f = 50MHz
any two pairs,
R
S
= R
L
= 50 ,
unbalanced,
f = 1.25GHz
Figure 3
R
S
= R
L
= 50
Signal = 0dBm,
R
S
= R
L
= 50 ,
Figure 3
Figure 4
Signaling Data Rate
Off-Isolation
NO_/NC_ Off-Capacitance
COM_ On-Capacitance
LOGIC INPUT
Input-Logic Low
Input-Logic High
Input-Logic Hysteresis
Input Leakage Current
POWER SUPPLY
Power-Supply Range
V+ Supply Current
Input Leakage Current
ESD PROTECTION
COM_+, COM_-
BR
V
ISO
C
NO_/NC_(OFF)
Figure 4
C
COM_(ON)
V
IL
V
IH
V
HYST
I
IN
V+
I+
I
IN
Note 2:
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 3:
ΔR
ON
= R
ON(MAX)
- R
ON(MIN)
.
Note 4:
Guaranteed by design. Not production tested.
Note 5:
Flatness is defined as the difference between the maximum and minimum value of on-resistance as measured over the
specified analog signal range.
_______________________________________________________________________________________
3
5.0Gbps PCI Express Passive Switches
MAX4888A/MAX4889A
Typical Operating Characteristics
(T
A
= +25°C, unless otherwise noted.)
ON-RESISTANCE vs. V
COM_
MAX4888A/89A toc01
ON-RESISTANCE vs. V
COM_
(V+ = +1.8V)
T
A
= +85°C
12
10
R
ON
(Ω)
8
6
4
T
A
= -40°C
T
A
= +25°C
MAX4888A/89A toc02
ON-RESISTANCE vs. V
COM_
(V+ = +2.5V)
T
A
= +85°C
12
10
R
ON
(Ω)
8
6
4
2
0
T
A
= -40°C
T
A
= +25°C
MAX4888A/89A toc03
10.0
9.5
9.0
8.5
R
ON
(Ω)
8.0
7.5
7.0
6.5
6.0
5.5
5.0
V+ = +3.3V
V+ = +2.5V
V+ = +1.8V
14
14
2
0
-0.1 0.1 0.3 0.5 0.7 0.9 1.1 1.3 1.5 1.7 1.9 2.1
V
COM_
(V)
-0.1
0
0.1
0.2 0.3
V
COM_
(V)
0.4
0.5
0.6
-0.1
0.1
0.3
0.5 0.7
V
COM_
(V)
0.9
1.1
1.3
ON-RESISTANCE vs. V
COM_
(V+ = +3.3V)
MAX4888A/89A toc04
SUPPLY CURRENT vs. TEMPERATURE
(MAX4889A)
MAX4888A/89A toc05
LOGIC THRESHOLD vs. SUPPLY VOLTAGE
MAX4888A/89A toc06
14
12
T
A
= +25°C
10
R
ON
(Ω)
8
6
4
2
0
T
A
= -40°C
T
A
= +85°C
80
70
SUPPLY CURRENT (μA)
60
V+ = +3.3V
50
40
30
20
10
0
-40
V+ = +1.8V
-15
10
35
TEMPERATURE (°C)
60
V+ = +2.5V
1.2
1.1
LOGIC THRESHOLD (V)
1.0
0.9
0.8
V
IL
0.7
0.6
0.5
V
IH
-0.1 0.1 0.3 0.5 0.7 0.9 1.1 1.3 1.5 1.7 1.9 2.1
V
COM_
(V)
85
1.6 1.8 2.0 2.2 2.4 2.6 2.8 3.0 3.2 3.4 3.6
SUPPLY VOLTAGE (V)
TURN-ON/-OFF TIME vs. SUPPLY VOLTAGE
MAX4888A/89A toc07
240
220
200
180
160
140
120
100
80
60
40
20
0
t
ON
/t
OFF
(ns)
NO_ t
ON
NC_ t
ON
NO_ t
OFF
NC_ t
OFF
1.6 1.8 2.0 2.2 2.4 2.6 2.8 3.0 3.2 3.4 3.6
SUPPLY VOLTAGE (V)
4
_______________________________________________________________________________________
5.0Gbps PCI Express Passive Switches
Typical Operating Characteristics (continued)
(T
A
= +25°C, unless otherwise noted.)
EYE DIAGRAM
(V+ = +1.8V, f = 1.25GHz,
600mV
P-P
PRBS SIGNAL, R
S
= R
L
= 50Ω)
†
MAX4888A/89A toc08
MAX4888A/MAX4889A
EYE DIAGRAM
(V+ = +2.5V, f = 1.25GHz,
600mV
P-P
PRBS SIGNAL, R
S
= R
L
= 50Ω)
†
MAX4888A/89A toc09
EYE DIAGRAM
(V+ = +3.3V, f = 1.25GHz,
600mV
P-P
PRBS SIGNAL, R
S
= R
L
= 50Ω)
†
V
COM_+
MAX4888A/89A toc10
V
COM_+
V
COM_+
50mV/div
50mV/div
50mV/div
V
COM_-
50ps/div
*PRBS = PSEUDORANDOM BIT SEQUENCE
† = GEN 1, 2.5Gbps; U1 = 400ps
V
COM_-
50ps/div
*PRBS = PSEUDORANDOM BIT SEQUENCE
† = GEN 1, 2.5Gbps; U1 = 400ps
V
COM_-
50ps/div
*PRBS = PSEUDORANDOM BIT SEQUENCE
† = GEN 1, 2.5Gbps; U1 = 400ps
EYE DIAGRAM
(V+ = +1.8V, f = 2.5GHz,
600mV
P-P
PRBS SIGNAL, R
S
= R
L
= 50Ω)
††
MAX4888A/89A toc11
EYE DIAGRAM
(V+ = +2.5V, f = 2.5GHz,
600mV
P-P
PRBS SIGNAL, R
S
= R
L
= 50Ω)
††
MAX4888A/89A toc12
EYE DIAGRAM
(V+ = +3.3V, f = 2.5GHz,
600mV
P-P
PRBS SIGNAL, R
S
= R
L
= 50Ω)
††
V
COM_+
MAX4888A/89A toc12
V
COM_+
V
COM_+
50mV/div
50mV/div
50mV/div
V
COM_-
25ps/div
*PRBS = PSEUDORANDOM BIT SEQUENCE
†† = GEN 11, 5.0Gbps; U1 = 200ps
V
COM_-
25ps/div
*PRBS = PSEUDORANDOM BIT SEQUENCE
†† = GEN 11, 5.0Gbps; U1 = 200ps
V
COM_-
25ps/div
*PRBS = PSEUDORANDOM BIT SEQUENCE
†† = GEN 11, 5.0Gbps; U1 = 200ps
_______________________________________________________________________________________
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