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General Description
The MAX4888/MAX4889 high-speed passive switches
route PCI Express
®
(PCIe) data between two possible
destinations. The MAX4888 is a quad single-pole/doublethrow (4 x SPDT) switch ideally suited for switching two
half lanes of PCIe data between two destinations. The
MAX4889 is an octal single-pole/double-throw (8 x SPDT)
switch ideal for switching four half lanes of PCIe data
between four destinations. The MAX4888/MAX4889 feature a single digital control input (SEL) to switch signal
paths.
The MAX4888/MAX4889 are fully specified to operate
from a single 3.0V to 3.6V power supply and also operate down to +1.65V. The MAX4888 is available
in a 3.5mm x 5.5mm, 28-pin TQFN package. The
MAX4889 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
Features
♦ Single 1.65V to 3.6V Power-Supply Voltage
♦ Low Same-Pair Skew of 7ps
♦ Low 120µA (Max) Quiescent Current
♦ Supports PCIe Gen I Data Rates
♦ Flow-Through Pin Configuration for Ease of
Layout
♦ Industry-Compatible Pinout
♦ Lead-Free Packaging
MAX4888/MAX4889
2.5Gbps PCI Express Passive Switches
________________________________________________________________
Maxim Integrated Products
1
Pin Configurations
Ordering Information/
Selector Guide
19-0724; Rev 0; 5/07
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.
Note: All devices are specified over the -40°C to +85°C operat-
ing temperature range.
+
Denotes lead-free package.
*
EP = Exposed paddle.
Typical Application Circuit appears at end of data sheet.
PCI Express is a registered trademark of PCI-Sig Corp.
PACKAGE
28 TQFN-EP*
42 TQFN-EP*
TOP VIEW
GND
V+
GND
V+
NO1-
NO1+
V+
GND
NC2-
NC2+
NC1-
NC1+
24 23 22 21 20 19 18 17 16 15
25
26
*EP
SEL
N.C.
MAX4888
COM1-
COM1+
COM2+
V+
COM2-
27
28
+
12345678910
GND
TQFN
NO2-
NO2+
GND
14
V+
13
12
GND
11
V+
N.C.
GND
*CONNECT EXPOSED PADDLE TO GROUND.
NC4+
NC4-
COM3-
NO3+
V+
GND
NC3-
NC3+
V+
NO2-
NO2+
NO1-
NO1+
NC2-
NC2+
NC1-
NC1+
38 37 36 35 34 33 32 31 30 29 28 27 26 25 24 23 22
39
GND
40
V+
41
GND
V+
*EP
42
+
1234567891011121314151617
COM1+
COM1-
GND
GND
MAX4889
COM2+
COM2-
V+
SEL
GND
COM3+
V+
TQFN
NO3-
COM4+
NO4+
COM4-
NO4-
21
20
19
18
GND
GND
V+
GND
V+
MAX4888/MAX4889
2.5Gbps PCI Express Passive Switches
2 _______________________________________________________________________________________
ABSOLUTE MAXIMUM RATINGS
ELECTRICAL CHARACTERISTICS
(V+ = 3.0V to 3.6V, TA= -40°C to +85°C, unless otherwise noted. Typical values are at V+ = 3.3V, TA= +25°C.) (Note 2)
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.
(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.
PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS
ANALOG SWITCH
V
,
Analog-Signal Range
Voltage Between COM and
NO/NC
On-Resistance R
On-Resistance Match Between
Pairs of Same Channel
On-Resistance Match
Between Channels
On-Resistance Flatness R
NO_ or NC_ Off-Leakage
Current
COM_ On-Leakage
Current
COM_
V
NO_, VNC_
| V
COM_
V
NO_
| V
COM_
V
NC_
ON
ΔR
ON
ΔR
ON
FLAT(ON
I
NO_(OFF
I
NC_(OFF
I
COM_(ON
-
| ,
-
|
V+ = 3.0V, I
or V
V
NO_
NC_
V+ = 3.0V, I
or V
V
NO_
NC_
V+ = 3.0V, I
or V
V
NO_
NC_
V+ = 3.0V, I
or V
V
NO_
NC_
V+ = 3.6V; V
V
or V
NO_
NC_
V+ = 3.6V; V
V
or V
NO_
NC_
= 15mA,
COM_
= 0V, 1.8V
= 15mA,
COM_
= 0V (Notes 3, 4)
= 15mA,
COM_
= 0V (Notes 3, 4)
= 15mA
COM_
= 0V, 1.8V (Notes 4, 5)
= 0V, 1.8V;
COM_
= 1.8V, 0V
= 0V, 1.8V;
COM_
= V
or unconnected
COM_
-0.1 (V+ - 1.2) V
0 1.8 V
7 Ω
0.1 1 Ω
0.6 2 Ω
0.06 2 Ω
-1 +1 µA
-1 +1 µA
MAX4888/MAX4889
2.5Gbps PCI Express Passive Switches
_______________________________________________________________________________________ 3
Note 2: All units are 100% production tested at TA= +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.
ELECTRICAL CHARACTERISTICS (continued)
(V+ = 3.0V to 3.6V, TA= -40°C to +85°C, unless otherwise noted. Typical values are at V+ = 3.3V, TA= +25°C.) (Note 2)
DYNAMIC
Turn-On Time t
Turn-Off Time t
Propagation Delay t
Output Skew Between Pairs t
Output Skew Between Same
Pair
On-Loss G
Crosstalk V
Signaling Data Rate BR RS = RL = 50Ω 3.0 Gbps
Off-Isolation V
NO_/NC_ Off-Capacitance
COM_ On-Capacitance C
LOGIC INPUT
Input-Logic Low V
Input-Logic High V
Input-Logic Hysteresis V
Input Leakage Current I
POWER SUPPLY
Power-Supply Range V+ 1.65 3.60 V
V+ Supply Current I+ V
PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS
V
ON
OFF
PD
SK1
t
SK2
LOS
CT1
ISO
C
N O_/N C _( OFF)
COM_(ON
IL
IH
HYST
IN
or V
NO_
V
or V
NO_
RS = RL = 50Ω, unbalanced, Figure 2 50 ps
RS = RL = 50Ω, unb al anced ; skew b etw een
any tw o p ai r s, Fi g ur e 2
RS = RL = 50Ω, unb al anced ; skew b etw een
tw o l i nes on sam e p ai r , Fi g ur e 2
RS = RL = 50Ω,
unbalanced,
Figure 3
Crosstalk between
any two pairs,
= RL = 50Ω,
R
S
unbalanced,
Figure 3
Signal = 0dBm,
R
= RL = 50Ω,
S
Figure 3
Figure 4 1 pF
Figure 4 2 pF
V
= 0V or V+ -1 +1 µA
SEL
= 0V or V+
SEL
= 1.0V, RL = 50Ω, Figure 1 90 250 ns
NC_
= 1.0V, RL = 50Ω, Figure 1 10 50 ns
NC_
50 ps
10 ps
1MHz < f < 100MHz -0.5
< f <
500M H z
1.25G H z-1.4
f = 50MHz -53
f = 1.25GHz -32
f = 10MHz -56
f = 1.25GHz -26
0.5 V
1.4 V
100 mV
MAX4888 60
MAX4889 120
dB
dB
dB
µA
MAX4888/MAX4889
2.5Gbps PCI Express Passive Switches
4 _______________________________________________________________________________________
Typical Operating Characteristics
(TA = +25°C, unless otherwise noted.)
ON-RESISTANCE vs. V
COM
V
COM
(V)
R
ON
(Ω)
MAX4888/89 toc01
-0.1 0.1 0.3 0.5 0.7 0.9 1.1 1.3 1.5 1.7 1.9 2.1
5.0
5.5
6.0
6.5
7.0
7.5
8.0
8.5
9.0
9.5
10.0
V+ = 3.3V
V+ = 2.5V
V+ = 1.8V
ON-RESISTANCE vs. V
COM
(V+ = 1.8V)
V
COM
(V)
R
ON
(Ω)
MAX4888/89 toc02
-0.1 0 0.1 0.2 0.3 0.4 0.5 0.6
0
2
4
6
8
10
12
14
TA = +85°C
TA = +25°C
TA = -40°C
ON-RESISTANCE vs. V
COM
(V+ = 2.5V)
V
COM
(V)
R
ON
(Ω)
MAX4888/89 toc03
-0.1 0.1 0.3 0.5 0.7 0.9 1.1 1.3
0
2
4
6
8
10
12
14
TA = +85°C
TA = +25°C
TA = -40°C
ON-RESISTANCE vs. V
COM
(V+ = 3.3V)
V
COM
(V)
R
ON
(Ω)
MAX4888/89 toc04
-0.1 0.1 0.3 0.5 0.7 0.9 1.1 1.3 1.5 1.7 1.9 2.1
0
2
4
6
8
10
12
14
TA = +85°C
TA = +25°C
TA = -40°C
SUPPLY CURRENT vs. TEMPERATURE
(MAX4888)
TEMPERATURE (°C)
SUPPLY CURRENT (μA)
MAX4888/89 toc05
-40 -15 10 35 60 85
0
10
20
30
40
50
60
70
80
V+ = 1.8V
V+ = 2.5V
V+ = 3.3V
MAX4888/MAX4889
2.5Gbps PCI Express Passive Switches
_______________________________________________________________________________________
5
Typical Operating Characteristics (continued)
(TA = +25°C, unless otherwise noted.)
EYE DIAGRAM
(V+ = 3.3V, f = 1.25GHz,
600mV
P-P
PRBS SIGNAL, RS = RL = 50Ω)
†
50ps/div
*PRBS = PSEUDORANDOM BIT SEQUENCE
†
GEN I; 2.5Gps; UI = 400ps
V
COM_+
V
COM_-
50mV/div
MAX4888/89 toc10
EYE DIAGRAM
(V+ = 2.5V, f = 1.25GHz,
600mV
P-P
PRBS SIGNAL, RS = RL = 50Ω)
†
50ps/div
*PRBS = PSEUDORANDOM BIT SEQUENCE
†
GEN I; 2.5Gps; UI = 400ps
V
COM_+
V
COM_-
50mV/div
MAX4888/89 toc09
LOGIC THRESHOLD vs. SUPPLY VOLTAGE
SUPPLY VOLTAGE (V)
LOGIC THRESHOLD (V)
MAX4888/89 toc06
1.6 1.8 2.0 2.2 2.4 2.6 2.8 3.0 3.2 3.4 3.6
0.5
0.6
0.7
0.8
0.9
1.0
1.1
1.2
V
IH
V
IL
TURN-ON/-OFF TIME vs. SUPPLY VOLTAGE
SUPPLY VOLTAGE (V)
t
ON
/t
OFF
(ns)
MAX4888/89 toc07
1.6 1.8 2.0 2.2 2.4 2.6 2.8 3.0 3.2 3.4 3.6
0
20
40
60
80
100
120
140
160
180
200
220
240
NO_ t
ON
NO_ t
OFF
NC_ tON
NC_ t
OFF
EYE DIAGRAM
(V+ = 1.8V, f = 1.25GHz,
600mV
P-P
PRBS SIGNAL, RS = RL = 50Ω)
†
50ps/div
*PRBS = PSEUDORANDOM BIT SEQUENCE
†
GEN I; 2.5Gps; UI = 400ps
V
COM_+
V
COM_-
50mV/div
MAX4888/89 toc08