Maxim MAX4888A User Manual

General Description

The MAX4888A/MAX4889A high-speed passive switches
route PCI Express

®

(PCIe) data between two possible
destinations. The MAX4888A is a quad single-pole/dou­ble-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 oper­ate from a single 3.0V to 3.6V power supply and also
operate down to +1.65V. 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

Features

o Single 1.65V to 3.6V Power-Supply Voltage

o Low Same-Pair Skew of 7ps

o Low 120µA (Max) Quiescent Current

o Supports PCIe Gen I and Gen || Data Rates

o Flow-Through Pin Configuration for Ease of

Layout

o Industry-Compatible Pinout

o Lead-Free Packaging

MAX4888A/MAX4889A

5.0Gbps PCI Express Passive Switches

________________________________________________________________

Maxim Integrated Products

1

Pin Configurations

Ordering Information/

Selector Guide

19-0770; Rev 0; 4/07

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.

PART

PIN-

CONFIGURATION

PKG

CODE

MAX4888AETI+

Two

Half Lanes

M A X4 8 8 9 A E TO +

Four Half

Lanes

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*

T283555-1

T423590M-1

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

MAX4888A

N.C.

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.

GND

GND

NC4+

NC4-

NO3+

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

40

V+

41

*EP

42

V+

+

1234567891011121314151617

COM1+

COM1-

GND

GND

MAX4889A

COM2+

COM2-

V+

SEL

GND

COM3-

COM3+

V+

TQFN

NO3-

V+

GND

COM4+

NO4+

COM4-

NO4-

21

20

19

18

GND

GND

V+

GND

V+

MAX4888A/MAX4889A

5.0Gbps 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.

ANALOG SWITCH

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

PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS

V

,

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_

V+ = 3.0V, I

or V

V

NO_

V+ = 3.0V, I

or V

V

NO_

V+ = 3.0V, I

or V

V

NO_

V+ = 3.6V, V
V

or V

NO_

V+ = 3.6V, V

or V

V

NO_

= 15mA,

COM_

= 0V, 1.8V

NC_

= 15mA,

COM_

= 0V (Notes 3, 4)

NC_

= 15mA,

COM_

= 0V (Notes 3, 4)

NC_

= 15mA

COM_

= 0V, 1.8V (Notes 4, 5)

NC_

= 0V, 1.8V,

COM_

= 1.8V, 0V

NC_

= 0V, 1.8V,

COM_

NC_

= 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

MAX4888A/MAX4889A

5.0Gbps 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 5.0 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,
R

= RL = 50Ω,

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 < 1.25G H z-1.4

500M H z

f = 50MHz -53

f = 1.25GHz -32

f = 10MHz -56

f = 1.25GHz -26

0.5 V

1.4 V

100 mV

MAX4888A 60

MAX4889A 120

dB

dB

dB

µA

MAX4888A/MAX4889A

5.0Gbps 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)

MAX4888A/89A 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)

MAX4888A/89A 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)

MAX4888A/89A 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)

MAX4888A/89A 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

(MAX4889A)

TEMPERATURE (°C)

SUPPLY CURRENT (μA)

MAX4888A/89A 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

LOGIC THRESHOLD vs. SUPPLY VOLTAGE

SUPPLY VOLTAGE (V)

LOGIC THRESHOLD (V)

MAX4888A/89A 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)

MAX4888A/89A 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

MAX4888A/MAX4889A

5.0Gbps 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 1, 2.5Gbps; U1 = 400ps

V

COM_+

V

COM_-

50mV/div

MAX4888A/89A toc10

EYE DIAGRAM

(V+ = 1.8V, f = 2.5GHz,

600mV

P-P

PRBS SIGNAL, RS = RL = 50Ω)

††

25ps/div

*PRBS = PSEUDORANDOM BIT SEQUENCE
††

= GEN 11, 5.0Gbps; U1 = 200ps

V

COM_+

V

COM_-

50mV/div

MAX4888A/89A toc11

EYE DIAGRAM

(V+ = 3.3V, f = 2.5GHz,

600mV

P-P

PRBS SIGNAL, RS = RL = 50Ω)

††

25ps/div

*PRBS = PSEUDORANDOM BIT SEQUENCE
††

= GEN 11, 5.0Gbps; U1 = 200ps

V

COM_+

V

COM_-

50mV/div

MAX4888A/89A toc12

EYE DIAGRAM

(V+ = 2.5V, f = 2.5GHz,

600mV

P-P

PRBS SIGNAL, RS = RL = 50Ω)

††

25ps/div

*PRBS = PSEUDORANDOM BIT SEQUENCE
††

= GEN 11, 5.0Gbps; U1 = 200ps

V

COM_+

V

COM_-

50mV/div

MAX4888A/89A toc12

EYE DIAGRAM

(V+ = 2.5V, f = 1.25GHz,

600mV

P-P

PRBS SIGNAL, RS = RL = 50Ω)

†

50ps/div

*PRBS = PSEUDORANDOM BIT SEQUENCE
†

= GEN 1, 2.5Gbps; U1 = 400ps

V

COM_+

V

COM_-

50mV/div

MAX4888A/89A toc09

EYE DIAGRAM

(V+ = 1.8V, f = 1.25GHz,

600mV

P-P

PRBS SIGNAL, RS = RL = 50Ω)†

50ps/div

*PRBS = PSEUDORANDOM BIT SEQUENCE
†

= GEN 1, 2.5Gbps; U1 = 400ps

V

COM_+

V

COM_-

50mV/div

MAX4888A/89A toc08