Maxim MAX4888AETI+, MAX4889AETO+ Specifications

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††. 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.

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

Applications

Desktop Computers

Servers/Storage Area Networks

Laptops

MAX4888A/MAX4889A

5.0Gbps PCI Express Passive Switches

________________________________________________________________

Maxim Integrated Products

1

Pin Configurations

19-0770; Rev 2; 5/09

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.

EVALUATION KIT

AVAILABLE

Typical Application Circuit appears at end of data sheet.

††

Contact factory if operating at +2.5V or +1.8V.

PCI Express is a registered trademark of PCI-SIG Corp.

PART TEMP RANGE PIN-PACKAGE CONFIGURATION

MAX4 888AETI+ -40°C to +85°C 28 TQFN-EP* Two Half Lanes

MAX4889AETO+ -40°C to +85°C 42 TQFN-EP* Four Half Lanes

Ordering Information/Selector Guide

+

Denotes lead(Pb)-free/RoHS-compliant package.

*

EP = Exposed paddle.

TOP VIEW

NO2-

NO2+

NO1-

NO1+

V+

GND

NC2-

NC2+

NC1-

NC1+

24 23 22 21 20 19 18 17 16 15

N.C.

14

13

12

11

GND

GND

V+

GND

V+

25

GND

26

V+

*EP

SEL

MAX4888A

N.C.

COM1+

COM1-

27

GND

28

V+

+

12345678910

GND

COM2+

V+

COM2-

TQFN

*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

V+

COM2+

COM2-

MAX4889A

V+

SEL

GND

COM3+

TQFN

NO3-

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 SW ITCH

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

R

R

FLAT(ON)

I

NO_(OFF)

I

NC_(OFF)

I

COM_(ON)

(V+ - 1.2) V

-

| ,

0 1.8 V

-

|

ON

ON

V+ = +3.0V, I
V

or V

NO_

NC_

V+ = +3.0V, I
V

or V

NO_

NC_

V+ = +3.0V, I
V

or V

NO_

NC_

V+ = +3.0V, I
V

or V

NO_

NC_

V+ = +3.6V, V

or V

V

NO_

NC_

V+ = +3.6V, V

or V

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_

7 

0.1 1 

0.6 2 

0.06 2 

-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 tON V

Turn-Off Time t

Propagation De la y tPD RS = RL = 50, unbalanced, Figure 2 50 ps

Output Skew Between Pairs t

Output Skew Between Same
Pair

On-Los s G

Crosstalk V

Signaling Data Rate BR RS = RL = 50 5.0 Gbps

Off-Isolation V

NO_/NC_ Off-Capacitance

COM_ On-Capacitance C

LOGI C I N PU T

Input-Logic Low VIL 0.5 V

Input-Logic High VIH 1.4 V

Input-Logic H ysteresis V

Input Leakage Current IIN V

POW ER SUPPL Y

Power-Supply Range V+ 1.65 3.60 V

V+ Supply Current I+ V

Input Leakage Current IIN V

ESD PROTECTION

COM_+, COM_- Human Body Model ±6 kV

PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS

or V

NO_

V

OFF

SK1

t

SK2

LOS

CT1

ISO

C

NO_ /NC_(OFF) Figure 4 1 pF

COM_(ON)

100 mV

HYST

or V

NO_

RS = RL = 50, unbalanced; skew between
any two pairs, Figure 2

RS = RL = 50, unbalanced; skew between
two lines on same pair, Figure 2

RS = RL = 50,
unbalanced,
Figure 3

Crosstalk between
any two pairs,
R

= RL = 50,

S

unbalanced,
Figure 3

Signal = 0dBm,
R

= RL = 50,

S

Figure 3

Figure 4 2 pF

= 0V or V+ -1 +1 μA

SEL

= 0V or V+

SEL

= 0V or V+ -1 +1 μA

SEL

= +1.0V, RL = 50, Figure 1 90 250 ns

NC_

= +1.0V, RL = 50, Figure 1 10 50 ns

NC_

50 ps

10 ps

1MHz < f < 100MHz -0.5

500MHz < f < 1.25GHz -1.4

f = 50MHz -53

f = 1.25GHz -32

f = 10MHz -56

f = 1.25GHz -26

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.)

10.0

9.5

9.0

8.5

8.0

(Ω)

7.5

ON

R

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 1.5 1.7 1.9 2.1

V+ = +1.8V

V+ = +2.5V

(V)

V

COM_

V+ = +3.3V

ON-RESISTANCE vs. V

COM_

MAX4888A/89A toc01

ON-RESISTANCE vs. V

(V+ = +1.8V)

14

12

10

8

(Ω)

ON

R

6

4

2

0

-0.1 0 0.1 0.2 0.3 0.4 0.5 0.6
V

TA = +25°C

TA = -40°C

(V)

COM_

TA = +85°C

COM_

MAX4888A/89A toc02

(Ω)

ON

R

14

12

10

ON-RESISTANCE vs. V

TA = +25°C

8

6

4

2

0

-0.1 0.1 0.3 0.5 0.7 0.9 1.1 1.3

(V+ = +2.5V)

V

(V)

COM_

COM_

TA = +85°C

MAX4888A/89A toc03

TA = -40°C

14

12

10

8

(Ω)

ON

R

6

4

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+ = +3.3V)

TA = +25°C

V

COM_

ON-RESISTANCE vs. V

COM_

TA = +85°C

MAX4888A/89A toc04

TA = -40°C

(V)

SUPPLY CURRENT vs. TEMPERATURE

80

70

60

50

40

30

SUPPLY CURRENT (μA)

20

10

0

-40 -15 10 35 60 85

TURN-ON/-OFF TIME vs. SUPPLY VOLTAGE

240
220
200
180
160
140

(ns)

120

OFF

/t

100

ON

NC_ tON

t

80
60

NO_ t

40
20

0

1.6 1.8 2.0 2.2 2.4 2.6 2.8 3.0 3.2 3.4 3.6

(MAX4889A)

V+ = +3.3V

V+ = +2.5V

V+ = +1.8V

TEMPERATURE (°C)

NO_ t

OFF

NC_ t

SUPPLY VOLTAGE (V)

OFF

LOGIC THRESHOLD vs. SUPPLY VOLTAGE

1.2

1.1

MAX4888A/89A toc05

1.0

0.9

0.8

LOGIC THRESHOLD (V)

0.7

0.6

0.5

ON

MAX4888A/89A toc07

V

IH

V

IL

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)

MAX4888A/89A toc06

MAX4888A/MAX4889A

5.0Gbps PCI Express Passive Switches

_______________________________________________________________________________________ 5

Typical Operating Characteristics (continued)

(TA = +25°C, unless otherwise noted.)

EYE DIAGRAM

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

PRBS SIGNAL, RS = RL = 50Ω)†

P-P

50ps/div

*PRBS = PSEUDORANDOM BIT SEQUENCE
†

= GEN 1, 2.5Gbps; U1 = 400ps

V

COM_+

50mV/div

V

COM_-

600mV

EYE DIAGRAM

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

PRBS SIGNAL, RS = RL = 50Ω)

P-P

V

COM_+

600mV

MAX4888A/89A toc08

††

EYE DIAGRAM

(V+ = +3.3V, f = 1.25GHz,

PRBS SIGNAL, RS = RL = 50Ω)

P-P

50ps/div

*PRBS = PSEUDORANDOM BIT SEQUENCE
†

= GEN 1, 2.5Gbps; U1 = 400ps

EYE DIAGRAM

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

PRBS SIGNAL, RS = RL = 50Ω)

P-P

V

COM_+

50mV/div

V

COM_-

V

COM_+

EYE DIAGRAM

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

600mV

PRBS SIGNAL, RS = RL = 50Ω)

P-P

50ps/div

*PRBS = PSEUDORANDOM BIT SEQUENCE
†

= GEN 1, 2.5Gbps; U1 = 400ps

EYE DIAGRAM

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

600mV

PRBS SIGNAL, RS = RL = 50Ω)

P-P

†

MAX4888A/89A toc09

††

V

COM_+

50mV/div

V

COM_-

V

COM_+

600mV

600mV

†

MAX4888A/89A toc10

††

50mV/div

V

COM_-

25ps/div

*PRBS = PSEUDORANDOM BIT SEQUENCE
††

= GEN 11, 5.0Gbps; U1 = 200ps

MAX4888A/89A toc11

50mV/div

V

COM_-

25ps/div

*PRBS = PSEUDORANDOM BIT SEQUENCE
††

= GEN 11, 5.0Gbps; U1 = 200ps

MAX4888A/89A toc12

50mV/div

V

COM_-

25ps/div

*PRBS = PSEUDORANDOM BIT SEQUENCE
††

= GEN 11, 5.0Gbps; U1 = 200ps

MAX4888A/89A toc12

MAX4888A/MAX4889A

5.0Gbps PCI Express Passive Switches

6 _______________________________________________________________________________________

Pin Description

PIN

MAX4 888A MAX4889A

1, 10, 12, 14,

20, 25, 27

2 9 SEL Digital Control Input

3, 9 — N.C. No Connection. Not internally connected.

4 2 COM1+ Analog Switch 1. Common Positive Termina l.
5 3 COM1- Analog Switch 1. Common Negative Terminal.
6 6 COM2+ Analog Switch 2. Common Positive Termina l.
7 7 COM2- Analog Switch 2. Common Negative Terminal.

8, 11, 13, 19,

26, 28

15 31 NO2- Analog Switch 2. Normall y Open Negative Terminal.

16 32 NO2+ Analog Switch 2. Normally Open Positive Terminal.

17 33 NO1- Analog Switch 1. Normall y Open Negative Terminal.

18 34 NO1+ Analog Switch 1. Normally Open Positive Terminal.

21 35 NC2- Analog Switch 2. Normally Closed Negative Terminal.

22 36 NC2+ Analog Switch 2. Normally C lo sed Positive Terminal.

23 37 NC1- Analog Switch 1. Normally Closed Negative Terminal.

24 38 NC1+ Analog Switch 1. Normally C lo sed Positive Terminal.

— 11 COM3+ Analog Switch 3. Common Posit ive Terminal.

— 12 COM3- Analog Switch 3. Common Negative Terminal.

— 15 COM4+ Analog Switch 4. Common Posit ive Terminal.

— 16 COM4- Analog Switch 4. Common Negative Terminal.

— 22 NO4- Analog Switch 4. Normally Open Negative Terminal.

— 23 NO4+ Analog Switch 4. Normal ly Open Posit ive Terminal.

— 24 NO3- Analog Switch 3. Normally Open Negative Terminal.

— 25 NO3+ Analog Switch 3. Normal ly Open Posit ive Terminal.

— 26 NC4- Analog Switch 4. Normally Closed Negative Terminal.

— 27 NC4+ Analog Switch 4. Normally Closed Positive Terminal.

— 28 NC3- Analog Switch 3. Normally Closed Negative Terminal.

— 29 NC3+ Analog Switch 3. Normally Closed Positive Terminal.

— — EP Exposed Paddle. Connect EP to GND.

1, 4, 10, 14, 17,

19, 21, 39, 41

5, 8, 13, 18,

20, 30,

40, 42

NAME FUNCTION

GND Ground

Positive-Supply Voltage Input. Connect V+ to a +3.0V to +3.6V supply voltage.

V+

Bypass V+ to GND with a 0.1μF capacitor placed as close to the device as
possible (See the Board Layout section).

MAX4888A/MAX4889A

5.0Gbps PCI Express Passive Switches

_______________________________________________________________________________________ 7

Figure 1. Switching Time

Test Circuits/Timing Diagrams

MAX4888A/MAX4889A

V

N_

LOGIC

INPUT

+3.3V

V+

L

NC_

COM_

R

L

)

ON

NO_
OR NC_

SEL

GND

CL INCLUDES FIXTURE AND STRAY CAPACITANCE.

V

OUT

RL + R

VN_ = V

= V

NO_

N_ (

R

OR V

V

LOGIC
INPUT

V

OUT

C

L

SWITCH
OUTPUT

IH

V

IL

0V

V

50%

t

ON

OUT

0.9 x V

0UT

tr < 5ns
tf < 5ns

t

OFF

0.9 x V

OUT

MAX4888A/MAX4889A

5.0Gbps PCI Express Passive Switches

8 _______________________________________________________________________________________

Test Circuits/Timing Diagrams (continued)

Figure 2. Propagation Delay and Output Skew

+3.3V

V+

MAX4888A/MAX4889A

NC_+

NC_-

COM

COM

_+

_-

IN+

NO_+ OR

R

S

NO_- OR

R

IN-

S

SEL

+1.5V

V

V

V

OUT+

IN+

0V

+1.5V

IN-

0V

t

PLHX

+1.5V

0V

50%

50%

50%

t

50%

50%

PHLX

50%

OUT+

RISE-TIME PROPAGATION DELAY = t

R

L

R

L

FALL-TIME PROPAGATION DELAY = t

t

=

DIFFERENCE IN PROPAGATION DELAY (RISE-FALL)

SK1

BETWEEN ANY TWO PAIRS

t

= | t

SK2

OUT-

t

INRISE

PLHX

BETWEEN TWO LINES ON THE SAME PAIR

90%

10% 10%

t

OUTRISE

90%

10% 10%

OR t

PLHX

PLHY

OR t

PHLX

PHLY

- t

PHLY

| OR | t

PHLX

t

INFALL

- t

|

PLHY

90%

t

OUTFALL

90%

+1.5V

V

OUT-

50%

0V

t

PHLY

t

50%

PLHY

MAX4888A/MAX4889A

5.0Gbps PCI Express Passive Switches

_______________________________________________________________________________________ 9

Detailed Description

The MAX4888A/MAX4889A high-speed passive switch­es route PCIe data between two possible destinations.
The MAX4888A/MAX4889A are ideal for routing PCIe sig­nals to change the system configuration. For example, in
a graphics application, the MAX4888A/MAX4889A create

two sets of eight lanes from a single 16-lane bus. 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

††

.

Digital Control Input (SEL)

The MAX4888A/MAX4889A provide a single digital con­trol input (SEL) to select the signal path between the
COM__ and NO__/NC__ channels. The truth tables for
the MAX4888A/MAX4889A are depicted in the

Functional Diagrams/Truth Table

section. Drive SEL rail-

to-rail to minimize power consumption.

Analog Signal Levels

The MAX4888A/MAX4889A accept standard PCIe sig­nals to a maximum of V+ - 1.2V. Signals on the COM_+
channels are routed to either the NO_+ or NC_+ chan­nels, and signals on the COM_- channels are routed to
either the NO_- or NC_- channels. The MAX4888A/
MAX4889A are bidirectional switches, allowing COM__,
NO__, and NC__ to be used as either inputs or outputs.

Figure 4. Channel Off-/On-Capacitance

Figure 3. On-Loss, Off-Isolation, and Crosstalk

Test Circuits/Timing Diagrams (continued)

††

Contact factory if operating at +2.5V or +1.8V.

0.1μF

+3.3V

0V OR V+

50Ω

MEASUREMENTS ARE STANDARDIZED AGAINST SHORTS AT IC TERMINALS.
OFF-ISOLATION IS MEASURED BETWEEN COM_ AND "OFF" NO_ OR NC_ TERMINAL ON EACH SWITCH.
ON-LOSS IS MEASURED BETWEEN COM_ AND "ON" NO_ OR NC_ TERMINAL ON EACH SWITCH.
CROSSTALK IS MEASURED BETWEEN ANY TWO PAIRS.
SIGNAL DIRECTION THROUGH SWITCH IS REVERSED; WORST VALUES ARE RECORDED.

SEL

NC_

V+

COM_

MAX4888A/MAX4889A

NO_

GND

V

NETWORK
ANALYZER

V

IN

V

OUT

50Ω

MEAS REF

50Ω 50Ω

50Ω

OFF-ISOLATION = 20log

ON-LOSS = 20log

CROSSTALK = 20log

OUT

V

IN

V

OUT

V

IN

V

OUT

V

IN

+3.3V

0.1μF

V+

CAPACITANCE

METER

COM_

NC_ or
NO_

MAX4888A/MAX4889A

GND

SEL

OR V

V

IL

IH

MAX4888A/MAX4889A

5.0Gbps PCI Express Passive Switches

10 ______________________________________________________________________________________

Functional Diagrams/Truth Table

V+

MAX4888A

COM1+

COM1-

COM2+

COM2-

SEL

SEL

0

1

GND

COM__TO

NC__

ON

OFF

COM__TO

NO__

OFF

ON

NC1+

NC1-

NO1+

NO1-

NC2+

NC2-

NO2+

NO2-

COM1+

COM1-

COM2+

COM2-

COM3+

COM3-

COM4+

COM4-

V+

MAX4889A

NC1+

NC1-

NO1+

NO1-

NC2+

NC2-

NO2+

NO2-

NC3+

NC3-

NO3+

NO3-

NC4+

NC4-

NO4+

NO4-

SEL

GND

MAX4888A/MAX4889A

5.0Gbps PCI Express Passive Switches

______________________________________________________________________________________ 11

Applications Information

PCIe Switching

The MAX4888A/MAX4889A primary applications are
aimed at reallocating PCIe lanes (see Figure 5). For
example, in graphics applications, several manufacturers
have found that it is possible to improve performance by
a factor of nearly two by splitting a single 16-lane PCIe
bus into two 8-lane buses. Two of the more prominent
examples are SLI™ (Scaled Link Interface) and
CrossFire™. The MAX4889A permits a computer
motherboard to operate properly with a single 16-lane
graphics card, and can later be updated to dual cards.
The same motherboard can be used with dual cards
where the user sets a jumper or a bit through software
to switch between single- or dual-card operation.
Common mode below 1V operation requirement.

Board Layout

High-speed switches require proper layout and design
procedures for optimum performance. Keep design­controlled impedance PCB traces as short as possible
or follow impedance layouts per the PCIe specification.
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.
Common mode below 1V operation requirement.

ESD Protection

As with all Maxim devices, ESD-protection structures
are incorporated on all pins to protect against electro­static discharges encountered during handling and
assembly. The COM_+ and COM_- lines have extra
protection against static electricity. Maxim’s engineers
have developed state-of-the-art structures to protect
these pins against ESD of ±6kV without damage. The
ESD structures withstand ±6kV of ESD in all states: nor­mal operation, state output mode, and powered down.

Human Body Model

The MAX4889A COM_+ and COM_- pins are character­ized for ±6kV ESD protection using the Human Body
Model (MIL-STD-883, Method 3015). Figure 6 shows
the Human Body Model and Figure 7 shows the current
waveform it generates when discharged into low
impedance. This model consists of a 100pF capacitor
charged to the ESD voltage of interest, which is then
discharged into the device through a resistor.

Figure 5. The MAX4888A/MAX4889A Used as a Single-Lane
Switch

CrossFire is a trademark of ATI Technologies, Inc.

SLI is a trademark of NVIDIA Corporation.

Chip Information

PROCESS: CMOS

Figure 6. Human Body ESD Test Model

Figure 7. Human Body Model Current Waveform

DATA

DIRECTION

HIGH-

VOLTAGE

DC

SOURCE

R

C

1MΩ

CHARGE-CURRENT-

LIMIT RESISTOR

C

s

100pF

R

D

1500Ω

DISCHARGE

RESISTANCE

STORAGE
CAPACITOR

DEVICE
UNDER

TEST

ONE LANE

NOTE: ONLY ONE LANE IS SHOWN FOR CLARITY

MAX4888A
MAX4889A

DATA IS ROUTED

TO EITHER

BOARD A OR B

AB

PEAK-TO-PEAK RINGING

I

r

(NOT DRAWN TO SCALE)

AMPERES

IP 100%

90%

36.8%

10%

0

0

t

RL

TIME

t

DL

CURRENT WAVEFORM

MAX4888A/MAX4889A

5.0Gbps PCI Express Passive Switches

12 ______________________________________________________________________________________

Typical Application Circuit

PCIe GRAPHICS INTERFACE

GRAPHICS

PCIe BUS

LANE 0 TX

LANE 1 TX

LANE 2 TX

LANE 3 TX

COM1+

COM1-

COM2+

COM2-

COM3+

COM3-

COM4+

COM4-

MAX4889A

SEL

NC1+

NC1-

NC2+

NC2-

NC3+

NC3-

NC4+

NC4-

NO1+

NO1-

NO2+

NO2-

NO3+

NO3-

NO4+

NO4-

CARD 1

GRAPHICS

CARD 2

LANE 0 RX

LANE 1 RX

LANE 2 RX

LANE 3 RX

COM1+

COM1-

COM2+

COM2-

COM3+

COM3-

COM4+

COM4-

MAX4889A

SEL

CHANNEL SELECT

NC1+

NC1-

NC2+

NC2-

NC3+

NC3-

NC4+

NC4-

NO1+

NO1-

NO2+

NO2-

NO3+

NO3-

NO4+

NO4-

CHANNEL SELECT

MAX4888A/MAX4889A

5.0Gbps PCI Express Passive Switches

______________________________________________________________________________________ 13

PACKAGE TYPE PACKAGE CODE DOCUMENT NO.

28 TQFN-EP T283555-1

21-0184

42 TQFN-EP T423590M-1

21-0181

Package Information

For the latest package outline information and land patterns, go to www.maxim-ic.com/packages.

MAX4888A/MAX4889A

5.0Gbps PCI Express Passive Switches

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.

14

____________________Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600

© 2009 Maxim Integrated Products Maxim is a registered trademark of Maxim Integrated Products. Inc.

Revision History

REVISION

NUMBER

REVISION

DATE

DESCRIPTION PAGES CHANGED

0 4/07 Initial release —

2 5/09 Updated voltage range, style edits. 1, 2, 3, 5–9, 13, 14