Rainbow Electronics MAX4889C User Manual

General Description

The MAX4889B/MAX4889C high-speed passive switch­es route PCI Express

®

(PCIe) data between two possi­ble destinations in desktop or notebook PCs. The
MAX4889B/MAX4889C are quad double-pole/double­throw (4 x DPDT) switches ideal for switching four half
lanes of PCIe data between two destinations. The
MAX4889B/MAX4889C feature a single digital control
input (SEL) to switch signal paths.

The MAX4889C is intended for use in systems (e.g.,
SAS) where both the input and output are capacitively
coupled, and provides a 10µA (typ) source current and
a 60kΩ (typ) internal biasing resistor to GND at the
_OUT_ terminals.

The MAX4889B/MAX4889C are fully specified to oper­ate from a single +3.3V (typ) power supply. Both
devices are available in an industry-standard 3.5mm x

9.0mm, 42-pin TQFN package. These devices operate
over the -40°C to +85°C extended temperature range.

Applications

Desktop PCs

Notebook PCs

Servers

Video Graphics Cards—SLI™
(Scaled Link Interface) and CrossFire™

Features

o Single +3.3V Power-Supply Voltage

o Support PCIe Gen I, Gen II Data Rates

o Supports SAS I, SAS II, and SAS 6.0Gbps

(MAX4889C)

o Superior Return Loss

Better than -14dB at 2.8GHz

o Small 3.5mm x 9.0mm, 42-Pin TQFN Package

o Industry-Standard Pinouts

MAX4889B/MAX4889C

2.5/5.0Gbps PCIe Passive Switches

________________________________________________________________

Maxim Integrated Products

1

Ordering Information

19-4148; Rev 1; 8/08

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 temperature

range.

+

Denotes a lead-free package.

*

EP = Exposed pad.

Pin Configuration

TOP VIEW

MAX4889B/

MAX4889C

TQFN

18

19

20

21

GND

V

CC

GND

V

CC

42

+

41

40

39

GND

V

CC

GND

V

CC

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17

38 37 36 35 34 33 32 31 30 29 28 27 26 25 24 23 22

COUTB+

COUTB-

DIN+

DIN-

DOUTB+

DOUTB-

CIN-

CIN+

V

CC

BOUTB-

BOUTB+

BIN-

BIN+

AOUTB-

AOUTB+

AIN-

AIN+

COUTA-

VCCGND

DOUTA+

DOUTA-

GND

COUTA+

GND

SEL

VCCBOUTA-

BOUTA+

VCCGND

AOUTA-

AOUTA+

GND

*CONNECT EXPOSED PAD TO GROUND.

*EP

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

SLI is a trademark of NVIDIA Corp.

CrossFire is a trademark of ATI Technologies, Inc.

Typical Operating Circuit appears at end of data sheet.

PART PIN-PACKAGE PKG CODE

MAX4889BETO+ 42 TQFN-EP* T423590M-1

MAX4889CETO+ 42 TQFN-EP* T423590M-1

MAX4889B/MAX4889C

2.5/5.0Gbps PCIe Passive Switches

2 _______________________________________________________________________________________

ABSOLUTE MAXIMUM RATINGS

ELECTRICAL CHARACTERISTICS

(VCC= +3.3V ±10%, TA=T

MIN

to T

MAX,

unless otherwise noted. Typical values are at VCC= +3.3V, TA= +25°C, unless otherwise

noted.) (Note 3)

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

CC

...........................................................................-0.3V to +4V

SEL, _IN_, _OUTA_, _OUTB_ (Note 1) .......-0.3V to (V

CC

+ 0.3V)

Continuous Current (AIN_ to AOUTA_/AOUTB_, BIN_ to

BOUTA_/BOUTB_, CIN_ to COUTA_/COUTB_, DIN_ to

DOUTA_/DOUTB_)........................................................±70mA

Peak Current (AIN_ to AOUTA_/AOUTB_, BIN_ to

BOUTA_/BOUTB_, CIN_ to COUTA_/COUTB_, DIN_ to

DOUTA_/DOUTB_)

(pulsed at 1ms, 10% duty cycle)..............................±70mA

Continuous Current (SEL).................................................±10mA

Peak Current (SEL)

(pulsed at 1ms, 10% duty cycle)..................................±10mA

Continuous Power Dissipation (T

A

= +70°C) for multilayer board:

42-Pin TQFN (derate 35.7mW/°C above +70°C) .......2857mW

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) ............................................................28.0°C/W

Package Junction-to-Case Thermal Resistance

(θ

JC

) (Note 2) ..............................................................2.0°C/W

Lead Temperature (soldering, 10s) .................................+300°C

)

)

Note 1: Signals on SEL, _IN_, _OUTA_, _OUTB_ exceeding VCCor 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, refer to www.maxim-ic.com/thermal-tutorial

.

PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS

DC PERFORMANCE

Analog Signal Range

On-Resistance R

On-Resistance Match Between
Pairs of Same Channel

On-Resistance Match Between
Channels

On-Resistance Flatness R

_OUTA_ or _OUTB_ Off-Leakage
Current

_IN_ On-Leakage Current I

Output Short-Circuit Current

Output Open-Circuit Voltage

_IN_,

_OUTA_,

_OUTB_

ON

ΔR

ON

ΔR

ON

FLAT (ON

I

_ OU TA _ ( OF F)

I

_ OU TB _ ( OF F)

_IN_ (ON

VCC = +3.0V, I

_OUTB_

= 0V, 1.2V

V

VCC = +3.0V, I
V

= 0V (Notes 4, 5)

_OUTB_

VCC = +3.0V, I
V

= 0V (Notes 4, 5)

_OUTB_

VCC = +3.0V, I
V

,

VCC = +3.6V , V
or V

= 0V, 1.2V (Notes 5, 6)

_OUTB_

_OUTB_

VCC = +3.6V , V
or V

_OUTB_

= 15mA, V

_IN_

= 15mA, V

_IN_

= 15mA, V

_IN_

= 15mA, V

_IN_

= 0V, 1.2V, V

_IN_

= 1.2V, 0V (MAX4889B)

= 0V, 1.2V, V

_IN_

= V

or unconnected

_IN_

(MAX4889B)

All other ports are unconnected
(MAX4889C)

All other ports are unconnected
(MAX4889C)

_OUTA_

_OUTA_

_OUTA_

_OUTA_

_OUTA_

_OUTA_

V

-

-0.3

,

,

,

,

6.4 8.4 Ω

0.1 0.5 Ω

0.2 Ω

0.3 Ω

CC

1.8

V

-1 +1 µA

-1 +1 µA

515µA

0.2 0.6 0.9 V

FREQUENCY RANGE

(GHz)

MAXIMUM INSERTION

LOSS (dB)

0–2.5

2.5–5

5 or greater

MAX4889B/MAX4889C

2.5/5.0Gbps PCIe Passive Switches

_______________________________________________________________________________________ 3

Note 3: 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 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.

ELECTRICAL CHARACTERISTICS (continued)

(VCC= +3.3V ±10%, TA=T

MIN

to T

MAX,

unless otherwise noted. Typical values are at VCC= +3.3V, TA= +25°C, unless otherwise

noted.) (Note 3)

Table 1. Insertion Loss Mask

1

5

f + 0.6

GHz

4

2

×

5

f - 1.0

GHz

6

×

5

f - 3.0

GHz

8

×

PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS

AC PERFORMANCE

SEL-to-Switch Turn-On Time t

SEL-to-Switch Turn-Off Time t

Propagation Delay t

Output Skew Between Pairs t

Output Skew Between Same Pair t

Differential Return Loss (Note 5) S

Differential Insertion Loss (Note 5) S

Differential Crosstalk (Note 5) S

Differential Off-Isolation (Note 5) S

CONTROL INPUT (SEL)

Input Logic High V

Input Logic Low V

Input Logic Hysteresis V

POWER SUPPLY

Power-Supply Range V

VCC Supply Current I

ON_SEL

OFF_SEL

PD

SKEW1

SKEW2

ZS = ZL = 50Ω 80 ns

ZS = ZL = 50Ω, Figure 1 15 ns

ZS = ZL = 50Ω, Figure 2 50 ps

ZS = ZL = 50Ω, Figure2 50 ps

ZS = ZL = 50Ω, Figure 2 10 ps

0Hz < f ≤ 2.8GHz -14

DD11

2.8GHz < f ≤ 5.0GHz -8

f > 5.0GHz -3

DD21

See Table 1 dB

0Hz < f ≤ 2.5GHz -40

DDCTK

2.5GHz < f ≤ 5.0GHz -30

f > 5.0GHz -25

0Hz < f ≤ 2.5GHz -15

DD21_OFF

2.5GHz < f ≤ 5.0GHz -12

f > 5.0GHz -12

IH

IL

HYST

CC

V

CC

SEL

= 0 or V

CC

dB

dB

dB

1.4 V

0.6 V

130 mV

3.0 3.6 V

1mA

MAX4889B/MAX4889C

2.5/5.0Gbps PCIe Passive Switches

4 _______________________________________________________________________________________

Test Circuits/Timing Diagrams

LOAD

SOURCE

V

OUT

Z

L

MAX4889B/

MAX4889C

SEL

Z

S

Σ

10%

90%

50%

50%

t

ON_SEL

t

OFF_SEL

V

OUT

SEL

THE FREQUENCY OF THE SIGNAL SHOULD BE ABOVE THE HIGHPASS FILTER CORNER OF THE COUPLING CAPACITORS.

Figure 1. Switching Time

MAX4889B/MAX4889C

2.5/5.0Gbps PCIe Passive Switches

Test Circuits/Timing Diagrams (continued)

LOAD

SOURCE

V

OUTp

Z

L

V

OUTn

Z

L

MAX4889B/

MAX4889C

SEL

CALIBRATION

TRACES

V

S+

Z

S

Σ

V

S-

Z

S

Σ

V

CALp

Z

L

V

CALn

Z

L

V

SC+

Z

S

Σ

V

SC-

Z

S

Σ

50%50%

VCM

50%50%

VCM

VCM

VCM

t

PDr

t

PDf

t

SK1

t

SK2

V

OUTn

THE FREQUENCY OF THE SIGNALS SHOULD BE APPROXIMATELY 1/20 OF THE LOWEST DATA RATE.

V

OUTp

tPD = max (t

PDr

, t

PDf

)

t

SKEW

= max (t

SK1

, t

SK2

)

V

OUTp

- V

OUTn

V

CALp

- V

CALn

Figure 2. Propagation Delay and Output Skew

_______________________________________________________________________________________ 5

MAX4889B/MAX4889C

2.5/5.0Gbps PCIe Passive Switches

6 _______________________________________________________________________________________

Typical Operating Characteristics

(VCC= +3.3V, TA= +25°C, unless otherwise noted.)

4.0

5.5

5.0

4.5

6.5

6.0

7.5

7.0

8.0

0 0.6 1.2 1.8

ON-RESISTANCE vs. V

_IN_

MAX4889B/9C toc01

V

_IN_

(V)

R

ON

(Ω)

VCC = +3.0V

VCC = +3.6V

VCC = +3.3V

3

2

4

5

6

7

8

9

10

0 0.3 0.6 0.9 1.2 1.5

ON-RESISTANCE vs. V

_IN_

MAX4889B/9C toc02

V

_IN_

(V)

R

ON

(Ω)

TA = +85°C

TA = -40°C TA = +25°C

250

350

300

500

450

400

650

600

550

700

-40 10-15 356085

SUPPLY CURRENT

vs. TEMPERATURE

MAX4889B/9C toc03

TEMPERATURE (°C)

SUPPLY CURRENT (μA)

MAX4889B
MAX4889C

VCC = +3.6V

VCC = +3.3V

VCC = +3.0V

VCC = +3.6V

VCC = +3.3V

VCC = +3.0V

0.9

1.0

1.2

1.1

1.3

1.4

3.0 3.23.1 3.3 3.4 3.5 3.6

LOGIC THRESHOLD

vs. SUPPLY VOLTAGE

MAX4889B/9C toc04

VCC (V)

LOGIC THRESHOLD (V)

V

IH

V

IL

0

10

20

60

50

40

30

80

70

90

TURN-ON/-OFF TIME

vs. SUPPLY VOLTAGE

MAX4889B/9C toc05

VCC (V)

TURN-ON/-OFF TIME (ns)

3.0 3.4 3.53.2 3.33.1 3.6

t

ON SEL

t

OFF SEL

-20

-16

-18

-12

-14

-8

-10

-6

-2

-4

0

0246810

DIFFERENTIAL INSERTION LOSS

vs. FREQUENCY

MAX4889B/9C toc06

FREQUENCY (GHz)

DIFFERENTIAL INSERITON LOSS (dB)

MAX4889B
MAX4889C

MASK

-50

-40

-45

-30

-35

-20

-25

-15

-5

-10

0

0246810

DIFFERENTIAL OFF-ISOLATION

vs. FREQUENCY

MAX4889B/9C toc07

FREQUENCY (GHz)

DIFFERENTIAL OFF-ISOLATION (dB)

-80

-60

-70

-50

-20

-10

-30

-40

0

0246810

DIFFERENTIAL CROSSTALK

vs. FREQUENCY

MAX4889B/9C toc08

FREQUENCY (GHz)

DIFFERENTIAL CROSSTALK (dB)

-40

-30

-35

-25

-10

-5

-15

-20

0

0246810

DIFFERENTIAL RETURN LOSS

vs. FREQUENCY

MAX4889B/9C toc09

FREQUENCY (GHz)

DIFFERENTIAL RETURN LOSS (dB)

MAX4889B
MAX4889C

MASK

MAX4889B/MAX4889C

2.5/5.0Gbps PCIe Passive Switches

_______________________________________________________________________________________ 7

Functional Diagram/Truth Table

AIN+

AIN-

BIN+

BIN-

V

CC

V

CC

MAX4889CMAX4889B

AOUTA+

AOUTA-

AOUTB+

AOUTB-

BOUTA+

BOUTA-

BOUTB+

BOUTB-

AIN+

AIN-

BIN+

BIN-

AOUTA+

AOUTA-

AOUTB+

AOUTB-

BOUTA+

BOUTA-

BOUTB+

BOUTB-

SEL

0 (DEFAULT)

1

_IN_ TO
_OUTA_

ON

OFF

_IN_ TO
_OUTB_

OFF

ON

CIN+

CIN-

DIN+

DIN-

CONTROL

SEL

GND

COUTA+

COUTA-

COUTB+

COUTB-

DOUTA+

DOUTA-

DOUTB+

DOUTB-

CIN+

CIN-

DIN+

DIN-

SEL

COUTA+

COUTA-

COUTB+

COUTB-

DOUTA+

DOUTA-

DOUTB+

DOUTB-

CONTROL

GND

MAX4889B/MAX4889C

2.5/5.0Gbps PCIe Passive Switches

8 _______________________________________________________________________________________

Pin Description

PIN

MAX4889B/

MAX4889C

1 AIN+ Analog Switch 1. Common Positive Terminal.

2 AIN- Analog Switch 1. Common Negative Terminal.

3 AOUTB+ Analog Switch 1. Normally Open Positive Terminal.

4 AOUTB- Analog Switch 1. Normally Open Negative Terminal.

5 BIN+ Analog Switch 2. Common Positive Terminal.

6 BIN- Analog Switch 2. Common Negative Terminal.

7 BOUTB+ Analog Switch 2. Normally Open Positive Terminal.

8 BOUTB- Analog Switch 2. Normally Open Negative Terminal.

9, 19, 21, 26, 31,

34, 39, 41

10 CIN+ Analog Switch 3. Common Positive Terminal.

11 CIN- Analog Switch 3. Common Negative Terminal.

12 COUTB+ Analog Switch 3. Normally Open Positive Terminal.

13 COUTB- Analog Switch 3. Normally Open Negative Terminal.

14 DIN+ Analog Switch 4. Common Positive Terminal.

15 DIN- Analog Switch 4. Common Negative Terminal.

16 DOUTB+ Analog Switch 4. Normally Open Positive Terminal.

17 DOUTB- Analog Switch 4. Normally Open Negative Terminal.

18, 20, 22, 25, 29,

35, 38, 40, 42

23 DOUTA- Analog Switch 4. Normally Closed Negative Terminal.

24 DOUTA+ Analog Switch 4. Normally Closed Positive Terminal.

27 COUTA- Analog Switch 3. Normally Closed Negative Terminal.

28 COUTA+ Analog Switch 3. Normally Closed Positive Terminal.

30 SEL Control Signal Input. SEL has a 70kΩ (typ) pulldown resistor to GND.

32 BOUTA - Analog Switch 2. Normally Closed Negative Terminal.

33 BOUTA+ Analog Switch 2. Normally Closed Positive Terminal.

36 AOUTA- Analog Switch 1. Normally Closed Negative Terminal.

37 AOUTA+ Analog Switch 1. Normally Closed Positive Terminal.

— EP Exposed Pad. Connect EP to GND.

NAME FUNCTION

V

CC

GND Ground

P osi ti ve S up p l y V ol tag e Inp ut. C onnect V
a 0.1µF cer am i c cap aci tor p l aced as cl ose as p ossi b l e to the d evi ce. S ee the Boar d Layout secti on.

to a 3.0V to 3.6V sup p l y vol tag e. Byp a ss V

C C

to GN D w i th

C C

Detailed Description

The MAX4889B high-speed passive switch routes PCI
Express (PCIe) data or other high-speed signals with
amplitude of ≤ 1.2V

P-P

differential, and common-mode
voltage close to 0V between two possible destinations.
The MAX4889B is ideal for routing PCIe signals to
change system configuration. For example, in a graphics
application, four MAX4889B devices create two sets of
eight lanes from a single 16-lane bus. The MAX4889C
feature a 10µA (typ) source current and a 60kΩ (typ)
internal biasing resistor to GND at the _OUT_ terminals.
The MAX4889C is ideal for dual capacitively coupled
applications such as SAS and SATA. The MAX4889B/
MAX4889C feature a single digital control input (SEL) to
switch signal paths. SEL has a 70kΩ (typ) pulldown
resistor to GND.

The MAX4889B/MAX4889C are fully specified to oper­ate from a single 3.0V to 3.6V power supply.

Digital Control Input (SEL)

The MAX4889B/MAX4889C provide a single digital
control input (SEL) to select the signal path between
the _IN_ and _OUT_ channels. The truth tables for the
MAX4889B/MAX4889C are illustrated in the

Functional

Diagram/Truth Table

. SEL has a 70kΩ (typ) pulldown

resistor to GND.

Analog Signal Levels

The MAX4889B/MAX4889C accept standard PCIe signals
to a maximum of (VCC- 1.8V). Signals on the _IN+ chan­nels are routed to either the _OUTA+ or _OUTB+ chan­nels. Signals on the _IN- channels are routed to either the
_OUTA- or _OUTB- channels. The MAX4889B/MAX4889C
are bidirectional switches, allowing _IN_ and _OUT_ to be
used as either inputs or outputs.

Applications Information

PCIe Switching

The MAX4889B/MAX4889C primary applications are
aimed at reallocating PCIe lanes (see the

Typical

Operating Circuit: Video Graphics Cards

). 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. Four
MAX4889Bs permit a computer motherboard to operate
properly with a single 16-lane graphics card, which can
later be upgraded to dual cards.

Board Layout

High-speed switches require proper layout and design
procedures for optimum performance. Keep controlled­impedance PCB traces as short as possible or follow
impedance layouts per the PCIe specification. Ensure
that power-supply bypass capacitors are placed as
close as possible to the device. Multiple bypass capac­itors are recommended. Connect all grounds and the
exposed pad to large ground planes.

MAX4889B/MAX4889C

2.5/5.0Gbps PCIe Passive Switches

_______________________________________________________________________________________ 9

MAX4889B/MAX4889C

2.5/5.0Gbps PCIe Passive Switches

10 ______________________________________________________________________________________

Typical Operating Circuit: Video Graphics Cards

CHANNEL

SELECT

PCIe

NORTH BRIDGE

SEL

LANE 0 TX

LANE 1 TX

LANE 2 TX

LANE 3 TX

AIN+

AIN-

BIN+

BIN-

CIN+

CIN-

DIN+

DIN-

MAX4889B

CHANNEL

SELECT

V

CC

GND

V

CC

AOUTA+

AOUTA-

BOUTA+

BOUTA-

COUTA+

COUTA-

DOUTA+

DOUTA-

AOUTB+

AOUTB-

BOUTB+

BOUTB-

COUTB+

COUTB-

DOUTB+

DOUTB-

PCIe GRAPHICS

CONNECTOR 1

PCIe GRAPHICS

CONNECTOR 2

AOUTA+

AOUTA-

BOUTA+

BOUTA-

COUTA+

COUTA-

DOUTA+

DOUTA-

AOUTB+

AOUTB-

BOUTB+

BOUTB-

COUTB+

COUTB-

DOUTB+

DOUTB-

LANE 0 RX

LANE 1 RX

LANE 2 RX

LANE 3 RX

SEL

AIN+

AIN-

BIN+

BIN-

CIN+

CIN-

DIN+

DIN-

MAX4889B

GND

MAX4889B/MAX4889C

2.5/5.0Gbps PCIe 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.

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

11

© 2008 Maxim Integrated Products is a registered trademark of Maxim Integrated Products, Inc.

SPRINGER

Package Information

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

.

PACKAGE TYPE PACKAGE CODE DOCUMENT NO.

42 TQFN T423590M-1

21-0181

Chip Information

PROCESS: CMOS