MAXIM MAX4890, MAX4891, MAX4892 User Manual

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General Description

The MAX4890/MAX4891/MAX4892 high-speed analog
switches meet the needs of 10/100/1000 Base-T appli­cations. These devices switch the signals from two
interface transformers and connect the signals to a sin­gle 10/100/1000 Base-T Ethernet PHY, simplifying
docking station design and reducing manufacturing
costs. The MAX4890/MAX4891/MAX4892 can also
route signals from a common interface transformer to
two different boards in board-redundancy applications.

The MAX4890/MAX4891/MAX4892 switches provide an
extremely low capacitance and on-resistance to meet
Ethernet insertion and return-loss specifications. The
MAX4891/MAX4892 feature one and three built-in LED
switches, respectively.

The MAX4890/MAX4891/MAX4892 are available in
space-saving 32- and 36-lead TQFN packages,
significantly reducing the required PC board area.
These devices operate over the -40°C to +85°C tem­perature range.

Applications

Notebooks and Docking Stations

Servers and Routers with Ethernet Interfaces

Board-Level Redundancy Protection

SONET/SDH Signal Routing

T3/E3 Redundancy Protection

Video Switching

Features

♦ Single +3.0V to +3.6V Power-Supply Voltage

♦ Low On-Resistance (R

ON

): 4Ω (typ), 6.5Ω (max)

♦ Ultra-Low On-Capacitance (CON): 6.5pF (typ)

♦ Low < 200ps Bit-to-Bit Skew

♦ -3dB Bandwidth: 1GHz

♦ Optimized Pin-Out for Easy Transformer and PHY

Interface

♦ Built-In LED Switches for Switching Indicators to

Docking Station

♦ Low 450µA (max) Quiescent Current

♦ Bidirectional 8 to 16 Multiplexer/Demultiplexer

♦ Space-Saving Packages

32-Pin, 5mm x 5mm, TQFN Package
36-Pin, 6mm x 6mm, TQFN Package

MAX4890/MAX4891/MAX4892

10/100/1000 Base-T Ethernet LAN Switch

________________________________________________________________ Maxim Integrated Products 1

Pin Configurations

Ordering Information

19-3577; Rev 1; 8/05

For pricing, delivery, and ordering information, please contact Maxim/Dallas Direct! at
1-888-629-4642, or visit Maxim’s website at www.maxim-ic.com.

All devices are available in the -40°C to +85°C operation tem­perature range.

Typical Operating Circuit appears at end of data sheet.

Pin Configurations continued at end of data sheet.

PART

MAX4890ETJ 32 TQFN — T-3255-4

MAX4891ETJ 32 TQFN 1 T-3255-4

MAX4892ETX 36 TQFN 3 T-3666-3

PIN­PACKAGE

LED

SWITCHES

PKG

CODE

TOP VIEW

A2

1

2

A3

3

N.C.

N.C.

4

5

N.C.

6

N.C.

A4

7

8

A5

A0

V+

A1

32 31 30 29 28 27 26

MAX4890*

9 101112131415

A6

A7

GND

TQFN

SEL

N.C.

1B1

0B1

7B2

6B2

1B2

0B2

25

2B1

24

23

3B1

22

2B2

21

3B2

20

4B1

19

5B1

4B2

18

17

5B2

16

7B1

6B1

MAX4890/MAX4891/MAX4892

10/100/1000 Base-T Ethernet LAN Switch

2 _______________________________________________________________________________________

ABSOLUTE MAXIMUM RATINGS

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.

V+ ……………………………………………………… -0.3V to +4V
SEL (Note 1) ………………………………….. -0.3V to (V+ +0.3V)
A_, _B_, LED_, _LED_ .……………………… -0.3V to (V+ +0.3V)

Continuous Current (A_ to _B_) ......................................±120mA

Continuous Current (LED_ to _LED_) .…………………… ±30mA
Peak Current (A_ to _B_)

(pulsed at 1ms, 10% duty cycle) ……………………. ±240mA

Continuous Power Dissipation (T

A

= +70°C)
32-Pin TQFN (derate 34.5mW/°C above +70°C) …….. 2.76W
36-Pin TQFN (derate 26.3mW/°C above +70°C) …….. 2.11W

Operating Temperature Range …………………. -40°C to +85°C
Junction Temperature.……………………………………. +150°C
Storage Temperature Range .…………………. -65°C to +150°C

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

ELECTRICAL CHARACTERISTICS

(V+ = +3V to +3.6V, TA= T

MIN

to T

MAX

, unless otherwise noted. Typical values are at V+ = 3.3V, TA= +25°C.) (Note 2)

)

)

)

Note 1: Signals on SEL, 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

On-Resistance R

On-Resistance
LED Switches

R

ONLED

ON

V+ = 3V,

= -40mA,

I

A_

1.5V ≤ V

V+ = 3V, I

A_

_LED_

≤ V+

MAX4891/MAX4892

TA = +25°C 4 5.5

to T

T

MIN

MAX

= -40mA, 1.5V ≤ V

A_

≤ V+,

6.5

Ω

40 Ω

ON

V+ = 3V,

= -40mA,

I

A_

1.5V ≤ V

A_

≤ V+

On-Resistance Match
Between Channels

∆R

(Note 3)

On-Resistance Flatness R

Off-Leakage Current I

On-Leakage Current I

FLAT(ON

LA_(OFF

LA_(ON

V+ = 3V, IA_ = -40mA, V

V+ = 3.6V, VA_ = 0.3V, 3.3V

or V

V

_B1

= 3.3V, 0.3V

_B2

V+ = 3.6V, VA_= 0.3V, 3.3V

or V

V

_B1

= 0.3V, 3.3V or floating

_B2

TA = +25°C 0.5 1.5

to T

T

MIN

MAX

= 1.5V, 2.7V 0.01 Ω

A_

-1 +1

-1 +1

ESD PROTECTION

ESD Protection Human Body Model ±2 kV

SWITCH AC PERFORMANCE

Insertion loss with typical transformer,

Insertion Loss I

LOS

R

= 100Ω, 1MHz < f < 100MHz, Figure 1

L

0.6 dB

(Note 3)

Return loss with
typical transformer,
R

= 100Ω, return

L

loss, f in MHz,
Figure 2 (Note 3)

1MHz < f < 40MHz -19

-13

40MHz < f < 100MHz

+20log

(f/80)

Return Loss

R

R

LOS1

LOS2

Ω

2

µA

dB

MAX4890/MAX4891/MAX4892

10/100/1000 Base-T Ethernet LAN Switch

_______________________________________________________________________________________ 3

ELECTRICAL CHARACTERISTICS (continued)

(V+ = +3V to +3.6V, TA= T

MIN

to T

MAX

, unless otherwise noted. Typical values are at V+ = 3.3V, TA= +25°C.) (Note 2)

Note 2: Specifications at -40°C are guaranteed by design.
Note 3: Guaranteed by design.

PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS

Differential Crosstalk

SWITCH DYNAMICS

On-Channel -3dB Bandwidth BW RL = 100Ω, Differential pair 1000 MHz

Off-Capacitance C

On-Capacitance C

Off-Capacitance, LED Switches C

On-Capacitance, LED Switches C

Turn-On Time t

Turn-Off Time t

Propagation Delay t

Output Skew Between Ports t

Output Skew Same Port t

SWITCH LOGIC

Input-Voltage Low V

Input-Voltage High V

Input-Logic Hysteresis V

Input Leakage Current I

Operating Supply-Voltage Range V+ 3 3.6 V

Quiescent Supply Current I+ V+ = 3.6V, V

V

CT1

V

CT2

V

CT3

V

DCT1

V

DCT2

V

DCT3

OFF

ON

OFFLED

ONLED

ON

OFF

PLH, tPHLCL

SK(o)

SK(p)

HYST

SEL

Any switch to any
switch R
Figure 3

RL = 100Ω,
Figure 4

f = 1MHz, _B_ inputs 3.5 pF

f = 1MHz, _B_ inputs 6.5 pF

f = 1MHz, _LED inputs 20 pF

f = 1MHz, _LED inputs 22 pF

VA_ = 1V, Figure 5 25 50 ns

V

Skew between A4 and A5 and any other
port, Figure 7

Skew between opposite transitions in same
port

IL

IH

V+ = 3.6V, V

= 100Ω,

L

= 1V, Figure 5 20 40 ns

A_

= 10pF, Figure 6 0.15 ns

SEL

SEL

1MHz < f < 30MHz -45

30MHz < f < 60MHz -40Crosstalk

60MHz < f < 100MHz -35

1MHz < f < 30MHz -60

30MHz < f < 60MHz -55

60MHz < f < 100MHz -50

2.0

= 0 or V+ -5 +5 uA

= 0 or V+ 280 450 µA

0.01 ns

0.07 ns

0.8

100 mV

dB

dB

V

MAX4890/MAX4891/MAX4892

10/100/1000 Base-T Ethernet LAN Switch

4 _______________________________________________________________________________________

Typical Operating Characteristics

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

3.0

3.2

3.6

3.4

3.8

4.0

ON-RESISTANCE vs. V

A_

MAX4890 toc01

VA_ (V)

R

ON

(Ω)

01.80.9 2.7 3.6

V+ = 3.0V, 3.3V, 3.6V

0

1

3

2

4

5

ON-RESISTANCE vs. V

A_

MAX4890 toc02

VA_ (V)

R

ON

(Ω)

0 1.1 2.2 3.3

TA = +85°C

TA = -40°C

TA = +25°C

0

6

4

2

8

10

12

14

16

18

20

0 0.9 1.8 2.7 3.6

LED_ ON-RESISTANCE vs. V

A_

MAX4890 toc03

VA_ (V)

R

ONLED

(Ω)

V+ = 3.6V

V+ = 3.3V

V+ = 3.0V

0

6

4

2

8

10

12

14

16

18

20

01.1

2.2

3.3

LED_ ON-RESISTANCE vs. TEMPERATURE

MAX4890 toc04

VA_ (V)

R

ONLED

(Ω)

TA = +25°C

TA = -40°C

TA = +85°C

0

400

200

1000

800

600

1600

1400

1200

1800

-40 10-15 356085

LEAKAGE CURRENT vs. TEMPERATURE

MAX4890 toc05

TEMPERATURE (°C)

LEAKAGE CURRENT (pA)

I

LA_(ON)

I

LA_(OFF)

0

100

5

20

15

25

30

0 1.1 2.2 3.3

CHARGE INJECTION vs. V

A_

MAX4890 toc06

VA_ (V)

CHARGE INJECTION (pC)

150

210

190

170

230

250

270

290

310

330

350

-40 10-15 35 60 85

QUIESCENT SUPPLY CURRENT

vs. TEMPERATURE

MAX4890 toc07

TEMPERATURE (°C)

QUIESCENT SUPPLY CURRENT (µA)

0

400

200

800

600

1000

1200

0 1.1 2.2 3.3

QUIESCENT SUPPLY CURRENT

vs. LOGIC LEVEL

MAX4890 toc08

LOGIC LEVEL (V)

QUIESCENT SUPPLY CURRENT (µA)

0

0.4

0.2

1.0

0.8

0.6

1.6

1.4

1.2

1.8

3.0 3.23.1 3.3 3.4 3.5 3.6

LOGIC THRESHOLD vs. SUPPLY VOLTAGE

MAX4890 toc09

SUPPLY VOLTAGE (V)

LOGIC THRESHOLD (V)

V

TH+

V

TH-

MAX4890/MAX4891/MAX4892

10/100/1000 Base-T Ethernet LAN Switch

_______________________________________________________________________________________ 5

Typical Operating Characteristics (continued)

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

TURN-ON/-OFF TIME

vs. SUPPLY VOLTAGE

25

20

15

(ns)

OFF

/t

ON

t

10

5

0

3.0 3.2 3.4 3.6

t

ON

t

OFF

SUPPLY VOLTAGE (V)

MAX4890 toc10

(ns)

OFF

/t

ON

t

RISE-/FALL-TIME PROPAGATION DELAY

vs. TEMPERATURE

250

t

200

150

100

OUTPUT RISE-/FALL-TIME DELAY (ps)

t

PHL

PLH

MAX4890 toc13

PULSE SKEW (ps)

TURN-ON/-OFF TIME

vs. TEMPERATURE

30

t

25

20

15

10

5

0

-40 10-15 35 60 85

ON

t

OFF

TEMPERATURE (°C)

PULSE SKEW vs. SUPPLY VOLTAGE

100

t

SK(p)

80

60

40

20

MAX4890 toc11

MAX4890 toc14

RISE-/FALL-TIME PROPAGATION DELAY

vs. SUPPLY VOLTAGE

250

t

PLH

200

150

100

OUTPUT RISE/FALL-TIME DELAY (ps)

50

3.0 3.3 3.6

t

PHL

SUPPLY VOLTAGE (V)

PULSE SKEW vs. TEMPERATURE

100

t

80

60

40

PULSE SKEW (ps)

20

SK(p)

MAX4890 toc12

MAX4890 toc15

50

-40 10-15 35 60 85
TEMPERATURE (°C)

OUTPUT SKEW

vs. SUPPLY VOLTAGE

20

10

0

OUTPUT SKEW (ps)

-10

-20

3.0 3.3 3.6
SUPPLY VOLTAGE (V)

t

SK(o)_FALL

t

SK(o)_RISE

MAX4890 toc16

OUTPUT SKEW (ps)

0

3.0 3.3 3.6
SUPPLY VOLTAGE (V)

OUTPUT SKEW vs. TEMPERATURE

20

t

SK(o)_FALL

10

0

t

SK(o)_RISE

-10

-20

-40 10-15 35 60 85
TEMPERATURE (°C)

0

-40 10-15 35 60 85

DIFFERENTIAL INSERTION LOSS

1

MAX4890 toc17

0

-1

-2

-3

-4

DIFFERENTIAL INSERTION LOSS (dB)

-5
1100

TEMPERATURE (°C)

vs. FREQUENCY

MAX4890 toc18

10

FREQUENCY (MHz)

MAX4890/MAX4891/MAX4892

10/100/1000 Base-T Ethernet LAN Switch

6 _______________________________________________________________________________________

Typical Operating Characteristics (continued)

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

DIFFERENTIAL RETURN LOSS

vs. FREQUENCY

0

-10

-20

-30

DIFFERENTIAL RETURN LOSS (dB)

-40
1 100

10

FREQUENCY (MHz)

0

-10

MAX4890 toc19

-20

-30

-40

-50

-60

-70

DIFFERENTIAL CROSSTALK (dB)

-80

-90

-100
1100

DIFFERENTIAL CROSSTALK

vs. FREQUENCY

MAX4890 toc20

SINGLE-ENDED OFF-ISOLATION (dB)

-100

10

FREQUENCY (MHz)

SINGLE-ENDED OFF-ISOLATION

vs. FREQUENCY

0

-10

-20

-30

-40

-50

-60

-70

-80

-90

1 100

10

FREQUENCY (MHz)

MAX4890 toc21

SINGLE-ENDED CROSSTALK

vs. FREQUENCY

0

-10

-20

-30

-40

-50

-60

-70

-80

SINGLE-ENDED CROSSTALK (dB)

-90

-100
1100

10

FREQUENCY (MHz)

MAX4890 toc22

0

-1

-2

-3

-4

SINGLE-ENDED INSERTION LOSS (dB)

-5

SINGLE-ENDED INSERTION LOSS

vs. FREQUENCY

1 1000

FREQUENCY (MHz)

10010

MAX4890 toc23