19-3577; Rev 2; 8/07
10/100/1000 Base-T Ethernet LAN Switch
General Description
The MAX4890/MAX4891/MAX4892 high-speed analog
switches meet the needs of 10/100/1000 Base-T appli-
cations. These devices switch the signals from two
interface transformers and connect the signals to a sin-
gle 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 tem-
perature range.
Features
♦
Single +3.0V to +3.6V Power-Supply Voltage
♦
Low On-Resistance (R
ON
): 4Ω (typ), 6.5Ω (max)
♦
Ultra-Low On-Capacitance (C
ON
): 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
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
PART
MAX4890ETJ
MAX4891ETJ
MAX4892ETX
Ordering Information
PIN-PACKAGE
32 TQFN-EP*
32 TQFN-EP*
36 TQFN-EP*
LED SWITCHES
—
1
3
Note:
All devices are specified for operation in the -40°C to
+85°C temperature range.
*EP
= Exposed pad.
Pin Configurations
1B1
SEL
0B1
0B2
1B2
A1
A0
V+
TOP VIEW
32
A2
A3
N.C.
N.C.
N.C.
N.C.
A4
A5
31
30
29
28
27
26
25
24
23
22
21
2B1
3B1
2B2
3B2
4B1
5B1
4B2
5B2
1
2
3
4
5
6
7
8
9
A6
*EP
MAX4890
20
19
18
17
10
A7
11
GND
12
N.C.
13
7B2
14
6B2
15
7B1
16
6B1
Functional Diagrams and Typical Operating Circuit appear
at end of data sheet.
TQFN
*EP = EXPOSED PAD. CONNECT EP TO GND OR LEAVE UNCONNECTED
Pin Configurations continued at end of data sheet.
________________________________________________________________
Maxim Integrated Products
1
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.
10/100/1000 Base-T Ethernet LAN Switch
MAX4890/MAX4891/MAX4892
ABSOLUTE MAXIMUM RATINGS
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
Note 1:
Signals on SEL, exceeding V+ or GND, are clamped by internal diodes. Limit forward-diode current to maximum current
rating.
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.
ELECTRICAL CHARACTERISTICS
(V+ = +3V to +3.6V, T
A
= T
MIN
to T
MAX
, unless otherwise noted. Typical values are at V+ = 3.3V, T
A
= +25°C.) (Note 2)
PARAMETER
ANALOG SWITCH
On-Resistance
On-Resistance
LED Switches
On-Resistance Match
Between Channels
On-Resistance Flatness
Off-Leakage Current
On-Leakage Current
ESD PROTECTION
ESD Protection
SWITCH AC PERFORMANCE
Insertion Loss
I
LOS
Insertion loss with typical transformer,
R
L
= 100Ω, 1MHz < f < 100MHz, Figure 1
(Note 3)
Return loss with
typical transformer,
R
L
= 100Ω, return
loss, f in MHz,
Figure 2 (Note 3)
1MHz < f < 40MHz
0.6
dB
Human Body Model
±2
kV
R
ON
V+ = 3V,
I
A_
= -40mA,
1.5V
≤
V
A_
≤
V+
T
A
= +25°C
T
MIN
to T
MAX
4
5.5
Ω
6.5
40
0.5
1.5
Ω
T
MIN
to T
MAX
0.01
-1
-1
+1
µA
I
LA_(ON)
V+ = 3.6V, V
A_
= 0.3V, 3.3V
V
_B1
or V
_B2
= 0.3V, 3.3V or floating
+1
2
Ω
Ω
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
R
ONLED
V+ = 3V, I
_LED_
= -40mA, 1.5V
≤
V
A_
≤
V+,
MAX4891/MAX4892
V+ = 3V,
I
A_
= -40mA,
1.5V
≤
V
A_
≤
V+
(Note 3)
T
A
= +25°C
ΔR
ON
R
FLAT(ON)
I
LA_(OFF)
V+ = 3V, I
A_
= -40mA, V
A_
= 1.5V, 2.7V
V+ = 3.6V, V
A_
= 0.3V, 3.3V
V
_B1
or V
_B2
= 3.3V, 0.3V
R
LOS1
Return Loss
R
LOS2
-19
-13
+20log
(f/80)
dB
40MHz < f < 100MHz
2
_______________________________________________________________________________________
10/100/1000 Base-T Ethernet LAN Switch
ELECTRICAL CHARACTERISTICS (continued)
(V+ = +3V to +3.6V, T
A
= T
MIN
to T
MAX
, unless otherwise noted. Typical values are at V+ = 3.3V, T
A
= +25°C.) (Note 2)
PARAMETER
Crosstalk
SYMBOL
V
CT1
V
CT2
V
CT3
V
DCT1
Differential Crosstalk
SWITCH DYNAMICS
On-Channel -3dB Bandwidth
Off-Capacitance
On-Capacitance
Off-Capacitance, LED Switches
On-Capacitance, LED Switches
Turn-On Time
Turn-Off Time
Propagation Delay
Output Skew Between Ports
Output Skew Same Port
SWITCH LOGIC
Input-Voltage Low
Input-Voltage High
Input-Logic Hysteresis
Input Leakage Current
Operating Supply-Voltage Range
Quiescent Supply Current
V
IL
V
IH
V
HYST
I
SEL
V+
I+
V+ = 3.6V, V
SEL
= 0 or V+
V+ = 3.6V, V
SEL
= 0 or V+
-5
3
280
2.0
100
+5
3.6
450
0.8
V
mV
uA
V
µA
BW
C
OFF
C
ON
C
OFFLED
C
ONLED
t
ON
t
OFF
t
PLH,
t
PHL
t
SK(o)
t
SK(p)
R
L
= 100Ω, Differential pair
f = 1MHz,
_B_
inputs
f = 1MHz,
_B_
inputs
f = 1MHz, _LED inputs
f = 1MHz, _LED inputs
V
A_
= 1V, Figure 5
V
A_
= 1V, Figure 5
C
L
= 10pF, Figure 6
Skew between A4 and A5 and any other
port, Figure 7
Skew between opposite transitions in same
port
1000
3.5
6.5
20
22
25
20
0.15
0.01
0.07
50
40
MHz
pF
pF
pF
pF
ns
ns
ns
ns
ns
V
DCT2
V
DCT3
CONDITIONS
Any switch to any
switch R
L
= 100Ω,
Figure 3
R
L
= 100Ω,
Figure 4
1MHz < f < 30MHz
30MHz < f < 60MHz
60MHz < f < 100MHz
1MHz < f < 30MHz
30MHz < f < 60MHz
60MHz < f < 100MHz
MIN
TYP
-45
-40
-35
-60
-55
-50
dB
dB
MAX
UNITS
MAX4890/MAX4891/MAX4892
Note 2:
Specifications at -40°C are guaranteed by design.
Note 3:
Guaranteed by design.
_______________________________________________________________________________________
3
10/100/1000 Base-T Ethernet LAN Switch
MAX4890/MAX4891/MAX4892
Typical Operating Characteristics
(V+ = 3.3V, T
A
= +25°C, unless otherwise noted.)
ON-RESISTANCE vs. V
A_
MAX4890 toc01
ON-RESISTANCE vs. V
A_
MAX4890 toc02
LED_ ON-RESISTANCE vs. V
A_
18
16
14
R
ONLED
(Ω)
V+ = 3.0V
MAX4890 toc03
4.0
5
20
3.8
V+ = 3.0V, 3.3V, 3.6V
R
ON
(Ω)
4
R
ON
(Ω)
3.6
3
T
A
= +85°C
T
A
= +25°C
T
A
= -40°C
12
10
8
6
V+ = 3.3V
V+ = 3.6V
3.4
2
3.2
1
4
2
3.0
0
0.9
1.8
V
A_
(V)
2.7
3.6
0
0
1.1
V
A_
(V)
2.2
3.3
0
0
0.9
1.8
V
A_
(V)
2.7
3.6
LED_ ON-RESISTANCE vs. TEMPERATURE
18
16
14
R
ONLED
(Ω)
12
10
8
6
4
2
0
0
1.1
V
A_
(V)
2.2
3.3
T
A
= -40°C
T
A
= +25°C
T
A
= +85°C
MAX4890 toc04
LEAKAGE CURRENT vs. TEMPERATURE
MAX4890 toc05
CHARGE INJECTION vs. V
A_
MAX4890 toc06
20
1800
1600
LEAKAGE CURRENT (pA)
1400
1200
1000
800
600
400
200
0
-40
-15
10
35
60
I
LA_(OFF)
I
LA_(ON)
30
25
CHARGE INJECTION (pC)
20
15
100
5
0
85
0
1.1
V
A_
(V)
2.2
3.3
TEMPERATURE (°C)
QUIESCENT SUPPLY CURRENT
vs. TEMPERATURE
MAX4890 toc07
QUIESCENT SUPPLY CURRENT
vs. LOGIC LEVEL
MAX4890 toc08
LOGIC THRESHOLD vs. SUPPLY VOLTAGE
1.6
LOGIC THRESHOLD (V)
1.4
1.2
1.0
0.8
0.6
0.4
V
TH-
V
TH+
MAX4890 toc09
350
QUIESCENT SUPPLY CURRENT (μA)
330
310
290
270
250
230
210
190
170
150
-40
-15
10
35
60
1200
QUIESCENT SUPPLY CURRENT (μA)
1000
800
600
400
200
1.8
0.2
0
85
0
1.1
2.2
3.3
TEMPERATURE (°C)
LOGIC LEVEL (V)
0
3.0
3.1
3.2
3.3
3.4
3.5
3.6
SUPPLY VOLTAGE (V)
4
_______________________________________________________________________________________
10/100/1000 Base-T Ethernet LAN Switch
Typical Operating Characteristics (continued)
(V+ = 3.3V, T
A
= +25°C, unless otherwise noted.)
TURN-ON/-OFF TIME
vs. SUPPLY VOLTAGE
MAX4890 toc10
MAX4890/MAX4891/MAX4892
TURN-ON/-OFF TIME
vs. TEMPERATURE
OUTPUT RISE/FALL-TIME DELAY (ps)
t
ON
25
20
15
t
OFF
10
MAX4890 toc11
RISE-/FALL-TIME PROPAGATION DELAY
vs. SUPPLY VOLTAGE
MAX4890 toc12
25
30
250
t
PLH
200
20
t
ON
t
ON
/t
OFF
(ns)
15
t
OFF
10
t
ON
/t
OFF
(ns)
150
100
t
PHL
50
5
5
0
3.0
3.2
3.4
3.6
-40
-15
10
35
60
85
SUPPLY VOLTAGE (V)
TEMPERATURE (°C)
0
3.0
3.3
SUPPLY VOLTAGE (V)
3.6
RISE-/FALL-TIME PROPAGATION DELAY
vs. TEMPERATURE
MAX4890 toc13
PULSE SKEW vs. SUPPLY VOLTAGE
MAX4890 toc14
PULSE SKEW vs. TEMPERATURE
t
SK(p)
80
PULSE SKEW (ps)
MAX4890 toc15
250
OUTPUT RISE-/FALL-TIME DELAY (ps)
t
PLH
200
100
t
SK(p)
80
PULSE SKEW (ps)
100
60
60
150
40
40
100
t
PHL
50
-40
-15
10
35
60
85
TEMPERATURE (°C)
20
20
0
3.0
3.3
SUPPLY VOLTAGE (V)
3.6
0
-40
-15
10
35
60
85
TEMPERATURE (°C)
OUTPUT SKEW
vs. SUPPLY VOLTAGE
MAX4890 toc16
OUTPUT SKEW vs. TEMPERATURE
MAX4890 toc17
DIFFERENTIAL INSERTION LOSS
vs. FREQUENCY
MAX4890 toc18
20
20
t
SK(o)_FALL
10
OUTPUT SKEW (ps)
1
DIFFERENTIAL INSERTION LOSS (dB)
0
-1
-2
-3
-4
-5
OUTPUT SKEW (ps)
10
t
SK(o)_FALL
0
t
SK(o)_RISE
-10
0
t
SK(o)_RISE
-10
-20
3.0
3.3
SUPPLY VOLTAGE (V)
3.6
-20
-40
-15
10
35
60
85
TEMPERATURE (°C)
1
10
FREQUENCY (MHz)
100
_______________________________________________________________________________________
5
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