19-1854; Rev 5; 9/07
+3.3V, 2.7Gbps Dual 2
General Description
The MAX3840 is a dual 2
✕
2 asynchronous crosspoint
switch for SDH/SONET DWDM and other high-speed
data switching applications where serial data stream
loop-through and protection channel switching are
required. It is ideal for OC-48 systems with forward
error correction. A high-bandwidth, fully differential sig-
nal path minimizes jitter accumulation, crosstalk, and
signal skew. Each 2
✕
2 crosspoint switch can fan out
and/or multiplex up to 2.7Gbps data and 2.7GHz clock
signals. All inputs and outputs are current mode logic
(CML) compatible and easily adaptable to interface
with an AC-coupled LVPECL signal. When not used,
each CML output stage can be powered down with an
enable control to conserve power. The typical power
consumption is 460mW with all outputs enabled.
The MAX3840 is compatible with the MAX3876
2.5Gbps clock and data recovery (CDR) circuit.
The MAX3840 is available in a 32-pin exposed-pad
QFN package (5mm
✕
5mm footprint) and operates
from a +3.3V supply over a temperature range of -40°C
to +85°C.
✕
2 Crosspoint Switch
Features
MAX3840
♦
Single +3.3V Supply
♦
460mW Power Consumption
♦
2ps
RMS
Random Jitter
♦
7ps
P-P
Deterministic Jitter
♦
Power-Down Feature for Deselected Outputs
♦
CML Inputs/Outputs
♦
6ps Channel-to-Channel Skew
♦
100ps Output Edge Speed
♦
5mm
✕
5mm 32 QFN or Thin QFN Package
Ordering Information
PART
MAX3840ETJ+
MAX3840EGJ
TEMP RANGE
-40°C to +85°C
-40°C to +85°C
PIN-
PACKAGE
32 TQFN
32 QFN
PKG
CODE
T3255-3
G3255-1
________________________Applications
SDH/SONET and DWDM Transport Systems
Add-Drop Multiplexers
ATM Switch Cores
WDM Cross-Connects
High-Speed Backplanes
+Denotes
a lead-free package.
Pin Configurations appear at end of data sheet.
Typical Application Circuit
V
CC
= +3.3V
MAX3866
TIA AND LA
MAX3876
CDR
DATA
MAX3869
LASER
DRIVER
CLOCK
MAX3866
TIA AND LA
MAX3876
CDR
DATA
MAX3840
CROSSPOINT
SWITCH
MAX3869
LASER
DRIVER
CLOCK
Z
O
= 50Ω TRANSMISSION LINE
________________________________________________________________
Maxim Integrated Products
1
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.
+3.3V, 2.7Gbps Dual 2
MAX3840
ABSOLUTE MAXIMUM RATINGS
✕
2 Crosspoint Switch
Supply Voltage, V
CC
.............................................-0.5V to +5.0V
Input Voltage (CML) .........................(VCC - 1.0) to (V
CC
+ 0.5V)
TTL Control Input Voltage...........................-0.5V to (V
CC
+ 0.5V)
Output Currents (CML) .......................................................22mA
Continuous Power Dissipation (T
A
= +85°C)
32-Pin TQFN
(derate 21.3mW/°C above +85°C) .................................1.38W
32-Pin QFN
(derate 21.3mW/°C above +85°C) .................................1.38W
Operating Temperature Range ...........................-40°C to +85°C
Operating Junction Temperature Range ...........-55°C to +150°C
Storage Temperature Range .............................-65°C to +160°C
Lead Temperature (soldering, 10s) .................................+300°C
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.
DC ELECTRICAL CHARACTERISTICS
(V
CC
= +3.0V to +3.6V, T
A
= -40°C to +85°C. Typical values are at V
CC
= +3.3V, T
A
= +25°C, unless otherwise noted.)
PARAMETER
Supply Current
CML Differential Output Swing
Differential Output Impedance
CML Output Common-Mode
Voltage
CML Single-Ended Input
Voltage Range
CML Differential Input Voltage
Swing
CML Single-Ended Input
Impedance
TTL SPECIFICATIONS
TTL Input High Voltage
TTL Input Low Voltage
TTL Input High Current
TTL Input Low Current
V
IH
V
IL
I
IH
I
IL
-10
-10
2.0
0.8
+10
+10
V
V
µA
µA
V
IS
R
L
= 50Ω to V
CC
V
CC
- 0.8
300
42.5
50
SYMBOL
I
CC
CONDITIONS
All outputs enabled
R
L
= 50Ω to V
CC
(Figure 2)
640
85
MIN
TYP
140
800
100
V
CC
- 0.2
V
CC
+ 0.5
2000
57.5
MAX
190
1000
115
UNITS
mA
mV
P-P
Ω
V
V
mV
P-P
Ω
CML INPUT AND OUTPUT SPECIFICATIONS
2
_______________________________________________________________________________________
+3.3V, 2.7Gbps Dual 2
AC ELECTRICAL CHARACTERISTICS
✕
2 Crosspoint Switch
MAX3840
(V
CC
= +3.0V to +3.6V, T
A
= -40°C to +85°C. Typical values are at V
CC
= +3.3V, T
A
= +25°C, unless otherwise noted.) (Note 1)
PARAMETER
CML Input and Output Data
Rate
CML Input and Output Clock
Rate
CML Output Rise and Fall Time
CML Output Random Jitter
CML Output Deterministic Jitter
CML Output Differential Skew
CML Output Channel-to-
Channel Skew
Propagation Delay from Input-
to-Output
CML Differential Output Swing
for 2.7Gbps Input Data
CML Differential Output Swing
for 2.7GHz Input Clock
t
r
, t
f
RJ
DJ
t
skew1
t
skew2
t
d
R
L
= 50Ω to V
CC
(Note 4)
R
L
= 50Ω to V
CC
(Note 5)
600
520
20% to 80%
(Note 2)
(Note 3)
Any differential pair
Any two outputs
SYMBOL
CONDITIONS
MIN
TYP
2.7
2.7
100
2
7
7
15
185
20
25
40
136
MAX
UNITS
Gbps
GHz
ps
ps
RMS
ps
P-P
ps
ps
ps
mV
P-P
mV
P-P
Note 1:
Note 2:
Note 3:
Note 4:
Note 5:
AC characteristics are guaranteed by design and characterization.
Measured with 100mV
P-P
noise (f
≤
2MHz) on the power supply.
Deterministic jitter (DJ) is the arithmetic sum of pattern-dependent jitter and pulse-width distortion.
Measured with 300mV
P-P
differential 1010... data pattern driving the inputs.
Measured with 300mV
P-P
differential clock at 2.7GHz driving the inputs.
_______________________________________________________________________________________
3
+3.3V, 2.7Gbps Dual 2
MAX3840
✕
2 Crosspoint Switch
Typical Operating Characteristics
(V
CC
= +3.3V, T
A
= +25°C, unless otherwise noted.)
SUPPLY CURRENT vs. TEMPERATURE
MAX3840 toc01
CML DIFFERENTIAL VOLTAGE
CML DIFFERENTIAL VOLTAGE (mV
P-P
)
750
700
650
600
550
500
450
400
350
300
250
200
MAX3840 toc02
160
4 OUTPUTS ENABLED
140
SUPPLY CURRENT (mA)
120
100
80
60
40
20
0
-50
-30
-10
50
30
TEMPERATURE (°C)
10
70
3 OUTPUTS ENABLED
2 OUTPUTS ENABLED
1 OUTPUT ENABLED
0 OUTPUTS ENABLED
800
90
-50
-30
-10
50
30
TEMPERATURE (°C)
10
70
90
2.7Gbps EYE DIAGRAM
INPUT = 2
23
- 1PRBS
MAX3840 toc03
CHANNEL-TO-CHANNEL SKEW
vs. TEMPERATURE
18
16
14
MAX3840 toc04
20
150mV/div
TMIE (ps)
12
10
8
6
4
2
0
CHANNEL A
-50
-30
-10
10
30
50
70
90
CHANNEL B
54ps/div
TEMPERATURE (°C)
4
_______________________________________________________________________________________
+3.3V, 2.7Gbps Dual 2
✕
2 Crosspoint Switch
Pin Description
MAX3840
PIN
1
2
3
4
5
6
7
8
9, 24
10, 13, 16, 17,
20, 23
11
12
14
15
18
19
21
22
25
26
27
28
29
30
31
32
EP
NAME
ENB1
DIB1+
DIB1-
ENB0
SELB0
DIB0+
DIB0-
SELB1
GND
V
CC
DOB0-
DOB0+
DOB1-
DOB1+
DOA1-
DOA1+
DOA0-
DOA0+
SELA1
DIA0+
DIA0-
SELA0
ENA0
DIA1+
DIA1-
ENA1
Exposed Pad
FUNCTION
Channel B1 Output Enable, TTL Input. A TTL low input powers down B1 output stage.
Channel B1 Positive Signal Input, CML
Channel B1 Negative Signal Input, CML
Channel B0 Output Enable, TTL Input. A TTL low input powers down B0 output stage.
Channel B0 Output Select, TTL Input. See Table 1.
Channel B0 Positive Signal Input, CML
Channel B0 Negative Signal Input, CML
Channel B1 Output Select, TTL Input. See Table 1.
Supply Ground
Positive Supply
Channel B0 Negative Output, CML
Channel B0 Positive Output, CML
Channel B1 Negative Output, CML
Channel B1 Positive Output, CML
Channel A1 Negative Output, CML
Channel A1 Positive Output, CML
Channel A0 Negative Output, CML
Channel A0 Positive Output, CML
Channel A1 Output Select, TTL Input. See Table 1.
Channel A0 Positive Signal Input, CML
Channel A0 Negative Signal Input, CML
Channel A0 Output Select, TTL Input. See Table 1.
Channel A0 Output Enable, TTL Input. A TTL low input powers down A0 output stage.
Channel A1 Positive Signal Input, CML
Channel A1 Negative Signal Input, CML
Channel A1 Output Enable, TTL Input. A TTL low input powers down A1 output stage.
Ground. The exposed pad must be soldered to the circuit board ground for proper
electrical and thermal operation.
_______________________________________________________________________________________
5
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