Maxim MAX3640UCM 3.3v, 622mbps lvds, dual 4:2 crosspoint switch Datasheet

19-4800; Rev 0; 3/00
3.3V, 622Mbps LVDS,
Dual 4:2 Crosspoint Switch
Features
The MAX3640 has a unique power-saving feature.
When a set of four output channels has been de-selected, the output drivers are powered down to reduce
power consumption by 165mW. The fully differential
architecture ensures low crosstalk, jitter accumulation,
and signal skew.
The MAX3640 is available in a 48-pin TQFP package
and operates from a +3.3V supply over the 0°C to
+85°C temperature range.
♦ Single +3.3V Supply
♦ 257mW Power Consumption (four output
channels enabled)
♦ 2.8psRMS Output Random Jitter
♦ 42ps Output Deterministic Jitter
♦ Power-Down Feature for Deselected Outputs
♦ 110ps Channel-to-Channel Skew
♦ 240ps Output Edge Speed
♦ LVDS Inputs/Outputs
♦ LVDS Output 3-State Enable
Ordering Information
Applications
SONET/SDH Backplanes
PART
TEMP. RANGE
High-Speed Parallel Links
MAX3640UCM
0°C to +85°C
Digital Cross-Connects
PIN-PACKAGE
48 TQFP
Pin Configuration appears at end of data sheet.
System Interconnects
ATM Switch Cores
Typical Operating Circuit
SONET
SOURCE A
MAX3869
LASER DRIVER
OPTICAL
TRANSCEIVER
2.5Gbps
MAX3831
4-CHANNEL
INTERCONNECT
MUX/DEMUX
MAX3640
CROSSPOINT
SWITCH
SONET
SOURCE B
622Mbps
622Mbps
MAX3866
TIA AND LA
MAX3876
CDR
PARALLEL DATA
OUTPUT
________________________________________________________________ Maxim Integrated Products
1
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For small orders, phone 1-800-835-8769.
MAX3640
General Description
The MAX3640 is a dual-path crosspoint switch for use
at OC-12 data rates. The MAX3640 can be used to
receive and transmit 622Mbps low-voltage differential
signals (LVDS) across a backplane with minimum jitter
accumulation. Each path incorporates input buffers,
multiplexers, a crosspoint switch, and output drivers.
The four output channels have a redundant set of outputs for test or fanning purposes. The device offers signal-path redundancy for critical data streams.
MAX3640
3.3V, 622Mbps LVDS,
Dual 4:2 Crosspoint Switch
ABSOLUTE MAXIMUM RATINGS
Supply Voltage, VCC ................................................-0.5V to 5.0V
Input Voltage (LVDS, TTL)..........................-0.5V to (VCC + 0.5V)
Output Voltage (LVDS) ...............................-0.5V to (VCC + 0.5V)
Continuous Power Dissipation (TA = +85°C)
48-Pin TQFP (derate 12.5mW/°C) .................................813mW
Operating Temperature Range...............................0°C to +85°C
Storage Temperature Range ............................ -55°C to +150°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
(VCC = +3.0V to 3.6V, LVDS differential load = 100Ω ±1%, TA = 0°C to +85°C. Typical values are at VCC = +3.3V, TA = +25°C,
unless otherwise noted.)
PARAMETER
Supply Current
SYMBOL
ICC
TYP
MAX
Eight outputs enabled
CONDITIONS
MIN
130
175
Four outputs enabled
78
UNITS
mA
LVDS INPUTS AND OUTPUTS
Input Voltage Range
VIN
0
2400
mV
Differential Input Threshold
VIDTH
-100
100
mV
Threshold Hysteresis
VHYST
Differential Input Impedance
90
RIN
85
Input Common-Mode Current
IOS
LVDS input, VOS = 1.2V
Output Voltage High
VOH
Figure 1
Output Voltage Low
VOL
Figure 1
0.925
Output Voltage Swing
|VOD|
Figure 1
250
Change in Magnitude of
Differential Output for
Complementary States
Offset Output Voltage
Change in Magnitude of
Output Offset Voltage for
Complementary States
100
Figure 1
1.125
ENA, ENB = GND
ENA, ENB = VCC
Output Current
1.475
V
400
mV
25
mV
1.275
mV
25
mV
V
|∆VOS|
Differential Output Impedance
Ω
µA
245
|∆VOD|
VOS
mV
115
1
80
Shorted together
MΩ
120
Ω
12
mA
TTL INPUTS
Input Voltage High
VIH
Input Voltage Low
VIL
Input Current High
IIH
VIH = 2.0V
-250
µA
Input Current Low
IIL
VIL = 0.8V
-550
µA
2
2.0
V
0.8
_______________________________________________________________________________________
V
3.3V, 622Mbps LVDS,
Dual 4:2 Crosspoint Switch
(VCC = +3.0V to 3.6V, LVDS differential load = 100Ω ±1%, TA = 0°C to +85°C. Typical values are at VCC = +3.3V, TA = +25°C,
unless otherwise noted.) (Note 1)
PARAMETER
SYMBOL
CONDITIONS
MIN
Parallel Input/Output Data Rate
TYP
MAX
622
Output Rise/Fall Time
tr, tf
Output Random Jitter
RJ
Output Deterministic Jitter
DJ
20% to 80%
150
(Note 2)
LVDS Output Differential Skew
tSKEW1
LVDS Output Channel-toChannel Skew
tSKEW2
UNITS
Mbps
240
350
ps
2.8
4
psRMS
42
200
ps
24
50
ps
110
ps
LVDS Output Enable Time
266
ns
LVDS Output Disable Time
66
ns
LVDS Propagation Delay from
Input to Output
2.5
tD
ns
Note 1: AC characteristics are guaranteed by design and characterization.
Note 2: Deterministic jitter (DJ) is the arithmetic sum of pattern-dependent jitter and pulse-width distortion. DJ is measured while
applying 100mVp-p noise (f ≤ 2MHz) to the power supply.
VOH
LVDS+
SINGLE ENDED
125mV MIN
200mV MAX
VOS = 1.2V ±75mV
250mV MIN
400mV MAX
VOL
VOH
VOS = 1.2V ±75mV
125mV MIN
200mV MAX
LVDSSINGLE ENDED
250mV MIN
400mV MAX
VOL
VOD
250mV MIN
400mV MAX
0
500mV MIN
800mV MAX
(LVDS+) - (LVDS-)
DIFFERENTIAL OUTPUT
VOLTAGE
Figure 1. LVDS Output Levels
_______________________________________________________________________________________
3
MAX3640
AC ELECTRICAL CHARACTERISTICS
Typical Operating Characteristics
(VCC = +3.3V, TA = +25°C, unless otherwise noted.)
DIFFERENTIAL OUTPUT VOLTAGE
vs. TEMPERATURE
SUPPLY CURRENT vs. TEMPERATURE
130
8 OUTPUTS ENABLED
120
110
100
90
80
4 OUTPUTS ENABLED
70
60
50
630
620
610
600
590
580
570
560
20
30
40
50
60
70
80
0
20
40
60
TEMPERATURE (°C)
TEMPERATURE (°C)
622Mbps EYE DIAGRAM
1.25Gbps EYE DIAGRAM
INPUT = 213 - 1 PRBS
CONTAINS 100 ZEROS
100mV/div
INPUT = 213 - 1 PRBS
CONTAINS 100 ZEROS
100mV/div
200ps/div
100ps/div
_______________________________________________________________________________________
80
MAX3640 toc04
10
MAX3640 toc03
0
4
640
MAX3640 toc02
140
DIFFERENTIAL OUTPUT VOLTAGE (mVp-p)
MAX3640 toc01
150
SUPPLY CURRENT (mA)
MAX3640
3.3V, 622Mbps LVDS,
Dual 4:2 Crosspoint Switch
3.3V, 622Mbps LVDS,
Dual 4:2 Crosspoint Switch
PIN
NAME
FUNCTION
1, 12, 25, 36,
41
VCC
Positive Supply Voltage
2, 11, 26, 35
GND
Supply Ground
3, 5, 45, 47
DIA3+, DIA4+, DIA1+,
DIA2+
Positive LVDS, Channel-A Data Input
4, 6, 46, 48
DIA3-, DIA4-, DIA1-,
DIA2-
Negative LVDS, Channel-A Data Input
7, 9, 13, 15
DIB1+, DIB2+, DIB3+,
DIB4+
Positive LVDS, Channel-B Data Input
8, 10, 14, 16
DIB1-, DIB2-, DIB3-,
DIB4-
Negative LVDS, Channel-B Data Input
17–20
SEL1–SEL4
21, 23, 27, 29
DOB4-, DOB3-, DOB2-,
DOB1-
Negative LVDS, Channel-B Data Output
22, 24, 28, 30
DOB4+, DOB3+,
DOB2+, DOB1+
Positive LVDS, Channel-B Data Output
31, 33, 37, 39
DOA4-, DOA3-, DOA2-,
DOA1-
Negative LVDS, Channel-A Data Output
32, 34, 38, 40
DOA4+, DOA3+,
DOA2+, DOA1+
Positive LVDS, Channel-A Data Output
42
ENB
Channel-B Output Enable, TTL Input. ENB = high enables DOB1−DOB4.
ENB = low powers down DOB1−DOB4 and sets them to a high-impedance state.
43
ENA
Channel-A Output Enable, TTL Input. ENA = high enables DOA1−DOA4.
ENA = low powers down DOA1−DOA4 and sets them to a high-impedance state.
44
IN_SEL
Crosspoint Switch Select, TTL Input. (Table 1)
Input Select Pin, TTL Input. Connect to logic high (or VCC) to select DIA1−DIA4.
Connect to logic low (or GND) to select DIB1−DIB4.
Detailed Description
Figure 2 shows the MAX3640’s architecture. It consists
of two data paths; each data path begins with four differential input buffers. The IN_SEL pin selects whether
the A or B channels are passed to the 2x2 crosspoint
switch that follows. The SEL_ pins control the routing of
the crosspoint switch. Each crosspoint switch output
drives a pair of LVDS output drivers. This provides a
redundant set of outputs that can be used for fan-out
or test purposes. Each set of outputs, DOA_ and
DOB_, is enabled or disabled by the ENA and ENB
pins. See Table 1 for routing controls.
LVDS Inputs and Outputs
The MAX3640 features LVDS inputs and outputs for
interfacing with high-speed digital circuitry. The LVDS
standard is based on the IEEE 1596.3 LVDS specification. This technology uses 500mV to 800mV differential
low-voltage swings to achieve fast transition times, low
power dissipation, and improved noise immunity.
For proper operation, the data outputs require 100Ω differential termination between the inverting and noninverting pins. Do not terminate these outputs to ground.
See Figure 1 for LVDS output voltage specifications.
The data inputs are internally terminated with 100Ω differential and therefore do not require external termination.
_______________________________________________________________________________________
5
MAX3640
Pin Description
MAX3640
3.3V, 622Mbps LVDS,
Dual 4:2 Crosspoint Switch
2x2 CROSSPOINT
SWITCH
DIA1+
1
MAX3640
DOA1+
0
DIA1-
DOA1DIB1+
DOB1+
1
0
DIB1-
DOB1SEL1
DIA2+
DOA2+
1
0
DIA2-
DOA2-
DIB2+
DOB2+
1
0
DIB2-
DOB2-
SEL2
2x2 CROSSPOINT
SWITCH
DIA3+
1
DIA3-
DOA3+
0
DOA3-
DIB3+
0
DOB3+
1
DIB3DOB3SEL3
DIA4+
DOA4+
1
DIA4-
0
DOA4-
DIB4+
0
1
DOB4+
DIB4DOB4SEL4
IN_SEL
ENA
ENB
Figure 2. Functional Diagram
6
_______________________________________________________________________________________
3.3V, 622Mbps LVDS,
Dual 4:2 Crosspoint Switch
MAX3640
Table 1. Output Routing
ROUTING CONTROLS
IN_SEL
SEL1
SEL2
OUTPUT SIGNALS
Signal at DOA1/DOB1
Signal at DOA2/DOB2
0
0
0
DIB1
DIB1
0
0
1
DIB1
DIB2
0
1
0
DIB2
DIB1
0
1
1
DIB2
DIB2
1
0
0
DIA1
DIA1
1
0
1
DIA1
DIA2
1
1
0
DIA2
DIA1
1
1
1
DIA2
DIA2
IN_SEL
SEL3
SEL4
Signal at DOA3/DOB3
Signal at DOA4/DOB4
0
0
0
DIB3
DIB3
0
0
1
DIB3
DIB4
0
1
0
DIB4
DIB3
0
1
1
DIB4
DIB4
1
0
0
DIA3
DIA3
1
0
1
DIA3
DIA4
1
1
0
DIA4
DIA3
1
1
1
DIA4
DIA4
Note: Disabling the outputs by using ENA or ENB will drive the DOA_ or DOB_ data outputs to a high-impedance state.
+3.3V
182Ω
48Ω
48Ω
Zo = 50Ω
LVPECL
DRIVER
MAX3640
Zo = 50Ω
48Ω
182Ω
48Ω
+3.3V
Figure 3. LVPECL to LVDS Interface
_______________________________________________________________________________________
7
MAX3640
3.3V, 622Mbps LVDS,
Dual 4:2 Crosspoint Switch
Applications Information
Interfacing LVPECL Outputs to
MAX3640 LVDS Inputs
To DC-couple between LVPECL and LVDS, use the
resistor network shown in Figure 3. Note that the
LVPECL output is optimized for a 50Ω load to VCC - 2V,
so an equivalent network is used. Also, the network
attenuation should be such that the LVPECL output signal after attenuation is well within the LVDS input range.
Note that the LVDS input impedance is a true 100Ω
between the inputs. The differential impedance does
not contribute to the DC termination impedance, but
does contribute to the AC termination impedance. This
means that AC and DC impedance will always be different.
Layout Techniques
For best performance, use good high-frequency layout
techniques. Filter voltage supplies, and keep ground
connections short. Use multiple vias where possible.
Also, use controlled-impedance transmission lines to
interface with the MAX3640 data inputs and outputs.
Interface Models
Figure 4 shows the interface model for the LVDS
inputs, while Figure 5 shows the model for the LVDS
outputs.
VCC
VCC
25k
MAX3640
1.5k
DIA1+
5k
50Ω
VCC
50Ω
DIA11.5k
Figure 4. LVDS Input Model
8
_______________________________________________________________________________________
3.3V, 622Mbps LVDS,
Dual 4:2 Crosspoint Switch
TRANSISTOR COUNT: 2453
VCC
DOA1+
45Ω
45Ω
VCC
DOA1-
MAX3640
Figure 5. LVDS Output Model
DIA2+
DIA1-
DIA1+
IN_SEL
ENA
ENB
VCC
DOA1+
DOA1-
DOA2+
DOA2-
47
46
45
44
43
42
40
39
38
37
41
DIA248
Pin Configuration
VCC
1
36
VCC
GND
2
35
GND
DIA3+
3
34
DOA3+
DIA3-
4
33
DOA3-
DIA4+
5
32
DOA4+
DIA4-
6
31
DOA4-
DIB1+
7
30
DOB1+
DIB1-
8
29
DOB1-
DIB2+
9
28
DOB2+
DIB2-
10
27
DOB2-
GND
VCC
11
26
12
25
GND
VCC
24
23
22
21
20
19
18
17
16
15
14
DIB3+
DIB3DIB4+
DIB4SEL1
SEL2
SEL3
SEL4
DOB4DOB4+
DOB3DOB3+
13
MAX3640
_______________________________________________________________________________________
9
MAX3640
Chip Information
VCC
MAX3640
3.3V, 622Mbps LVDS,
Dual 4:2 Crosspoint Switch
32L/48L,TQFP.EPS
Package Information
10
______________________________________________________________________________________
3.3V, 622Mbps LVDS,
Dual 4:2 Crosspoint Switch
MAX3640
NOTES
______________________________________________________________________________________
11
MAX3640
3.3V, 622Mbps LVDS,
Dual 4:2 Crosspoint Switch
NOTES
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.
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