MAXIM MAX3783

19-2197; Rev 0; 10/01
2.7Gbps Dual Mux/Buffer with Loopback
Features
♦ Provides Redundant Serial I/O
Operating from a single 3.3V supply, this device has
current-mode logic (CML) inputs and outputs, which
can be AC-coupled for PECL compatibility, if desired.
The IC is packaged in a compact 48-pin TQFP-EP package with exposed pad. Typical power consumption is
1.12W.
♦ 3.3V Power Supply
♦ 11ps Deterministic Jitter
♦ Selectable Loopback
♦ On-Chip 50Ω Termination Resistors
♦ Two-Port Integration
Ordering Information
Applications
2.7Gbps Serial Communications
System Interconnect
Serial Backplane
PART
TEMP. RANGE
MAX3783UCM
PIN-PACKAGE
0°C to +85°C
48 TQFP-EP*
* Exposed pad
Fail-Over and Protection Switching
VCC
GND
38
37
LO2A+
LO2A40
39
VCC
41
42
VCC
LO1A+
LO1A44
43
SOA+
SOA46
45
SELA
VCC
47
Typical Application Circuit appears at end of data sheet.
48
Pin Configuration
GND
SIA-
1
36
2
35
SIA+
VCC
LB1A
LB2A
LB1B
LB2B
VCC
SIB+
SIBGND
3
34
4
33
5
32
6
31
MAX3783
7
30
24
23
21
LO2B+
LO2B-
VCC
LI1A+
LI1AGND
GND
LI1BLI1B+
VCC
LI2BLI2B+
VCC
GND
20
22
19
18
VCC
SOB+
SOB-
SELB
VCC
17
25
VCC
LO1B+
LO1B-
26
12
16
27
11
15
28
10
14
29
9
13
8
LI2A+
LI2A-
TQFP-EP*
*EXPOSED PAD MUST BE SOLDERED TO
SUPPLY GROUND ON THE CIRCUIT BOARD
________________________________________________________________ Maxim Integrated Products
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.
1
MAX3783
General Description
The MAX3783 is a dual serial multiplexer (mux) and
buffer with selectable line-side loopback for system
interconnect and serial backplane applications up to
2.7Gbps. Each independent channel consists of a transmitter with fanout of two and a receiver with a 2:1 input
mux. Selectable loopback paths support system testing.
MAX3783
2.7Gbps Dual Mux/Buffer with Loopback
ABSOLUTE MAXIMUM RATINGS
Supply Voltage, VCC ...............................................-0.5V to 4.0V
Continuous Current at Serial Outputs...............................±36mA
Voltage at SEL_, LB_ Pins ..........................-0.5V to (VCC + 0.5V)
Common-Mode Input Voltage (SI_, LI_) .....-0.5V to (VCC + 0.5V)
Differential Input Voltage (SI_, LI_) (Note 1) .......................±2.8V
Continuous Power Dissipation (TA = +85°C)
48-Pin TQFP-EP (derate 27mW/°C above +85°C) .........1.76W
Storage Ambient Temperature ..........................-55°C to +150°C
Lead Temperature (soldering, 10s) .................................+300°C
Note 1: The sum of the common-mode voltage and differential voltage on any input pin must be within -0.5V to (VCC + 0.5V).
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
(VCC = 3.0V to 3.6V, serial data rate = 2.75Gbps, TA = 0°C to +85°C. Typical values at VCC = 3.3V, TA = +25°C, unless otherwise
noted.)
PARAMETER
SYMBOL
CONDITIONS
Maximum Serial Data Rate
Power Dissipation
ICC
CML Differential Output Voltage
VOD
CML Differential Input Voltage
VID
CML Input Impedance
ROUT
RIN
Random Jitter
RL = 50Ω to VCC, or 100Ω differential (Note 2)
Single ended
Differential
(Note 3)
1.12
MAX
UNITS
Gbps
1.68
W
340
466
mA
1200
1500
2200
mVp-p
200
1600
2200
mVp-p
42.5
50
57.5
Ω
85
100
116
Ω
1
2
psRMS
psp-p
Deterministic Jitter
(Notes 3, 4, 5)
11
25
CML Output Edge Speed
(20% to 80%)
2.5Gbps input (Note 3)
70
135
1.25Gbps input (Note 3)
80
200
Propagation Delay
LI_ to SO_, SI_ to LO_, LI_ to LO_ (Note 3)
340
500
ps
Multiplexer Switch Time
SEL_ or LB_ to valid output
TTL Input Current High
VIH = +2.0V to (VCC +0.3V)
180
µA
TTL Input Current Low
VIL = -0.3V to +0.8V
440
µA
Note 2:
Note 3:
Note 4:
Note 5:
2
TYP
3.125
AC-coupled inputs, outputs
Supply Current
CML Output Impedance
MIN
2.75
tR, tF
9
ps
ns
Typical value measured using a repeating 1010 pattern at 500Mbps.
AC specifications are guaranteed by design and characterization.
Deterministic jitter is measured with a repeating K28.5 pattern.
With the peak-to-peak input swing on the selected (transmitted) CML input equal to or greater than that on the nonselected
inputs.
_______________________________________________________________________________________
2.7Gbps Dual Mux/Buffer with Loopback
ELECTRICAL EYE DIAGRAM
2.75 Gbps, K28.5 PATTERN
ELECTRICAL EYE DIAGRAM
3.125 Gbps, K28.5 PATTERN
195mV/
div
195mV/
div
88ps/div
88ps/div
88ps/div
CML DIFFERENTIAL OUTPUT VOLTAGE
vs. CML DIFFERENTIAL INPUT VOLTAGE
SUPPLY CURRENT vs. TEMPERATURE
450
MEASURED USING 1010
PATTERN, 500Mbps
1.55
400
VOD (V)
1.50
350
1.45
300
250
1.40
0
15
30
45
60
75
200
90
700
1200
1700
TEMPERATURE (°C)
VID (mV)
DETERMINISTIC JITTER vs. CML
DIFFERENTIAL INPUT VOLTAGE
MULITPLEXER SWITCH TIME
MAX3783 toc06
25
20
2200
MAX3783 toc07
SUPPLY CURRENT (mA)
1.60
MAX3783 toc04
500
MAX3783 toc05
195mV/
div
MAX3783 toc03
MAX3783 toc01
MAX3783 toc02
ELECTRICAL EYE DIAGRAM
2.75 Gbps, 223 - 1 PRBS PATTERN
DJ (ps)
LO2A+
15
10ns
3.125Gbps
9ns
10
LB2A
LO2A-
2.75Gbps
5
0
200
700
1200
VID (mV)
1700
2200
10ns/div
_______________________________________________________________________________________
3
MAX3783
Typical Operating Characteristics
(VCC = 3.3V, TA = +25°C, unless otherwise noted.)
2.7Gbps Dual Mux/Buffer with Loopback
MAX3783
Pin Description
PIN
NAME
1, 12, 24, 30,
31, 37
GND
Supply Ground
2
SIA-
Serial Input A Negative, CML
3
SIA+
Serial Input A Positive, CML
4, 9, 14, 17,
20, 23, 27,
34, 38, 41,
44, 47
VCC
+3.3V Supply
5
LB1A
Line Out 1A Loopback Mode Select. TTL low selects loopback.
6
LB2A
Line Out 2A Loopback Mode Select. TTL low selects loopback.
7
LB1B
Line Out 1B Loopback Mode Select. TTL low selects loopback.
8
LB2B
Line Out 2B Loopback Mode Select. TTL low selects loopback.
10
SIB+
Serial Input B Positive, CML
11
SIB-
Serial Input B Negative, CML
13
SELB
Serial Output B Input Select, TTL
15
SOB+
Serial Output B Positive, CML
16
SOB-
Serial Output B Negative, CML
18
LO1B+
Line Out 1B Positive, CML
19
LO1B-
Line Out 1B Negative, CML
21
LO2B+
Line Out 2B Positive, CML
22
LO2B-
Line Out 2B Negative, CML
25
LI2B+
Line In 2B Positive, CML
26
LI2B-
Line In 2B Negative, CML
28
LI1B+
Line In 1B Positive, CML
29
LI1B-
Line In 1B Negative, CML
32
LI1A-
Line In 1A Negative, CML
33
LI1A+
Line In 1A Positive, CML
35
LI2A-
Line In 2A Negative, CML
36
LI2A+
Line In 2A Positive, CML
39
LO2A-
Line Out 2A Negative, CML
40
LO2A+
Line Out 2A Positive, CML
42
LO1A-
Line Out 1A Negative, CML
43
LO1A+
45
SOA-
46
SOA+
48
SELA
Exposed
Pad
EP
4
FUNCTION
Line Out 1A Positive, CML
Serial Output A Negative, CML
Serial Output A Positive, CML
Serial Out A Input Select, TTL
Ground. Must be soldered to the circuit board for proper thermal and electrical performance (see
EP Package).
_______________________________________________________________________________________
2.7Gbps Dual Mux/Buffer with Loopback
MAX3783
SOA
2
1
CML
0
CML
2
Input Stages
The input amplifiers accept CML or AC-coupled PECL
signals and each input has an on-chip 100Ω differential
impedance for optimal termination, as shown in Figure 1.
LI1A
CML
VCC
15kΩ
2
LI2A
VCC
1
MAX3783
CML
SELA
2
LO2A
IN+
VCC
0
50Ω
1.2kΩ
15kΩ
VCC - 0.5V
LB2A
SIA
CML
2
VCC
50Ω
1
CML
2
LO1A
IN-
VCC
0
15kΩ
LB1A
Figure 1. Input Structure
SOB
2
1
CML
0
CML
2
LI1B
CML
VCC
15kΩ
Control Lines
2
LI2B
1
CML
SELB
2
LO2B
VCC
0
15kΩ
LB2B
SIB
2
CML
TTL-compatible control lines are provided to select the
MAX3783’s operating mode (Table 1). SELA and SELB
set the mux for channels A and B, respectively, to
select LI1_ or LI2_ to connect to the SO_ output. LB1A,
LB1B, LB2A, and LB2B enable loopback mode for
each of the four LO_ outputs. All control lines are internally pulled high through 15kΩ resistors.
Table 1. Operating Modes
1
CML
2
LO1B
VCC
0
SEL_
SO_
LB_
LO_
0
LI2_
0
LI_
1
LI1_
1
SI_
15kΩ
LB1B
Detailed Description
The MAX3783 is a 2.7Gbps dual serial mux/buffer with
selectable line-side loopback for system test. Each half
of the MAX3783 provides a transmitter with a fanout of
two and a receiver with a 2:1 mux, as shown in the functional diagram.
Output Buffers
The outputs are high-speed CML interfaces with 50Ω
back termination, as shown in Figure 2.
Exposed-Pad (EP) Package
The exposed pad on the 48-pin TQFP-EP provides a
very low thermal-resistance path for heat removal from
the IC. The pad is also electrical ground on the
MAX3783 and must be soldered to the circuit board for
proper thermal and electrical performance.
_______________________________________________________________________________________
5
MAX3783
Functional Diagram
2.7Gbps Dual Mux/Buffer with Loopback
MAX3783
Chip Information
TRANSISTOR COUNT: 2816
PROCESS: Bipolar
MAX3783
VCC
50Ω
50Ω
OUT+
OUT-
32mA
Figure 2. CML Output Structure
6
_______________________________________________________________________________________
2.7Gbps Dual Mux/Buffer with Loopback
VCC
VCC
LO1A+
IN
SOA+
IN
LO1ASOA-
SERDES
A
LI1A+
OUT
SIA+
LI1A-
OUT
SIA-
SWITCH
1
LO1B+
IN
MAX3783
SELA
LO1B-
LI1B+
OUT
SELB
LI1BLB1A
LB2A
LB1B
LO2A+
LB2B
IN
LO2A-
LI2A+
OUT
LI2ASWITCH
2
SOB+
IN
SOB-
SERDES
B
LO2B+
IN
LO2B-
SIB+
OUT
SIBLI2B+
OUT
GND
LI2B-
NOTE: COUPLING CAPACITORS AND BIAS RESISTORS ARE OPTIONAL, SHOWN FOR LVPECL OPERATION.
REFER TO APPLICATION NOTES HFAN-01.0 AND HFAN-01.1 REGARDING LVPECL/CML INTERFACE.
THIS SYMBOL INDICATES A CONTROLLED-IMPEDANCE TRANSMISSION LINE OF CHARACTERISTIC IMPEDANCE Z0 = 50Ω.
_______________________________________________________________________________________
7
MAX3783
Typical Application Circuit
2.7Gbps Dual Mux/Buffer with Loopback
48L,TQFP.EPS
MAX3783
Package Information
8
_______________________________________________________________________________________
2.7Gbps Dual Mux/Buffer with Loopback
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 _____________________ 9
© 2001 Maxim Integrated Products
Printed USA
is a registered trademark of Maxim Integrated Products.
MAX3783
Package Information (continued)