MAX3983UGK [MAXIM]
Quad Copper-Cable Signal Conditioner;
| 型号： | MAX3983UGK |
| 厂家： | 
MAXIM INTEGRATED PRODUCTS |
| 描述： | Quad Copper-Cable Signal Conditioner |
| 文件： | 总17页 (文件大小：337K) |
| 中文： | 中文翻译 | 下载： | 下载PDF数据表文档文件 |
19-2928; Rev 1; 2/07
Quad Copper-Cable Signal Conditioner
MAX983
General Description
Features
The MAX3983 is a quad copper-cable signal conditioner
that operates from 2.5Gbps to 3.2Gbps. It provides com-
pensation for 4x copper InfiniBand and 10Gbase-CX4
Ethernet links, allowing spans of 20m with 24AWG and
15m with 28AWG. The cable driver section provides four
selectable preemphasis levels. The input to the cable
driver compensates for up to 0.5m of FR4 circuit board
material. The cable receiver section provides additional
fixed input equalization while offering selectable preem-
phasis to drive FR4 circuit boards up to 0.5m.
♦ Link Features
Span 20m with 24AWG, 15m with 28AWG
Span 0.5m of FR4 on Each Host
1.6W Total Power with 3.3V Supply
Loopback Function
♦ Cable Driver Features
Selectable Output Preemphasis
FR4 Input Equalization
Signal Detect for Each Channel
Output Disable
The MAX3983 also features signal detection on all eight
inputs and internal loopback that allows for diagnostic
testing. It is packaged in a 10mm x 10mm, 68-pin QFN
and operates from 0°C to +85°C.
♦ Cable Receiver Features
Selectable FR4 Output Preemphasis
Cable Input Equalization
Signal Detect for Each Channel
Output Disable
Applications
4x InfiniBand (4 x 2.5Gbps)
Ordering Information
10Gbase-CX4 Ethernet (4 x 3.125Gbps)
10G Fibre Channel XAUI (4 x 3.1875Gbps)
PIN-
PART
TEMP RANGE
PKG CODE
PACKAGE
4x Copper-Cable or Backplane Transmission
(1Gbps to 3.2Gbps)
MAX3983UGK
0°C to +85°C 68 QFN
G6800-4
G6800-4
MAX3983UGK+ 0°C to +85°C 68 QFN
+Denotes lead-free package.
Pin Configuration appears at end of data sheet.
Typical Application Circuit
4x COPPER CABLE ASSEMBLY
≤20m (24AWG)
3.3V
≤0.5m
≤15m (28AWG)
0.01μF
0.01μF
V
CC
[1:4]
TX_IN1
TX_OUT1
TX_OUT2
TX_OUT3
TX_OUT4
TX_IN2
TX
TX_IN3
TX_IN4
SERDES
TO MAX3983
RX_OUT1
RX_IN1
RX_IN2
RX_IN3
RX_IN4
RX_OUT2
RX
RX_OUT3
RX_OUT4
TX_PE0
V
OR
GND
CC
TX_ENABLE
RX_ENABLE
TX_PE1
RX_PE
3V TO 5.5V
3V TO 5.5V
POR
TO HOST
LOOPBACK
C
POR
4.7kΩ
4.7kΩ
MAX3983
RX_SD1
RX_SD2
RX_SD3
RX_SD4
TX_SD1
TX_SD2
TX_SD3
TX_SD4
GND
TO HOST
________________________________________________________________ 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.
Quad Copper-Cable Signal Conditioner
ABSOLUTE MAXIMUM RATINGS
Supply Voltage, V ..............................................-0.5V to +6.0V
CC
Continuous Power Dissipation (T = +85°C)
A
Continuous CML Output Current at
68-Pin QFN (derate 41.7mW/°C above +85°C)………….2.7W
TX_OUT[1:4] , RX_OUT[1:4] ..........................………. 25mA
Voltage at TX_IN[1:4] , RX_IN[1:4] , RX_SD[1:4],
TX_SD[1:4], RX_ENABLE, TX_ENABLE, RX_PE,
TX_PE[0:1], LOOPBACK, POR
Operating Junction Temperature Range (T )....-55°C to +150°C
J
Storage Ambient Temperature Range (T ) .......-55°C to +150°C
S
(with series resistor ≥4.7kΩ)...................-0.5V to (V
+ 0.5V)
CC
MAX983
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
= +3.0V to +3.6V, T = 0°C to +85°C. Typical values are at V
= +3.3V and T = +25°C, unless otherwise noted.)
CC A
CC
A
PARAMETER
SYMBOL
CONDITIONS
MIN
TYP
360
365
495
MAX
430
430
580
UNITS
RX_EN = V , TX_EN = 0V
CC
Supply Current
mA
RX_EN = 0V, TX_EN = V
CC
RX_EN = V , TX_EN = V
CC
CC
OPERATING CONDITIONS
Supply Voltage
V
3.0
3.3
40
25
3.6
V
CC
Supply Noise Tolerance
Operating Ambient Temperature
Bit Rate
1MHz ≤ f < 2GHz
mV
P-P
T
0
85
3.2
10
°C
A
NRZ data (Note 1)
2.5
Gbps
Bits
CID
Consecutive identical digits (bits)
STATUS OUTPUTS: RX_SD[1:4], TX_SD[1:4]
Signal detect asserted
0
25
µA
Signal detect unasserted V ≤ 0.4V with 4.7kΩ
pullup resistor
OL
1.0
1.11
0.35
mA
Signal-Detect Open-Collector
Current Sink
V
= 0V, pullup supply = 5.5V, external pullup
CC
0
25
µA
µs
resistor ≥4.7kΩ
Time from RX_IN[1:4] or TX_IN[1:4] dropping
Signal-Detect Response Time
below 85mV
or rising above 175mV
to
P-P
P-P
50% point of signal detect
Signal-Detect Transition Time
Power-On Reset Delay
Rise time or fall time (10% to 90%)
1µF capacitor on POR to GND
200
6
ns
ms
CONTROL INPUTS: RX_ENABLE, TX_ENABLE, RX_PE, TX_PE0, TX_PE1, LOOPBACK
Voltage, Logic High
Voltage, Logic Low
Current, Logic High
Current, Logic Low
V
1.5
V
IH
V
0.5
V
IL
I
V
V
= V
CC
-150
-150
+150
+150
µA
µA
IH
IH
IL
I
= 0V
IL
2
_______________________________________________________________________________________
Quad Copper-Cable Signal Conditioner
MAX983
ELECTRICAL CHARACTERISTICS (continued)
(V
= +3.0V to +3.6V, T = 0°C to +85°C. Typical values are at V
= +3.3V and T = +25°C, unless otherwise noted.)
CC A
CC
A
PARAMETER
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
TX SECTION (CABLE DRIVER)
Measured differentially at the signal source
(Note 1)
PC Board Input Swing
800
1600
115
mV
P-P
Input Resistance
Input Return Loss
TX_IN[1:4]+ to TX_IN[1:4]-, differential
100MHz to 2GHz (Note 1)
85
10
100
17
Ω
dB
TX_ENABLE = high (Notes 1, 2)
TX_ENABLE = low
1300
1500
1600
30
Output Swing
mV
P-P
TX_OUT[1:4]+ or TX_OUT[1:4]- to V , single
CC
ended
Output Resistance
42
10
50
13
58
Ω
Output Return Loss
Output Transition Time
Random Jitter
100MHz to 2GHz (Note 1)
20% to 80% (Notes 1, 3)
(Notes 1, 3)
dB
ps
t , t
80
r
f
1.6
ps
RMS
TX_PE1
TX_PE0
0
0
1
1
0
1
0
1
3
6
Output Preemphasis
See Figure 1
dB
9
12
Source to
TX_IN
TX_OUT to
Load
TX_PE1 TX_PE0
1m, 28AWG
5m, 28AWG
10m, 24AWG
15m, 24AWG
0
0
1
1
0
1
0
1
Residual Output Deterministic
Jitter at 2.5Gbps (Notes 1, 4, 5)
0.10
0.15
0.15
0.20
UI
P-P
6-mil FR4 ≤
20in
Source to
TX_IN
TX_OUT to
Load
TX_PE1 TX_PE0
1m, 28AWG
5m, 28AWG
10m, 24AWG
15m, 24AWG
0
0
1
1
0
1
0
1
Residual Output Deterministic
Jitter at 3.2Gbps (Notes 1, 4, 5)
UI
P-P
6-mil FR4 ≤
20in
Signal-Detect Assert Level
Signal-Detect Off
TX_IN for TX_SD = high (Note 6)
TX_IN for TX_SD = low (Note 6)
800
mV
mV
P-P
P-P
200
RX SECTION (CABLE RECEIVER)
Measured differentially at the signal source
(Note 1)
Cable Input Swing
1000
175
1600
mV
mV
P-P
P-P
Measured differentially at the input of the
MAX3983 (Note 1)
Input Vertical Eye Opening
1600
115
Input Resistance
Input Return Loss
RX_IN[1:4]+ to RX_IN[1:4]-, differential
100MHz to 2GHz (Note 1)
85
10
100
18
Ω
dB
_______________________________________________________________________________________
3
Quad Copper-Cable Signal Conditioner
ELECTRICAL CHARACTERISTICS (continued)
(V
= +3.0V to +3.6V, T = 0°C to +85°C. Typical values are at V
= +3.3V and T = +25°C, unless otherwise noted.)
CC A
CC
A
PARAMETER
SYMBOL
CONDITIONS
RX_ENABLE = high (Notes 1, 7)
RX_ENABLE = low
MIN
TYP
MAX
1500
30
UNITS
mV
1100
Output Swing
P-P
RX_OUT[1:4]+ or RX_OUT[1:4]- to V , single
CC
ended
Output Resistance
42
10
50
58
Ω
MAX983
Output Return Loss
Output Transition Time
Random Jitter
100MHz to 2GHz (Note 1)
20% to 80% (Notes 1, 8)
(Notes 1, 8)
15
45
dB
ps
t , t
80
r
f
1.6
ps
RMS
RX_PE = low
3
6
Output Preemphasis
dB
RX_PE = high
Source to
RX_IN
RX_OUT to
Load
RX_PE
Residual Output Deterministic
Jitter at 2.5Gbps
(Notes 1, 5, 9, 10)
5m, 28AWG
IB Cable
Assembly
without
0in, 6-mil FR4
20in, 6-mil FR4
0
0.10
0.15
UI
P-P
1
RX_PE
0
preemphasis
Source to
RX_IN
RX_OUT to
Load
Residual Output Deterministic
Jitter at 3.2Gbps
(Notes 1, 5, 9, 10)
5m, 28AWG
IB cable
assembly
without
0in, 6-mil FR4
20in, 6-mil FR4
0.15
0.20
85
UI
P-P
1
preemphasis
Signal-Detect Assert Level
Signal-Detect Off
RX_IN for RX_SD = high (Note 11)
RX_IN for RX_SD = low (Note 11)
175
mV
mV
P-P
P-P
END-TO-END JITTER (TX AND RX COMBINED PERFORMANCE)
Source to
TX_IN
TX_OUT to
RX_IN
Residual Output Deterministic
Jitter at 2.5Gbps
0.15
0.2
0.20
0.25
UI
P-P
(Notes 1, 12, 13, 14)
1m, 24AWG
15m, 24AWG
20m, 24AWG
0
1
1
0
1
1
0in
0
1
1
20in
20in
6-mil FR4 ≤
20in
4
_______________________________________________________________________________________
Quad Copper-Cable Signal Conditioner
MAX983
ELECTRICAL CHARACTERISTICS (continued)
(V
= +3.0V to +3.6V, T = 0°C to +85°C. Typical values are at V
= +3.3V and T = +25°C, unless otherwise noted.)
CC A
CC
A
PARAMETER
SYMBOL
CONDITIONS
MIN
TYP
0.20
0.25
MAX
0.25
0.3
UNITS
Source to
TX_IN
Residual Output Deterministic
Jitter at 3.2Gbps
(Notes 1, 12, 13, 14)
UI
P-P
1m, 24AWG
15m, 24AWG
20m, 24AWG
0
0
1
1
5in
0
1
1
6-mil FR4 ≤
20 in
1
1
20in
20in
Note 1: Guaranteed by design and characterization.
Note 2: Measured with 2in of FR4 through InfiniBand connector with TX_PE1 = TX_PE0 =1.
Note 3: Measured at the chip using 0000011111 or equivalent pattern. TX_PE1 = TX_PE0 = 0 for minimum preemphasis.
Note 4: All channels under test are not transmitting during test. Channel tested with XAUI CJPAT, as well as this pattern: 19 zeros,
1, 10 zeros, 1010101010 (D21.5 character), 1100000101 (K28.5+ character), 19 ones, 0, 10 ones, 0101010101 (D10.2
character), 0011111010 (K28.5- character).
Note 5: Cables are unequalized, Amphenol Spectra-Strip 24AWG and 28AWG or equivalent equipped with Fujitsu “MicroGiga”
connector or equivalent. All other channels are quiet. Residual deterministic jitter is the difference between the source jit-
ter and the output jitter at the load. The deterministic jitter (DJ) at the output of the transmission line must be from media-
induced loss and not from clock-source modulation. Depending upon the system environment, better results can be
achieved by selecting different preemphasis levels.
Note 6: Tested with a 1GHz sine wave applied at TX_IN under test with less than 5in of FR4.
Note 7: Measured with 3in of FR4 with RX_PE = 1.
Note 8: Measured at the chip using 0000011111 or equivalent pattern. RX_PE = low (minimum). Signal source is 1V
with 5m,
P-P
28AWG InfiniBand cable.
Note 9: All other receive channels are quiet. TX_ENABLE = 0. Channel tested with XAUI CJPAT as well as this pattern: 19 zeros,
1, 10 zeros, 1010101010 (D21.5 character), 1100000101 (K28.5+ character), 19 ones, 0, 10 ones, 0101010101 (D10.2
character), 0011111010 (K28.5- character).
Note 10: FR4 board material: 6-mil-wide, 100Ω, edge-coupled stripline (tanδ = 0.022, 4.0 < ε < 4.4).
R
Note 11: Tested with a 1GHz sine wave applied at RX_IN under test with less than 5in of FR4.
Note 12: Channel tested with XAUI CJPAT as well as this pattern: 19 zeros, 1, 10 zeros, 1010101010 (D21.5 character), 1100000101
(K28.5+ character), 19 ones, 0, 10 ones, 0101010101 (D10.2 character), 0011111010 (K28.5- character).
Note 13: Cables are unequalized, Amphenol Spectra-Strip 24AWG or equivalent equipped with Fujitsu “MicroGiga” connector or
equivalent. Residual deterministic jitter is the difference between the source jitter at point A and the load jitter at point B in
Figure 2. The deterministic jitter (DJ) at the output of the transmission line must be from media-induced loss and not from
clock-source modulation. Depending upon the system environment, better results can be achieved by selecting different
preemphasis levels.
Note 14: Valid with pattern generator deterministic jitter as high as 0.17UI
.
P-P
_______________________________________________________________________________________
5
Quad Copper-Cable Signal Conditioner
PE = 12dB
PE = 3dB
DIFFERENTIAL
OUTPUT = 1.5V
V
EYE
= 0.375V
V = 1.06V
EYE P-P
P-P
P-P
MAX983
Figure 1. Illustration of TX Preemphasis in dB
END-TO-END TESTING
PC BOARD (FR4)
A
SIGNAL
SOURCE
InfiniBand CABLE
ASSEMBLY
MAX3983
6 mils
6 mils
TX_IN
TX_OUT
1in ≤ L ≤ 20in
1in ≤ L ≤ 20in
1in ≤ L ≤ 3in
1in ≤ L ≤ 3in
FUJITSU
MICROGIGA
CONNECTORS
SMA CONNECTORS
MAX3983
6 mils
RX_OUT
RX_IN
6 mils
FR4
OSCILLOSCOPE OR
ERROR DETECTOR
4.0 ≤ ε ≤ 4.4
R
B
tanδ = 0.022
Figure 2. End-to-End Test Setup. The points labeled A and B are referenced for AC parameter test conditions.
6
_______________________________________________________________________________________
Quad Copper-Cable Signal Conditioner
MAX983
Typical Operating Characteristics
(V
= +3.3V, T = +25°C, unless otherwise noted.)
CC
A
VERTICAL EYE OPENING
vs. CABLE LENGTH
END-TO-END DETERMINISTIC JITTER
vs. CABLE LENGTH
TRANSIENT REPSONSE
MAX3983 toc01
1000
900
800
700
600
500
400
300
200
100
0
350
300
250
200
150
100
50
2.5Gbps XAUI CJPAT
ALL CHANNELS TRANSMITTING
10in FR4 AT TX_IN
TX_PE[1,0] = 00
TX_PE[1,0] = 01
A
10in FR4 AT RX_OUT
B
C
D
SOURCE DJ = 23ps
D
V
OUT
TX_PE[1,0] = 10
TX_PE[1,0] = 11
A
D
C
B
A
E
B
C
C
3.125Gbps
K28.7 PATTERN
MEASURED DIRECTLY AT PART
2.5Gbps XAUI CJPAT
24AWG CABLE
D
A, B
0
0
5
10
15
20
A = 3dB, TX_PE = 00
B = 6dB, TX_PE = 01
C = 9dB, TX_PE = 10
D = 12dB, TX_PE = 11
0
5
10
15
20
CABLE LENGTH (m)
CABLE LENGTH (m)
A = 24AWG, TX_PE[1,0] = 00 D = 24AWG, TX_PE[1,0] = 11
B = 24AWG, TX_PE[1,0] = 01 E = 28AWG, TX_PE[1,0] = 11
C = 24AWG, TX_PE[1,0] = 10
10m 24AWG UNEQUALIZED CABLE
10m 24AWG UNEQUALIZED CABLE ASSEMBLY
TX_IN INPUT RETURN LOSS
vs. FREQUENCY
ASSEMBLY OUTPUT WITHOUT MAX3983
OUTPUT WITH MAX3983 PREEMPHASIS
MAX3983 toc04
MAX3983 toc05
0
USING AGILENT 8720ES AND ATN MICROWAVE
ATN-4112A S-PARAMETER TEST SET
DE-EMBEDDING SMA CONNECTOR,
3.125Gbps
PREEMPHASIS,
1500mV
3.125Gbps
P-P
-5
XAUI CJPAT TX_PE[1, 0] = 10
AT TRANSMITTER XAUI CJPAT
CABLE ONLY
-10
-15
-20
-25
-30
-35
-40
-45
-50
COUPLING CAPACITOR, AND 3in TRACE
320mV
P-P
60ps/div
0
0.4 0.8 1.2 1.6 2.0 2.4 2.8 3.2 3.6 4.0
FREQUENCY (GHz)
60ps/div
_______________________________________________________________________________________
7
Quad Copper-Cable Signal Conditioner
Typical Operating Characteristics (continued)
(V
= +3.3V, T = +25°C, unless otherwise noted.)
CC
A
TX_OUT OUTPUT RETURN LOSS
vs. FREQUENCY
RX_IN INPUT RETURN LOSS
vs. FREQUENCY
0
-5
0
-5
USING AGILENT 8720ES AND ATN MICROWAVE
ATN-4112A S-PARAMETER TEST SET
DE-EMBEDDING SMA CONNECTOR,
USING AGILENT 8720ES AND ATN MICROWAVE
ATN-4112A S-PARAMETER TEST SET
DE-EMBEDDING SMA CONNECTOR,
-10
-15
-20
-25
-30
-35
-40
-45
-50
COUPLING CAPACITOR, AND 3in TRACE
COUPLING CAPACITOR, AND 3in TRACE
MAX983
-10
-15
-20
-25
-30
-35
0
0.4 0.8 1.2 1.6 2.0 2.4 2.8 3.2 3.6 4.0
FREQUENCY (GHz)
0
0.4 0.8 1.2 1.6 2.0 2.4 2.8 3.2 3.6 4.0
FREQUENCY (GHz)
RX_OUT OUTPUT RETURN LOSS
vs. FREQUENCY
POWER-ON RESET DELAY
WITH SUPPLY RAMP
0
-5
USING AGILENT 8720ES AND ATN MICROWAVE
ATN-4112A S-PARAMETER TEST SET
DE-EMBEDDING SMA CONNECTOR,
COUPLING CAPACITOR, AND 3in TRACE
-10
-15
-20
-25
-30
-35
-40
1V/div
1μF CAPACITOR FROM
POR PIN TO GROUND
V
CC
200mA/div
I
CC
0
0.4 0.8 1.2 1.6 2.0 2.4 2.8 3.2 3.6 4.0
FREQUENCY (GHz)
2ms/div
8
_______________________________________________________________________________________
Quad Copper-Cable Signal Conditioner
MAX983
Pin Description
PIN
NAME
FUNCTION
PC Board Receiver Signal Detect, TTL Output. This output is open-collector TTL, and therefore
TX_SD1 to
TX_SD4
1, 2, 16, 17
requires an external 4.7kΩ to 10kΩ pullup resistor to V . These outputs sink current when the input
CC
signal level is not valid.
3, 15
V
1
CC
Power-Supply Connection for TX Inputs. Connect to +3.3V.
TX_IN1- to PC Board Receiver Negative Data Inputs, CML. These inputs are internally differentially terminated to
TX_IN4- the corresponding TX_IN+ with 100Ω.
4, 7, 10, 13
TX_IN1+ to PC Board Receiver Positive Data Inputs, CML. These inputs are internally differentially terminated to
5, 8, 11, 14
TX_IN4+
the corresponding TX_IN- with 100Ω.
6, 9, 12, 40,
43, 46
GND
Circuit Ground
Cable Transmitter Enable Input, LVTTL with 40kΩ Internal Pullup. This pin enables all four cable
transmitter outputs TX_OUT[1:4]. When low, differential output is less than 30mV . Set high or open
for normal operation.
18
19
TX_ENABLE
N.C.
P-P
No Connection. Do not connect this pin.
20, 23, 26,
29, 32
V
2
CC
Power-Supply Connection for TX Outputs. Connect to +3.3V.
21, 24, 27, TX_OUT1+ to
Cable Transmitter Positive Data Outputs, CML. These outputs are terminated with 50Ω to V 2.
CC
30
TX_OUT4+
22, 25, 28, TX_OUT1- to
Cable Transmitter Negative Data Outputs, CML. These outputs are terminated with 50Ω to V 2.
CC
31
33
TX_OUT4-
TX_PE0
Cable Transmitter Preemphasis Control Input, LVTTL with 40kΩ Internal Pullup. This pin is the least
significant bit of the 2-bit preemphasis control. Set high or open to assert this bit.
Cable Transmitter Preemphasis Control Input, LVTTL with 40kΩ Internal Pullup. This pin is the most
significant bit of the 2-bit preemphasis control. Set high or open to assert this bit.
34
TX_PE1
Cable Receiver Signal Detect, TTL Output. This output is open-collector TTL, and therefore it requires
35, 36, 50,
51
RX_SD4 to
RX_SD1
an external 4.7kΩ to 10kΩ pullup resistor to V . These outputs sink current when the input signal
CC
level is not valid.
37, 49
V
3
CC
Power-Supply Connection for RX Inputs. Connect to +3.3V.
38, 41, 44,
47
RX_IN4- to Cable Receiver Negative Data Inputs, CML. These inputs are internally differentially terminated to the
RX_IN1- corresponding RX_IN+ with 100Ω.
39, 42, 45,
48
RX_IN4+ to Cable Receiver Positive Data Inputs, CML. These inputs are internally differentially terminated to the
RX_IN1+
corresponding RX_IN- with 100Ω.
PC Board Transmitter Enable Input, LVTTL with 40kΩ Internal Pullup. This pin enables all four PC
52
RX_ENABLE board transmitter outputs RX_OUT[1:4]. When low, differential output is less than 30mV . Set high
P-P
or open for normal operation.
Power-On Reset Connection. Connect external capacitor 0.1µF ≤ C
Detailed Description.
≤ 10µF to ground. See the
POR
53
POR
54, 57, 60,
63, 66
V
4
CC
Power-Supply Connection for RX Outputs. Connect to +3.3V.
_______________________________________________________________________________________
9
Quad Copper-Cable Signal Conditioner
Pin Description (continued)
PIN
NAME
FUNCTION
PC Board Transmitter Positive Data Outputs, CML. These outputs are terminated with 50Ω to V 4.
55, 58, 61, RX_OUT4+ to
CC
64
RX_OUT1+
56, 59, 62, RX_OUT4- to
PC Board Transmitter Negative Data Outputs, CML. These outputs are terminated with 50Ω to V 4.
CC
65
67
RX_OUT1-
RX_PE
MAX983
PC Board Transmitter Preemphasis Control Input, LVTTL with 40kΩ Internal Pullup. Set high or open
to assert this bit.
Loopback Enable Input, LVTTL with 40kΩ Internal Pullup. Set low for normal operation. Set high or
open for internal connection of TX_IN to RX_OUT. TX_OUT continues to transmit when loopback is
enabled.
68
EP
LOOPBACK
Exposed Pad. Signal and supply ground. For optimal high-frequency performance and thermal
conductivity, this pad must be soldered to the circuit board ground.
Exposed Pad
V 1
CC
40kΩ
V 2
CC
2
LVTTL
TX_PE[0:1]
V 2
CC
V 1
CC
LIMITER
TX_OUT[1:4]+
TX_OUT[1:4]-
TX_IN[1:4]+
TX_IN[1:4]-
FIXED
EQUALIZER
PRE-
EMPHASIS
CML
CML
TX_SD[1:4]
V 1
CC
V 2
CC
V
V
1
CC
SIGNAL
DETECT
40kΩ
V
V
2
4
CC
TX_ENABLE
LOOPBACK
LVTTL
LVTTL
3
CC
40kΩ
POWER
MANAGEMENT
CC
POR
V 4
CC
V 4
CC
V 3
CC
1
0
RX_OUT[1:4]+
RX_OUT[1:4]-
PRE-
EMPHASIS
CML
4
RX_IN[1:4]+
RX_IN[1:4]-
FIXED
EQUALIZER
V
V
3
CML
CC
LIMITER
40kΩ
V
V
CC
RX_ENABLE
LVTTL
LVTTL
3
CC
40kΩ
4
CC
MAX3983
RX_PE
RX_SD[1:4]
V 4
CC
V 3
CC
SIGNAL
DETECT
GND
Figure 3. Functional Diagram
10 ______________________________________________________________________________________
Quad Copper-Cable Signal Conditioner
MAX983
Signal-Detect Outputs
Detailed Description
Signal detect (SD) is provided on all eight data inputs.
The MAX3983 comprises a PC board receiver and
Pullup resistors should be connected from the SD out-
puts to a supply in the 3.0V to 5.5V range. The signal-
detect outputs are not valid until power-up is complete.
Typical signal-detect response time is 0.35µs.
cable driver section (TX), as well as a cable receiver
and PC board driver section (RX). Equalization and sig-
nal detection are provided in each receiver, and pre-
emphasis is included in each transmitter. The MAX3983
includes separate enable control for the TX outputs and
RX outputs. Loopback is provided for diagnostic testing.
In the RX section, the SD output asserts high when the
RX_IN signal amplitude is greater than 175mV
.
P-P
RX_SD deasserts low when the RX_IN signal amplitude
drops below 85mV
PC Board Receiver and Cable Driver
(TX_IN and TX_OUT)
.
P-P
In the TX section, the SD output asserts high when the
TX_IN signal amplitude is greater than 800mV
Data is fed into the MAX3983 from the host through a
CML input stage and fixed equalization stage. The
fixed equalizer in the PC board receiver corrects for up
to 20in of PC board loss on FR4 material. The cable dri-
ver includes four-state preemphasis to compensate for
up to 20m of 24AWG, 100Ω balanced cable. Table 1 is
provided for easy translation between preemphasis
expressions. Residual jitter of the MAX3983 is indepen-
.
P-P
TX_SD deasserts low when the TX_IN signal amplitude
drops below 200mV
.
P-P
TX and RX Enable
The TX_ENABLE and RX_ENABLE pins enable TX and
RX, respectively. Typical enable time is 15ns, and typi-
cal disable time is 25ns. The enable inputs may be
connected to signal-detect outputs to automatically
detect an incoming signal (see the Autodetect section).
dent of up to 0.17UI
source jitter.
P-P
Cable Receiver and PC Board Driver
(RX_IN and RX_OUT)
The fixed equalizer on each RX input provides approxi-
mately 6dB equalization to correct for up to 5m of
28AWG, 100Ω balanced cable. The PC board driver
includes two-state preemphasis to compensate for up
to 20in of FR4 material.
Power-On Reset
To limit inrush current, the MAX3983 includes internal
power-on reset circuitry. Connect a capacitor 0.1µF ≤
C
≤ 10µF from POR to ground. With C
= 1µF,
POR
POR
power-on delay is 6ms (typ).
Table 1. Preemphasis Translation
α
RATIO
10Gbase-CX4
IN dB
V
V
− V
V
LOW _PP
⎡
⎤
⎥
⎦
⎛
⎞
HIGH_PP
HIGH_PP
LOW _PP
V
HIGH_PP
1 −
V
⎢
HIGH_PP
20 log
⎜
⎟
V
V
+ V
V
HIGH_PP
LOW _PP
HIGH_PP
LOW _PP
V
⎢
⎣
⎥
⎝
⎠
LOW _PP
V
LOW_PP
1.41
2.00
2.82
4.00
0.17
0.33
0.48
0.60
0.29
0.50
0.65
0.75
3
6
9
12
______________________________________________________________________________________ 11
Quad Copper-Cable Signal Conditioner
noise amplification can occur and create undesirable
Applications Information
Signal-Detect Output Leakage Current
Considerations
output signals. Autodetect is recommended to eliminate
noise amplification or possible oscillation. When using
autodetect, the link length is determined by the received
signal strength. It is possible to reach longer distances if
the autodetect configuration is not used.
If all four RX or TX signal-detect outputs are to be con-
nected together to form one signal detect, the leakage
current of the output stage needs to be considered.
Each SD output sinks a maximum of 25µA when assert-
ed, so when four are connected together, a maximum of
100µA is possible. The value of the pullup resistor con-
Using Loopback with Autodetect
If the MAX3983 is configured for autodetection,
RX_ENABLE is controlled by the RX_SD[1:4] outputs.
Since loopback requires RX_ENABLE to be high, a sim-
ple OR gate can be used to enable the RX outputs
when either RX_SD[1:4] is high or when LOOPBACK is
high (Figure 5).
MAX983
nected to pullup voltage V
should be selected so
PULLUP
the leakage current does not cause the output voltage to
fall below the threshold of the next stage. For example, if
the signal-detect outputs are connected together and to
a stage with a logic-high threshold of 1.5V, the pullup
InfiniBand and 10Gbase-CX4 Transition
Time Specification
resistor needs to be chosen so V
- I
PULLUP
x
PULLUP
> 1.5V. In this case, if V
LEAKAGE
R
R
= 3.0V,
PULLUP
PULLUP
InfiniBand specifies a minimum transition time (20% to
80%) of 100ps and CX4 specifies a minimum of 60ps.
Both are specified at the connector interface to the
cable. The output transition times of the MAX3983 are
45ps (typ) and therefore require some care to increase
this time. Approximately 3in of FR4 with 4-mil-wide lines
is sufficient to lengthen the transition time to 60ps. For
100ps transition times, additional length can be used or
an additional 1.5pF capacitor can be placed across the
outputs of the MAX3983. Do not use high-speed dielec-
tric material for the circuit board if the application
requires the use of the InfiniBand or CX4 type connector
system. With such materials, the fast edges of the
should be less than 15kΩ.
Autodetect
The MAX3983 can automatically detect an incoming sig-
nal and enable the appropriate outputs. Autodetect of
the RX side is done by connecting RX_SD[1:4] together
with a pullup resistor (value 4.7kΩ to 10kΩ to V ) to
CC
RX_ENABLE. For the TX side, this is done by connecting
TX_SD[1:4] together with a pullup resistor (value 4.7kΩ
to 10kΩ to V ) to TX_ENABLE (Figure 4). If signal is
CC
detected on all channels, SD is high and forces the cor-
responding ENABLE high. Leaving the inputs to the
MAX3983 open (i.e., floating) is not recommended, as
3.0V ≤ V
≤ 5.5V
PULLUP
3.0V ≤ V
≤ 5.5V
PULLUP
4.7kΩ ≤ R ≤ 10kΩ
4.7kΩ ≤ R ≤ 10kΩ
RX_SD1
RX_SD2
RX_SD3
RX_SD4
RX OR TX_SD1
RX OR TX_SD2
RX OR TX_SD3
RX OR TX_SD4
MAX3983
MAX3983
RX_ENABLE
LOOPBACK
RX OR TX_ENABLE
TO HOST
Figure 4. Autodetection Using Corresponding Signal-Detect
Outputs and Enable Input
Figure 5. Loopback in Autodetect Mode
12 ______________________________________________________________________________________
Quad Copper-Cable Signal Conditioner
MAX983
MAX3983 will produce excessive crosstalk in InfiniBand
and CX4 cable assemblies.
Interface Schematics
Crosstalk
V
CC
X
For InfiniBand and 10Gbase-CX4 applications, it is
imperative to know the near-end crosstalk characteristics
of the cable assemblies. 10Gbase-CX4 has defined the
upper limit over frequency for near-end crosstalk (NEXT)
with single and multiple aggressors. InfiniBand has only
specified a percentage as measured in the time domain
relative to the transmitter output. Regardless of the spec-
ification method, NEXT is a critical component of the link
performance. When using larger amounts of preempha-
sis, the received eye height is small and vulnerable to
NEXT. For those situations requiring a large transmit pre-
emphasis, the NEXT should be less than -30dB at fre-
quencies from 1GHz to 3GHz. It should be noted that
cables that meet the 10Gbase-CX4 NEXT and MDNEXT
should provide adequate isolation.
5pF
RX_IN[1:4]+
TX_IN[1:4]+
50Ω
50Ω
V
CC
X - 1.5V
RX_IN[1:4]-
TX_IN[1:4]-
Layout Considerations
Circuit board layout and design can significantly affect
the performance of the MAX3983. Use good high-fre-
quency design techniques, including minimizing
ground inductance and using controlled-impedance
transmission lines on the data signals. Power-supply
GND
decoupling should also be placed as close to the V
CC
pins as possible. There should be sufficient supply fil-
tering. Always connect all V s to a power plane. Take
CC
Figure 6. RX_IN and TX_IN Equivalent Input Structure
care to isolate the input from the output signals to
reduce feedthrough. The performance of the equalizer
is optimized for lossy environments. For best results,
use board material with a dielectric tangential loss of
approximately 0.02 and 4-mil-wide transmission lines.
High-speed materials with tangential loss of less than
0.01 can be used, but require special care to reduce
near-end crosstalk in cable assemblies.
V
X
CC
50Ω
50Ω
Exposed-Pad Package
The exposed-pad, 68-pin QFN package incorporates
features that provide a very low thermal resistance path
for heat removal from the IC. The pad is electrical
ground on the MAX3983 and must be soldered to the
circuit board for proper thermal and electrical perfor-
mance. For more information on exposed-pad pack-
ages, refer to Maxim Application Note HFAN-08.1:
Thermal Considerations of QFN and Other Exposed-
Paddle Packages.
RX_OUT[1:4]+
TX_OUT[1:4]+
RX_OUT[1:4]-
TX_OUT[1:4]-
GND
Figure 7. RX_OUT and TX_OUT Equivalent Output Structure
______________________________________________________________________________________ 13
Quad Copper-Cable Signal Conditioner
V
Y
CC
V
X
CC
RX_SD[1:4]
TX_SD[1:4]
40kΩ
LVTTL IN
MAX983
GND
GND
V
CC
X
V
Y
PIN NAME
RX_ENABLE,
CC
V
3
1
V
4
2
CC
CC
LOOPBACK, RX_PE
TX_ENABLE,
TXPE[0:1]
V
V
CC
CC
Figure 8. LVTTL Equivalent Input Structure
Figure 9. Signal-Detect Equivalent Output Structure
14 ______________________________________________________________________________________
Quad Copper-Cable Signal Conditioner
MAX983
Pin Configuration
TOP VIEW
68 67 66 65 64 63 62 61 60 59 58 57 56 55 54 53 52
TX_SD1
TX_SD2
1
2
51 RX_SD1
50 RX_SD2
V
1
V
49
3
CC
3
CC
TX_IN1-
TX_IN1+
GND
4
48 RX_IN1+
47 RX_IN1-
46 GND
5
6
TX_IN2-
TX_IN2+
GND
7
45
44
43
42
41
40
39
38
37
36
35
RX_IN2+
RX_IN2-
GND
8
9
MAX3983
TX_IN3-
TX_IN3+
GND
10
11
12
13
14
15
16
17
RX_IN3+
RX_IN3-
GND
TX_IN4-
TX_IN4+
RX_IN4+
RX_IN4-
V
CC
1
V
CC
3
TX_SD3
TX_SD4
RX_SD3
RX_SD4
18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34
68 QFN*
*THE EXPOSED PAD OF THE QFN PACKAGE MUST BE SOLDERED TO GROUND
FOR PROPER THERMAL AND ELECTRICAL OPERATION OF THE MAX3983.
Chip Information
TRANSISTOR COUNT: 7493
PROCESS: SiGe Bipolar
______________________________________________________________________________________ 15
Quad Copper-Cable Signal Conditioner
Package Information
(The package drawing(s) in this data sheet may not reflect the most current specifications. For the latest package outline information,
go to www.maxim-ic.com/packages.)
MAX983
PACKAGE OUTLINE, 68L QFN, 10x10x0.9 MM
1
21-0122
C
2
PACKAGE OUTLINE, 68L QFN, 10x10x0.9 MM
1
21-0122
C
2
16 ______________________________________________________________________________________
Quad Copper-Cable Signal Conditioner
MAX983
Revision History
Rev 0; 7/03: Initial data sheet release.
Rev 1; 2/07: Added lead-free package to Ordering Information table (page 1).
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 ____________________ 17
© 2007 Maxim Integrated Products
is a registered trademark of Maxim Integrated Products, Inc.
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