MAX3982UTE [MAXIM]
SFP Copper-Cable Preemphasis Driver; SFP铜缆预加重驱动器
| 型号： | MAX3982UTE |
| 厂家： | 
MAXIM INTEGRATED PRODUCTS |
| 描述： | SFP Copper-Cable Preemphasis Driver |
| 文件： | 总15页 (文件大小：1139K) |
| 中文： | 中文翻译 | 下载： | 下载PDF数据表文档文件 |
19-3354; Rev 0; 8/04
SFP Copper-Cable Preemphasis Driver
General Description
Features
The MAX3982 is a single-channel, copper-cable preem-
phasis driver that operates from 1Gbps to 4.25Gbps. It
provides compensation for copper links, such as
4.25Gbps Fibre Channel, allowing spans of up to 15m
with 24AWG. The cable driver provides four selectable
preemphasis levels. The input compensates for up to
10in of FR4 circuit board material at 4.25Gbps.
♦ Drives Up to 15m with 24AWG Cable
♦ Drives Up to 30in of FR4
♦ 0.25W Total Power with +3.3V Supply
♦ Selectable 1600mV
or 1200mV
Differential
P-P
P-P
Output Swing
♦ Selectable Output Preemphasis
♦ Fixed Input Equalization
The MAX3982 also features SFP-compliant loss-of-signal
detection with selectable sensitivity and TX_DISABLE.
Selectable output swing reduces EMI and power con-
sumption. It is packaged in a 3mm x 3mm, 16-pin thin
QFN and operates from 0°C to +85°C temperature range.
♦ Loss-of-Signal Detection with Selectable
Sensitivity
♦ Transmit Disable
Applications
SFP Active Copper-Cable Assemblies
Backplanes
Ordering Information
1.0625Gbps, 2.125Gbps, and 4.25Gbps Fibre
Channel
TEMP
PIN-
PKG
PART
RANGE
PACKAGE
CODE
1.25Gbps Ethernet
2.488Gbps STM16
InfiniBand
MAX3982UTE 0°C to +85°C 16 Thin QFN
T1633-4
Pin Configuration appears at end of data sheet.
PCI Express
Typical Application Circuit
DISK
ENCLOSURE
FABRIC SWITCH
SFP ACTIVE CABLE ASSEMBLY
≤ 5V
+3.3V
+3.3V
≥ 4.7kΩ
V
≤ 15m (24AWG)
V
CC
CC
TX_DISABLE
PE0
PE1
LOSLEV
OUTLEV
UP TO 4.25Gbps
LOS
V
OR
CC
GND
LOS
MAX3982
4.25Gbps LIMITING
SWITCH OR
SERDES
COPPER-CABLE
DIFFERENTIAL 100Ω TWIN-AX
SWITCH OR
SERDES
AMPLIFIER
0.01µF
0.01µF
0.01µF
T
R
IN+
IN-
OUT+
OUT-
IN+
IN-
OUT+
OUT-
X+
X+
0.01µF
0.01µF
0.01µF
T
R
X-
X-
GND
GND
+3.3V
+3.3V
0.01µF
0.01µF
0.01µF
V
V
CC
CC
R
T
OUT+
OUT-
IN+
IN-
OUT+
OUT-
IN+
IN-
X+
X+
X-
0.01µF
0.01µF
0.01µF
R
T
X-
4.25Gbps LIMITING
AMPLIFIER
MAX3982
≤ 5V
PE0
PE1
LOSLEV
OUTLEV
V
OR
GND
LOS
CC
≥4.7kΩ
TX_DISABLE
LOS
GND
GND
________________________________________________________________ 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.
SFP Copper-Cable Preemphasis Driver
ABSOLUTE MAXIMUM RATINGS
Supply Voltage, V ..............................................-0.5V to +6.0V
LOS Open Collector Supply Voltage
CC
Continuous CML Output Current
at OUT+, OUT-..............................................-25mA to +25mA
Voltage at IN+, IN-, LOSLEV, LOS,
with ≥ 4.7kΩ Pullup Resistor..............................-0.5V to +5.5V
Continuous Power Dissipation at +85°C
(derate 20.8mW/°C above +85°C).................................1.35W
Operating Junction Temperature Range (T )....-55C° to +150°C
J
TX_DISABLE, PE0, PE1, OUTLEV ..........-0.5V to (V
+ 0.5V)
CC
Storage Ambient Temperature Range (T ) .......-55C° to +150°C
S
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 T = +25°C and V
= +3.3V, unless otherwise noted.)
CC
A
A
CC
PARAMETER
SYMBOL
CONDITIONS
MIN
TYP
MAX
97
UNITS
mA
Supply Current
TX_DISABLE=low
75
Inrush Current
Current beyond steady-state current
10
mA
Power-On-Reset Delay
t
1
40
ms
POR
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
4.25
10
°C
A
NRZ data (Note 1)
1.0
Gbps
Bits
CID
Consecutive identical digits (bits) (Note 1)
CONTROL INPUTS: TX_DISABLE, PE0, PE1, OUTLEV, LOSLEV
Voltage, Logic High
Voltage, Logic Low
Current, Logic High
Current, Logic Low
STATUS OUTPUT: LOS
V
2.0
V
IH
V
0.8
-150
350
V
IL
I
V
V
= V + 0.5V
CC
µA
µA
IH
IH
IL
I
= 0.8V
IL
LOS asserted
0
25
µA
LOS unasserted, V ≤ 0.4V with 4.7kΩ
pullup resistor, pullup supply = 5.5V
OL
1.0
mA
LOS Open Collector Current Sink
V
= 0V, pullup supply = 5.5V, external
CC
0
25
µA
pullup resistor ≥ 4.7kΩ
LOSLEV = high (Note 1)
LOSLEV = low (Note 1)
LOSLEV = high (Note 1)
LOSLEV = low (Note 1)
LOSLEV = high (Note 1)
LOSLEV = low (Note 1)
100
50
mV
mV
mV
mV
mV
mV
P-P
P-P
P-P
P-P
P-P
P-P
LOS Assert Level
LOS Deassert Level
LOS Hysteresis
300
120
20
4
Time from IN dropping below assert level,
or rising above deassert level to 50% point
of LOS
LOS Response Time
LOS Transition Time
10
µs
Rise-time or fall-time (10% to 90%), external
pullup resistor = 4.7kΩ
250
ns
2
_______________________________________________________________________________________
SFP Copper-Cable Preemphasis Driver
ELECTRICAL CHARACTERISTICS (continued)
(V
= +3.0V to +3.6V, T = 0°C to +85°C. Typical values are at T = +25°C and V
= +3.3V, unless otherwise noted.)
CC
A
A
CC
PARAMETER
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
EQUALIZER AND CABLE DRIVER SPECIFICATIONS
Measured differentially at point A of Figure
2 (Note 1)
Input Swing
600
2000
115
mV
P-P
Input Resistance
Input Return Loss
Measured differentially
100MHz to 2GHz (Note 1)
TX_DISABLE = low,
85
10
100
Ω
dB
1450
1000
1800
1350
Measured
OUTLEV = high
differentially at point
B of Figure 2
(Notes 1, 2)
Differential Output Swing
mV
P-P
TX_DISABLE = low,
OUTLEV = low
TX_DISABLE = high
40
(OUT+) + (OUT-), measured at point B of
Figure 2; TX_DISABLE = low, OUTLEV =
high (Notes 1, 2)
Common-Mode Output
60
58
mV
P-P
Output Resistance
Output Return Loss
Output Transition Time
Random Jitter
OUT+ or OUT- to V , single ended
CC
42
10
50
50
Ω
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
PE1 PE0
0
0
1
1
0
1
0
1
2
4
Output Preemphasis
See Figure 1
Source to IN
dB
8
14
OUT to Load PE1 PE0
1m, 24AWG
5m, 24AWG
10m, 24AWG
15m, 24AWG
0
0
1
1
0
1
0
1
Residual Output Deterministic
Jitter at 1.0625Gbps to
2.125Gbps (Notes 1, 4, 5)
0.10
0.15
0.15
0.20
UI
P-P
6 mil
FR4 ≤ 10in
Source to IN
OUT to Load PE1 PE0
1m, 24AWG
5m, 24AWG
10m, 24AWG
15m, 24AWG
0
0
1
1
0
1
0
1
Residual Output Deterministic
Jitter at 4.25Gbps (Notes 1, 4, 5)
UI
P-P
6 mil
FR4 ≤ 10in
Note 1: Guaranteed by design and characterization.
Note 2: PE1 = PE0 = 1 for maximum preemphasis, load is 50Ω 1% at each side, and the pattern is 0000011111 at 1Gbps.
Note 3: Measured at point B in Figure 2 using 0000011111 at 1Gbps. PE1 = PE0 = 0 for minimum preemphasis. For transition time,
the 0% reference level is the steady-state level after four zeros, just before the transition. The 100% reference level is the
maximum voltage of the transition.
Note 4: Tested with CJTPAT, 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. Residual deterministic jitter is the difference between the source
jitter at point A, and load jitter at point D in Figure 2. The deterministic jitter at the output of the transmission line must be
from media-induced loss and not from clock-source modulation.
_______________________________________________________________________________________
3
SFP Copper-Cable Preemphasis Driver
V
V
LOW_PP HIGH_PP
V
HIGH_PP
PE(dB) = 20 log
V
LOW _PP
Figure 1. Illustration of Tx Preemphasis in dB
TEST SETUP
PCBOARD (FR4)
A
SIGNAL
SOURCE
B
MAX3982
24AWG 100Ω TWIN-AX
6 mil
6 mil
IN
OUT
L = 2in
1in ≤ L ≤ 10in
SMA CONNECTORS
SMA CONNECTORS
OSCILLOSCOPE OR
ERROR DETECTOR
L ≤ 1in
6 mil
FR4
4.0 ≤ ε ≤ 4.4
R
tan δ = 0.022
D
Figure 2. Test Setup. The points labeled A, B, and D are referenced for AC parameter test conditions. Deterministic jitter and eye
diagrams measured at point D.
4
_______________________________________________________________________________________
SFP Copper-Cable Preemphasis Driver
TEST SETUP
PC BOARD (FR4)
A
SIGNAL
SOURCE
B
MAX3982
24AWG 100Ω TWIN-AX
6 mil
6 mil
IN
OUT
L = 2in
1in ≤ L ≤ 12in
L ≤ 1in
SMA CONNECTORS
SMA CONNECTORS
L ≤ 1in
39Ω
OSCILLOSCOPE OR
ERROR DETECTOR
22pF
MAX3748
6 mil
FR4
IN
OUT
22pF
4.0 ≤ ε ≤ 4.4
R
D
tan δ = 0.022
39Ω
Figure 3. End-to-End Test Setup Using the MAX3748 as a Receiver. Deterministic jitter and eye diagrams measured at point D.
Typical Operating Characteristics
7
7
(V = +3.3V, T = +25°C, unless otherwise noted. PRBS7 + 100CID pattern is PRBS 2 , 100 zeros, 1010, PRBS 2 , 100 ones, 0101.)
CC
A
END-TO-END DETERMINISTIC JITTER
vs. CABLE LENGTH AT 4.25Gbps
END-TO-END DETERMINISTIC JITTER
vs. CABLE LENGTH AT 2.125Gbps
TRANSIENT RESPONSE
MAX3982 toc01
1.0
0.9
0.8
0.7
0.6
0.5
0.4
0.3
0.2
0.1
0
1.0
0.9
0.8
0.7
0.6
0.5
0.4
0.3
0.2
0.1
0
4.25Gbps K28.7 PATTERN
OUTLEV = HIGH
4.25Gbps PRBS7 + 100CID
2.125Gbps PRBS7 + 100CID
PE[1,0] = 00
12in FR4 AT INPUT
USING MAX3748 AS RECEIVER,
AS SHOWN IN FIGURE 3
A
B
C
D
PE[1,0] = 01
12in FR4 AT INPUT
USING MAX3748 AS
RECEIVER, AS SHOWN
IN FIGURE 3
PE[1,0] = 00
PE[1,0] = 01
PE[1,0] = 10
PE[1,0] = 10
D
C
B
A
PE[1,0] = 11
PE[1,0] = 11
A = 2dB, PE = 00
B = 4dB, PE = 01
C = 8dB, PE = 10
D = 14dB, PE = 11
0
5
10
CABLE LENGTH (m)
15
20
0
5
10
15
20
CABLE LENGTH (m)
_______________________________________________________________________________________
5
SFP Copper-Cable Preemphasis Driver
Typical Operating Characteristics (continued)
7
7
(V = +3.3V, T = +25°C, unless otherwise noted. PRBS7 + 100CID pattern is PRBS 2 , 100 zeros, 1010, PRBS 2 , 100 ones, 0101.)
CC
A
END-TO-END EYE DIAGRAM,
END-TO-END EYE DIAGRAM,
END-TO-END EYE DIAGRAM,
20m 24AWG CABLE AT 4.25Gbps
20m 24AWG CABLE AT 2.125Gbps
20m 24AWG CABLE AT 1.0625Gbps
MAX3982 toc04
MAX3982 toc05
MAX3982 toc06
4.25Gbps PRBS7 + 100CID PATTERN,
0in FR4 AT INPUT, USING MAX3748
AS RECEIVER, AS SHOWN IN FIGURE 3
2.125Gbps PRBS7 + 100CID PATTERN,
0in FR4 AT INPUT, USING MAX3748
AS RECEIVER, AS SHOWN IN FIGURE 3
1.0625Gbps PRBS7 + 100CID PATTERN,
0in FR4 AT INPUT, USING MAX3748
AS RECEIVER, AS SHOWN IN FIGURE 3
VERTICAL EYE OPENING
vs. CABLE LENGTH WITH OUTLEV = LOW
END-TO-END DETERMINISTIC JITTER
vs. CABLE LENGTH AT 1.0625Gbps
700
600
500
400
300
200
100
0
0.50
0.45
0.40
0.35
0.30
0.25
0.20
0.15
0.10
0.05
0
1.0625Gbps PRBS7 + 100CID
PE[1,0] = 00
12in FR4 AT INPUT
USING MAX3748 AS RECEIVER,
AS SHOWN IN FIGURE 3
PE[1,0] = 00
PE[1,0] = 01
PE[1,0] = 01
PE[1,0] = 10
PE[1,0] = 11
PE[1,0] = 10
PE[1,0] = 11
4.25Gbps PRBS7 + 100CID
0
5
10
15
0
5
10
15
20
CABLE LENGTH (m)
CABLE LENGTH (m)
VERTICAL EYE OPENING
vs. CABLE LENGTH WITH OUTLEV = LOW
INPUT RETURN LOSS vs. FREQUENCY
0
-5
700
600
500
400
300
200
100
0
USING AGILENT 8720ES AND ATN MICROWAVE
ATN-4112A S-PARAMETER TEST SET
DE-EMBEDDING SMA CONNECTOR, COUPLING
CAPACITOR, AND 1cm TRACE
PE[1,0] = 00
-10
-15
-20
-25
-30
-35
-40
PE[1,0] = 01
PE[1,0] = 10
PE[1,0] = 11
4.25Gbps PRBS7 + 100CID
100
1000
10,000
0
5
10
15
FREQUENCY (MHz)
CABLE LENGTH (m)
6
_______________________________________________________________________________________
SFP Copper-Cable Preemphasis Driver
Typical Operating Characteristics (continued)
7
7
(V = +3.3V, T = +25°C, unless otherwise noted. PRBS7 + 100CID pattern is PRBS 2 , 100 zeros, 1010, PRBS 2 , 100 ones, 0101.)
CC
A
15m 24AWG CABLE ASSEMBLY
OUTPUT WITHOUT MAX3982,
4.25Gbps CJTPAT
15m 24AWG CABLE ASSEMBLY
OUTPUT WITH MAX3982
DETERMINISTIC JITTER
vs. CABLE LENGTH
PREEMPHASIS, 4.25Gbps CJTPAT
MAX3982 toc11
MAX3982 toc12
1.0
0.8
0.6
0.4
0.2
0
4.25Gbps
PRBS7 + 100CID
PE[1,0] = 00
PE[1,0] = 01
PE[1,0] = 10
PE[1,0] = 11
PREEMPHASIS, PE[1,0] = 11, OUTLEV = HIGH
0
5
10
15
CABLE LENGTH (m)
15m 24AWG CABLE ASSEMBLY
OUTPUT WITHOUT MAX3982,
4.25Gbps PRBS7 + 100CID
15m 24AWG CABLE ASSEMBLY
OUTPUT WITH MAX3982
OUTPUT RETURN LOSS
vs. FREQUENCY
PREEMPHASIS, 4.25Gbps PRBS7 + 100CID
MAX3982 toc14
MAX3982 toc15
0
-5
USING AGILENT 8720ES AND ATN MICROWAVE
ATN-4112A S-PARAMETER TEST SET
DE-EMBEDDING SMA CONNECTOR, COUPLING
CAPACITOR, AND 1cm TRACE
-10
-15
-20
-25
-30
-35
-40
PREEMPHASIS, PE[1,0] = 11, OUTLEV = HIGH
100
1000
10,000
FREQUENCY (MHz)
_______________________________________________________________________________________
7
SFP Copper-Cable Preemphasis Driver
Typical Operating Characteristics (continued)
7
7
(V = +3.3V, T = +25°C, unless otherwise noted. PRBS7 + 100CID pattern is PRBS 2 , 100 zeros, 1010, PRBS 2 , 100 ones, 0101.)
CC
A
15m 24AWG CABLE ASSEMBLY
OUTPUT WITHOUT MAX3982,
4.25Gbps PRBS31
15m 24AWG CABLE ASSEMBLY
OUTPUT WITH MAX3982
HOT-PLUG WITH TX_DISABLE LOW
PREEMPHASIS, 4.25Gbps PRBS31
MAX3982 toc17
MAX3982 toc19
MAX3982 toc18
3.3V
V
CC
0V
LOW
TX_DISABLE
OUT+
t
= 27ms
POR
PREEMPHASIS, PE[1,0] = 11, OUTLEV = HIGH
10ms/div
30in FR4 OUTPUT
WITH MAX3982 PREEMPHASIS,
4.25Gbps CJTPAT
30in FR4 OUTPUT
WITHOUT MAX3982,
4.25Gbps CJTPAT
DETERMINISTIC JITTER
vs. FR4 LENGTH
MAX3982 toc20
MAX3982 toc21
1.2
1.0
0.8
0.6
0.4
0.2
0
4.25Gbps PRBS7
PE[1,0] = 00
DRIVING FR4 AT OUT+ AND
OUT-, NO FR4 AT INPUT
PE[1,0] = 01
PE[1,0] = 10
PE[1,0] = 11
PREEMPHASIS, PE[1,0] = 10,
OUTLEV = HIGH
0
10
20
30
40
50
FR4 LENGTH (in)
8
_______________________________________________________________________________________
SFP Copper-Cable Preemphasis Driver
Typical Operating Characteristics (continued)
7
7
(V = +3.3V, T = +25°C, unless otherwise noted. PRBS7 + 100CID pattern is PRBS 2 , 100 zeros, 1010, PRBS 2 , 100 ones, 0101.)
CC
A
30in FR4 OUTPUT
WITHOUT MAX3982
4.25Gbps PRBS7 + 100CID
30in FR4 OUTPUT
WITH MAX3982 PREEMPHASIS,
4.25Gbps PRBS7 + 100CID
TRANSMITTER ENABLE
MAX3982 toc23
MAX3982 toc24
MAX3982 toc25
V
CC
3.3V
HIGH
TX_DISABLE
OUT+
LOW
PREEMPHASIS, PE[1,0] = 10,
OUTLEV = HIGH
200ns/div
30in FR4 OUTPUT
WITH MAX3982 PREEMPHASIS,
4.25Gbps PRBS31
30in FR4 OUTPUT
WITHOUT MAX3982,
4.25Gbps PRBS31
TRANSMITTER DISABLE
MAX3982 toc28
MAX3982 toc27
MAX3982 toc26
V
CC
3.3V
LOW
HIGH
TX_DISABLE
OUT+
PREEMPHASIS, PE[1,0] = 10, OUTLEV = HIGH
200ns/div
_______________________________________________________________________________________
9
SFP Copper-Cable Preemphasis Driver
Pin Description
PIN
NAME
FUNCTION
Power-Supply Connection for Input. Connect to +3.3V.
Positive Data Input, CML. This input is internally terminated with 50Ω to V
1
V
CC1
2
3
IN+
IN-
.
CC1
Negative Data Input, CML. This input is internally terminated with 50Ω to V
.
CC1
4, 8, 9
GND
Circuit Ground
Output-Swing Control Input, LVTTL with 40kΩ Internal Pullup. Set to TTL high or open for maximum
output swing, or set to TTL low for reduced swing.
5
6
7
OUTLEV
PE1
Output Preemphasis Control Input, LVTTL with 10kΩ Internal Pullup. This pin is the most significant bit
of the 2-bit preemphasis control. Set high or open to assert this bit.
Output Preemphasis Control Input, LVTTL with 10kΩ Internal Pullup. This pin is the least significant bit
of the 2-bit preemphasis control. Set high or open to assert this bit.
PE0
10
11
OUT-
Negative Data Output, CML. This output is terminated with 50Ω to V
.
CC2
OUT+
Positive Data Output, CML. This output is terminated with 50Ω to V
.
CC2
12, 13
V
Power-Supply Connection for Output. Connect to +3.3V.
CC2
Transmitter Disable Input, LVTTL with 10kΩ Internal Pullup. When high or open, differential output is
14
TX_DISABLE
40mV . Set low for normal operation.
P-P
Loss-of-Signal Detect, TTL Output. This output is open-collector TTL, and therefore requires an external
15
LOS
4.7kΩ to 10kΩ pullup resistor (5.5V maximum). This output sinks current when the input signal level is
valid.
LOS Sensitivity Control Input, LVTTL with 40kΩ Internal Pullup. Set to TTL high or open for less
sensitivity (higher assert threshold). Set to TTL low for more sensitivity (lower assert threshold).
16
EP
LOSLEV
EXPOSED
PAD
Exposed Pad. For optimal thermal conductivity, this pad must be soldered to the circuit board ground.
Pin Configuration
TOP VIEW
16 15 14 13
V
V
CC2
1
2
3
4
12
11
10
9
CC1
IN+
MAX3982UTE
OUT+
OUT-
GND
IN-
GND
EXPOSED PAD*
5
6
7
8
THIN QFN
*THE EXPOSED PAD OF THE QFN PACKAGE MUST BE SOLDERED TO GROUND
FOR PROPER THERMAL OPERATION OF THE MAX3982.
10 ______________________________________________________________________________________
SFP Copper-Cable Preemphasis Driver
V
CC2
V
CC2
MAX3982
10kΩ
2
2
PE0
PE1
LVTTL
V
CC2
V
CC1
IN+
LIMITER
OUT+
OUT-
LOS
FIXED
EQUALIZER
PREEMPHASIS
SIGNAL DETECT
CML
CML
IN-
V
V
V
CC1
40kΩ
V
CC1
V
CC2
V
CC2
LOSLEV
TX_DISABLE
OUTLEV
LVTTL
LVTTL
LVTTL
CC2
10kΩ
CC2
40kΩ
GND
Figure 4. Functional Diagram
1600mV . Residual jitter of the MAX3982 is indepen-
P-P
Detailed Description
dent of up to 0.20UI
source jitter.
P-P
The MAX3982 comprises a PC board receiver, a cable
driver, and a loss-of-signal detector with adjustable
threshold (Figure 4). Equalization is provided in the
receiver. Selectable preemphasis and selectable output
amplitude are included in the transmitter. The MAX3982
also includes transmit disable control for the output.
Loss-of-Signal (LOS) Output
Loss-of-signal detection is provided on the data input.
Pullup resistors should be connected from LOS to a
supply in the range of +3.0V to +5.5V. The LOS output
is not valid until power-up is complete. Typical LOS
response time is 100ns.
PC Board Receiver and Cable Driver
Data is fed into the MAX3982 through a CML input
stage and fixed equalization stage. The fixed equalizer
in the receiver corrects for up to 10in of PC board loss
on FR4 material at 4.25Gbps.
The LOS assert and deassert levels are set by the
LOSLEV pin. When LOSLEV is LVTTL high or open, the
LOS assert threshold is 180mV . When LOSLEV is
P-P
LVTTL low, the LOS assert threshold is 85mV
.
P-P
The cable driver includes four-state preemphasis to
compensate for up to 15m of 24AWG, 100Ω balanced
cable. Table 1 is provided for easy translation between
preemphasis expressions. The OUTLEV pin selects the
output amplitude. When OUTLEV is low, the amplitude
TX Disable
Transmit disable is provided to turn off the output when
desired. The TX_DISABLE pin can be connected to
LOS to automatically squelch the output when the
incoming signal is below the threshold set by LOSLEV
(see the Autodetect section).
is 1200mV . When OUTLEV is high, the amplitude is
P-P
______________________________________________________________________________________ 11
SFP Copper-Cable Preemphasis Driver
Table 1. Preemphasis Translation
Ratio
α
10Gbase–CX4
IN dB
V
V
− V
V
V
HIGH_PP
HIGH_PP
LOW _PP
LOW _PP
HIGH_PP
1 −
20 log
V
V
+ V
V
V
LOW _PP
HIGH_PP
LOW _PP
HIGH_PP
LOW _PP
V
V
LOW_PP HIGH_PP
1.26
1.58
2.51
5.01
0.11
0.21
0.37
0.6
2
4
0.23
0.43
0.67
8
0.8
14
Layout Considerations
Applications Information
Circuit board layout and design can significantly affect
the performance of the MAX3982. Use good high-fre-
quency design techniques, including minimizing ground
inductance and using controlled-impedance transmis-
sion lines on the data signals. Power-supply decoupling
Autodetect
The MAX3982 can automatically detect an incoming
signal and enable the data outputs. Autodetect can be
accomplished by connecting the LOS pin to TX_DIS-
ABLE. TX_DISABLE has a 10kΩ internal pullup resistor.
If a loss-of-signal is detected, the TX_DISABLE pin is
forced high and disables the outputs. Leaving the
inputs to the MAX3982 open (i.e., floating) is not recom-
mended as noise amplification may occur and create
undesirable output signals. Autodetect is recommend-
ed to eliminate noise amplification or possible oscilla-
tion. For periods much greater than 100ns without data
transitions, autodetect disables the output.
should also be placed as close to the V
pins as possi-
CC
ble. This should be sufficient supply filtering. Always con-
nect all V
pins to a power plane. Take care to isolate
the input from the output signals to reduce feedthrough.
CC
Exposed Pad Package
The exposed-pad, 16-pin QFN package incorporates
features that provide a very low thermal resistance path
for heat removal from the IC. The exposed pad on the
MAX3982 must be soldered to the circuit board for
proper thermal performance. For more information on
exposed-pad packages, refer to Maxim Application
Note HFAN-08.1: Thermal Considerations of QFN and
Other Exposed-Paddle Packages.
Interface Schematics
V
CC2
V
CC1
50Ω
50Ω
50Ω
50Ω
OUT+
OUT-
IN+
IN-
GND
GND
Figure 5. IN+/IN- Equivalent Input Structure
Figure 6. OUT+/OUT- Equivalent Output Structure
12 ______________________________________________________________________________________
SFP Copper-Cable Preemphasis Driver
LOS
V
CCX
R
PULLUP
GND
LVTTL IN
Figure 8. Loss-of-Signal Equivalent Output Structure
GND
Chip Information
R
(kΩ)
V
CCX
V
CC1
V
CC2
V
CC2
PIN NAME
LOSLEV
OUTLEV
TX_DISABLE, PE0, PE1
PULLUP
TRANSISTOR COUNT: 2957
40
PROCESS: SiGe Bipolar
40
10
Figure 7. LVTTL Equivalent Input Structure
______________________________________________________________________________________ 13
SFP Copper-Cable Preemphasis Driver
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.)
D2
b
0.10 M
C
A
B
D
D2/2
D/2
E/2
E2/2
(NE - 1)
X e
C
E
E2
L
L
k
e
C
L
(ND - 1)
X e
C
L
C
L
0.10
C
0.08 C
A
A2
A1
L
L
e
e
PACKAGE OUTLINE
12, 16L, THIN QFN, 3x3x0.8mm
1
E
21-0136
2
14 ______________________________________________________________________________________
SFP Copper-Cable Preemphasis Driver
Package Information (continued)
(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.)
EXPOSED PAD VARIATIONS
DOWN
BONDS
ALLOWED
NOTES:
1. DIMENSIONING & TOLERANCING CONFORM TO ASME Y14.5M-1994.
2. ALL DIMENSIONS ARE IN MILLIMETERS. ANGLES ARE IN DEGREES.
3. N IS THE TOTAL NUMBER OF TERMINALS.
4. THE TERMINAL #1 IDENTIFIER AND TERMINAL NUMBERING CONVENTION SHALL CONFORM TO
JESD 95-1 SPP-012. DETAILS OF TERMINAL #1 IDENTIFIER ARE OPTIONAL, BUT MUST BE LOCATED
WITHIN THE ZONE INDICATED. THE TERMINAL #1 IDENTIFIER MAY BE EITHER A MOLD OR
MARKED FEATURE.
5. DIMENSION b APPLIES TO METALLIZED TERMINAL AND IS MEASURED BETWEEN 0.20 mm AND 0.25 mm
FROM TERMINAL TIP.
6. ND AND NE REFER TO THE NUMBER OF TERMINALS ON EACH D AND E SIDE RESPECTIVELY.
7. DEPOPULATION IS POSSIBLE IN A SYMMETRICAL FASHION.
8. COPLANARITY APPLIES TO THE EXPOSED HEAT SINK SLUG AS WELL AS THE TERMINALS.
9. DRAWING CONFORMS TO JEDEC MO220 REVISION C.
PACKAGE OUTLINE
12, 16L, THIN QFN, 3x3x0.8mm
2
E
21-0136
2
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 ____________________ 15
© 2004 Maxim Integrated Products
Printed USA
is a registered trademark of Maxim Integrated Products.
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