General Description
The MAX3982 is a single-channel, copper-cable preemphasis 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.
The MAX3982 also features SFP-compliant loss-of-signal
detection with selectable sensitivity and TX_DISABLE.
Selectable output swing reduces EMI and power consumption. It is packaged in a 3mm x 3mm, 16-pin thin
QFN and operates from 0°C to +85°C temperature range.
Applications
SFP Active Copper-Cable Assemblies
Backplanes
1.0625Gbps, 2.125Gbps, and 4.25Gbps Fibre
Channel
1.25Gbps Ethernet
2.488Gbps STM16
InfiniBand
PCI Express
Features
♦ Drives Up to 15m with 24AWG Cable
♦ Drives Up to 30in of FR4
♦ 0.25W Total Power with +3.3V Supply
♦ Selectable 1600mV
P-P
or 1200mV
P-P
Differential
Output Swing
♦ Selectable Output Preemphasis
♦ Fixed Input Equalization
♦ Loss-of-Signal Detection with Selectable
Sensitivity
♦ Transmit Disable
MAX3982
SFP Copper-Cable Preemphasis Driver
________________________________________________________________ Maxim Integrated Products 1
Ordering Information
19-3354; Rev 2; 2/06
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.
EVALUATION KIT
AVAILABLE
PART
TEMP
RANGE
PINPACKAGE
PKG
CODE
MAX3982UTE
16 Thin QFN
T1633-4
MAX3982UTE+
16 Thin QFN
T1633-4
MAX3982
+3.3V
TX_DISABLE
PE0
PE1
LOSLEV
IN+
OUTLEV
IN-
LOS
OUT+
OUT-
0.01μF
0.01μF
V
CC
OR
GND
SWITCH OR
SERDES
T
X+
T
X-
4.25Gbps LIMITING
AMPLIFIER
+3.3V
OUT+
OUT-
IN+
IN-
LOS
0.01μF
0.01μF
R
X+
R
X-
≤ 5V
≥4.7kΩ
V
CC
GND
V
CC
GND
4.25Gbps LIMITING
AMPLIFIER
+3.3V
TX_DISABLE
PE0
PE1
LOSLEV
IN+
OUTLEV
IN-
LOS
OUT+
OUT-
0.01μF
0.01μF
0.01μF
0.01μF
MAX3982
+3.3V
OUT+
OUT-
IN+
IN-
LOS
0.01μF
0.01μF
0.01μF
0.01μF
V
CC
GND
V
CC
GND
SWITCH OR
SERDES
R
X+
R
X-
T
X+
T
X-
DISK
ENCLOSURE
FABRIC SWITCH
V
CC
OR
GND
≤ 5V
≥ 4.7kΩ
COPPER-CABLE
DIFFERENTIAL 100Ω TWIN-AX
SFP ACTIVE CABLE ASSEMBLY
≤ 15m (24AWG)
UP TO 4.25Gbps
Typical Application Circuit
Pin Configuration appears at end of data sheet.
+Denotes lead-free package.
0°C to +85°C
0°C to +85°C
MAX3982
SFP Copper-Cable Preemphasis Driver
2 _______________________________________________________________________________________
ABSOLUTE MAXIMUM RATINGS
ELECTRICAL CHARACTERISTICS
(VCC= +3.0V to +3.6V, TA= 0°C to +85°C. Typical values are at TA= +25°C and VCC= +3.3V, unless otherwise noted.)
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.
Supply Voltage, VCC..............................................-0.5V to +6.0V
Continuous CML Output Current
at OUT+, OUT-..............................................-25mA to +25mA
Voltage at IN+, IN-, LOSLEV, LOS,
TX_DISABLE, PE0, PE1, OUTLEV ..........-0.5V to (V
CC
+ 0.5V)
LOS Open Collector Supply Voltage
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
J
) ....-55C° to +150°C
Storage Ambient Temperature Range (T
S
) .......-55C° to +150°C
PARAMETER
CONDITIONS
Supply Current TX_DISABLE=low 75 97 mA
Inrush Current Current beyond steady-state current 10 mA
Power-On-Reset Delay t
POR
140ms
OPERATING CONDITIONS
Supply Voltage V
CC
3.0 3.3 3.6 V
Supply-Noise Tolerance 1MHz ≤ f < 2GHz 40
Operating Ambient Temperature
T
A
02585°C
Bit Rate NRZ data (Note 1) 1.0
CID Consecutive identical digits (bits) (Note 1) 10 Bits
CONTROL INPUTS: TX_DISABLE, PE0, PE1, OUTLEV, LOSLEV
Voltage, Logic High V
IH
2.0 V
Voltage, Logic Low V
IL
0.8 V
Current, Logic High I
IH
VIH = VCC + 0.5V
µA
Current, Logic Low I
IL
VIL = 0.8V
µA
STATUS OUTPUT: LOS
LOS asserted 0 25 µA
LOS unasserted, VOL ≤ 0.4V with 4.7kΩ
pullup resistor, pullup supply = 5.5V
1.0 mA
LOS Open Collector Current Sink
VCC = 0V, pullup supply = 5.5V, external
pullup resistor ≥ 4.7kΩ
025µA
LOSLEV = high (Note 1)
LOS Assert Level
LOSLEV = low (Note 1) 50
LOSLEV = high (Note 1)
LOS Deassert Level
LOSLEV = low (Note 1)
LOSLEV = high (Note 1) 20
LOS Hysteresis
LOSLEV = low (Note 1) 4
LOS Response Time
Time from IN dropping below assert level,
or rising above deassert level to 50% point
of LOS
10 µs
LOS Transition Time
Rise-time or fall-time (10% to 90%), external
pullup resistor = 4.7kΩ
ns
SYMBOL
MIN TYP MAX UNITS
100 mV
250
mV
P-P
4.25 Gbps
-150
350
P-P
mV
P-P
300 mV
120 mV
mV
mV
P-P
P-P
P-P
P-P
MAX3982
SFP Copper-Cable Preemphasis Driver
_______________________________________________________________________________________ 3
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.
ELECTRICAL CHARACTERISTICS (continued)
(VCC= +3.0V to +3.6V, TA= 0°C to +85°C. Typical values are at TA= +25°C and VCC= +3.3V, unless otherwise noted.)
PARAMETER
CONDITIONS
UNITS
EQUALIZER AND CABLE DRIVER SPECIFICATIONS
Input Swing
Measured differentially at point A of Figure
2 (Note 1)
mV
P-P
Input Resistance Measured differentially 85
Ω
Input Return Loss 100MHz to 2GHz (Note 1) 10 dB
TX_DISABLE = low,
OUTLEV = high
TX_DISABLE = low,
OUTLEV = low
Differential Output Swing
Measured
differentially at point
B of Figure 2
(Notes 1, 2)
40
mV
P-P
Common-Mode Output
high (Notes 1, 2)
60
mV
P-P
Output Resistance OUT+ or OUT- to VCC, single ended 42 50 58 Ω
Output Return Loss 100MHz to 2GHz (Note 1) 10 dB
Output Transition Time tr, t
f
20% to 80% (Notes 1, 3) 50 80 ps
Random Jitter (Notes 1, 3) 1.6
ps
RMS
2
4
8
Output Preemphasis See Figure 1
14
dB
Source to IN
Residual Output Deterministic
Jitter at 1.0625Gbps to
2.125Gbps (Notes 1, 4, 5)
6 mil
FR4 ≤ 10in
UI
P-P
Source to IN
Residual Output Deterministic
Jitter at 4.25Gbps (Notes 1, 4, 5)
6 mil
FR4 ≤ 10in
UI
P-P
SYMBOL
TX_DISABLE = high
(OUT+) + (OUT-), measured at point B of
Figure 2; TX_DISABLE = low, OUTLEV =
PE1 PE0
00
OUT to Load PE1 PE0
1m, 24AWG 0 0
5m, 24AWG 0 1
10m, 24AWG 1 0
15m, 24AWG 1 1
OUT to Load PE1 PE0
1m, 24AWG 0 0
5m, 24AWG 0 1
10m, 24AWG 1 0
15m, 24AWG 1 1
01
10
11
MIN TYP MAX
600 2000
100 115
1450 1800
1000 1350
0.10 0.15
0.15 0.20
MAX3982
SFP Copper-Cable Preemphasis Driver
4 _______________________________________________________________________________________
Figure 1. Illustration of Tx Preemphasis in dB
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.
V
LOW_PP
V
HIGH_PP
⎡
PE dB
( ) log
⎢
=
20
⎢
⎣
SIGNAL
SOURCE
SMA CONNECTORS
OSCILLOSCOPE OR
ERROR DETECTOR
A
⎛
V
HIGH PP
⎜
⎜
V
⎝
LOW PP
⎤
⎞
_
⎥
⎟
⎟
⎥
⎠
_
⎦
6 mil
1in ≤ L ≤ 10in
TEST SETUP
PCBOARD (FR4)
MAX3982
IN OUT
L ≤ 1in
6 mil
L = 2in
B
24AWG 100Ω TWIN-AX
SMA CONNECTORS
6 mil
FR4
≤ 4.4
4.0 ≤ ε
R
D
tan δ = 0.022
MAX3982
SFP Copper-Cable Preemphasis Driver
_______________________________________________________________________________________ 5
Figure 3. End-to-End Test Setup Using the MAX3748 as a Receiver. Deterministic jitter and eye diagrams measured at point D.
SIGNAL
SOURCE
1in ≤ L ≤ 12in
L ≤ 1in
IN OUT
6 mil
6 mil
L = 2in
L ≤ 1in
PC BOARD (FR4)
A
D
OSCILLOSCOPE OR
ERROR DETECTOR
B
SMA CONNECTORS
24AWG 100Ω TWIN-AX
TEST SETUP
SMA CONNECTORS
FR4
4.0 ≤ ε
R
≤ 4.4
tan δ = 0.022
MAX3982
6 mil
22pF
22pF
39Ω
39Ω
OUT IN
MAX3748
Typical Operating Characteristics
(VCC= +3.3V, TA= +25°C, unless otherwise noted. PRBS7 + 100CID pattern is PRBS 27, 100 zeros, 1010, PRBS 27, 100 ones, 0101.)
TRANSIENT RESPONSE
MAX3982 toc01
A = 2dB, PE = 00
B = 4dB, PE = 01
C = 8dB, PE = 10
D = 14dB, PE = 11
4.25Gbps K28.7 PATTERN
OUTLEV = HIGH
A
B
C
D
D
C
B
A
END-TO-END DETERMINISTIC JITTER
vs. CABLE LENGTH AT 4.25Gbps
MAX3982 toc02
CABLE LENGTH (m)
DETERMINISTIC JITTER (UI)
15105
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1.0
0
020
4.25Gbps PRBS7 + 100CID
PE[1,0] = 00
PE[1,0] = 01
PE[1,0] = 10
PE[1,0] = 11
12in FR4 AT INPUT
USING MAX3748 AS
RECEIVER, AS SHOWN
IN FIGURE 3
END-TO-END DETERMINISTIC JITTER
vs. CABLE LENGTH AT 2.125Gbps
MAX3982 toc03
CABLE LENGTH (m)
DETERMINISTIC JITTER (UI)
15105
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1.0
0
020
2.125Gbps PRBS7 + 100CID
PE[1,0] = 01
PE[1,0] = 10
PE[1,0] = 11
12in FR4 AT INPUT
USING MAX3748 AS RECEIVER,
AS SHOWN IN FIGURE 3
PE[1,0] = 00
MAX3982
SFP Copper-Cable Preemphasis Driver
6 _______________________________________________________________________________________
END-TO-END EYE DIAGRAM,
20m 24AWG CABLE AT 1.0625Gbps
MAX3982 toc06
1.0625Gbps PRBS7 + 100CID PATTERN,
0in FR4 AT INPUT, USING MAX3748
AS RECEIVER, AS SHOWN IN FIGURE 3
END-TO-END EYE DIAGRAM,
20m 24AWG CABLE AT 4.25Gbps
MAX3982 toc04
4.25Gbps PRBS7 + 100CID PATTERN,
0in FR4 AT INPUT, USING MAX3748
AS RECEIVER, AS SHOWN IN FIGURE 3
END-TO-END EYE DIAGRAM,
20m 24AWG CABLE AT 2.125Gbps
MAX3982 toc05
2.125Gbps PRBS7 + 100CID PATTERN,
0in FR4 AT INPUT, USING MAX3748
AS RECEIVER, AS SHOWN IN FIGURE 3
END-TO-END DETERMINISTIC JITTER
vs. CABLE LENGTH AT 1.0625Gbps
MAX3982 toc07
CABLE LENGTH (m)
DETERMINISTIC JITTER (UI)
15105
0.05
0.10
0.15
0.20
0.25
0.30
0.35
0.40
0.45
0.50
0
020
1.0625Gbps PRBS7 + 100CID
PE[1,0] = 01
PE[1,0] = 10
PE[1,0] = 11
12in FR4 AT INPUT
USING MAX3748 AS RECEIVER,
AS SHOWN IN FIGURE 3
PE[1,0] = 00
VERTICAL EYE OPENING
vs. CABLE LENGTH WITH OUTLEV = LOW
MAX3982 toc08
CABLE LENGTH (m)
VERTICAL EYE OPENING (mV
P-P
)
105
100
200
300
400
500
600
700
0
015
PE[1,0] = 00
PE[1,0] = 01
PE[1,0] = 10
PE[1,0] = 11
4.25Gbps PRBS7 + 100CID
VERTICAL EYE OPENING
vs. CABLE LENGTH WITH OUTLEV = LOW
MAX3982 toc09
CABLE LENGTH (m)
VERTICAL EYE OPENING (mV
P-P
)
105
100
200
300
400
500
600
700
0
015
PE[1,0] = 00
PE[1,0] = 01
PE[1,0] = 10
PE[1,0] = 11
4.25Gbps PRBS7 + 100CID
INPUT RETURN LOSS vs. FREQUENCY
MAX3982 toc10
FREQUENCY (MHz)
DIFFERENTIAL S11 (dB)
1000
-35
-30
-25
-20
-15
-10
-5
0
-40
100 10,000
USING AGILENT 8720ES AND ATN MICROWAVE
ATN-4112A S-PARAMETER TEST SET
DE-EMBEDDING SMA CONNECTOR, COUPLING
CAPACITOR, AND 1cm TRACE
Typical Operating Characteristics (continued)
(VCC= +3.3V, TA= +25°C, unless otherwise noted. PRBS7 + 100CID pattern is PRBS 27, 100 zeros, 1010, PRBS 27, 100 ones, 0101.)
MAX3982
SFP Copper-Cable Preemphasis Driver
_______________________________________________________________________________________ 7
15m 24AWG CABLE ASSEMBLY
OUTPUT WITHOUT MAX3982,
4.25Gbps CJTPAT
MAX3982 toc11
15m 24AWG CABLE ASSEMBLY
OUTPUT WITH MAX3982
PREEMPHASIS, 4.25Gbps CJTPAT
MAX3982 toc12
PREEMPHASIS, PE[1,0] = 11, OUTLEV = HIGH
40mV/div
DETERMINISTIC JITTER
vs. CABLE LENGTH
MAX3982 toc13
CABLE LENGTH (m)
DETERMINISTIC JITTER (UI)
105
0.2
0.4
0.6
0.8
1.0
0
015
4.25Gbps
PRBS7 + 100CID
PE[1,0] = 00
PE[1,0] = 01
PE[1,0] = 10
PE[1,0] = 11
15m 24AWG CABLE ASSEMBLY
OUTPUT WITHOUT MAX3982,
4.25Gbps PRBS7 + 100CID
MAX3982 toc14
15m 24AWG CABLE ASSEMBLY
OUTPUT WITH MAX3982
PREEMPHASIS, 4.25Gbps PRBS7 + 100CID
MAX3982 toc15
PREEMPHASIS, PE[1,0] = 11, OUTLEV = HIGH
40mV/div
OUTPUT RETURN LOSS
vs. FREQUENCY
MAX3982 toc16
FREQUENCY (MHz)
DIFFERENTIAL S22 (dB)
1000
-35
-30
-25
-20
-15
-10
-5
0
-40
100 10,000
USING AGILENT 8720ES AND ATN MICROWAVE
ATN-4112A S-PARAMETER TEST SET
DE-EMBEDDING SMA CONNECTOR, COUPLING
CAPACITOR, AND 1cm TRACE
Typical Operating Characteristics (continued)
(VCC= +3.3V, TA= +25°C, unless otherwise noted. PRBS7 + 100CID pattern is PRBS 27, 100 zeros, 1010, PRBS 27, 100 ones, 0101.)
MAX3982
SFP Copper-Cable Preemphasis Driver
8 _______________________________________________________________________________________
15m 24AWG CABLE ASSEMBLY
OUTPUT WITHOUT MAX3982,
4.25Gbps PRBS31
MAX3982 toc17
15m 24AWG CABLE ASSEMBLY
OUTPUT WITH MAX3982
PREEMPHASIS, 4.25Gbps PRBS31
MAX3982 toc18
PREEMPHASIS, PE[1,0] = 11, OUTLEV = HIGH
40mV/div
HOT-PLUG WITH TX_DISABLE LOW
MAX3982 toc19
10ms/div
TX_DISABLE
V
CC
OUT+
3.3V
0V
LOW
t
POR
= 27ms
30in FR4 OUTPUT
WITHOUT MAX3982,
4.25Gbps CJTPAT
MAX3982 toc20
30in FR4 OUTPUT
WITH MAX3982 PREEMPHASIS,
4.25Gbps CJTPAT
MAX3982 toc21
PREEMPHASIS, PE[1,0] = 10,
OUTLEV = HIGH
100mV/div
DETERMINISTIC JITTER
vs. FR4 LENGTH
MAX3982 toc22
FR4 LENGTH (in)
DETERMINISTIC JITTER (UI)
40302010
0.2
0.4
0.6
0.8
1.0
1.2
0
050
4.25Gbps PRBS7
DRIVING FR4 AT OUT+ AND
OUT-, NO FR4 AT INPUT
PE[1,0] = 01
PE[1,0] = 10
PE[1,0] = 11
PE[1,0] = 00
Typical Operating Characteristics (continued)
(VCC= +3.3V, TA= +25°C, unless otherwise noted. PRBS7 + 100CID pattern is PRBS 27, 100 zeros, 1010, PRBS 27, 100 ones, 0101.)
MAX3982
SFP Copper-Cable Preemphasis Driver
_______________________________________________________________________________________ 9
30in FR4 OUTPUT
WITHOUT MAX3982
4.25Gbps PRBS7 + 100CID
MAX3982 toc23
30in FR4 OUTPUT
WITH MAX3982 PREEMPHASIS,
4.25Gbps PRBS7 + 100CID
MAX3982 toc24
PREEMPHASIS, PE[1,0] = 10,
OUTLEV = HIGH
100mV/div
TRANSMITTER ENABLE
MAX3982 toc25
200ns/div
TX_DISABLE
V
CC
OUT+
3.3V
LOW
HIGH
30in FR4 OUTPUT
WITHOUT MAX3982,
4.25Gbps PRBS31
MAX3982 toc26
30in FR4 OUTPUT
WITH MAX3982 PREEMPHASIS,
4.25Gbps PRBS31
MAX3982 toc27
PREEMPHASIS, PE[1,0] = 10, OUTLEV = HIGH
100mV/div
TRANSMITTER DISABLE
MAX3982 toc28
200ns/div
TX_DISABLE
V
CC
OUT+
3.3V
LOW
HIGH
Typical Operating Characteristics (continued)
(VCC= +3.3V, TA= +25°C, unless otherwise noted. PRBS7 + 100CID pattern is PRBS 27, 100 zeros, 1010, PRBS 27, 100 ones, 0101.)
MAX3982
SFP Copper-Cable Preemphasis Driver
10 ______________________________________________________________________________________
PIN NAME FUNCTION
1V
CC1
Power-Supply Connection for Input. Connect to +3.3V.
2 IN+ Positive Data Input, CML. This input is internally terminated with 50Ω to V
CC1
.
3 IN- Negative Data Input, CML. This input is internally terminated with 50Ω to V
CC1
.
4, 8, 9 GND Circuit Ground
5 OUTLEV
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.
6 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.
7 PE0
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.
10 OUT- Negative Data Output, CML. This output is terminated with 50Ω to V
CC2
.
11 OUT+ Positive Data Output, CML. This output is terminated with 50Ω to V
CC2
.
12, 13 V
CC2
Power-Supply Connection for Output. Connect to +3.3V.
14
Transmitter Disable Input, LVTTL with 10kΩ Internal Pullup. When high or open, differential output is
40mV
P-P
. Set low for normal operation.
15 LOS
Loss-of-Signal Detect, TTL Output. This output is open-collector TTL, and therefore requires an external
4.7kΩ to 10kΩ pullup resistor (5.5V maximum). This output sinks current when the input signal level is
valid.
16 LOSLEV
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).
EP
EXPOSED
PAD
Exposed Pad. For optimal thermal conductivity, this pad must be soldered to the circuit board ground.
Pin Description
V
CC1
1
IN+
2
IN-
3
GND
4
V
CC2
12
OUT+
11
OUT-
10
GND
9
OUTLEV
5
PE16PE0
7
GND
8
LOSLEV16LOS15TX_DISABLE14V
CC2
13
MAX3982UTE
EXPOSED PAD*
*THE EXPOSED PAD OF THE QFN PACKAGE MUST BE SOLDERED TO GROUND
FOR PROPER THERMAL OPERATION OF THE MAX3982.
TOP VIEW
THIN QFN
Pin Configuration
TX_DISABLE
Detailed Description
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.
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 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
is 1200mV
P-P
. When OUTLEV is high, the amplitude is
1600mV
P-P
. Residual jitter of the MAX3982 is indepen-
dent of up to 0.20UI
P-P
source jitter.
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.
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
P-P
. When LOSLEV is
LVTTL low, the LOS assert threshold is 85mV
P-P
.
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).
MAX3982
SFP Copper-Cable Preemphasis Driver
______________________________________________________________________________________ 11
Figure 4. Functional Diagram
MAX3982
OUT+
OUT-
2
V
CC2
LVTTL
CML
FIXED
EQUALIZER
IN-
IN+
TX_DISABLE
V
CC1
PE0
PE1
10kΩ
LIMITER
OUTLEV
LOSLEV
LVTTL
PREEMPHASIS
LOS
SIGNAL DETECT
GND
CML
2
V
CC2
V
CC2
40kΩ
V
CC1
V
CC1
LVTTL
10kΩ
V
CC2
V
CC2
LVTTL
40kΩ
V
CC2
V
CC2
MAX3982
Applications Information
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_DISABLE. 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 recommended as noise amplification may occur and create
undesirable output signals. Autodetect is recommended to eliminate noise amplification or possible oscillation. For periods much greater than 100ns without data
transitions, autodetect disables the output.
Layout Considerations
Circuit board layout and design can significantly affect
the performance of the MAX3982. Use good high-frequency design techniques, including minimizing ground
inductance and using controlled-impedance transmission lines on the data signals. Power-supply decoupling
should also be placed as close to the VCCpins as possible. This should be sufficient supply filtering. Always connect all VCCpins to a power plane. Take care to isolate
the input from the output signals to reduce feedthrough.
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.
SFP Copper-Cable Preemphasis Driver
12 ______________________________________________________________________________________
Ratio α 10Gbase–CX4 IN dB
1.26 0.11 0.21 2
1.58 0.23 0.37 4
2.51 0.43 0.6 8
5.01 0.67 0.8 14
Figure 5. IN+/IN- Equivalent Input Structure
GND
V
CC2
50Ω50Ω
OUT+
OUT-
Figure 6. OUT+/OUT- Equivalent Output Structure
Interface Schematics
Table 1. Preemphasis Translation
V
HIGH PP
V
LOW PP__
VV
HIGH PP LOW PP
VV
HIGH PP LOW PP
−
__
+
__
1
−
V
LOW PP
V
HIGH PP
⎡
⎛
_
_
20 log
V
HIGH PP
⎢
⎜
⎜
⎢
V
⎝
LOW PP
⎣
⎤
⎞
_
⎥
⎟
⎟
⎥
⎠
_
⎦
V
LOW_PP
V
HIGH_PP
V
CC1
50Ω50Ω
IN+
IN-
GND
MAX3982
SFP Copper-Cable Preemphasis Driver
______________________________________________________________________________________ 13
Chip Information
TRANSISTOR COUNT: 2957
PROCESS: SiGe Bipolar
GND
LVTTL IN
V
CCX
R
PULLUP
PIN NAME
LOSLEV
V
CCX
V
CC1
OUTLEV
TX_DISABLE, PE0, PE1
V
CC2
R
PULLUP
(kΩ)
V
CC2
40
40
10
Figure 7. LVTTL Equivalent Input Structure
LOS
GND
Figure 8. Loss-of-Signal Equivalent Output Structure
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
.)
MAX3982
SFP Copper-Cable Preemphasis Driver
14 ______________________________________________________________________________________
12x16L QFN THIN.EPS
0.10 C 0.08 C
0.10 M C A B
D
D/2
E/2
E
A1
A2
A
E2
E2/2
L
k
e
(ND - 1) X e
(NE - 1) X e
D2
D2/2
b
L
e
L
C
L
e
C
L
L
C
L
C
PACKAGE OUTLINE
21-0136
2
1
I
8, 12, 16L THIN QFN, 3x3x0.8mm
MARKING
AAAA
MAX3982
SFP Copper-Cable Preemphasis Driver
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
© 2006 Maxim Integrated Products is a registered trademark of Maxim Integrated Products, Inc.
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
CODES
PKG.
T1233-1
MIN.
0.95
NOM.
1.10
D2
NOM.
1.10
MAX.
1.25
MIN.
0.95
MAX.
1.25
E2
12N
k
A2
0.25
NE
A1
ND
0
0.20 REF
-
-
3
0.0230.05
L
e
E
0.45
2.90
b
D
A
0.20
2.90
0.70
0.50 BSC.
0.55
3.00
0.65
3.10
0.25
3.00
0.75
0.30
3.10
0.80
16
0.20 REF
0.25
-
040.02
4
-
0.05
0.50 BSC.
0.30
2.90
0.40
3.00
0.20
2.90
0.70
0.25
3.00
0.75
3.10
0.50
0.80
3.10
0.30
PKG
REF. MIN.
12L 3x3
NOM. MAX. NOM.
16L 3x3
MIN. MAX.
0.35 x 45°
PIN ID
JEDEC
WEED-1
T1233-3
1.10
1.25
0.95 1.10 0.35 x 45°1.25 WEED-10.95
T1633F-3
0.65
T1633-4 0.95
0.80
0.95
0.65
0.80
1.10 1.25 0.95 1.10
0.225 x 45°
0.95
WEED-2
0.35 x 45°
1.25
WEED-2
T1633-2 0.95
1.10
1.25
0.95
1.10
0.35 x 45°
1.25
WEED-2
PACKAGE OUTLINE
21-0136
2
2
I
8, 12, 16L THIN QFN, 3x3x0.8mm
WEED-11.25
1.100.95
0.35 x 45°
1.251.10
0.95
T1233-4
T1633FH-3 0.65 0.80 0.95
0.225 x 45°
0.65 0.80
0.95
WEED-2
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 T ERMINALS.
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.
10. MARKING IS FOR PACKAGE ORIENTATION REFERENCE ONLY.
11. NUMBER OF LEADS SHOWN ARE FOR REFERENCE ONLY.
12. WARPAGE NOT TO EXCEED 0.10mm.
0.25 0.30 0.35
2
0.25
0
0.20 REF
-
-
0.02
0.05
0.35
8
2
0.55 0.75
2.90
2.90 3.00 3.10
0.65 BSC.
3.00 3.10
8L 3x3
MIN.
0.70 0.75 0.80
NOM. MAX.
TQ833-1 1.250.25 0.70 0.35 x 45° WEEC1.250.700.25
T1633-5 0.95
1.10
1.25
0.35 x 45° WEED-2
0.95
1.10 1.25
Revision History
Rev 2; 2/06: Added lead-free package to Ordering Information table (page 1); updated package outline
(pages 14, 15).
Loading...