Maxim MAX3802 3.2gbps quad adaptive cable equalizer with cable driver Datasheet

19-2289; Rev 0; 1/02
KIT
ATION
EVALU
E
L
B
A
AVAIL
3.2Gbps Quad Adaptive Cable Equalizer
with Cable Driver
Features
♦ Single 3.3V Operation
♦ Four Independent Equalizers and Drivers
♦ 725mW at 3.3V Typical Power Dissipation
♦ Data Rates Up to 3.2Gbps
♦ Equalizer Automatically Adjusts for Different
Cable Lengths
♦ 0 to 30dB Equalization at 1.6GHz (3.2Gbps)
♦ Loss-of-Signal (LOS) Indicator
♦ On-Chip Input and Output Terminations
♦ Low External Component Count
♦ 0°C to +85°C Operating Temperature Range
Applications
♦ ESD Protection on Cable Inputs and Outputs
High-Speed Links in Communications and Data
Systems
Ordering Information
Backplane and Twin-Axial Cable Interconnects
Category 5 UTP-Based Systems
PART
TEMP RANGE
MAX3802UGK
Digital Video Systems
PIN-PACKAGE
0°C to +85°C
68 QFN*
*Exposed pad
Pin Configuration appears at end of data sheet.
Typical Application Circuit
3.3V
EP*
3.3V
VCC
EP*
DIN_
4
CARD 1
DOUT_
4
COAX, TWIN-AX, OR PC BOARD x 4
4
4
CARD 2
MAX3802
EIN_
EOUT_
EOUT_
EIN_
MAX3802
4
VCC
4
COAX, TWIN-AX, OR PC BOARD x 4
4
DIN_
DOUT_
LOS_
RMOD_
CIM_
LOS_
RMOD_
4
4
4
4
4
RMOD_
4
CIM_
4
RMOD_
THIS SYMBOL INDICATES A CONTROLLED-IMPEDANCE TRANSMISSION LINE.
*EP MUST BE SOLDERED TO GROUND FOR
PROPER THERMAL AND ELECTRICAL PERFORMANCE.
________________________________________________________________ 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
MAX3802
General Description
The MAX3802 has four independent adaptive cable
equalizers and cable drivers on a single chip. It is
designed for coaxial and twin-axial cable point-to-point
scrambled-data communication applications. The driver features differential current-mode logic (CML)
inputs and outputs. The equalizer includes differential
CML data inputs and outputs and a TTL loss-of-signal
(LOS) output.
The adaptive cable equalizer can equalize differential
or single-ended signals at data rates up to 3.2Gbps. It
automatically adjusts to attenuation caused by skineffect losses of 30dB at 1.6GHz. The equalizer effectively extends the usable length of copper cable in
high-frequency interconnect applications.
MAX3802
3.2Gbps Quad Adaptive Cable Equalizer
with Cable Driver
ABSOLUTE MAXIMUM RATINGS
Supply Voltage, VCC..............................................-0.5V to +6.0V
Voltage at LOS_, CIM_, and RMOD_ .........-0.5V to (VCC + 0.5V)
Voltage at EIN_+, EIN_-,
DIN_+, and DIN_- ..........................(VCC - 1V) to (VCC + 0.5V)
Current Out of EOUT_+, EOUT_-,
DOUT_+, and DOUT_- ...................................................25mA
Continuous Power Dissipation (TA = +85°C)
68-Pin QFN (derate 44.8mW/°C above +85°C) .............1.44W
Operating Ambient Temperature Range ................0°C to +85°C
Storage Ambient 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 = 3.14V to 3.46V, TA = 0°C to +85°C. Typical values are at VCC = 3.3V and TA = +25°C, unless otherwise noted.)
PARAMETER
Supply Current
SYMBOL
ICC
CONDITIONS
MIN
Includes external load current (Note 1)
TYP
MAX
UNITS
220
345
mA
CABLE DRIVER INPUT SPECIFICATIONS
Input Voltage (Single Ended)
Input Voltage (Differential)
VDIN_+,
VDIN_-
VCC 0.6
VCC +
0.2
V
VDIN_
400
1100
mVP-P
Ω
Input Impedance
Single ended
40
50
60
RMOD_ = 10kΩ (Note 2)
750
825
1000
RMOD_ = 20kΩ (Note 2)
400
445
550
Single ended
50
62.5
75
Ω
400
mVP-P
CABLE DRIVER OUTPUT SPECIFICATIONS
Output Voltage (Differential)
Output Impedance
mVP-P
CABLE EQUALIZER INPUT SPECIFICATIONS
Minimum Cable Input
(Differential)
3.2Gbps, 30dB cable loss (Note 3)
Maximum Cable Input
(Differential)
600
Input Impedance
40
50
mVP-P
60
Ω
1000
mVP-P
75
Ω
CABLE EQUALIZER OUTPUT SPECIFICATIONS
Output Voltage (Differential)
(Note 2)
500
Output Impedance
Single ended
50
Output high (Note 4)
2.4
Voltage at LOS_
2
62.5
Output low (Note 4)
_______________________________________________________________________________________
0.4
V
3.2Gbps Quad Adaptive Cable Equalizer
with Cable Driver
(VCC = 3.14V to 3.46V, TA = 0°C to +85°C. Typical values are at VCC = 3.3V and TA = +25°C, unless otherwise noted.)
PARAMETER
SYMBOL
CONDITIONS
Maximum Input Data Rate
MIN
TYP
MAX
3.2
UNITS
Gbps
CABLE DRIVER SPECIFICATIONS
Random Jitter
3.2Gbps input
2.7
4
mUIRMS
Deterministic Jitter
(Notes 6, 9)
20
60
mUIP-P
Output Edge Speed
20% to 80%
60
90
ps
Input Return Loss
(Differential)
≤ 2.5GHz
-20
dB
Output Return Loss
(Differential)
≤ 2.5GHz
-13
dB
EQUALIZER SPECIFICATIONS
Residual Jitter (Notes 7, 9)
0dB cable loss (Note 8)
0.10
0.24
24dB cable loss (Note 8)
0.11
0.20
30dB cable loss (Note 8)
0.08
0.20
90
UIP-P
Output Edge Speed
20% to 80%
60
Input Return Loss
(Differential)
≤ 2.5GHz
-16
dB
Output Return Loss
(Differential)
≤ 2.5GHz
-14
dB
Equalizer Compensation
1.6GHz (skin-effect losses only)
Equalizer Time Constant
(Note 10)
30
ps
dB
6
µs
Equalizer total currents (equalizer with maximum equalization) and RMOD = 10kΩ (maximum driver swing).
Input voltage within specification limits, 50Ω to VCC at each output.
Minimum cable input for LOS_ to deassert high.
100kΩ load to ground. The minimum input signal level that turns off the LOS_ alarm depends on the data rate and cable length.
AC electrical characteristics are guaranteed by design and characterization.
VDIN_ = 400mVP-P to 1100mVP-P (differential), 10kΩ ≤ RMOD_ ≤ 20kΩ, 3.2Gbps 213 -1 PRBS plus 100 consecutive ones and
100 consecutive zeros.
Note 7: Includes random jitter and deterministic jitter for BER of 10-12.
Note 8: Differential cable input voltage = 400mVP-P, 3.2Gbps 213 -1 PRBS plus 100 consecutive ones and 100 consecutive zeros.
Note 9: Isolation test: three channels driven with identical 3.2Gbps PRBS with maximum input signal to each equalizer and maximum input signal on driver. The measured channel meets the residual and random jitter specifications with an uncorrelated
3.2Gbps PRBS data at minimum input signal level on equalizer and maximum signal level on driver.
Note 10: Equalizer time constant measured from data on to closed-loop operation.
Note 1:
Note 2:
Note 3:
Note 4:
Note 5:
Note 6:
_______________________________________________________________________________________
3
MAX3802
AC ELECTRICAL CHARACTERISTICS
Typical Operating Characteristics
(VCC = 3.3V, TA = +25°C, all jitter measurements done at 3.2Gbps, 600mV cable input with 213 - 1 PRBS pattern with 100 consecutive ones and
100 consecutive zeros substituted. Note: Test pattern produces near-worst-case jitter results. Results vary with pattern, unless otherwise noted.)
210
180
1100
40
30
20
1000
900
800
30
50
70
-10
-20
600
-30
500
-40
-50
4
90
7
10
13
16
19
0
22
DRIVER OUTPUT RETURN LOSS (S22)
30
40
30
30
10
GAIN (dB)
10
GAIN (dB)
20
10
0
-10
0
-10
-20
-20
-20
-30
-30
-30
-40
-40
-40
-50
-50
0.8
1.6
2.4
3.2
4.0
4.0
40
20
-10
3.2
50
20
0
2.4
EQUALIZER OUTPUT RETURN LOSS (S22)
EQUALIZER INPUT RETURN LOSS (S11)
MAX3802 toc05
40
1.6
FREQUENCY (GHz)
50
MAX3802 toc04
50
0
0.8
RMOD (kΩ)
TEMPERATURE (°C)
-50
0
0.8
1.6
2.4
3.2
0
4.0
0.8
1.6
2.4
3.2
4.0
FREQUENCY (GHz)
FREQUENCY (GHz)
FREQUENCY (GHz)
EQUALIZER RESIDUAL JITTER vs. POWER-SUPPLY
NOISE (100mVP-P SINE WAVE) (40ft OF TENSOLITE
TWIN-AX, 400mVP-P DIFFERENTIAL INPUT)
EQUALIZER RESIDUAL JITTER vs. CABLE
INPUT AMPLITUDE (RG179B 75Ω COAXIAL
CABLE, SINGLE ENDED)
EQUALIZER RESIDUAL JITTER vs. CABLE
INPUT AMPLITUDE (TENSOLITE
TWIN-AX–DIFFERENTIAL)
115
95
105
85
65
JITTER (psP-P)
JITTER (psP-P)
25ft
75
95
72ft
85
75
55
1
NOISE FREQUENCY (MHz)
10
100
10ft
40ft
35
45
0.1
65
45
55
0.01
70ft
75
55
65
45
0.001
MAX3802 toc09
85
105
MAX3802 toc08
125
MAX3802 toc07
95
4
0
MAX3802 toc06
10
10
700
400
-10
MAX3802 toc03
MAX3802 toc02
1200
150
GAIN (dB)
50
GAIN (dB)
240
1300
DRIVER OUTPUT VOLTAGE (mV)
270
SUPPLY CURRENT (mA)
MAX3802 toc01
RMOD = 15kΩ
ALL CHANNELS AT
MAX EQUALIZATION
DRIVER INPUT RETURN LOSS (S11)
CABLE DRIVER OUTPUT vs. RMOD
SUPPLY CURRENT vs. TEMPERATURE
300
JITTER (psP-P)
MAX3802
3.2Gbps Quad Adaptive Cable Equalizer
with Cable Driver
150
300
450
600
750
900
CABLE INPUT AMPLITUDE (mVP-P)
300
450
600
750
900
1050
1200
CABLE DIFFERENTIAL INPUT AMPLITUDE (mVP-P)
_______________________________________________________________________________________
3.2Gbps Quad Adaptive Cable Equalizer
with Cable Driver
45
70
3.2Gbps
60
35
25
50
50
60
70
40
25
35
45
55
40
65
50
60
70
80
90
CABLE LENGTH (ft)
CABLE LENGTH (ft)
LINE LENGTH (in)
CIM VOLTAGE vs. CABLE LENGTH (TENSOLITE
TWIN-AX, 400mVP-P DIFFERENTIAL)
EQUALIZER INPUT AFTER 115ft OF
CABLE (TOP) EQUALIZER OUTPUT (BOTTOM)
EQUALIZER OUTPUT EYE DIAGRAM AFTER
155ft OF 50Ω GORE-89 CABLE (400mVP-P)
MAX3802 toc15
0.25
MAX3802 toc14
MAX3802 toc13
0.30
0.20
0.15
0.10
0.05
0
10
20
30
40
50
60
70
48ps/div (3.2Gbps)
CABLE LENGTH (ft)
EQUALIZER OUTPUT EYE DIAGRAM AFTER 70ft
OF TENSOLITE TWIN-AX CABLE (27 - 1 PRBS)
60ps/div (2.5Gbps)
MAX3802 toc17
EQUALIZER OUTPUT EYE DIAGRAM AFTER 72ft
OF 75Ω RG179 CABLE
(300mVP-P SINGLE ENDED, 223 - 1 PRBS)
60ps/div (2.5Gbps)
MAX3802 toc18
CABLE OUTPUT EYE DIAGRAM AFTER 70ft
OF TENSOLITE TWIN-AX CABLE (27 - 1 PRBS
NO EQUALIZATION)
MAX3802 toc16
CIM VOLTAGE (VCC - VCIM) (V)
622Mbps
40
40
2.5Gbps
622Mbps
622Mbps
30
3.2Gbps
70
2.5Gbps
50
20
80
60
2.5Gbps
10
90
JITTER (psP-P)
3.2Gbps
55
80
JITTER (psP-P)
65
100
MAX3802 toc11
75
JITTER (psP-P)
90
MAX3802 toc10
85
EQUALIZER RESIDUAL JITTER vs. LINE
LENGTH (FR-4 6mil STRIPLINE, 300mVP-P
SINGLE ENDED)
EQUALIZER RESIDUAL JITTER vs. CABLE
LENGTH (RG179B 75Ω COAXIAL, 300mVP-P
SINGLE ENDED)
MAX3802 toc12
EQUALIZER RESIDUAL JITTER vs. CABLE
LENGTH (TENSOLITE TWIN-AX, 400mVP-P
DIFFERENTIAL INPUT)
48ps/div (3.2Gbps)
_______________________________________________________________________________________
5
MAX3802
Typical Operating Characteristics (continued)
(VCC = 3.3V, TA = +25°C, all jitter measurements done at 3.2Gbps, 600mV cable input with 213 - 1 PRBS pattern with 100 consecutive ones and
100 consecutive zeros substituted. Note: Test pattern produces near-worst-case jitter results. Results vary with pattern, unless otherwise noted.)
Typical Operating Characteristics (continued)
(VCC = 3.3V, TA = +25°C, all jitter measurements done at 3.2Gbps, 600mV cable input with 213 - 1 PRBS pattern with 100 consecutive ones and
100 consecutive zeros substituted. Note: Test pattern produces near-worst-case jitter results. Results vary with pattern, unless otherwise noted.)
EQUALIZER OUTPUT EYE DIAGRAM AFTER 288ft
OF RG59 CABLE (300mVP-P SINGLE ENDED,
223 - 1 PRBS)
60ps/div (2.5Gbps)
EQUALIZER OUTPUT EYE DIAGRAM AFTER 50ft
OF MADISON 14887 SHIELDED TWISTED-PAIR
CABLE (27 - 1 PRBS)
60ps/div (2.5Gbps)
MAX3802 toc21
MAX3802 toc20
EQUALIZER OUTPUT EYE DIAGRAM AFTER 60in OF
FR-4 6mil STRIPLINE (DIFFERENTIAL, 27 - 1 PRBS)
MAX3802 toc19
MAX3802
3.2Gbps Quad Adaptive Cable Equalizer
with Cable Driver
60ps/div (2.5Gbps)
Pin Description
6
PIN
NAME
1, 4, 6, 9
VCCE1
3.3V Supply Voltage for Equalizer 1
FUNCTION
2
EIN1-
Negative Equalizer 1 Input, CML
3
EIN1+
Positive Equalizer 1 Input, CML
5
CIM1
Cable Integrity Monitor 1 Output
7
EOUT1-
8
EOUT1+
Negative Equalizer 1 Output, CML
Positive Equalizer 1 Output, CML
10
RMOD1
Driver 1 Output Modulation Adjust
11, 14
VCCD1
3.3V Supply Voltage for Driver 1
12
DOUT1-
Negative Driver 1 Output, CML
13
DOUT1+
Positive Driver 1 Output, CML
15
DIN1-
Negative Driver 1 Input, CML
16
DIN1+
Positive Driver 1 Input, CML
17
LOS1
Equalizer 1 Loss-of-Signal, TTL, Active Low
18, 21, 23, 26
VCCE2
3.3V Supply Voltage for Equalizer 2
19
EIN2-
Negative Equalizer 2 Input, CML
20
EIN2+
Positive Equalizer 2 Input, CML
22
CIM2
Cable Integrity Monitor 2 Output
24
EOUT2-
Negative Equalizer 2 Output, CML
25
EOUT2+
Positive Equalizer 2 Output, CML
27
RMOD2
Driver 2 Output Modulation Adjust
28, 31
VCCD2
3.3V Supply Voltage for Driver 2
29
DOUT2-
Negative Driver 2 Output, CML
30
DOUT2+
Positive Driver 2 Output, CML
_______________________________________________________________________________________
3.2Gbps Quad Adaptive Cable Equalizer
with Cable Driver
PIN
NAME
FUNCTION
32
DIN2-
33
DIN2+
Negative Driver 2 Input, CML
Positive Driver 2 Input, CML
34
LOS2
Equalizer 2 Loss-of-Signal, TTL, Active Low
35, 38, 40, 43
VCCE3
3.3V Supply Voltage for Equalizer 3
36
EIN3-
Negative Equalizer 3 Input, CML
37
EIN3+
Positive Equalizer 3 Input, CML
39
CIM3
Cable Integrity Monitor 3 Output
41
EOUT3-
Negative Equalizer 3 Output, CML
42
EOUT3+
Positive Equalizer 3 Output, CML
44
RMOD3
Driver 3 Output Modulation Adjust
45, 48
VCCD3
3.3V Supply Voltage for Driver 3
46
DOUT3-
Negative Driver 3 Output, CML
47
DOUT3+
Positive Driver 3 Output, CML
49
DIN3-
Negative Driver 3 Input, CML
50
DIN3+
Positive Driver 3 Input, CML
51
LOS3
Equalizer 3 Loss-of-Signal, TTL, Active Low
52, 55, 57, 60
VCCE4
3.3V Supply Voltage for Equalizer 4
53
EIN4-
Negative Equalizer 4 Input, CML
54
EIN4+
Positive Equalizer 4 Input, CML
56
CIM4
Cable Integrity Monitor 4 Output
58
EOUT4-
Negative Equalizer 4 Output, CML
59
EOUT4+
Positive Equalizer 4 Output, CML
61
RMOD4
Driver 4 Output Modulation Adjust
62, 65
VCCD4
3.3V Supply Voltage for Driver 4
63
DOUT4-
Negative Driver 4 Output, CML
64
DOUT4+
Positive Driver 4 Output, CML
66
DIN4-
Negative Driver 4 Input, CML
67
DIN4+
Positive Driver 4 Input, CML
68
LOS4
Equalizer 4 Loss-of-Signal, TTL, Active Low
EP
Exposed
Pad
Ground. Must be soldered to the circuit board ground for proper thermal and electrical
performance (see EP Package).
_______________________________________________________________________________________
7
MAX3802
Pin Description (continued)
to 3.2Gbps. It automatically adjusts to attenuation levels of 30dB at 1.6GHz (due to skin-effect losses in copper cable). The equalizer consists of a CML input
buffer, a flat-response amplifier, a skin-effect compensation amplifier, a current-steering network, a dual
power-detector feedback loop, an output limiting amplifier, and a CML output buffer (Figure 1).
Detailed Description
The MAX3802 has four independent adaptive equalizers (receivers) and four independent drivers. Disconnecting the power pins of unused equalizers and
drivers lowers the power consumption of the MAX3802.
Equalizer and driver descriptions apply to the four identical sections.
General Theory of Operation
The shape of the power spectrum of a random bit
stream can be described by the square of the wellknown sinc function, where sinc(f) = sin(πf)/(πf) for f ≠ 0.
For sufficiently long bit patterns (nonrandom bit
stream), sinc2(f) is a good approximation. From the
shape of the sinc2(f) function, the ratio of the power
densities at any two frequencies can be estimated. The
MAX3802 adaptive equalizer employs this principle by
incorporating a feedback loop that continuously monitors the power at high- and low-frequency bands and
Cable Driver
The cable driver accepts differential or single-ended
CML input data at rates up to 3.2Gbps. The maximum
CML output of the driver can be adjusted over a typical
range of 445mV to 825mV by changing the value of the
RMOD_ resistor between 10kΩ and 20kΩ (resistor connected between RMOD_ pin and ground).
Adaptive Cable Equalizer
The adaptive cable equalizer is capable of equalizing
differential or single-ended CML input data at rates up
LOOP
FILTER
|H(f)|
FLAT
RESPONSE
AMP
EIN_
POWER
DETECTOR
LOS_
DOUT_
VARIABLE
ATTENUATOR
Σ
CML
2
SKINEFFECT
COMP
AMP
|H(f)|
600MHz
PWR DETECTOR
MAX3802
200MHz
PWR DETECTOR
MAX3802
3.2Gbps Quad Adaptive Cable Equalizer
with Cable Driver
LIMITING
AMP
CML
EOUT_
VARIABLE
ATTENUATOR
CURRENT-STEERING NETWORK
√f
2
CML
CABLE
DRIVER
CML
RMOD_
RMOD_
Figure 1. MAX3802 Functional Diagram
8
2
_______________________________________________________________________________________
2
DIN_
3.2Gbps Quad Adaptive Cable Equalizer
with Cable Driver
CML Input and Output Buffers
The input and output buffers are implemented using
CML. Equivalent circuits are shown in Figures 2 and 3.
For details on interfacing with CML, refer to Maxim
Application Note HFAN-01.0, Interfacing Between CML,
PECL, and LVDS.
VCC
MAX3802
50Ω
50Ω
_IN_+
_IN_-
ESD
STRUCTURES
Figure 2. CML Input Structure
VCC
MAX3802
62.5Ω
ESD
STRUCTURES
62.5Ω
_OUT_+
_OUT_-
Flat-Response and Skin-Effect
Compensation Amplifiers
The buffered input waveform is fed equally to two
amplifiers—the flat-response amplifier and the skineffect compensation amplifier. The flat-response amplifier has a constant gain over the entire frequency range
of the device, and the skin-effect compensation amplifier has a gain characteristic that approximates the
inverse of the skin-effect attenuation in copper cable.
The skin-effect attenuation, in dB per unit length, is proportional to the square root of the frequency. The output currents from the amplifiers are supplied to the
current-steering network.
Current-Steering Network
The function of the current-steering network is to combine adjustable quantities of the output currents from
the flat-response and skin-effect compensation amplifiers in order to achieve a desired current ratio. The
ratio adjustment is controlled by the dual power-detector feedback loop.
The current-steering network is implemented with a pair
of variable attenuators that feed into a current-summing
node. The variable attenuators are used to attenuate
the output currents of the flat-response and skin-effect
compensation amplifiers under control of the dual
power-detector feedback loop. The outputs of the two
attenuators are combined at the summing node and
then fed to the output-limiting amplifier and the feedback loop.
Dual Power-Detector Feedback Loop
The outputs of the current-steering network are applied
to the inputs of 200MHz and 600MHz power detectors.
The outputs of the power detectors are applied to the
loop-filter amplifier. This amplifier controls the variable
attenuators in the current-steering network.
Output Limiting Amplifier
The output limiting amplifier amplifies the signal from
the current-steering network to achieve the specified
output voltage swing.
Applications Information
Refer to Maxim Application Note HFDN-10.0,
Equalizing Gigabit Copper Cable Links with the
MAX3800 (available at www.maxim-ic.com) for additional application information.
Figure 3. CML Output Structure
Selecting RMOD
The cable driver output amplitude can be adjusted by
connecting a resistor (RMOD) with a value from 10kΩ to
20kΩ between the RMOD_ pin and ground. The exact
output amplitude of the driver is dependent on several
_______________________________________________________________________________________
9
MAX3802
dynamically adjusts the equalizer to maintain the correct power ratio.
Data Spectrum for Equalizer
Layout Considerations
The MAX3802’s performance can be significantly
affected by circuit board layout and design. Use good
high-frequency design techniques, including minimizing ground inductance and using controlled-impedance transmission lines for the high-frequency data
signals. Power-supply decoupling capacitors should be
placed as close as possible to VCC.
10
63 62 61 60 59 58
EIN4-
VCCE4
EIN4+
VCCE4
CIM4
VCCE4
EOUT4-
VCCE4
EOUT4+
RMOD4
VCCD4
DOUT4-
DOUT4+
DIN4-
67 66 65 64
57 56 55 54 53 52
VCCE1
1
51 LOS3
EIN1-
2
50 DIN3+
EIN1+
3
49 DIN3-
VCCE1
4
48 VCCD3
CIM1
5
47 DOUT3+
VCCE1
6
46 DOUT3-
EOUT1-
7
45 VCCD3
EOUT1+
8
VCCE1
9
44 RMOD3
MAX3802
43 VCCE3
RMOD1 10
42 EOUT3+
VCCD1 11
41 EOUT3-
DOUT1- 12
40 VCCE3
DOUT1+ 13
39 CIM3
VCCD1 14
38 VCCE3
DIN1- 15
37 EIN3+
DIN1+ 16
36 EIN3-
LOS1 17
35 VCCE3
QFN*
*THE EXPOSED PAD OF THE QFN PACKAGE MUST BE SOLDERED TO GROUND
FOR PROPER THERMAL AND ELECTRICAL OPERATION OF THE MAX3802.
______________________________________________________________________________________
LOS2
DIN2+
DIN2-
VCCD2
DOUT2+
VCCD2
DOUT2-
RMOD2
VCCE2
EOUT2+
EOUT2-
VCCE2
18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34
CIM2
Single-Ended Operation
For single-ended operation of the cable driver or equalizer, connect the unused input to ground through a
series combination of a capacitor (of equal value to
other AC-coupling capacitors) and a 50Ω resistor. Note
that the MAX3802 is specified for differential operation.
68
VCCE2
The MAX3802 equalizer design requires the data
stream be scrambled or coded to provide a rich frequency spectrum for the adaptation algorithm.
Scrambled patterns or coded patterns with scrambled
content, such as 64b/66b or SONET PRBS, are ideal.
Some coded patterns, such as 8b/10b, lack low-frequency energy and can be nonoptimal, requiring the
user to characterize the specific application. In the
absence of an input signal (nonstandard application),
amplified noise may appear at the output due to the
large gain of the device.
DIN4+
TOP VIEW
VCCD4
Pin Configuration
EIN2+
Loss-of-Signal (LOS_) Output
Loss of signal is indicated by the LOS_ output. A low
level on LOS_ indicates that the equalizer input power
has dropped below a threshold. When there is sufficient input voltage to the channel (typically greater than
250mV), LOS_ is high. The LOS_ output is suitable for
indicating problems with the transmission link caused
by, for example, a broken cable or a defective driver.
Chip Information
TRANSISTOR COUNT: 5408
PROCESS: Bipolar (silicon germanium)
LOS4
Cable Integrity Monitor
The CIM_ output voltage is directly proportional to the
output current of the loop amplifier (which controls the
current-steering network; see Detailed Description).
This is an analog voltage output that indicates the
amount of equalization being applied.
The amount of equalization (and thus the CIM_ output
level) is affected by cable type, cable length, signal
bandwidth, etc. See the Typical Operating Characteristics CIM Voltage vs. Cable Length for typical values under specific conditions.
Exposed-Pad Package
The EP on the 68-pin QFN provides a very low thermal
resistance path for heat removal from the IC. The pad is
the electrical ground on the MAX3802 and must be soldered to the circuit board ground for proper thermal and
electrical performance. Refer to Maxim Application Note
HFAN-08.1, Thermal Considerations for QFN and Other
Exposed-Pad Packages (available at www.maximic.com) for additional application information.
EIN2-
factors. See the Typical Operating Characteristics Cable
Driver Output Voltage vs. RMOD for typical values.
VCCE2
MAX3802
3.2Gbps Quad Adaptive Cable Equalizer
with Cable Driver
3.2Gbps Quad Adaptive Cable Equalizer
with Cable Driver
68L QFN, 10x10x09,EPS
______________________________________________________________________________________
11
MAX3802
Package Information
3.2Gbps Quad Adaptive Cable Equalizer
with Cable Driver
MAX3802
Package Information (continued)
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.
12 ____________________Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600
© 2002 Maxim Integrated Products
Printed USA
is a registered trademark of Maxim Integrated Products.
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