Maxim MAX3784UGE 5gbps pcb equalizer Datasheet

19-2565; Rev 4; 10/07
5Gbps PCB Equalizer
Features
The MAX3784/MAX3784A 5Gbps equalizers provide
compensation for transmission-medium losses in up to
40in of FR-4. They are optimized for short-run length
and balanced codes such as 8b10b, as found in multiplexed 1.25Gbps Ethernet systems and 4.25Gbps
Fibre Channel.
The equalizers use differential CML data inputs and
outputs. A standby mode reduces power consumption
when the parts are not in use. The MAX3784/
MAX3784A are available in a 4mm × 4mm, 16-pin QFN
package that consumes only 185mW at +3.3V.
♦ Spans 40in (1m) of FR-4 PCB
♦ 0.18UI Deterministic Jitter Up to 40in
♦ Low Power Consumption: 185mW (MAX3784)
♦ Equalization Reduces Intersymbol Interference
♦ Single +3.3V Supply
♦ Standby Mode
♦ Small 4mm × 4mm, 16-Pin QFN Package
OUT+
OUT-
GND
TOP VIEW
VCC
Pin Configurations
12
11
10
9
Chassis Life Extension
4.25Gbps Fibre Channel
4x Multiplexed 1.25Gbps Ethernet (5Gbps)
EN 13
8
N.C.
N.C. 14
7
VCC
6
GND
5
N.C.
MAX3784/
MAX3784A
N.C. 15
TEMP
RANGE
PART
G1644-1
1
2
3
4
MAX3784UTE+
0°C to +85°C 16 TQFN-EP*
T1644-3
GND
0°C to +85°C 16 QFN-EP*
PKG
CODE
IN-
MAX3784UGE
PINPACKAGE
IN+
*EP
Ordering Information
VCC
N.C. 16
Applications
MAX3784AUGE
0°C to +85°C 16 QFN-EP*
G1644-1
MAX3784AUTE+
0°C to +85°C 16 TQFN-EP*
T1644-3
QFN
* THE EXPOSED PAD MUST BE SOLDERED TO SUPPLY GROUND
FOR CORRECT THERMAL AND ELECTRICAL PERFORMANCE.
+Denotes a lead-free package.
*Exposed pad.
Pin Configurations continued at end of data sheet.
Typical Application Circuit
1.25Gbps
Rx
Tx
SWITCH CARD
PCB
BACKPLANE
LINE CARD
T/R 1
+3.3V
SWITCH
1.25Gbps
Rx
Tx
T/R 2
T/R 1
Tx
IN
+3.3V
T/R 2
1.25Gbps
Rx
Tx
T/R 3
Rx
T/R 4
1.25Gbps
Rx
Tx
5Gbps
T/R 3
OUT
MAX3784/
MAX3784A
IN
MAX3784/
MAX3784A
OUT
Rx
EQUALIZER
Tx
EQUALIZER
T/R 4
________________________________________________________________ Maxim Integrated Products
For pricing, delivery, and ordering information, please contact Maxim Direct at 1-888-629-4642,
or visit Maxim’s website at www.maxim-ic.com.
1
MAX3784/MAX3784A
General Description
MAX3784/MAX3784A
5Gbps PCB Equalizer
ABSOLUTE MAXIMUM RATINGS
Operating Ambient Temperature Range ................0°C to +85°C
Storage Temperature Range .............................-55°C to +150°C
Lead Temperature (soldering, 10s) .................................+300°C
Supply Voltage, VCC.................................................-0.5V to +6V
Input Voltage............................................(-0.5V) to (VCC + 0.5V)
Continuous Output Current ...............................-25mA to +25mA
Continuous Power Dissipation (TA = +85°C)
16-Pin QFN (derate 25mW/°C above +85°C) ............1600mW
Stresses beyond those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. These are stress ratings only, and functional
operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to
absolute maximum rating conditions for extended periods may affect device reliability.
ELECTRICAL CHARACTERISTICS
(VCC = +3V to +3.6V, TA = 0°C to +85°C. Typical values are at VCC = +3.3V and TA = +25°C, unless otherwise noted.)
PARAMETER
SYMBOL
CONDITIONS
MIN
TYP
MAX
185
250
EN = low
Supply Power
30
EN = high
Supply-Noise Tolerance
(Note 1)
Latency
From input to output
10Hz < f < 100Hz
100
100Hz < f < 1MHz
40
1MHz < f < 2.5GHz
UNITS
mW
mVP-P
10
200
ps
CML RECEIVER INPUT
Input Voltage Swing
VIN
Measured differentially at point A in Figure 1
Return Loss
100MHz to 2.5GHz
Input Resistance
Differential
400
1000
15
80
mVP-P
dB
100
120
20in
0.13
0.21
40in
0.18
0.23
20in
0.08
0.14
40in
0.13
0.28
20in
0.04
0.07
40in
0.07
0.15
1.3
1.9
Ω
EQUALIZATION
Residual Deterministic Jitter,
5Gbps
Table 1 (Notes 2–5)
Residual Deterministic Jitter,
2.5Gbps
Table 1 (Notes 2–5)
Residual Deterministic Jitter,
1.25Gbps
Table 1 (Notes 2–5)
Random Jitter
(Notes 5, 6)
UIP-P
UIP-P
UIP-P
psRMS
CML TRANSMITTER OUTPUT (into 100Ω ±1Ω)
MAX3784
400
600
MAX3784A
550
750
Output Voltage Swing
VO
Differential swing, measured
differentially at point C in Figure 1
Transition Time
tf, tr
20% to 80% (Notes 5, 8)
30
45
60
ps
Single ended
40
50
60
Ω
Output Resistance
2
_______________________________________________________________________________________
mVP-P
5Gbps PCB Equalizer
(VCC = +3V to +3.6V, TA = 0°C to +85°C. Typical values are at VCC = +3.3V and TA = +25°C, unless otherwise noted.)
PARAMETER
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
ENABLE CONTROL PIN
Input High Voltage
1.5
V
Input Low Voltage
0.5
V
Input High Current
(Note 7)
-150
+10
µA
Input Low Current
(Note 7)
-150
+10
µA
Note 1: Allowed supply noise during jitter tests.
Note 2: Test pattern. This is a combination of K28.5± characters running at the full bit rate and at one-quarter the bit rate. This simulates the multiplexing of four each 1.25Gbps Ethernet data streams.
Pattern (hex) 100 bits
00 FFFF F0F0 FF 0000 0F0F
(quarter rate K28.5+, quarter rate K28.5-)
3EB05
(K28.5± 00 1111 1010 11 0000 0101)
Note 3: Difference in deterministic jitter between reference points A and C in Figure 1.
Note 4: Signal source amplitude range is 400mVP-P to 1000mVP-P differential. Signal is applied differentially at point A as shown in
Figure 1. The deterministic jitter at point B must be from media-induced loss and not from clock-source modulation.
Deterministic jitter is measured at the 50% vertical level of the signal at point C.
Note 5: Guaranteed by design and characterization.
Note 6: Test pattern is K28.5 with 40in trace.
Note 7: On-chip pullup resistor of 40kΩ (typ). Negative current indicates equalizer sources current.
Note 8: Using 00 0001 1111 or equivalent pattern. Measured over entire input voltage range, max and min media loss and within 2in
of output pins.
SIGNAL
SOURCE
MAX3784/MAX3784A
EQUALIZER
BACKPLANE PCB
A
SMA CONNECTOR
SMA CONNECTOR
B
C
IN
OUT
6mil LINE
L ≤ 40in
Figure 1. Test Conditions
Table 1. PCB Assumptions (PCB material is FR-4)
PARAMETER
CONDITIONS
MIN
Transmission Line
Edge-coupled stripline
Relative Permittivity
FR-4 or similar
4.4
Loss Tangent
FR-4 or similar
0.02
Metal Thickness
0.7 mils (0.5oz copper)
Impedance
Differential
TYP
MAX
6
mils
4.5
0.022
0.7
90
100
UNITS
—
—
mils
110
_______________________________________________________________________________________
3
MAX3784/MAX3784A
ELECTRICAL CHARACTERISTICS (continued)
Typical Operating Characteristics
(VCC = +3.3V, measurements done at 5Gbps, 800mVP-P board input with 100-bit pattern from Note 2 of the EC Table, TA = +25°C,
unless otherwise noted.)
EQUALIZER INPUT EYE DIAGRAM
BEFORE EQUALIZATION AT 5Gbps
(40in, FR-4, 6-mil STRIPLINE)
80mV/
div
32ps/div
35ps/div
35ps/div
DIFFERENTIAL RETURN LOSS
DETERMINISTIC JITTER
vs. LINE LENGTH
DETERMINISTIC JITTER vs. AMPLITUDE
(20in FR-4 STRIPLINE)
10
5
0
1.25GHz
70
60
2.5GHz
50
40
5GHz
30
90
1
2
3
4
70
60
50
40
10
10
5
2.5GHz
30
20
10
20
30
40
50
200
60
DETERMINISTIC JITTER vs. AMPLITUDE
(40in FR-4 STRIPLINE)
LATENCY vs. TEMPERATURE
80
400
50
1.25GHz
40
LATENCY (ps)
70
2.5GHz
300
200
5GHz
30
100
20
0
200
400
600
800
1000
INPUT AMPLITUDE (mVP-P)
(FIGURE 1, POINT A)
1200
1000
1200
70
ICC MAX3784A
60
ICC MAX3784
50
40
30
20
10
10
0
800
SUPPLY CURRENT vs. TEMPERATURE
SUPPLY CURRENT (mA)
90
600
80
MAX3784/4A toc08
MAX3784/4A toc07
500
400
INPUT AMPLITUDE (mVP-P)
(FIGURE 1, POINT A)
LINE LENGTH (in)
(FR-4 6-mil STRIPLINE)
100
5GHz
1.25GHz
0
0
FREQUENCY (GHz)
60
80
20
0
0
MAX3784/4A toc06
MAX3784/4A toc05
80
100
MAX3784/4A toc09
15
90
DETERMINISTIC JITTER (ps)
20
100
DETERMINISTIC JITTER (ps)
MAX3784/4A toc04
25
RETURN LOSS (dB)
MAX3784/4A toc03
MAX3784/4A toc02
MAX3784/4A toc01
80mV/
div
30
4
EQUALIZER OUTPUT EYE DIAGRAM
AFTER EQUALIZATION AT 5Gbps
(40in, FR-4, 6-mil STRIPLINE, MAX3784A)
EQUALIZER OUTPUT EYE DIAGRAM
AFTER EQUALIZATION AT 5Gbps
(40in, FR-4, 6-mil STRIPLINE, MAX3784)
55mV/
div
DETERMINISTIC JITTER (ps)
MAX3784/MAX3784A
5Gbps PCB Equalizer
ISHUTDOWN
0
0
25
50
TEMPERATURE (°C)
75
100
0
25
50
TEMPERATURE (°C)
_______________________________________________________________________________________
75
5Gbps PCB Equalizer
PIN
NAME
FUNCTION
1, 7, 12
VCC
2
IN+
Positive Input, CML
3
IN-
Negative Input, CML
4, 6, 9
GND
Supply Ground
5, 8, 14, 15,
16
N.C.
No Connection. Leave unconnected.
10
OUT-
Negative Output, CML
11
OUT+
Positive Output, CML
13
EN
EP
Exposed
Pad
+3.3V Supply Voltage
Enable Equalizer. A logic high or open selects normal operation. A logic low selects low-power
standby mode.
Connect to Ground. The exposed pad must be soldered to the circuit board ground plane for proper
thermal and electrical performance.
5Gbps EQUALIZER
VCC
OFFSET
CANCELLATION
LOWPASS FILTER
IN+
100Ω
MAX3784/
MAX3784A
50Ω
50Ω
OUT+
EQUALIZER
LIMITER
OUT-
INVCC
40kΩ
EN
Figure 2. Functional Diagram
Detailed Description
General Theory of Operation
The MAX3784/MAX3784A adaptive equalizers extend
the reach of transmission lines in high-frequency backplane interconnect applications. They can be used for
4.25Gbps Fibre Channel, 4x 1.25Gbps Ethernet (5Gbps)
and other NRZ, 8b10b or short (≤ 20 bits) CID data
types. Internally, the MAX3784/MAX3784A are comprised of an equalizer control loop and limiting output
driver. The equalizer block reduces intersymbol interference (ISI), compensating for frequency-dependent
media-induced loss. The equalization control detects the
spectral contents of the input signal and provides a control voltage to the equalizer core, adapting it to different
media. The equalizer operation is optimized for short-run,
DC-balanced transmission codes.
Standby Mode
Standby saves power when the equalizer is not in use.
The EN logic input must be set high or open for normal
operation. Logic low at EN forces the equalizer into the
standby state.
CML Input and Output Buffers
The input and output buffers are implemented using current-mode logic (CML). Equivalent circuits are shown in
Figures 3 and 4. For details on interfacing with CML,
refer to Maxim Application Note HFAN-01.0: Introduction
to LVDS, PECL, and CML. The common-mode voltage
of the input and output is above +2.5V. AC-coupling
capacitors are required when interfacing this part with
devices terminated in voltages such as +1.8V. Values of
0.10µF or greater are recommended.
_______________________________________________________________________________________________________
5
MAX3784/MAX3784A
Pin Description
VCC
VCC
50Ω
50Ω
OUT+
OUT-
50Ω
50Ω
250μA
Figure 3. CML Input Equivalent Circuit
Figure 4. CML Output Equivalent Circuit
Applications Information
Alternate Data Rates
The MAX3784/MAX3784A is optimized for automatic
operation at 5Gbps. Equalization at other data rates,
such as 1.25Gbps and 2.5Gbps, is possible. See the
Typical Operating Characteristics for Deterministic Jitter
vs. Line Length and Deterministic Jitter vs. Amplitude
for typical performance at these data rates.
Layout Considerations
Circuit board layout and design can significantly affect
the MAX3784/MAX3784As’ performance. Use good
high-frequency design techniques, including minimizing ground inductance and connections and using controlled-impedance transmission lines for the
high-frequency data signals. Route signals differentially
to reduce EMI susceptibility and crosstalk. Solder the
exposed pad to supply ground for proper thermal and
electrical operation.
Place power-supply decoupling capacitors as close as
possible to the VCC pins.
OUT+
OUT-
GND
TOP VIEW
VCC
Pin Configurations (continued)
12
11
10
9
EN 13
8
N.C.
N.C. 14
7
VCC
6
GND
5
N.C.
MAX3784
MAX3784A
N.C. 15
*EP
1
2
3
4
IN-
GND
+
IN+
N.C. 16
VCC
MAX3784/MAX3784A
5Gbps PCB Equalizer
TQFN
* THE EXPOSED PAD MUST BE SOLDERED TO SUPPLY GROUND
FOR CORRECT THERMAL AND ELECTRICAL PERFORMANCE.
6
_______________________________________________________________________________________
5Gbps PCB Equalizer
PACKAGE TYPE
DOCUMENT NO.
16 QFN
21-0106
16 TQFN
21-0139
Revision History
Pages changed at Rev 4: 1–7 (removed package drawings, replaced with table)
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 _____________________ 7
© 2007 Maxim Integrated Products
is a registered trademark of Maxim Integrated Products.
MAX3784/MAX3784A
Package Information
For the latest package outline information, go to
www.maxim-ic.com/packages.
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