MAXIM MAX3755CCM

19-2098; Rev 1; 1/02
Dual-Rate, 1Gbps/2Gbps Fibre Channel
Quad-Port Bypass ICs with Repeater
Features
♦ Pin Selectable 1.0625Gbps/2.125Gbps Dual-Rate
Operation
♦ Meets Fibre Channel Jitter Tolerance
♦ 1400mV Typical Differential Output Swing
♦ 3.0V to 3.6V Operation
♦ No Reference Clock Required
♦ Frequency Lock Indication
♦ 1W Power Consumption (MAX3754) at +3.3V
♦ 150Ω or 100Ω Differential L-Port Impedance
Available
Pin Configuration
LIN337
38
LOUT3GND
LIN3+
39
40
41
GND
GND
LOUT3+
42
43
44
GND
LIN2+
LIN245
46
Storage Area Networks
LOUT2+
LOUT2-
Fibre Channel Data Storage Systems
47
1.0625Gbps/2.125Gbps Dual-Rate Fibre Channel
48
Applications
Fibre Channel Hubs
1
36
2
35
3
34
GND
LOUT1-
4
33
LOUT1+
GND
GND
6
8
29
ININ+
GND
CLKEN
9
28
10
27
11
26
12
25
5
32
23
24
VCC
22
CDREN
RATESEL
21
30
20
19
31
SEL3
SEL4
VCC
18
16
15
14
VCC
SEL1
SEL2
13
VCC
7
17
MAX3754
MAX3755
CF+
CF-
Typical Operating Circuit appears at end of data sheet.
GND
LIN1LIN1+
GND
LOUT4+
LOUT4GND
LIN4+
LIN4GND
GND
OUTOUT+
GND
LOCK
TQFP-EP*
*EXPOSED PAD MUST BE CONNECTED TO GROUND
Ordering Information
PART
TEMP RANGE
PIN-PACKAGE
DIFFERENTIAL LIN
AND LOUT
TERMINATION
DIFFERENTIAL IN
AND OUT
TERMINATION
MAX3754CCM
0°C to +70°C
48 TQFP-EP
150Ω
100Ω
MAX3755CCM
0°C to +70°C
48 TQFP-EP
100Ω
100Ω
________________________________________________________________ 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
MAX3754/MAX3755
General Description
The MAX3754/MAX3755 quad-port bypass circuits
(PBCs) are designed for use in Fibre Channel Arbitrated
Loop applications. Each consists of four serially connected port bypass circuits and a repeater that provides
clock and data recovery. The quad-PBC allows connection of up to four Fibre Channel L-ports; each can be
enabled or bypassed by individual logic inputs. To
reduce the external parts count, all signal inputs and
outputs have internal termination resistors. The
MAX3754/MAX3755 comply with Fibre Channel jitter tolerance requirements and can recover data signals with
up to 0.7 unit intervals (UIs) of high-frequency jitter.
These devices operate from a single +3.3V supply.
MAX3754/MAX3755
Dual-Rate, 1Gbps/2Gbps Fibre Channel
Quad-Port Bypass ICs with Repeater
ABSOLUTE MAXIMUM RATINGS
VCC ...........................................................................-0.5V to +5V
Current into OUT±, LOUT1±, LOUT2±,
LOUT3±, LOUT4±.......................................................... 22mA
Voltage at OUT±, LOUT1±, LOUT2±,
LOUT3±, LOUT4± .....................(VCC - 1.65V) to (VCC + 0.5V)
Voltage at IN±, LIN1±, LIN2±, LIN3±,
LIN4±......................................................-0.5V to (VCC + 0.5V)
Voltage at CLKEN, CF+, CF-, CDREN, RATESEL,
SEL_, LOCK............................................-0.5V to (VCC + 0.5V)
Current into LOCK...............................................-1mA to +10mA
Continuous Power Dissipation (TA = +70°C)
48-Pin TQFP-EP (derate 30.0mW/°C above +70°C) ...........2W
Operating Junction Temperature Range ...........-55°C to +150°C
Operating Temperature Range .........................-55°C to +110°C
Storage 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.
ELECTRICAL CHARACTERISTICS
(VCC = +3.0V to +3.6V, CLKEN = GND, 8B/10B data coding, CF = 0.047µF, TA = 0°C to +70°C, unless otherwise noted.
Typical values are at VCC = +3.3V, TA = +25°C.)
PARAMETER
CONDITIONS
CDREN = GND
Supply Current (Note 1)
CDREN = VCC
Input Data Rate Range
MIN
MAX
MAX3754
245
285
MAX3755
285
334
MAX3754
308
362
MAX3755
349
-100
+100
2.125Gbps operation, RATESEL = VCC
-100
+100
200
2200
VCC 0.45
Input Common-Mode Voltage
RLOAD = RSOURCE
UNITS
mA
411
1.0625Gbps operation, RATESEL = GND
Differential Input Voltage Swing
Differential Output Voltage
Swing
TYP
ppm
mVP-P
V
1000
1400
1800
mVP-P
Differential L-Port Input
Resistance
MAX3754
118
150
182
MAX3755
78
100
122
Differential L-Port Output
Resistance
MAX3754
118
150
182
MAX3755
78
100
122
Differential Input Resistance at
IN±
78
100
122
Ω
Differential Output Resistance at
OUT±
78
100
122
Ω
0.8
V
50
µA
TTL Low Input Voltage
TTL High Input Voltage
2
TTL Input Current
0 ≤ TTL input voltages ≤ VCC
LOCK Output Low Voltage
IOL = +1mA (sinking)
LOCK Output High Voltage
IOH = -100µA (sourcing)
-50
Data Propagation Delay
2
0.4
V
V
VCC
IN± to OUT±, SEL_ = GND, CDREN = VCC
3
LIN(n)± to LOUT(n+1)±, LIN4± to OUT±
1
_______________________________________________________________________________________
Ω
V
2.4
Differential Voltage across CF±
Ω
V
ns
Dual-Rate, 1Gbps/2Gbps Fibre Channel
Quad-Port Bypass ICs with Repeater
(VCC = +3.0V to +3.6V, CLKEN = GND, 8B/10B data coding, CF = 0.047µF, TA = 0°C to +70°C, unless otherwise noted.
Typical values are at VCC = +3.3V, TA = +25°C.)
PARAMETER
CONDITIONS
Channel Select Delay to Data
Valid
SEL(n)± to LOUT(n+1)± , SEL4 to OUT±
Data Transition Time
20% to 80%
Supply Noise Tolerance (Note 2)
MIN
TYP
MAX
9
65
110
10Hz ≤ f < 100Hz
100
100Hz ≤ f < 1MHz
40
1MHz ≤ f < 2.5GHz
10
CDR Lock Time
ns
160
Deterministic Jitter at OUT±,
L-Port Outputs±
µs
1.6
4.1
psRMS
3
Pattern = K28.5+, CDREN = GND (Note 7)
29
60
Pattern = K28.5+, CDREN = VCC
19
50
Pattern = RPAT, CDREN = VCC (Notes 6, 8, 9)
28
50
Total Jitter at OUT±, LOUT_±
Pattern = RPAT, CDREN = VCC (Notes 6, 8, 9)
Sinusoidal Component of Jitter
Tolerance (BER = 10-12)
Pattern = CJTPAT
(Notes 6, 10)
f = 85kHz sine wave
ps
mVP-P
530
OPERATION AT 2.125Gbps (Note 3)
Pattern = K28.7, CDREN = GND (Note 4)
Random Jitter at OUT±,
Pattern = K28.7, CDREN = VCC
L-Port Outputs±
Pattern = CRPAT, CDREN = VCC (Notes 5, 6)
UNITS
105
psP-P
psP-P
1.5
f = 1.27MHz sine wave
0.1
f = 10MHz sine wave
0.1
UI
Deterministic Jitter Tolerance
CJTPAT (Note 10)
0.4
UI
Total High-Frequency Jitter
Tolerance
Pattern = CJTPAT (Notes 6, 10, 11)
0.7
UI
Jitter Transfer Bandwidth
Jitter Transfer Peaking
6
(Note 12)
OPERATION AT 1.0625Gbps (Note 3)
Pattern = K28.7, CDREN = GND (Note 4)
Random Jitter at OUT±,
Pattern = K28.7, CDREN = VCC
L-Port Outputs±
Pattern = CRPAT, CDREN = VCC (Notes 5, 6)
Deterministic Jitter at OUT±,
L-Port Outputs±
10
MHz
0.05
dB
1.7
psRMS
5.4
3.8
Pattern = K28.5+, CDREN = GND (Note 7)
27
60
Pattern = K28.5+, CDREN = VCC
19
50
Pattern = RPAT, CDREN = VCC (Notes 6, 8, 9)
37
75
Total Jitter at OUT±, LOUT_±
Pattern = RPAT, CDREN = VCC (Notes 6, 8, 9)
Sinusoidal Component of Jitter
Tolerance (BER = 10-12)
Pattern = CJTPAT
(Notes 6, 10)
135
f = 42.5kHz sine wave
1.5
f = 635kHz sine wave
0.1
f = 5MHz sine wave
0.1
psP-P
psP-P
UI
_______________________________________________________________________________________
3
MAX3754/MAX3755
ELECTRICAL CHARACTERISTICS (continued)
MAX3754/MAX3755
Dual-Rate, 1Gbps/2Gbps Fibre Channel
Quad-Port Bypass ICs with Repeater
ELECTRICAL CHARACTERISTICS (continued)
(VCC = +3.0V to +3.6V, CLKEN = GND, 8B/10B data coding, CF = 0.047µF, TA = 0°C to +70°C, unless otherwise noted.
Typical values are at VCC = +3.3V, TA = +25°C.)
PARAMETER
Deterministic Jitter Tolerance
Total High-Frequency Jitter
Tolerance
CONDITIONS
CJTPAT (Note 10)
MIN
0.4
Pattern = CJTPAT (Notes 6, 10, 11)
0.7
Jitter Transfer Bandwidth
Jitter Transfer Peaking
TYP
MAX
UNITS
UI
UI
3
(Note 12)
5
MHz
0.05
dB
Includes output currents.
Meets jitter output specifications with noise applied.
AC characteristics are guaranteed by design and characterization.
K28.7 Pattern: 00 1111 1000
Compliant Random Pattern in hex (CRPAT):
Pattern Sequence:
Repetitions:
3E AA 2A AA AA
6
3E AA A6 A5 A9
1
86 BA 6C64 75 D0 E8 DC A8 B4 79 49 EA A6 65
16
72 31 9A 95 AB
1
C1 6A AA 9A A6
1
Note 6: Parameter measured with 0.40UI deterministic and 0.20UI random jitter (BER = 10-12 ) applied to the input. All ports are
bypassed, SEL_ = TTL low. Jitter is in compliance with the inter-enclosure, Fibre Channel jitter tolerance (at compliance
point αR) and jitter output (at compliance point αT) specifications (FC-PI rev 10.0). Output jitter is specified as an output
total given a non-zero jitter input.
Note 7: K28.5± Pattern: 00 1111 1010 11 0000 0101
Note 8: Random Pattern in Hex (RPAT): 3EB0 5C67 85D3 172C A856 D84B B6A6 65
Note 9: Using differential drive over the entire input amplitude range. The input signal bandwidth is limited to 0.75 ✕ (bit-rate) by a
4th-order Bessel-Thompson filter or equivalent. Total jitter (TJ) is the range of the eye pattern where the bit error rate
exceeds 10-12. TJ can be estimated as TJ = DJ + (14 ✕ RJ). DJ is deterministic jitter. RJ is one sigma distribution (RMS) of
random jitter.
Note 10: Compliant Jitter Tolerance Pattern in Hex (CJTPAT):
Pattern Sequence:
Repetitions:
3E AA 2A AA AA
6
3E AA A6 A5 A9
1
87 1E 38 71 E3
41
87 1E 38 70 BC 78 F4 AA AA AA
1
AA AA AA AA AA
12
AA A1 55 55 E3 87 1E 38 71 E1
1
AB 9C 96 86 E6
1
C1 6A AA 9A A6
1
Note 11: Parameter measured with 0.1UI sinusoidal jitter at 10MHz for 2.125Gbps data rate, or 5MHz for 1.0625Gbps.
Note 12: Simulation shows peaking of 0.01dBm max. Characterization results limited by test equipment.
Note 1:
Note 2:
Note 3:
Note 4:
Note 5:
4
_______________________________________________________________________________________
Dual-Rate, 1Gbps/2Gbps Fibre Channel
Quad-Port Bypass ICs with Repeater
OUTPUT EYE DIAGRAM AT OUT±
(1.0625Gbps CRPAT, CDR ENABLED)
CDR ENABLED
300
280
INPUT =
400mVP-P
DJ = 0.4UI
RJ = 0.2UI
200mV/
div
260
INPUT =
400mVP-P
DJ = 0.4UI
RJ = 0.2UI
200mV/
div
CDR DISABLED
240
220
200
20
30
40
50
60
100ps/div
200ps/div
70
TEMPERATURE (°C)
1.0625Gbps CRPAT AT INPUT
(DJ = 0.4UI, RJ = 0.2UI)
0.2
0.4
0.6
0.8
2.125Gbps CRPAT AT INPUT
(DJ = 0.4UI, RJ = 0.2UI)
0
1.0
0.2
0.4
0.6
0.8
DATA SAMPLING TIME RELATIVE TO
FIRST ZERO CROSSING (UI)
DATA SAMPLING TIME RELATIVE TO
FIRST ZERO CROSSING (UI)
JITTER TOLERANCE
1.0625Gbps
JITTER TOLERANCE
2.125Gbps
10
CJTPAT
DJ = 0.4UI
RJ = 0.2UI
10
SINUSOIDAL JITTER (UIP-P)
0
1
10-1
10-2
10-3
10-4
10-5
10-6
10-7
10-8
10-9
10-10
10-11
10-12
1
FIBRE CHANNEL
MASK
0.1
0.01
CJTPAT
DJ = 0.4UI
RJ = 0.2UI
1.0
MAX3754 toc07
BIT ERROR RATE
MAX3754 toc04
1
10-1
10-2
10-3
10-4
10-5
10-6
10-7
10-8
10-9
10-10
10-11
10-12
MAX3754 toc05
OUTPUT JITTER BATHTUB PLOT
(2.125Gbps)
OUTPUT JITTER BATHTUB PLOT
(1.0625Gbps)
MAX3754 toc06
10
BIT ERROR RATE
0
SINUSOIDAL JITTER (UIP-P)
SUPPLY CURRENT (mA)
320
MAX3754 toc03
MAX3754 toc01
340
OUTPUT EYE DIAGRAM AT OUT±
(2.125Gbps CRPAT, CDR ENABLED)
MAX3754 toc02
SUPPLY CURRENT vs. TEMPERTURE
(MAX3754)
1
FIBRE CHANNEL
MASK
0.1
0.01
10k
100k
1M
FREQUENCY (Hz)
10M
10k
100k
1M
10M
FREQUENCY (Hz)
_______________________________________________________________________________________
5
MAX3754/MAX3755
Typical Operating Characteristics
(VCC = +3.3V, CF = 0.047µF, TA = +25°C, unless otherwise noted.)
Dual-Rate, 1Gbps/2Gbps Fibre Channel
Quad-Port Bypass ICs with Repeater
MAX3754/MAX3755
Pin Description
6
PIN
NAME
DESCRIPTION
1, 4, 7, 8, 11, 26, 29, 30,
33, 36, 39, 42, 43, 46
GND
Electrical Ground
2
LIN1-
Inverted Data Input for L-Port 1
3
LIN1+
Noninverted Data Input for L-Port 1
5
LOUT1-
Inverted Data Output for L-Port 1
6
LOUT1+
Noninverted Data Output for L-Port 1
9
IN-
Inverted Data Input
10
IN+
Noninverted Data Input
12
CLKEN
Clock Enable. A TTL high level enables clock output at L-Port 1.
13, 16, 21, 24
VCC
14
CF+
Supply Voltage
CDR Filter Capacitor Positive Connection. CF = 0.047µF.
15
CF-
CDR Filter Capacitor Negative Connection. CF = 0.047µF.
17
SEL1
Select 1. A TTL low on SEL1 selects data from IN. TTL high on SEL1 selects data from LIN1.
18
SEL2
Select 2. A TTL low on SEL2 selects data from the previous port bypass circuit. A TTL high
on SEL2 selects data from LIN2.
19
SEL3
Select 3. A TTL low on SEL3 selects data from the previous port bypass circuit. A TTL high
on SEL3 selects data from LIN3.
20
SEL4
Select 4. A TTL low on SEL4 selects data from the previous port bypass circuit. A TTL high
on SEL4 selects data from LIN4.
22
CDREN
CDR Enable Input (TTL). A high input enables the CDR for data recovery. A low input
disables the CDR (no data recovery).
23
RATESEL
Rate Select Pin. TTL low selects 1.0625Gbps operation. TTL high selects 2.125Gbps
operation.
25
LOCK
27
OUT+
Noninverted Data Output
28
OUT-
Inverted Data Output
31
LIN4-
Inverted Data Input for L-Port 4
32
LIN4+
Noninverted Data Input for L-Port 4
34
LOUT4-
Inverted Data Output for L-Port 4
35
LOUT4+
Noninverted Data Output for L-Port 4
Frequency Lock Indicator. When data is present, a high level indicates the PLL is frequencylocked. The output of the LOCK pin may chatter when large jitter is applied to the input.
37
LIN3-
Inverted Data Input for L-Port 3
38
LIN3+
Noninverted Data Input for L-Port 3
40
LOUT3-
41
LOUT3+
44
LIN2-
Inverted Data Input for L-Port 2
45
LIN2+
Noninverted Data Input for L-Port 2
Inverted Data Output for L-Port 3
Noninverted Data Output for L-Port 3
47
LOUT2-
Inverted Data Output for L-Port 2
48
LOUT2+
Noninverted Data Output for L-Port 2
EP
Exposed
Pad
The exposed pad must be soldered to the circuit board ground for proper thermal
performance.
_______________________________________________________________________________________
Dual-Rate, 1Gbps/2Gbps Fibre Channel
Quad-Port Bypass ICs with Repeater
MAX3754/MAX3755
0.047µF
CF+
CF-
RATESEL
LOCK
IN+
IN-
LOOP
FILTER
PHASE/FREQ
DETECTOR
100Ω
1
VCO
CDREN
CLKEN
D
Q
0
÷2
1
0
0
1
0
0
0
0
1
1
1
1
SEL4
LIN4+
LIN4-
LOUT4+
LOUT4-
SEL3
LIN3+
LIN3-
SEL2
LOUT3+
LOUT3-
LIN2+
LIN2-
LOUT2+
LOUT2-
SEL1
LIN1+
LIN1-
LOUT1+
LOUT1-
100Ω
OUT+
OUT-
OPTIONAL
100Ω OR 150Ω TERMINATION
FOR LOUT AND LIN
Figure 1. MAX3754/MAX3755 Functional Diagram
Detailed Description
The MAX3754/MAX3755 quad port bypass circuits
(PBCs) consist of an input buffer, a rate-selectable
clock and data recovery (CDR) circuit (for optional jitter
attenuation), four serially connected port bypass circuits, and an output buffer (Figure 1). The circuit
design is optimized for both 1.0625Gbps and
2.125Gbps operation at 3.3V.
Input Buffer
The input buffer provides line termination and level conversion. It accepts a differential input voltage of 200mV
to 2200mV at IN±. Internal resistors terminate the inputs
to 100Ω differentially eliminating the need for external
resistors.
Clock and Data Recovery
The purpose of the CDR is to improve jitter transfer performance by attenuating jitter that may be present in
the input data. The CDR can recover 1.0625Gpbs or
2.125Gbps data signals that are corrupted by up to
0.7UI of high-frequency jitter (BER = 10-12 ). When jitter
attenuation is not needed, the CDR may be disabled in
order to save power.
The input buffer drives the CDR circuit, as well as one
input of a 2:1 multiplexer. A TTL high on CDREN
enables the CDR and connects the CDR data output to
the port bypass circuits. The recovered clock signal is
available for test purposes at LOUT1 when CLKEN is
asserted high. A TTL low on CDREN disables the CDR
and connects the output of the input buffer directly to
the port bypass circuits. A RATESEL pin is included to
switch the CDR between data rates. The VCO output
has a divide-by-2 block that is switched into the PLL
when RATESEL is TTL low for 1.0625Gbps operation
(see Figure 1).
Phase and Frequency Detector
The frequency difference between the VCO clock and
the received data is derived by sampling the in-phase
and quadrature VCO outputs on the edges of the input
data signal. The frequency detector drives the VCO
until the frequency difference is reduced to zero. Once
frequency acquisition is complete, the phase detector
produces a voltage proportional to the phase difference between the incoming data and the internal clock.
The PLL drives this error voltage to zero, aligning the
recovered clock to the center of the incoming eye.
_______________________________________________________________________________________
7
MAX3754/MAX3755
Dual-Rate, 1Gbps/2Gbps Fibre Channel
Quad-Port Bypass ICs with Repeater
Loop Filter, VCO, and Latch
The phase detector and frequency detector outputs are
summed into a loop filter. An external capacitor
(between CF+ and CF-) is required to set the PLL
damping factor. The fully integrated VCO contains an
internal current reference and filter circuitry to minimize
the influence of VCC noise. The VCO creates a clock
output with frequency proportional to the control voltage applied by the loop filter. Data recovery is accomplished by using the recovered clock signal to latch the
incoming data to the CML output buffers, significantly
reducing output jitter.
LOCK Output
An active high LOCK output monitor derived from the
frequency detector indicates that the PLL is frequency
locked onto the input data. Without input data, the
LOCK signal may settle at TTL High or TTL Low. The
use of a low-pass RC filter is recommended to reduce
the effects of chatter that could be caused by a high
input jitter content.
RATESEL Input
The RATESEL input is used to select between input
data rates of 2.125Gbps and 1.0625Gbps. This function allows the repeater to sample data at the correct
data rate by selecting an optional a divide-by-2 network. RATESEL selects between the VCO tuned frequency and half that frequency, allowing maximum
jitter tolerance at both data rates. The loop bandwidth
of the repeater scales with the selected frequency; i.e.,
the loop-bandwidth at an input rate of 1.0625Gbps is
half that at the input rate of 2.125Gbps.
Port Bypass Circuits
The output of the 2:1 input multiplexer drives a cascaded series of four PBCs. Each PBC consists of a differential output buffer, a differential input buffer, and a 2:1
multiplexer. The multiplexer select input (SEL_) controls
whether a port is included in the loop. A TTL low on a
multiplexer select pin routes the data signal from the
previous stage to the multiplexer output (port bypass
mode). A TTL high on the multiplexer select pin routes
the data signal from the input buffer to the multiplexer
output (port enable mode). The output of the last PBC
drives the output buffer.
The MAX3754 has 150Ω differential termination on the
inputs and 75Ω single-ended terminations to VCC on
the outputs (see Input/Output Structures for specifics)
of the L-ports to match Fibre Channel Arbitrated Loop
specifications. The MAX3755 is terminated with 100Ω
and 50Ω, respectively. Testing a MAX3754 using standard 50Ω test equipment requires an impedance
matching network
8
Output Buffer
The output signal of the last PBC drives the differential
high-power output buffer. The output buffer drives the
output port (OUT±). Internal resistors terminate each
output with 50Ω to VCC (100Ω differentially), eliminating
the need for external termination resistors. The output
buffer produces a differential peak-to-peak output voltage of 1V to 1.8V when driving a differential load.
Applications Information
The MAX3754/MAX3755 quad-PBC is designed for
hard-disk array applications using the Fibre Channel
Arbitrated Loop network protocol. In applications where
data storage reliability is critical, it may be desirable to
create a disk array where the data is stored redundantly on more than one physical drive.
The Fibre Channel Arbitrated Loop protocol enables
multiple physical drives to be connected in a loop
topology. Each physical drive is connected to the Fibre
Channel loop through an L-port that may be individually
addressed and controlled to create an array of logical
drives. Data is transmitted over the loop as an encoded
serial bit stream. Using the Fibre Channel Arbitrated
Loop protocol, the configuration of the disk array can
be rearranged under software control to achieve
desired objectives (such as data reliability or fast
access).
The port bypass circuit allows any L-port to be enabled
(connected to the loop) or bypassed (disconnected
from the loop) while the loop is operating. This enables
hot swapping of physical drives (inserting or removing
physical drives while the loop is operating) so that drives may be replaced with minimal disruption to the disk
array system. Figure 2 shows a disk array.
Filter Capacitor Requirements
The MAX3754/MAX3755 phase lock loop’s (PLL) filter
capacitor is required to be supplied in a port bypass
design. This capacitor sets the damping factor of the
device. It also determines how fast the PLL can acquire
initial lock. This device is specified and tested with the
recommended filter capacitor value of 0.047µF that limits transfer peaking.
Input/Output Structures
Figures 3 and 4 show models for the MAX3754/
MAX3755 inputs and outputs, modeling package parasitics, and ESD diodes.
Cascading Port Bypass Circuits
Two or more MAX3754/MAX3755 quad-PBCs can be
cascaded by directly connecting the OUT± pins of one
_______________________________________________________________________________________
Dual-Rate, 1Gbps/2Gbps Fibre Channel
Quad-Port Bypass ICs with Repeater
MAX3754/MAX3755
IN±
IN±
MAX377x
MAX377x
MAX377x
MAX377x
MAX377x
MAX377x
MAX377x
MAX377x
MAX377x
MAX377x
MAX377x
MAX377x
PRIMARY LOOP
MAX377x
1
MAX3750 PBC 0
MAX377x
MAX375x PBC
MAX375x PBC
MAX377x
REPEATER
REPEATER
MAX377x
MAX375x PBC
MAX375x PBC
MAX377x
REPEATER
REPEATER
MAX377x
MAX375x PBC
MAX375x PBC
MAX3750 PBC
MAX377x
REPEATER
PORT CONTROL
FC-AL DRIVES
PORT CONTROL
REPEATER
FAIL-OVER LOOP
MAX377x
OUT±
OUT±
Figure 2. Disk Array Implemented with Port Bypass Circuits
_______________________________________________________________________________________
9
MAX3754/MAX3755
Dual-Rate, 1Gbps/2Gbps Fibre Channel
Quad-Port Bypass ICs with Repeater
PACKAGE
PARASITICS
DIE
VCC
ESD
STRUCTURES
1.2kΩ
2.2nH
0.2pF
0.4pF
2.2nH
0.2pF
0.4pF
50Ω
*(75Ω)
50Ω
*(75Ω)
VCC - 0.45V
*MAX3754 LIN_ ± INPUTS
Figure 3. MAX3754/MAX3755 Input Structure
VCC
quad-PBC to the IN± pins of the next quad-PBC. See
Typical Operating Circuit.
Layout Considerations
50Ω
*(75Ω)
50Ω
*(75Ω)
DIE
PACKAGE
PARASITICS
ESD
STRUCTURES
2.2nH
For best performance, carefully lay out the PC board
using high-frequency techniques. Filter voltage supplies, keep ground connections short with multiple vias
where possible. Use controlled impedance transmission lines to interface with the MAX3754/MAX3755
high-speed inputs and outputs. Power-supply decoupling capacitors should be placed very close to VCC
pins. Isolate the input signals from the output signals as
much as possible.
OUT+
0.4pF
2.2nH
OUT0.4pF
*MAX3754 LOUT_ ± OUTPUTS
Figure 4. MAX3754/MAX3755 Output Structure
10
0.2pF
______________________________________________________________________________________
0.2pF
Dual-Rate, 1Gbps/2Gbps Fibre Channel
Quad-Port Bypass ICs with Repeater
IN OUT SEL
IN OUT SEL
LOUT2±
LOUT1±
LOUT2±
CF+
CLKEN
CF-
RATESEL
DOWNSTREAM L_PORT
OUT-
SEL4
CF
0.047µF
IN-
LIN4±
SEL4
RATESEL
LIN4±
CF-
LOUT4±
CLKEN
SEL3
CF+
Z0 = 50Ω
OUT+
MAX3754
MAX3755
LOUT4±
OUT-
LOCK
IN+
SEL3
MAX3754
MAX3755
VCC
CDREN
GND
Z0 = 50Ω
LIN3±
OUT+
VCC
LOUT3±
LOCK
IN+
LIN3±
VCC
CDREN
GND
INCF
0.047µF
VCC
SEL2
IN OUT SEL
LIN2±
IN OUT SEL
SEL1
L_PORT n+5
LIN1±
L_PORT n+4
SEL2
L_PORT n+1
LIN2±
L_PORT n
SEL1
DISK
DRIVE
LIN1±
DISK
DRIVE
LOUT3±
UPSTREAM L_PORT
VCC
DISK
DRIVE
LOUT1±
VCC
DISK
DRIVE
IN OUT SEL
IN OUT SEL
IN OUT SEL
IN OUT SEL
L_PORT n+2
L_PORT n+3
L_PORT n+6
L_PORT n+7
DISK
DRIVE
DISK
DRIVE
DISK
DRIVE
DISK
DRIVE
NOTE: ALL HIGH-SPEED INPUTS AND OUTPUTS (IN±, OUT±, LIN±, AND LOUT±) SHOULD BE CONNECTED USING CONTROLLEDIMPEDANCE TRANSMISSION LINES. AC-COUPLING MAY ALSO BE REQUIRED. ALL CAPACITORS ARE 0.1µF UNLESS OTHERWISE INDICATED.
FIGURE SHOWS 1.0625Gbps OPERATION. FOR 2.125Gbps OPERATION, CONNECT RATESEL TO VCC.
______________________________________________________________________________________
11
MAX3754/MAX3755
Typical Operating Circuit
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.)
48L,TQFP.EPS
MAX3754/MAX3755
Dual-Rate, 1Gbps/2Gbps Fibre Channel
Quad-Port Bypass ICs with Repeater
12
______________________________________________________________________________________
Dual-Rate, 1Gbps/2Gbps Fibre Channel
Quad-Port Bypass ICs with Repeater
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 ____________________ 13
© 2002 Maxim Integrated Products
Printed USA
is a registered trademark of Maxim Integrated Products.
MAX3754/MAX3755
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.)