iT6135C
11.1 Gb/s NRZ-to-RZ Converter & Driver
Description
Features
The iT6135C is a NRZ-to-RZ encoder and twostage LiNbO3 modulator driver in a single
package. It is designed for use in long-haul and
submarine systems that generate RZ data using
a single optical modulator. The iT6135C employs
an NRZ-to-RZ retiming front-end in conjunction
with low-jitter amplifier stages. By applying an
NRZ data stream and line-rate clock to the device
inputs, the incoming data stream is converted to
an inverted RZ format with a maximum amplitude
of 7.5 Vpp. For output control optimization, a
single pin is used to precisely set the output
amplitude of the RZ waveform, and an integrated
detector produces a DC voltage proportional to
the output amplitude.
ƒ Complete solution for generating high-level RZ format
from a NRZ data stream and clock signal
ƒ Optimized for 11.1 Gb/s long-haul LiNbO3 applications
ƒ Maintains peak-to-peak jitter of <8 ps over
its operational temperature range
ƒ Small form factor: 16-mm LCC SMT package
ƒ High input sensitivity: 400 to 500 mVpp for data and
clock inputs
ƒ Wide dynamic output range: RZ amplitude
adjustable between 4 and 7.5 Vpp typical
ƒ Integrated amplitude detector
ƒ AC-coupled inputs and outputs
This detector and an on-chip reference diode
create a closed-loop amplitude control network
that provides precise output stabilization over the
operating temperature range. On-board DC
supply filtering provides an extra degree of
protection when using noisy regulated DC
supplies. The iT6135C is housed in a 16-mm
leadless surface mount package with impedancematched transitions to ensure signal integrity.
Applications
Drives LiNbO3 modulator drivers in
transceivers employed in metro and longhaul lightwave communications systems
Ordering Information
Part
iT6135
iT6135EVB
Temp. Range
0o to +85o C
NA
Pin-Package
28-pin, 16-mm
SMT
Evaluation
board
Typical iT6135 application
For pricing, delivery, and ordering information, please contact GigOptix at (650) 424-1937,
e-mail: sales@gigoptix.com, or visit our site at www.GigOptix.com.
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iT6135C
11.1 Gb/s NRZ-to-RZ Converter & Driver
ABSOLUTE MAXIMUM RATINGS1
Symbol
Parameter
Min
Typ
Max
Units
Vcc
Positive supply voltage
0
8.4
Vdc
Vee
Negative supply voltage
-5.5
0
Vdc
VDIN
Input data amplitude
1.0
Vpp
VCIN
Input clock amplitude
1.0
Vpp
Vctrl
Amplitude control voltage
0
5.0
Vdc
0
-40
2
2
2
75
125
Vdc
mAdc
mW
o C
o C
VR
IF
PD
Tbase
Tstg
Ref. diode reverse voltage breakdown
Reference diode forward current
Reference diode forward power dissipation
Base operating temperature
Storage temperature
Note:
1. Functional performance is specified over the recommended operating conditions for power
supply and temperature. AC and DC device characteristics at or beyond the absolute
maximum ratings are not assured or implied. Operation at or beyond the maximum ratings
may cause damage to this product or lead to reduced reliability (MTTF).
For pricing, delivery, and ordering information, please contact GigOptix at (650) 424-1937,
e-mail: sales@gigoptix.com, or visit our site at www.GigOptix.com.
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iT6135C
11.1 Gb/s NRZ-to-RZ Converter & Driver
Recommended Operating Conditions
Symbol
Parameter
Min
Typ
Vcc
Positive supply voltage1
Icc
Positive supply current2
Vee
Negative supply voltage1
-5.2
Iee
Negative supply current
380
Tbase
Base operating temperature3
Max
8.0
140
0
215
Units
Vdc
260
mAdc
Vdc
400
mAdc
50
oC
Notes:
1.
The negative power supply (Vee) must be applied before the positive power supply.
Failure to follow this sequence will cause excessive current draw from the positive power
supply and could damage the device.
2.
Icc is a function of the amplitude control setting (Vctrl). Current increases as RZ output
amplitude is increased.
3.
The iT6135C is a heat-down device. This means that its primary heat conduction path is
through the base of the package. Proper PCB thermal design is required. The design will
depend upon the particular application considering orientation, airflow, and other physical
and mechanical constraints.
For pricing, delivery, and ordering information, please contact GigOptix at (650) 424-1937,
e-mail: sales@gigoptix.com, or visit our site at www.GigOptix.com.
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iT6135C
11.1 Gb/s NRZ-to-RZ Converter & Driver
Electrical Characteristics
(See notes next page)
Symbol
Fb
Parameter
Min
Input data rate
Fb
Output data rate1
S11
Input match6
Data input
Clock input
Max
Unit
Condition
10.709
11.1
Gb/s
NRZ format
10.709
11.1
Gb/s
Inverted RZ format
(See Input/Output
Data Format)
VDIN
VCIN
Output match6
Input amplitude range
Data input
Clock input
Td
Negative edge clock offset2
T1
Input data phase margin3
60
DC
Duty cycle
42
Jpp
Eye jitterpp
VRZ
Guaranteed output amplitude
range4
VCtrl
Amplitude control voltage5
ICtrl
Amplitude control current
S22
400
400
Typ
-8
-15
dB
50 MHz to 12 GHz
8 GHz to 12 GHz
-8
dB
50 MHz - 12 GHz
mVpp
50 ohm
single-ended source
450
450
500
500
37
ps
65
ps
54
%
Measured at
50% of Vpp
8
ps
Measured with
precision timebase
4.0
7.5
Vpp
Typical Vctrl ≈ 0 V to
5.0 V
1.5
5.0
VDC
Typical VRZOUT ≈ 4.0
V to 7.5 V
5
mADC
6.1
3
VF
0.830
0.620
Reference diode
forward voltage
mVDC
0.520
0.420
VDET
Detector output voltage
Fb = 10.709 Gb/s,
Data duty cycle
50%
At 10.709 Gb/s
6.3
6.5
7.1
Typical Vctrl ≈ 0 V
to 5.0 V.
IF = 1.0 mA
IF = 0.1 mA
IF = 0.01 mA
IF = 0.001 mA
7.7
VDC
VRZOUT ≈ 4.0 Vpp
VRZOUT ≈ 7.5 Vpp
For pricing, delivery, and ordering information, please contact GigOptix at (650) 424-1937,
e-mail: sales@gigoptix.com, or visit our site at www.GigOptix.com.
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iT6135C
11.1 Gb/s NRZ-to-RZ Converter & Driver
Electrical Characteristics (Continued)
Notes:
1.
The distinguishing characteristic of an inverted RZ signal is that the zero’s level
creates the top rail of the RZ eye pattern. That is, a logic one level at the NRZ input
corresponds to a negative-going pulse at the RZ output. This logic inversion is easily
managed in the optical domain by properly biasing the modulator so that negativegoing electrical pulses are translated to positive-going optical pulses.
2.
Td is the nominal time delay of the negative clock edge after the data transition to
achieve symmetrical phase margin.
3.
T1 is the maximum phase deviation available before errors are incurred from incorrect
sampling at the converter’s DFF(measured at 10.709 Gb/s).
4.
Operation is not specified or recommended outside the guaranteed output amplitude
range.
5.
The Vctrl voltage necessary to achieve output amplitude within the guaranteed range
will be between 2.0 V and 5.0 V. Operation is not specified or recommended at Vctrl
voltages other than those necessary to achieve output amplitude within the
guaranteed range.
6.
Return loss measurements are taken using a GigOptix test fixture.
For pricing, delivery, and ordering information, please contact GigOptix at (650) 424-1937,
e-mail: sales@gigoptix.com, or visit our site at www.GigOptix.com.
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iT6135C
11.1 Gb/s NRZ-to-RZ Converter & Driver
Typical Eye Diagrams
Voutpp = 7.5 V
Voutpp = 7.0 V
Voutpp = 4.0 V
For pricing, delivery, and ordering information, please contact GigOptix at (650) 424-1937,
e-mail: sales@gigoptix.com, or visit our site at www.GigOptix.com.
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iT6135C
11.1 Gb/s NRZ-to-RZ Converter & Driver
Input/Output Data Format
NRZ Input Data Stream
1
1
1
0
1
0
1
0
1
Bit Period
Inverted RZ Output Data Stream
0
0
0
Input Timing Diagram
1 Bit Period
Td
T1
50 Duty Cycle %
2
T1
2
50% Level
1 Clock Cycle
For pricing, delivery, and ordering information, please contact GigOptix at (650) 424-1937,
e-mail: sales@gigoptix.com, or visit our site at www.GigOptix.com.
7
iT6135C
11.1 Gb/s NRZ-to-RZ Converter & Driver
Package Details
See also GigOptix Application Note 11, “16 mm X 16 mm
Pattern and Stencil Guidelines” at www.gigoptix.com
For pricing, delivery, and ordering information, please contact GigOptix at (650) 424-1937,
e-mail: sales@gigoptix.com, or visit our site at www.GigOptix.com.
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iT6135C
11.1 Gb/s NRZ-to-RZ Converter & Driver
Pad Details
Pad
1
Function
Ground
Pad
13
Function
Ground
Pad
25
Function
Ground
Pad
37
Function
Ground
2
Ground
14
Open
26
Ground
38
External Coil
3
Ground
Ground
15
Ground
27
39
Ground
16
Ground
28
40
External coil
Ground
17
Ground
29
Ground
RZ data
out
Ground
41
Ground
42
+8.0 V
43
Ground
44
Control voltage
45
Ground
46
External coil
47
Ground
48
External coil
4
5
Detector
output
6
Ground
18
-5.2
30
7
Ground
19
Ground
31
8
Ground
20
Ground
32
9
Ground
21
Ground
33
10
Clock In
22
Ground
34
11
Ground
23
Ground
35
Ground
(+) Ref.
diode
Ground
(–) Ref.
diode
Ground
12
NRZ In
24
Ground
36
Ground
Pad 14 should be left available for a duty factor adjustment. A DC control (-5 V /+5 V) should be
included on this pad during PCB layout to facilitate the addition of a duty factor adjustment at a
later date should one be incorporated into the iT6135C.
For pricing, delivery, and ordering information, please contact GigOptix at (650) 424-1937,
e-mail: sales@gigoptix.com, or visit our site at www.GigOptix.com.
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iT6135C
11.1 Gb/s NRZ-to-RZ Converter & Driver
PC Board Considerations
Information regarding guidelines for pad dimensions, thermal vias, solder mask, solder
paste stencils, and reflow recommendations can be found in GigOptix Application Note 011
“GigOptix 16-mm X 16- mm Pattern and Stencil Guidelines”, available at www.gigoptix.com.
All RF lines are configured for a 50-ohm impedance on 0.008-in.-thick Rogers 4003
laminate.
The application note is intended for the general use of the 16 mm X 16 mm ceramic
package, so some modifications are required to implement the 6135C. The iT6135C requires
two external inductors to complete the internal bias choke networks. The manufacturer is
Coilcraft, and the part number is DO1608C-224. Complete information including pad
dimensions can be found on Coilcraft’s Web site at http://www.coi1craft.com/ds/do1608.pdf
The iT6135C contains a 1.0-µF decoupling capacitor on the +8.0 V and –5.2 V power supply
inputs. Additional decoupling may be required depending on the quality of the power
supplies used on the application board. An external capacitance of 10 µF or more should be
sufficient to mitigate any issues. Refer to the Pad Details when examining layout
precautions. Please note the following layout precautions:
ƒ All unused device pads with the exception of pad 14 should be DC/RF grounded within
0.03 in. from the device.
ƒ Placement of the two external inductors should be as near to the iT6135C as the PCB
layout permits. Placement of the two external inductors in excess of 0.3 in. may affect
low-frequency gain response.
ƒ Clock In and Data In should be routed away from each other to reduce RF coupling.
ƒ Clock In and Data In line lengths should be kept to minimum to reduce RF coupling and
RF loss.
ƒ RZ Out line length should be kept to minimum to reduce RF coupling and RF loss.
ƒ DC lines near the RZ output should be routed away to reduce RF coupling.
ƒ The grounded pad between Clock In and Data In should be extended to increase isolation
and reduce RF coupling.
ƒ The grounded pad between RZ Out and Det. Out Volts should be extended to increase
isolation and reduce RF coupling.
For pricing, delivery, and ordering information, please contact GigOptix at (650) 424-1937,
e-mail: sales@gigoptix.com, or visit our site at www.GigOptix.com.
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iT6135C
11.1 Gb/s NRZ-to-RZ Converter & Driver
Evaluation Platform
The PC board shown below was designed to provide a platform on which to evaluate the
iT6135C. All necessary RF and DC inputs and outputs are routed from the package to an
appropriate connector along the board perimeter. Surface mount test points allow power
supply and control inputs to be conveniently attached to the board using common clip
leads. The high-speed transmission lines are implemented as 50-ohm grounded coplanar
waveguide structures designed on 0.008-in.-thick Rogers 4003 laminate. The high-speed
connections from the board are accomplished with straddle-mount, edge-launch SMA
female connectors.
Handling Precautions
Always observe proper ESD practices while handling and testing the iT6135C module. Do
not over-tighten SMA connections. Doing so may mechanically stress the PC board and
damage the iT6135C’s solder connections.
Revision History
Revision
0
Date
Change
8/20/07
For pricing, delivery, and ordering information, please contact GigOptix at (650) 424-1937,
e-mail: sales@gigoptix.com, or visit our site at www.GigOptix.com.
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