Decision Circuit with Phase Detector...................................................................................................... 15
Oki Semiconductor
10-GHz GaAs Family
fT (GHz)
Gate Delays
(ps)
Application
High-Speed Optical Communications Systems
INTRODUCTION
Oki’s 10-GHz logic devices are manufactured using a 0.2-µm, ion-implanted process, which is similar to
Oki’s familiar 0.5-µm telecommunications process. However, the 0.2-µm process uses a phase-shifting
edge line (PEL) masking method for gate fabrication. Gold-based, three-level metal interconnections are
used for high density and shorter wiring paths. Layers 1 and 2 are signal lines. Layer 3, which is formed
by electroplating, is used for ground or power supply lines because of its lower resistance. An optional
buried “p” channel structure is adopted for reducing short channel effects.
The following table shows the digital GaAs logic processes of the 10-GHz GaAs family.
GaAs Logic Processes
Basic FET Process
MESFETDCFL or SBFLI-line printing0.53025< 2.4 Gbps standard cell
MESFETDCFL or SBFLPEL< 0.2609>12-Gbps hand-routed logic
Pseudomorphic-inverted HEMT DCFL or SBFLPEL0.2> 607> 20-Gbps low-density logic
The key to operating reliably at 10 Gbps is logic circuitry that can easily manipulate data at over 13 Gbps.
The higher frequency overhead is required to meet the different clock skews encountered when designing and routing 10-Gbps data management hardware.
The logic is either direct-coupled FET logic (DCFL) or source-coupled FET logic (SCFL). The low-drive
disadvantage of DCFL can be improved by using super-buffer FET logic (SBFL). The basic speed of SBFL
is slower than DCFL, but SBFL is faster with higher fanouts and longer metal runs. A designer selects the
best performing logic for each logic element application. SBFLs used for clock distribution, output buffers, etc. Typical gate delays of 9 ps and power of 2 mW per gate are achieved. Register logic elements like
D-flip flops are assembled using memory cell flip flops (MCFF) as shown in Figure 1 .The operation speed
of a MCFF, which is about twice that of a conventional 6 NOR-gate circuit, operates at very low power.
To simplify device interconnections, AC-coupled clock and data input lines are created using the circuit
shown in Figure 2 .
Gate Length
(µm)
FEATURES
• 10-Gbps operation: highest speed available
• ECL level logic swings: easy interface to other
logic
• Inputs internally terminated: reduces noise and
phase jitter
• 50-Ω I/Os: easy to interconnect hardware
1Oki Semiconductor
10-GHz GaAs Family ■ ––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––
Data
Data
MasterSlave
ClockClock
Data
ClockClock
Figure 1. Memory Cell Flip-Flops
Data or Clock In
Master/Slave Flip-Flop
Flip-Flop
Out
Q
■
Q
50Ω
Reference
Dummy Gate
Figure 2. AC-Coupled, Self-Biased Logic Input
Many 10-Gbps inputs are self-biased and 50coupled to drive 50-
Ω
ground terminated lines.
Ω
terminated, for capacitance coupling. The outputs are DC-
DATA SHEETS
This document contains data sheets for the KGL4201, KGL4202, GHDD4411, and GHDD4414 10-Gbps
GaAs High-Speed Optical Communication Systems.
Data sheets for other communication devices may be obtained from the Oki Semiconductor WEB site,
www.okisemi.com or from the local sales office.
2Oki Semiconductor
KGL4201
10-GHz 8:1 Multiplexer
GENERAL DESCRIPTION
Oki’s KGL4201 is a 10-GHz 8:1 multiplexer designed to operate in 10-Gbps communication links. This
circuit synchronously merges eight 1.25-Gbps data streams, clocked at low frequency rates into a single
10-Gbps stream, clocked at the higher frequency. In the KGL4201 multiplexer, the 10-GHz master clock is
first divided by two, then by four. The lower frequency components are first multiplexed by four, then
the two groups are merged into a single data stream using the master 10-Gbps clock. Complementary
1/8 synchronous clock outputs are made available from the KGL4201 for use in synchronizing lower frequency logic.
All signal interfaces are 50-
1.25-Gbps clock outputs. The 10-Gbps data output and 10-GHz clock input are AC-capacitively-coupled
for ease of interfacing at microwave speeds and reducing ground noise induced phase jitter. All package
clock and data pins are separated by either ground or supply voltage pins to control the I/O impedance,
maintain signal isolation and reduce phase noise.
The KGL4201 is shipped in a 40-pin ceramic flat-package with impedance-controlling ground plane and
flush mounting bottom heat sink.
Ω
with direct DC coupling on the 1.25-Gbps data inputs and phase-locked
FEATURES
• AC-coupled 10 Gbps I/O: eliminates DC
coupled phase jitter
• 1/8 clock generated on chip: easy to
synchronize downstream logic
• 2 V, 2.4 W
• Isolated I/O pins: minimize noise and
impedance variation
• Packaged in 40-pin ceramic flat-package with
ground plane and heat sink.
Oki’s KGL4202 is a 10-GHz 1:8 demultiplexer designed to operate in 10-Gbps communication links. This
circuit synchronously separates a single 10-Gbps data stream, clocked at up to 10 GHz, into eight lower
frequency data streams, clocked at lower frequency rates. In the KGL4202 demultiplexer, the 10-GHz
master clock is first divided by two, then by four. The 10-Gbps data stream is first divided into two synchronous serial paths, then these two data streams are separated into four each lower speed data streams
and brought out to data latched outputs. Complementary 1/8 synchronous clock outputs are made available from the KGL4202 for use in synchronizing lower frequency logic.
All signal interfaces are 50 Ω with all inputs internally terminated in 50 Ω. Direct DC coupling is used on
the 10-Gbps data input, the 1.25-Gbps data outputs and phase-locked 1.25-Gbps clock outputs. The 10GHz clock input is AC-capacitively-coupled for ease of interfacing at microwave speeds and reducing
ground noise induced phase jitter. The package 10-GHz clock and 10-Gbps data pins are separated by
ground pins to control the I/O impedance, maintain signal isolation and reduce phase noise. The eight
data outputs are distributed to opposite sides of the package to facilitate hardware layout and reduce
noise. Over one third of the chip power is due to the ten 50-Ω outputs.
The KGL4202 is shipped in a 40-pin ceramic flat-package with impedance-controlling ground plane and
flush-mounting bottom heat sink.
FEATURES
• AC-coupled 10 Gbps I/O: eliminates DC
coupled phase jitter
• 1/8 clock generated on chip: easy to
synchronize downstream logic
• Isolated I/O pins: minimizes noise and
impedance variation
• 2 V, 3.2 W
• Packaged in 40-pin ceramic flat-package with
ground plane and heat sink
Oki’s GHDD4411 is a 10-GHz exclusive-OR/NOR circuit designed to function in 10-Gbps high-speed
communication serial bit streams. The EX-OR must operate from both rising and falling edges at an
equivalent speed of 20-Gbps non-return-to-zero (NRZ) signal to extract a 10-Gbps clock from a 10-Gbps
signal. Using closely matched Gilbert cell circuitry, this device operates at over 10 Gbps using DCFL and
SBFL logic from inverted HEMT technology. Internal input 50-Ω terminations and a self-referencing bias
voltage allow capacitive coupling, simplifying interconnections.
The GHDD4411 EX-OR circuit is high-speed in a 28-pin ceramic flat package with impedance-controlling
ground plane and flush-mounting bottom heat sink.
FEATURES
• EX-OR and EX-NOR: outputs optimized for
performance
• 1.5 V, 0.6 W: lowest power with 50-Ω interfaces
• Packaged in 28-pin ceramic flat package with
ground plane and heat sink
Data output voltage amplitudeV
Data output rise/fall timeτ 20ps
DD
B
S
ID
OD
Capacitive coupling0.20.8V
50-Ω load,
Capacitive coupling
-0.32.3V
-0.32.3V
-45100°C
-45125°C
1.41.51.6V
1.41.51.6V
070°C
P-P
0.7V
P-P
OUTPUT WAVEFORM
14Oki Semiconductor
I63A-7, DEC12,5-7, 25C, P
Horizontal - 20ps/Div, Vertical - 200 mV/div
GHDD4414
Decision Circuit with Phase Detectors
GENERAL DESCRIPTION
Oki’s GHDD4414 is a 10-GHz decision circuit designed to strip data from high-speed serial bit streams in
10-Gbps communication links. Using a clock input at up to 10 GHz and using D-flip-flops, EX-ORs, and
phase detectors, this circuit separates a 10-Gbps data stream into: clock output, data output, “phase”
variation output, and data density output.
A 10-GHz master clock drives two D-flip-flops in this circuit. Buffered input data is clocked through the
first flip-flop, then the second, “data out” is taken from the first flip-flop. The data input buffer is composed of a series of inverters to delay the signal and obtain a small decision ambiguity. A phase comparison is made of the buffered data and data from flip-flop one; a second phase comparison is made of the
output of flip-flops one and two. The phase detectors are modified EX-OR circuits with resistor summing
of the logic gates to permit analog measurement of their outputs. Any change in the timing relationships
between the clock and data is seen at the output of the first phase detector. The second flip-flop operates
as a 1-bit shift register with fixed 360-deg phase shift. The second phase detector output depends only
upon the transition density (speed of rise and fall transitions) of the input data signal.
All signal interfaces are 50-Ω with all inputs internally terminated in 50 Ω. The 10-GHz clock and data
inputs are AC capacitively-coupled for ease of interfacing at microwave speeds and reducing ground
noise induced phase jitter. Data and phase outputs are DC-coupled.
FEATURES
• Phase detectors on chip: verifies data integrity
• Isolated 10-Gbps input pins: minimizes noise
and impedance variation
• 1.5 V, 1 W: lowest power with 50-Ω interfaces
• 28-pin ceramic flat package with impedance
controlling ground plane and flush mount heat
sink
The information contained herein can change without notice owing to product and/or technical improvements.
Please make sure before using the product that the information you are referring to is up-to-date.
The outline of action and examples of application circuits described herein have been chosen as an explanation of the standard action
and performance of the product. When you actually plan to use the product, please ensure that the outside conditions are reflected in
the actual circuit and assembly designs.
Oki assumes no responsibility or liability whatsoever for any failure or unusual or unexpected operation resulting from misuse, neglect,
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When designing your product, please use our product below the specified maximum ratings and within the specified operating ranges,
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The products listed in this document are intended for use in general electronics equipment for commercial applications (e.g.,office
automation, communication equipment, measurement equipment, consumer electronics, etc.).These products are not authorized for
use in any system or application that requires special or enhanced quality and reliability characteristics nor in any system or application
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Copyright 1999 Oki Semiconductor
Oki Semiconductor reserves the right to make changes in specifications at anytime and without notice. This information furnished by
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