MICREL SY88149CLKG

SY88149CL
3.3V, 1.25Gbps PECL Limiting Post
Amplifier w/High Gain TTL Signal Detect
General Description
The SY88149CL is a high-sensitivity limiting post
amplifier designed for use in fiber-optic receivers. These
devices connect to typical transimpedance amplifiers
(TIAs). The linear signal output from TIAs can contain
significant amounts of noise and may vary in amplitude
over time. The SY88149CL quantizes these signals and
outputs PECL level waveforms.
The SY88149CL operates from a single +3.3V power
supply, over temperatures ranging from –40oC to +85oC.
With its wide bandwidth and high gain, signals with data
rates up to 1.25Gbps, and as small as 5mVpp, can be
amplified to drive devices with PECL inputs.
The SY88149CL generates a high-gain signal-detect
(SD) open-collector TTL output. The SD function has a
high gain input stage for increased sensitivity. A
programmable Signal Detect level set pin (SDLVL) sets
the sensitivity of the input amplitude detection. SD
asserts high if the input amplitude rises above the
threshold set by SDLVL and de-asserts low otherwise.
The enable input (EN) de-asserts the true output signal
without removing the input signal. The SD output can be
fed back to the EN input to maintain output stability
under a loss-of-signal condition. Typically, 3.4dB SD
hysteresis is provided to prevent chattering.
All support documentation can be found on Micrel’s web
site at: www.micrel.com.
Features
February 2007
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•
•
•
•
•
•
Single 3.3V power supply
Fast SD enable/disable time
622Mbps to 1.25Gbps operation
Low-noise PECL data outputs
High-gain SD
Chatter-free Open-Collector TTL signal detect (SD)
output with internal 4.75kΩ pull-up resistor
• TTL EN input
• Programmable SD level set (SDLVL)
• Available in a tiny 10-pin MSOP package
Applications
•
•
•
•
•
•
GE-PON/GPON/EPON
Gigabit Ethernet
1062Mbps Fibre Channel
OC-12/24 SONET/SDH
High-gain line driver and line receiver
Low-gain TIA interface
Markets
• FTTH/FTTP
• Datacom/Telecom
• Optical transceiver
M9999-021207-B
[email protected] or (408) 955-1690
Micrel, Inc.
SY88149CL
Typical Application Circuit
February 2007
2
M9999-021207-B
[email protected] or (408) 955-1690
Micrel, Inc.
SY88149CL
Ordering Information(1)
Part Number
Package
Type
Operating
Range
Package Marking
Lead Finish
K10-1
Industrial
149C with Pb-Free bar line indicator
NiPdAu Pb-Free
K10-1
Industrial
149C with Pb-Free bar line indicator
NiPdAu Pb-Free
SY88149CLKG
SY88149CLKGTR
(1)
Note:
1.
Tape and Reel.
Pin Configuration
10-Pin MSOP (K10-1)
Pin Description
Pin Number
Pin Name
Type
1
EN
TTL Input: Default is
HIGH.
2
DIN
Data Input
True data input.
3
/DIN
Data Input
Complementary data input.
4
VREF
5
SDLVL
6
GND
Ground
7
SD
Open-collector TTL
output w/internal 4.75kΩ
pull-up resistor
8
/DOUT
PECL Output
Complementary data output.
9
DOUT
PECL Output
True data output.
10
VCC
Power Supply
Positive power supply.
February 2007
Pin Function
Enable: This input enables the outputs when it is HIGH. Note
that this input is internally connected to a 25kΩ pull-up resistor
and will default to a logic HIGH state if left open.
Reference voltage: Placing a capacitor here to VCC helps
stabilize SDLVL.
Input
Signal Detect Level Set: a resistor from this pin to VCC sets the
threshold for the data input amplitude at which SD will be
asserted.
Device ground.
Signal-Detect asserts high when the data input amplitude rises
above the threshold set by SDLVL.
3
M9999-021207-B
[email protected] or (408) 955-1690
Micrel, Inc.
SY88149CL
Absolute Maximum Ratings(1)
Operating Ratings(2)
Supply Voltage (VCC) ....................................... 0V to +7.0V
Input Voltage (DIN, /DIN) .......................................0 to VCC
Output Current (IOUT)
Continuous........................................................ ±50mA
Surge .............................................................. ±100mA
EN Voltage .............................................................0 to VCC
VREF Current .......................................... -800µA to +500µA
SDLVL Voltage ................................................... VREF to VCC
Lead Temperature (soldering, 20sec.) ..................... 260°C
Storage Temperature (Ts) ....................... –65°C to +150°C
Supply Voltage (VCC)............................. +3.0V to +3.6V
Ambient Temperature (TA) ................... –40°C to +85°C
Junction Temperature (TJ) ................. –40°C to +120°C
Junction Thermal Resistance
MSOP (θJA) Still-air ................................... 113°C/W
DC Electrical Characteristics
VCC = 3.0 to 3.6V; RL = 50Ω to VCC-2V; TA = –40°C to +85°C, typical values at VCC = 3.3V, TA = 25°C.
Symbol
Parameter
Condition
Min
Typ
ICC
Power Supply Current
No output load
SDLVL
SDLVL Voltage
VOH
PECL Output HIGH Voltage
VCC-1.085 VCC-0.955 VCC-0.880
VOL
PECL Output LOW Voltage
VCC-1.830 VCC-1.705 VCC-1.555
V
VIHCMR
Common Mode Range
GND+2.0
V
VREF
Reference Voltage
VCC-1.48 VCC-1.32 VCC-1.16
26
VREF
Max
Units
39
mA
VCC
V
VCC
V
V
TTL DC Electrical Characteristics
VCC = 3.0 to 3.6V; RL = 50Ω to VCC-2V; TA = –40°C to +85°C, typical values at VCC = 3.3V, TA = 25°C.
Symbol
Parameter
VIH
EN Input HIGH Voltage
VIL
EN Input LOW Voltage
IIH
EN Input HIGH Current
IIL
EN Input LOW Current
VOH
SD Output HIGH Level
VOL
SD Output LOW Level
Condition
Min
Typ
Max
2.0
VIN = 2.7V
VIN = VCC
Units
V
0.8
V
20
µA
100
µA
VIN = 0.5V
-0.3
VCC > 3.3V, IOH-MAX < 160µA
2.4
V
VCC < 3.3V, IOH-MAX < 160µA
2.0
V
IOL = +2mA
mA
0.5
V
Notes:
1.
Permanent device damage may occur if absolute maximum ratings are exceeded. This is a stress rating only and functional operation is not
implied at conditions other than those detailed in the operational sections of this data sheet. Exposure to absolute maximum rating conditions
for extended periods may affect device reliability.
2.
The data sheet limits are not guaranteed if the device is operated beyond the operating ratings.
3.
Thermal performance assumes the use of a 4-layer PCB. Exposed pad must be soldered (or equivalent) to the device’s most negative potential
on the PCB.
February 2007
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M9999-021207-B
[email protected] or (408) 955-1690
Micrel, Inc.
SY88149CL
AC Electrical Characteristics
VCC = 3.0V to 3.6V; RLOAD = 50Ω to VCC–2V; TA = –40°C to +85°C.
Symbol
Parameter
Condition
tr, tf
Output Rise/Fall Time
(20% to 80%)
Min
Typ
Max
Note 4
tJITTER
Deterministic
Note 5
15
psPP
Random
Note 6
5
psRMS
VID
Differential Input Voltage Swing
Figure 1
VOD
Differential Output Voltage
Swing
VID > 18mVPP Figure 1
TOFF
SD Release Time
100
500
ns
TON
SD Assert Time
100
500
ns
SDAL
Low SD Assert Level
SDDL
Low SD De-assert Level
HYSL
Low SD Hysteresis
SDAM
Medium SD Assert Level
RSDLVL = 5kΩ, Note 8
6.2
SDDM
Medium SD De-assert Level
RSDLVL = 5kΩ, Note 8
3
HYSM
Medium SD Hysteresis
RSDLVL = 5kΩ, Note 7
2
SDAH
High SD Assert Level
RSDLVL = 100Ω, Note 8
SDDH
High SD De-assert Level
RSDLVL = 100Ω, Note 8
8
10.8
HYSH
High SD Hysteresis
RSDLVL = 100Ω, Note 7
2
3.4
B-3dB
3dB Bandwidth
1
GHz
AV(Diff)
Differential Voltage Gain
42
dB
S21
Single-ended Small-Signal Gain
36
dB
260
5
1800
ps
mVPP
mVPP
1500
RSDLVL = 15kΩ, Note 8
Units
3.4
mVPP
RSDLVL = 15kΩ, Note 8
2.3
mVPP
RSDLVL = 15kΩ, Note 7
3.4
dB
8
4.2
mVPP
mVPP
3.4
5
dB
16.4
20
mVPP
mVPP
5
dB
Notes:
4.
5.
6.
7.
Amplifier in limiting mode. Input is a 200MHz square wave.
Deterministic jitter measured using 1.25Gbps K28.5 pattern, VID = 10mVPP.
Random jitter measured using 1.25Gbps K28.7 pattern, VID = 10mVPP.
This specification defines electrical hysteresis as 20log(SD Assert/SD De-assert). The ratio between optical hysteresis and
electrical hysteresis is found to vary between 1.5 and 2 depending upon the level of received optical power and ROSA
characteristics. Based upon that ratio, the optical hysteresis corresponding to the electrical hysteresis range 2dB-5dB, shown
in the AC characteristics table, will be 1dB-4dB optical Hysteresis.
8. See “Typical Operating Characteristics” for a graph showing how to choose a particular RSDLVL for a particular SD assert and
its associated de-assert amplitude.
February 2007
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M9999-021207-B
[email protected] or (408) 955-1690
Micrel, Inc.
SY88149CL
Typical Operating Characteristics
VCC = 3.3V, TA = 25°C, RL = 50Ω to VCC–2V, unless otherwise stated.
RSDLVL (kΩ)
RSDLVL (kΩ)
February 2007
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M9999-021207-B
[email protected] or (408) 955-1690
Micrel, Inc.
SY88149CL
Functional Block Diagram
Detailed Description
Signal Detect
The SY88149CL high-sensitivity limiting post amplifier
operates from a single +3.3V power supply, over
temperatures from –40°C to +85°C. Signals with data
rates up to 1.25Gbps and as small as 5mVPP can be
amplified. Figure 1 shows the allowed input voltage
swing. The SY88149CL generates an SD output,
allowing feedback to EN for output stability. SDLVL sets
the sensitivity of the input amplitude detection.
The SY88149CL generates a chatter-free Signal-Detect
(SD) open-collector TTL output with internal 4.75kΩ pullup resistor, as shown in Figure 4. SD is used to
determine that the input amplitude is too small to be
considered a valid input. SD asserts high if the input
amplitude rises above threshold set by SDLVL and deasserts low otherwise. SD can be fed back to the enable
(EN) input to maintain output stability under a SDs of
signal condition. EN de-asserts low the true output
signal without removing the input signals. Typically,
3.4dB SD hysteresis is provided to prevent chattering.
Input Amplifier/Buffer
Figure 2 shows a simplified schematic of the input
stage. The high-sensitivity of the input amplifier allows
signals as small as 5mVPP to be detected and amplified.
The input amplifier allows input signals as large as
1800mVPP. Input signals are linearly amplified with a
typically 42dB differential voltage gain. Since it is a
limiting amplifier, the SY88149CL outputs typically
1500mVPP voltage-limited waveforms for input signals
that are greater than 12mVPP. Applications requiring the
SY88149CL to operate with high-gain should have the
upstream TIA placed as close as possible to the
SY88149CL’s input pins. This ensures the best
performance of the device.
Output Buffer
The SY88149CL’s PECL output buffer is designed to
drive 50Ω lines. The output buffer requires appropriate
termination for proper operation. An external 50Ω
resistor to VCC–2V for each output pin provides this.
Figure 3 shows a simplified schematic of the output
stage.
February 2007
Signal Detect Level Set
A programmable SD level set pin (SDLVL) sets the
threshold of the input amplitude detection. Connecting
an external resistor between VCC and SDLVL sets the
voltage at SDLVL. This voltage ranges from VCC to VREF.
The external resistor creates a voltage divider between
VCC and VREF, as shown in Figure 5.
Hysteresis
The SY88149CL provides typically 3.4dB SD electrical
hysteresis. By definition, a power ratio measured in dB
is 10log (power ratio). Power is calculated as V2IN/R for
an electrical signal. Hence the same ratio can be stated
as 20log (voltage ratio). While in linear mode, the
electrical voltage input changes linearly with the optical
power and hence the ratios change linearly. Therefore,
the optical hysteresis in dB is half the electrical
hysteresis in dB given in the data sheet. The
SY88149CL is an electrical device; this data sheet
refers to hysteresis in electrical terms. With 3.4dB SD
hysteresis, a voltage factor of 1.5 is required to assert or
de-assert SD.
7
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[email protected] or (408) 955-1690
Micrel, Inc.
SY88149CL
Figure 1. VIS and VID Definition
Figure 2. Input Structure
Figure 3. Output Structure
Figure 4. SD Output Structure
Figure 5. SDLVL Setting Circuit
Note: Recommended value for RSDLVL is 15kΩ or less.
February 2007
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M9999-021207-B
[email protected] or (408) 955-1690
Micrel, Inc.
SY88149CL
Related Product and Support Documentation
Part Number
Function
Data Sheet Link
SY88933AL
3.3V/5V 1.25Gbps PECL High-Sensitivity
Limiting Post Amplifier with TTL SD
http://www.micrel.com/product-info/sy88933al.shtml
Application Notes
Notes on Sensitivity and Hysteresis in Micrel
Post Amplifiers
http://www.micrel.com/product-info/app_hints+notes.shtml
February 2007
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M9999-021207-B
[email protected] or (408) 955-1690
Micrel, Inc.
SY88149CL
Package Information
10-Pin MSOP (K10-1)
MICREL, INC. 2180 FORTUNE DRIVE SAN JOSE, CA 95131 USA
TEL +1 (408) 944-0800 FAX +1 (408) 474-1000 WEB http://www.micrel.com
The information furnished by Micrel in this data sheet is believed to be accurate and reliable. However, no responsibility is assumed by Micrel for
its use. Micrel reserves the right to change circuitry and specifications at any time without notification to the customer.
Micrel Products are not designed or authorized for use as components in life support appliances, devices or systems where malfunction of a
product can reasonably be expected to result in personal injury. Life support devices or systems are devices or systems that (a) are intended for
surgical implant into the body or (b) support or sustain life, and whose failure to perform can be reasonably expected to result in a significant
injury to the user. A Purchaser’s use or sale of Micrel Products for use in life support appliances, devices or systems is a Purchaser’s own risk
and Purchaser agrees to fully indemnify Micrel for any damages resulting from such use or sale.
© 2005 Micrel, Incorporated.
February 2007
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[email protected] or (408) 955-1690