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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
* * * * * * 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 4.75k pull-up resistor * TTL EN input * Programmable SD level set (SDLVL) * Available in a tiny 10-pin MSOP package
Applications
* * * * * * GE-PON/BPON/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
October 2005
1
M9999-100605-A hbwhelp@micrel.com or (408) 955-1690
Micrel, Inc.
SY88149CL
Typical Application Circuit
October 2005
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M9999-100605-A hbwhelp@micrel.com or (408) 955-1690
Micrel, Inc.
SY88149CL
Ordering Information(1)
Part Number SY88149CLKG SY88149CLKGTR
Notes: 1. Tape and Reel.
(1)
Package Type K10-1 K10-1
Operating Range Industrial Industrial
Package Marking SY88149CL with Pb-Free bar line indicator SY88149CL with Pb-Free bar line indicator
Lead Finish NiPdAu Pb-Free NiPdAu Pb-Free
Pin Configuration
10-Pin MSOP (K10-1)
Pin Description
Pin Number 1 Pin Name EN Type TTL Input: Default is HIGH. Data Input Data Input Pin Function Enable: This input enables the outputs when it is HIGH. Note that this input is internally connected to a 25k pull-up resistor and will default to a logic HIGH state if left open. True data input. Complementary data input. 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. Complementary data output. True data output. Positive power supply.
2 3 4 5
DIN /DIN VREF SDLVL
6 7
GND SD
Ground Open-collector TTL output w/internal 4.75k pull-up resistor PECL Output PECL Output Power Supply
8 9 10
/DOUT DOUT VCC
October 2005
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Micrel, Inc.
SY88149CL
Absolute Maximum Ratings(1)
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 .......................................... -800A to +500A SDLVL Voltage ................................................... VREF to VCC Lead Temperature (soldering, 20sec.) ..................... 260C Storage Temperature (Ts) ....................... -65C to +150C
Operating Ratings(2)
Supply Voltage (VCC)............................. +3.0V to +3.6V Ambient Temperature (TA) ................... -40C to +85C Junction Temperature (TJ) ................. -40C to +120C Junction Thermal Resistance MSOP (JA) Still-air ................................... 113C/W
DC Electrical Characteristics
VCC = 3.0 to 3.6V; RL = 50 to VCC-2V; TA = -40C to +85C, typical values at VCC = 3.3V, TA = 25C.
Symbol ICC SDLVL VOH VOL VIHCMR VREF Parameter Power Supply Current SDLVL Voltage PECL Output HIGH Voltage PECL Output LOW Voltage Common Mode Range Reference Voltage Condition No output load VREF Min Typ 26 Max 39 VCC Units mA V V V V V
VCC-1.085 VCC-0.955 VCC-0.880 VCC-1.830 VCC-1.705 VCC-1.555 GND+2.0 VCC VCC-1.48 VCC-1.32 VCC-1.16
TTL DC Electrical Characteristics
VCC = 3.0 to 3.6V; RL = 50 to VCC-2V; TA = -40C to +85C, typical values at VCC = 3.3V, TA = 25C.
Symbol VIH VIL IIH IIL VOH VOL
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. The data sheet limits are not guaranteed if the device is operated beyond the operating ratings. 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.
Parameter EN Input HIGH Voltage EN Input LOW Voltage EN Input HIGH Current EN Input LOW Current SD Output HIGH Level SD Output LOW Level
Condition
Min 2.0
Typ
Max 0.8
Units V V A A mA V V
VIN = 2.7V VIN = VCC VIN = 0.5V VCC > 3.3V, IOH-MAX < 160A VCC < 3.3V, IOH-MAX < 160A IOL = +2mA -0.3 2.4 2.0
20 100
0.5
V
2. 3.
October 2005
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M9999-100605-A hbwhelp@micrel.com or (408) 955-1690
Micrel, Inc.
SY88149CL
AC Electrical Characteristics
VCC = 3.0V to 3.6V; RLOAD = 50 to VCC-2V; TA = -40C to +85C.
Symbol tr, tf tJITTER VID VOD TOFF TON SDAL SDDL HYSL SDAM SDDM HYSM SDAH SDDH HYSH B-3dB AV(Diff) S21
Notes:
Parameter Output Rise/Fall Time (20% to 80%) Deterministic Random Differential Input Voltage Swing Differential Output Voltage Swing SD Release Time SD Assert Time Low SD Assert Level Low SD De-assert Level Low SD Hysteresis Medium SD Assert Level Medium SD De-assert Level Medium SD Hysteresis High SD Assert Level High SD De-assert Level High SD Hysteresis 3dB Bandwidth Differential Voltage Gain Single-ended Small-Signal Gain
Condition Note 4 Note 5 Note 6 Figure 1 VID > 18mVPP Figure 1
Min
Typ
Max 260
Units ps psPP psRMS
15 5 5 1500 100 100 500 500 1800
mVPP mVPP ns ns mVPP mVPP dB
RSDLVL = 15k, Note 8 RSDLVL = 15k, Note 8 RSDLVL = 15k, Note 7 RSDLVL = 5k, Note 8 RSDLVL = 5k, Note 8 RSDLVL = 5k, Note 7 RSDLVL = 100, Note 8 RSDLVL = 100, Note 8 RSDLVL = 100, Note 7 8 2 3 2
3.4 2.3 3.4 6.2 4.2 3.4 16.4 10.8 3.4 1 42 36 5 5 20 8
mVPP mVPP dB mVPP mVPP dB GHz dB dB
4. 5. 6. 7.
8.
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. 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.
October 2005
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Micrel, Inc.
SY88149CL
Typical Operating Characteristics
VCC = 3.3V, TA = 25C, RL = 50 to VCC-2V, unless otherwise stated.
RSDLVL (k)
RSDLVL (k)
October 2005
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M9999-100605-A hbwhelp@micrel.com or (408) 955-1690
Micrel, Inc.
SY88149CL
Functional Block Diagram
Detailed Description
The SY88149CL high-sensitivity limiting post amplifier operates from a single +3.3V power supply, over temperatures from -40C to +85C. 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.
Signal Detect
The SY88149CL generates a chatter-free Signal-Detect (SD) open-collector TTL output with internal 4.75k 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 ensure the best performance of the device.
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.
Output Buffer
The SY88149CL's PECL output buffer is designed to drive 50 lines. The output buffer requires appropriate termination for proper operation. An external 50 resistor to VCC-2V for each output pin provides this. Figure 3 shows a simplified schematic of the output stage.
October 2005
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M9999-100605-A hbwhelp@micrel.com 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 15k or less.
October 2005
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M9999-100605-A hbwhelp@micrel.com or (408) 955-1690
Micrel, Inc.
SY88149CL
Related Product and Support Documentation
Part Number SY88933AL Application Notes Function 3.3V/5V 1.25Gbps PECL High-Sensitivity Limiting Post Amplifier with TTL SD Notes on Sensitivity and Hysteresis in Micrel Post Amplifiers Data Sheet Link http://www.micrel.com/product-info/sy88933al.shtml http://www.micrel.com/product-info/app_hints+notes.shtml
October 2005
9
M9999-100605-A hbwhelp@micrel.com 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. (c) 2005 Micrel, Incorporated.
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