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SY88993AL
3.3V 3.2Gbps High-Speed Limiting Post Amplifier with High Input Sensitivity
General Description
The SY88993AL limiting post amplifier, with its wide bandwidth, is ideal for use as a post amplifier in fiber-optic receivers with data rates up to 3.2Gbps. Signals as small as 4mVPP can be amplified to drive devices with CML inputs or AC-coupled PECL inputs. The SY88993AL generates a chatter-free Loss-of-Signal (LOS) open collector TTL output using an external resistor, as shown Figure 1. The SY88993AL incorporates a programmable level detect function to identify when the input signal has been lost. This information can be fed back to the /EN input of the device to maintain stability under loss of signal conditions. Using LOSLVL pin the sensitivity of the level detect can be adjusted. The LOSLVL voltage can be set by connecting a resistor divider between VCC and VREF, Figure 5. Datasheets and support documentation can be found on Micrel's web site at: www.micrel.com.
Features
* * * * * * * * Up to 3.2Gbps operation Low noise CML data outputs Chatter-Free LOS generation Open Collector TTL LOS output TTL /EN Input Differential PECL inputs for data Single 3.3V power supply Available in a tiny 10-pin (3mm x 3mm) MSOP
Applications
* * * * * * PON SFP/SFF/GBIC optical transceivers Gigabit Ethernet 1X and 2X Fibre Channel SONET/SDH: OC 3/12/24/48 - STM 1/4/8/16 Line driver and line receiver
Markets
* FTTX * Datacom/Telecom
Figure 1. LOSLVL resistor configuration
Micrel Inc. * 2180 Fortune Drive * San Jose, CA 95131 * USA * tel +1 (408) 944-0800 * fax + 1 (408) 474-1000 * http://www.micrel.com
September 2008
M9999-093008-A hbwhelp@micrel.com or (408) 955-1690
Micrel, Inc.
SY88993AL
Block Diagram
Detailed Description
The SY88993AL is a high-sensitivity limiting post amplifier that operates from a single +3.3V power o o supply, over temperatures from -40 C to +85 C. Signals with data rates up to 3.2Gbps and as small as 4mVPP can be amplified. Figure 2 shows the allowed input voltage swing. The SY88993AL generates a LOS output. LOSLVL sets the sensitivity of the input amplitude detection. Input Amplifier/Buffer Figure 3 shows a simplified schematic of the SY88993AL's input stage. The high-sensitivity of the input amplifier allows signals as small as 4mVPP to be detected and amplified. The input amplifier also allows input signals as large as 1800mVPP. Input signals below 6mVpp are linearly amplified with a typical 38dB differential voltage gain. Since it is a limiting amplifier, the SY88993AL outputs typically 800mVPP voltagelimited waveforms for input signals that are greater than 10mVPP. Applications requiring the SY88993AL to operate with high-gain should have the upstream TIA placed as close as possible to the SY88993AL's input pins to ensure the best performance of the device. Output Buffer The SY88993AL's CML output buffer is designed to drive 50 lines. The output buffer requires appropriate termination for proper operation. An external 50 resistor to VCC for each output pin provides this. Figure 4 shows a simplified schematic of the output stage. Loss-of-Signal The SY88993AL generates a chatter-free LOS opencollector TTL output which requires an external pull-up September 2008 2 resistor, as shown in Figure 1. LOS is used to determine that the input amplitude is large enough to be considered a valid input. LOS asserts high if the input amplitude falls below the threshold sets by LOSLVL and de-asserts low otherwise. LOS can be fed back to the enable bar (/EN) input to maintain output stability under a loss of signal condition. /EN de-asserts the true output signal without removing the input signals. Typically, 5.6dB LOS hysteresis is provided to prevent chattering. Loss-of-Signal Level Set The SY88993AL incorporates a programmable level detect function to identify when the input signal has been lost. This information can be fed back to the /EN input of the device to maintain stability under loss of signal conditions. Using LOSLVL pin the sensitivity of the level detect can be adjusted. The LOSLVL voltage can be set by connection a resistor divider between VCC and VREF, Figure 5. Hysteresis The SY88993AL typically provides 5.6dB LOS electrical hysteresis. By definition, a power ratio measured in dB is 2 10log (power ratio). Power is calculated as V IN/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 therefore, the ratios change linearly. Thus, the optical hysteresis in dB is half the electrical hysteresis in dB given in the data sheet. Since the SY88993AL is an electrical device, this data sheet refers to hysteresis in electrical terms. With 5.6dB LOS hysteresis, a voltage factor of about 2 is required to assert or de-assert LOS.
M9999-093008-A hbwhelp@micrel.com or (408) 955-1690
Micrel, Inc.
SY88993AL
Ordering Information
Part Number SY88993ALKG SY88993ALKGTR
Note: 1. Tape and reel.
(1)
Package Type K10-1 K10-1
Operating Range Industrial Industrial
Package Marking 993L with Pb-Free bar-line indicator 993L with Pb-Free bar-line indicator
Lead Finish Pb-Free NiPdAu Pb-Free NiPdAu
Pin Configuration
10-Pin MSOP (K10-1)
Pin Description
Pin Number 1 2 3 4 5 6 7 8 9 10 Pin Name /EN DIN /DIN VREF LOSLVL GND LOS /DOUT DOUT VCC Pin Function TTL (Input): Output enable (Active Low). Data (Input): Data input. Data (Input): Complementary data input. Output: Reference voltage output for LOS Level Set (See Figure 3). Input: Loss-of-Signal Level Set Ground. TTL Output (Open Collector): Loss-of-Signal indicator (Active High). CML (Output): Inverting data output. CML (Output): Data output. Power Supply: Positive power supply.
September 2008
3
M9999-093008-A hbwhelp@micrel.com or (408) 955-1690
Micrel, Inc.
SY88993AL
Absolute Maximum Ratings(1)
Supply Voltage (VCC) ......................................... 0V to +4.0V Input Voltage (DIN, /DIN) ...................................... 0V to VCC Lead Temperature (soldering, #sec.) ......................... 260C Storage Temperature (Ts) ........................... -55C to +85C
Operating Ratings(2)
Supply Voltage (VIN) ..................................... +3.0V to +3.6V Ambient Temperature (TA) .......................... -40C to +85C Junction Thermal Resistance MSOP (JA) ......................................................113C/W o MSOP (JB) ....................................................... 96 C/W
DC Electrical Characteristics
VCC = +3.3V 10%; RLOAD = 50 to VCC; TA = -40C to +85C, unless noted. Typical values at Vcc = 3.3V, TA = 25C
Symbol ICC IOH LOSLVL VOH VOL ZO VREF VOFFSEST VCMR Parameter Power Supply Current LOS Output Leakage LOSLVL Level Output HIGH Voltage Output LOW Voltage Single-Ended Output Impedance Reference Voltage Differential Output Offset Common Mode Range GND 2 Note 9 Note 10 Condition No output load. Vcc = 3.6V VREF VCC-20 Vcc-350 40 VCC-1.38 VCC-5 VCC-400 50 VCC-1.32 Min Typ 40 Max 55 100 VCC VCC Vcc-475 60 VCC-1.26 80 VCC-0.2 Units mA A V mV mV V mV V
TTL DC Electrical Characteristics
VCC = +3.3V 10%; RLOAD = 50 to VCC; TA = -40C to +85C, unless noted.
Symbol VIH VIL IIH IIL Parameter /EN Input HIGH Voltage /EN Input LOW Voltage /EN Input HIGH Current /EN Input LOW Current VIN = 2.7V VIN = VCC VIN = 0.5V -300 Condition Min 2.0 0.8 20 100 V A A A Typ Max Units
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.
September 2008
4
M9999-093008-A hbwhelp@micrel.com or (408) 955-1690
Micrel, Inc.
SY88993AL
AC Electrical Characteristics
VCC = +3.3V 10%; RLOAD = 50 to VCC; TA = -40C to +85C, unless noted.
Symbol LOSAH LOSDH HYSH LOSAM LOSDM HYSM LOSAL LOSDL HYSL PSRR tOFFL tOFFH tONL tr , tf VID VOD VSR AV(Diff) B-3dB S21
Notes: 4. Input referred noise = RMS output noise/low frequency gain. Input referred, 55MHz. 5. Input is a 200MHz square wave, tr < 300ps. 6. With input signal VID > 50mVPP with 50 load. 7. Input is a 200MHz square wave, tr < 300ps, 50 load. 8. VID > 10mVPP. 9. Output levels are based on 50 impedance. If the load impedance is different, the output level will be changed. 10. See output structure.
Parameter High LOS Assert Level High LOS De-assert Level High LOS Hysteresis Medium LOS Assert Level Medium LOS De-assert Level Medium LOS Hysteresis Low LOS Assert Level Low LOS De-assert Level Low LOS Hysteresis Power Supply Rejection Ratio LOS Release Time Minimum Input LOS Release Time Maximum Input LOS Assert Time Differential Output Rise/Fall Time (20% to 80%) Input Voltage Range Differential Output Voltage Swing LOS Sensitivity Range Differential Voltage Gain 3dB Bandwidth Single-Ended Small Signal-Gain
Condition VLOSLVL = VCC VLOSLVL = VCC
Min 30 2
Typ 43 83 5.6 31 55
Max 95 8 65 8 45 8 0.5 0.5 0.5 120 1800
Units mVPP mVPP dB mVPP mVPP dB mVPP mVPP dB dB s s s Ps mVPP mVPP mVPP DB GHz dB
VLOSLVL = VCC - 400mV VLOSLVL = VCC - 400mV
20 2
5.6 19 31 5.6 35 0.1 0.1 0.2 60
VLOSLVL = VCC - 800mV VLOSLVL = VCC - 800mV
10 2
Note 4 Note 5 Note 5 Note 5 Note 6 4 Note 7, 8, 9, 10 700 4
800 38 2.5
950 50
26
32
September 2008
5
M9999-093008-A hbwhelp@micrel.com or (408) 955-1690
Micrel, Inc.
SY88993AL
Typical Characteristics
Functional Characteristics
September 2008
6
M9999-093008-A hbwhelp@micrel.com or (408) 955-1690
Micrel, Inc.
SY88993AL
Figure 2. VIS and VID
Figure 3. Differential Input Configuration
Figure 4. Differential Output Configuration
Notes: 1. Resistor Divider = R2/ (R1 + R2) 2. R1 + R2 5k
Figure 5. LOSLVL Circuit
September 2008
7
M9999-093008-A hbwhelp@micrel.com or (408) 955-1690
Micrel, Inc.
SY88993AL
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) 2008 Micrel, Incorporated.
September 2008
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M9999-093008-A hbwhelp@micrel.com or (408) 955-1690

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