SY88347DL 3.3V, 3.2Gbps PECL Limiting Post Amplifier with High-Gain TTL Loss-of-Signal General Description Features The SY88347DL low-power limiting post amplifier is designed for use in fiber-optic receivers. The device connects 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 SY88347DL quantizes these signals and outputs PECL-level waveforms. The SY88347DL 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 3.2Gbps, and as small as 5mVPP, can be amplified to drive devices with PECL inputs. The SY88347DL generates a high-gain loss-of-signal (LOS) open-collector TTL output. The LOS function has a high-gain input stage for increased sensitivity. A programmable loss-of-signal level set pin (LOSLVL) sets the sensitivity of the input amplitude detection. LOS asserts high if the input amplitude falls below the threshold sets by LOSLVL and de-asserts low otherwise. The enable bar input (/EN) de-asserts the true output signal without removing the input signal. The LOS output can be fed back to the /EN input to maintain output stability under a loss-of-signal condition. Typically, 3.3dB LOS hysteresis is provided to prevent chattering. Datasheet and support documentation can be found on Micrel’s web site at: www.micrel.com. • • • • • Single 3.3V power supply 155Mbps to 3.2Gbps operation Low-noise PECL data outputs High-gain LOS output Chatter-free Open-Collector TTL Loss-of-Signal (LOS) output • TTL /EN input • Programmable LOS level set (LOSLVL) • Ideal for multi-rate applications • Available in a tiny 10-pin EPAD-MSOP Applications • • • • • APON, BPON, EPON, GEPON, and GPON Gigabit Ethernet 1X and 2X Fibre Channel SONET/SDH:OC-3/12/24/48 – STM 1/4/8/16 High-gain line driver and line receiver Markets • • • • • FTTP Optical transceivers Datacom/Telecom Low-gain TIA interface Long reach FOM MLF and MicroLeadFrame are registered trademarks of Amkor Technology. Micrel Inc. • 2180 Fortune Drive • San Jose, CA 95131 • USA • tel +1 (408) 944-0800 • fax + 1 (408) 474-1000 • http://www.micrel.com February 2007 M9999-021707-B [email protected] or (408) 955-1690 Micrel, Inc. SY88347DL Typical Application Pin Configuration 10-Pin EPAD-MSOP (K10-2) Ordering Information Part Number SY88347DLEY SY88347DLEYTR (1) Package Type Operating Range Package Marking Lead Finish K10-2 Industrial 347D with Pb-Free bar line indicator Matte-Sn K10-2 Industrial 347D with Pb-Free bar line indicator Matte-Sn Note: 1. Tape and Reel. February 2007 2 M9999-021707-B [email protected] or (408) 955-1690 Micrel, Inc. SY88347DL Pin Description Pin Number MSOP February 2007 Pin Name Type Pin Functioon 1 /EN TTL Input: Default is HIGH. 2 DIN Data Input True data input. 3 /DIN Data Input Complementary data input. 4 VREF 5 LOSLVL Input Loss-of-Signal Level Set: a resistor from this pin to VCC sets the threshold for the data input amplitude at which LOS will be asserted. 6 GND, Exposed Pad Ground Device ground. GND and Exposed pad are to be tied to the same ground plane. 7 LOS Open-collector TTL output 8 /DOUT PECL Output Complementary data output. 9 DOUT PECL Output True data output. 10 VCC Power Supply Positive power supply. /Enable: This input enables the outputs when it is LOW. Note that this input is internally connected to a 25kΩ pullup resistor and will default to logic HIGH state if left open. Reference Voltage: Bypass with 0.1µF low ESR capacitor from VREF to VCC to stabilize LOSLVL and VREF. Loss-of-Signal: asserts high when the data input amplitude falls below the threshold set by LOSLVL. 3 M9999-021707-B [email protected] or (408) 955-1690 Micrel, Inc. SY88347DL Absolute Maximum Ratings(1) Storage Temperature (Ts) .....................-65°C to +150°C Supply Voltage (VCC) .................................. 0V to +4.0V Input Voltage (DIN, /DIN) ................................... 0 to VCC Output Current (IOUT) Continuous.....................................................+50mA Surge ...........................................................+100mA /EN Voltage ........................................................ 0 to VCC VREF Current .......................................-800µA to +500µA LOSLVL Voltage.............................................. VREF to VCC Lead Temperature (soldering, 20sec.) .................. 260°C Operating Ratings(2) Supply Voltage (VCC)............................+3.0V to +3.6V Ambient Temperature (TA) ..................–40°C to +85°C Junction Temperature (TJ) ................–40°C to +125°C Junction Thermal Resistance(3) EPAD-MSOP θJA (Still-Air) ..............................................38oC/W ψJB .............................................................22oC/W DC Electrical Characteristics VCC = 3.0V to 3.6V; RL = 50Ω to VCC-2V; TA = –40°C to +85°C; typical values at VCC = 3.3V, TA = 25oC. Symbol Parameter Condition ICC Power Supply Current No output load Min Typ Max Units 40 60 mA VCC V VLOSLVL LOSLVL Voltage VOH PECL Output HIGH Voltage VCC-1.085 VCC-0.955 VCC-0.880 VREF V VOL PECL Output LOW Voltage VCC-1.880 VCC-1.705 VCC-1.555 V VOFFSET Differential Output Offset VREF Reference Voltage VCC-1.48 VIHCMR Input Common Mode Range GND+2.0 VCC-1.32 +120 mV VCC-1.16 V VCC V Max Units TTL DC Electrical Characteristics VCC = 3.0V to 3.6V; TA = –40°C to +85°C. Symbol Parameter VIH /EN Input HIGH Voltage VIL /EN Input LOW Voltage IIH /EN Input HIGH Current Condition Min Typ 2.0 V 0.8 V VIN = 2.7V 20 µA VIN = VCC 100 µA IIL /EN Input LOW Current VIN = 0.5V IOH LOS Output Leakage VOH = 3.6V -300 100 µA uA VOL LOS Output LOW Level IOL = +2mA 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 4 M9999-021707-B [email protected] or (408) 955-1690 Micrel, Inc. SY88347DL AC Electrical Characteristics VCC = 3.0V 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 tr, tf Output Rise/Fall Time (20% to 80%) Note 4 tJITTER Min Typ Max 150 Units ps Deterministic Note 5 15 psPP Random Note 6 5 psRMS VID Differential Input Voltage Swing Figure 1 VOD Differential Output Voltage Swing VID > 12mVPP, Figure 1 TOFF LOS Release Time 2 10 µs TON LOS Assert Time 2 10 µs LOSAL Low LOS Assert Level LOSDL Low LOS De-assert Level HYSL Low LOS Hysteresis LOSAM Medium LOS Assert Level RLOSLVL = 5kΩ, Note 8 LOSDM Medium LOS De-assert Level RLOSLVL = 5kΩ, Note 8 HYSM Medium LOS Hysteresis RLOSLVL = 5kΩ, Note 7 LOSAH High LOS Assert Level RLOSLVL = 100Ω, Note 8 LOSDH High LOS De-assert Level RLOSLVL = 100Ω, Note 8 HYSH High LOS Hysteresis RLOSLVL = 100Ω, Note 7 B-3dB 3dB Bandwidth 2 GHz AV(Diff) Differential Voltage Gain 42 dB S21 Single-ended Small-Signal Gain 36 dB 5 1800 1500 RLOSLVL = 15kΩ, Note 8 mVPP mVPP 2.3 mVPP RLOSLVL = 15kΩ, Note 8 4.0 mVPP RLOSLVL = 15kΩ, Note 7 4.8 dB 4.8 7 3.3 13.2 19.5 3.4 mVPP 2 2 10 2 30 9 4.5 mVPP dB mVPP 23 4.5 mVPP dB Notes: 4. Amplifier in limiting mode. Input is a 200MHz, 100mVpp square wave. 5. Deterministic jitter measured using 3.2Gbps K28.5 pattern, VID = 10mVPP. 6. Random jitter measured using 3.2Gbps K28.7 pattern, VID = 10mVPP. 7. This specification defines electrical hysteresis as 20log (LOS De-assert/LOS 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-4.5dB, shown in the AC characteristics table, will be 1dB-3dB Optical Hysteresis. 8. See “Typical Operating Characteristics” for a graph showing how to choose a particular RLOSLVL for a particular LOS assert and its associated de-assert amplitude. February 2007 5 M9999-021707-B [email protected] or (408) 955-1690 Micrel, Inc. SY88347DL Typical Characteristics RLOSLVL (kΩ) February 2007 RLOSLVL (kΩ) 6 M9999-021707-B [email protected] or (408) 955-1690 Micrel, Inc. SY88347DL Functional Block Diagram Detailed Description The SY88347DL low-power, high-sensitivity limiting post amplifier operates from a single +3.3V power supply, over temperatures from –40oC to +85oC. Signals with data rates up to 3.2Gbps and as small as 5mVPP can be amplified. Figure 1 shows the allowed input voltage swing. The SY88347DL generates a LOS output allowing feedback to /EN for output stability. LOSLVL sets the sensitivity of the input amplitude detection. Input Amplifier/Buffer Figure 2 shows a simplified schematic of the SY88347DL’s input stage. The high-sensitivity of the input amplifier allows signals as small as 5mVPP to be detected and amplified. The input amplifier also allows input signals as large as 1800mVPP. Input signals are linearly amplified with a typical 42dB differential voltage gain. Since it is a limiting amplifier, the SY88347DL outputs typically 1500mVPP voltage-limited waveforms for input signals that are greater than 12mVPP. Applications requiring the SY88347DL to operate with high-gain should have the upstream TIA placed as close as possible to the SY88347DL’s input pins. This ensures the best performance of the device. Output Buffer The SY88347DL’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 Loss-of-Signal The SY88347DL generates a chatter-free LOS opencollector TTL output, as shown in Figure 4. 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, 3.3dB LOS hysteresis is provided to prevent chattering. Loss-of-Signal Level Set A programmable LOS level set pin (LOSLVL) sets the threshold of the input amplitude detection. Connecting an external resistor between VCC and LOSLVL sets the voltage at LOSLVL. 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 SY88347DL typically provides 3.3dB LOS 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 therefore, the ratios will change linearly. Thus, the optical hysteresis in dB is half the electrical hysteresis in dB given in the data sheet. Since the SY88347DL is an electrical device, this data sheet refers to hysteresis in electrical terms. With 3.3dB LOS hysteresis, a voltage factor of 1.46 is required to assert or de-assert LOS. 7 M9999-021707-B [email protected] or (408) 955-1690 Micrel, Inc. SY88347DL Figure 1. VIS and VID February 2007 Figure 2. Input Structure Figure 3. Output Structure Figure 4. LOS Output Structure Figure 5. LOSLVL Setting Circuit 8 M9999-021707-B [email protected] or (408) 955-1690 Micrel, Inc. SY88347DL Package Information 10-Pin EPAD-MSOP (K10-2) 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. © 2006 Micrel, Incorporated. February 2007 9 M9999-021707-B [email protected] or (408) 955-1690