SY84113BU Low Power 2.5V 1.25Gbps Limiting Post Amplifier with Ultra Wide LOS Range General Description Features The SY84113BU low power limiting post amplifier is • Ultra wide LOS Range (5mVpp to 100mVpp) designed for use in fiber-optic optical modules for • Single 2.5V power supply multirate applications up to 1.25Gbps. The device • Ultra low power consumption (55mW typ) connects to a typical transimpedance amplifier (TIA) and • 125Mbps to 1.25 Gbps operation can produce output signals to CML-level waveforms. • Low-noise CML data outputs Intended for the GbE and Fibre Channel applications, the SY84113BU offers a wide LOS range. It is able to • TTL /EN input detect input signals for as low as 5mVpp and as high as • Programmable LOS level (LOSLVL) 100mVpp. The SY84113BU is intended to be used in • Internal 50Ohm termination AC-coupled input applications. • Available in a tiny 3mm x 3mm QFN package The SY84113BU generates a Loss-of-Signal (LOS) open-collector TTL output. A programmable Loss-ofSignal level set pin (LOSLVL) sets the sensitivity of the Applications input amplitude detection. LOS asserts high if the input • Gigabit Ethernet amplitude falls below the threshold set by LOSLVL and de-asserts low otherwise. The enable input (/EN) de• Fibre Channel asserts the true output signal without removing the input • GEPON signal. The LOS output can be fed back to the /EN input to implement the squelch function that maintains output Markets stability under a loss-of-signal condition. The SY84113BU operates on a single 2.5V power • Datacom/telecom supply and offers ultra low power consumption. This • Compact SFP/SFF Optical transceiver device is perfectly suited to meet the stringent power • SFP/SFF Optical transceiver requirements of the CSFP/SFP/SFF optical modules. All support documentation can be found on Micrel’s web site at: www.micrel.com. _________________________________________________________________________________________________________ Typical Application Micrel Inc. • 2180 Fortune Drive • San Jose, CA 95131 • USA • tel +1 (408) 944-0800 • fax + 1 (408) 474-1000 • http://www.micrel.com January 2011 M9999-011711-A [email protected] or (408) 955-1690 Micrel, Inc. SY84113BU Ordering Information Part Number Package Type Operating Range Package Marking Lead Finish QFN-16 Industrial 113B with Pb-Free bar line indicator NiPdAu Pb-Free QFN-16 Industrial 113B with Pb-Free bar line indicator NiPdAu Pb-Free SY84113BUMG SY84113BUMGTR (1) Notes: 1. Tape and Reel. Pin Configuration 16-Pin (3mm x 3mm) QFN-16 Pin Description Pin Number Pin Name Type 15 /EN TTL Input /Enable: This input enables the outputs when LOW. Internally connected to a 25kΩ pull-up resistor and will default to a logic HIGH state if left open. 1, 4 DIN, /DIN Data Input Differential data inputs. Each input is internally terminated to the VREF pin by a 50Ω resistor. 6 VREF 14 LOSLVL DC Input 2, 3, 10, 11, EPAD GND Ground 7 LOS Open-collector TTL output 12, 9 /DOUT, DOUT CML Output Differential data outputs. Unused output should be terminated 50Ω to VCC. 5, 8, 13, 16 VCC Positive Rail Positive power supply. . Bypass with a 0.1uF || 0.01uF low ESR capacitor as close to VCC pin as possible. January 2011 Pin Function Reference Voltage: Place 0.1uF capacitor to Vcc to help stabilize LOSLVL 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. Device ground. Exposed pad must be connected to PCB ground plane. Loss-of-Signal: asserts high when the data input amplitude falls below the threshold set by LOSLVL. 2 M9999-011711-A [email protected] or (408) 955-1690 Micrel, Inc. SY84113BU Absolute Maximum Ratings(1) Operating Ratings(2) Supply Voltage (VCC) ....................................... 0V to +4.0V Input Voltage (DIN, /DIN) .......................................0 to VCC Output Current (IOUT) ............................................... ±25mA EN Voltage .............................................................0 to VCC VREF Current .......................................... -800µA to +500µA LOSLVL Voltage................................................. VREF to VCC Lead Temperature (soldering, 20sec.) ..................... 260°C Storage Temperature (Ts) ....................... –65°C to +150°C Supply Voltage (VCC) ......................+2.375 to +2.625V Ambient Temperature (TA).................. –40°C to +85°C Junction Temperature (TJ)................ –40°C to +120°C Package Thermal Resistance(3) (θJA) Still-air ............................................... 60°C/W (ψJB) ........................................................... 33°C/W DC Electrical Characteristics VCC = 2.5 ± 5%; TA = –40°C to +85°C, typical values at VCC = 2.5V, TA = 25°C. Symbol Parameter Condition Min Typ Max Units ICC Power Supply Current Outputs terminated 50Ohm to Vcc 22 35 mA LOSLVL LOSLVL Voltage VOH DOUT, /DOUT HIGH Voltage VCC-0.020 VCC-0.005 VCC V VCC V VOL DOUT, /DOUT LOW Voltage VCC-0.475 VCC-0.400 VCC-0.350 V VREF Reference Voltage Vcc – 0.6 V VREF Z0 Single-Ended Output Impedance 40 50 60 Ω ZI Single-Ended Input Impedance 40 50 60 Ω Min Typ Max Units Vcc V 0.8 V TTL DC Electrical Characteristics VCC = 2.5 ± 5%; TA = –40°C to +85°C, typical values at VCC = 2.5V, TA = 25°C. Symbol Parameter VIH /EN Input HIGH Voltage VIL /EN Input LOW Voltage IIH /EN Input HIGH Current VIN = VCC IIL /EN Input LOW Current VIN = 0.5V VOH LOS Output HIGH Level Vcc = 2.5V. IOH < 50uA VOL LOS Output LOW Level IOL = 2mA January 2011 Condition 2.0 20 mA 2 V 0.5 3 µA -0.3 V M9999-011711-A [email protected] or (408) 955-1690 Micrel, Inc. SY84113BU AC Electrical Characteristics VCC = 2.5 ± 5%; TA = –40°C to +85°C, typical values at VCC = 2.5V, TA = 25°C.; RLoad = 50Ω to VCC; Symbol Parameter tr, tf Output Rise/Fall Time Typ Max Units Note 4 150 260 ps Deterministic Note 5 15 psPP Random Note 6 5 psRMS (20% to 80%) tJITTER VID Differential Input Voltage Swing VOD Differential Output Voltage Swing Condition Min 5 Note 4 700 800 1800 mVPP 950 mVPP TOFF LOS Release Time Note 9 2 10 uS TON LOS Assert Time 2 10 uS LOSAL Low LOS Assert Level Note 9 RLOSLVL = 10kΩ, Note 7 LOSDL Low LOS De-assert Level RLOSLVL = 10kΩ, Note 7 HYSL Low LOS Hysteresis RLOSLVL = 10kΩ, Note 8 2 3.1 LOSAM Medium LOS Assert Level RLOSLVL = 5kΩ, Note 7 7 9.2 LOSDM Medium LOS De-assert Level RLOSLVL = 5kΩ, Note 7 HYSM Medium LOS Hysteresis RLOSLVL = 5kΩ, Note 8 LOSAH High LOS Assert Level RLOSLVL = 100Ω, Note 7 LOSDH High LOS De-assert Level RLOSLVL = 100Ω, Note 7 HYSH High LOS Hysteresis RLOSLVL = 100Ω, Note 8 B-3dB 3dB Bandwidth 850 MHz AV(Diff) Differential Voltage Gain 38 dB S21 Single-Ended Small-Signal Gain 32 dB 3.9 mVPP 5.6 mVPP 4.5 mVPP 13.6 16 2 3.4 4.5 60 73 2 26 dB mVPP dB mVPP 103 130 3.0 4.5 mVPP dB 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 ratings 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. Package Thermal Resistance assumes exposed pad is soldered (or equivalent) to the devices most negative potential on the PCB. ψJB uses a 4-layer and θJA in still air unless otherwise stated. 4. Amplifier in limiting mode. Input is a 200MHz square wave. 5. Deterministic jitter measured using 1.250 Gbps K28.5 pattern, VID = 60mVPP. 6. Random jitter measured using 1.250Gbps K28.7 pattern, VID = 60mVPP. 7. 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. 8. 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 on that ratio, the optical hysteresis corresponding to the electrical hysteresis range 2dB-4.5 dB, shown in the AC characteristics table, will be 1dB-3dB Optical Hysteresis. 9. In real world applications, the LOS Release/Assert time can be strongly influenced by the RC time constant of the AC-coupling cap and the 50Ω input termination. To keep this time low, use a decoupling cap with the lowest value that is allowed by the data rate and the number of consecutive identical bits in the application (typical values are in the range of 0.001µF to 1.0µF). January 2011 4 M9999-011711-A [email protected] or (408) 955-1690 Micrel, Inc. SY84113BU Typical Functional Characteristics VCC = 2.5 ± 5%; TA = –40°C to +85°C, typical values at VCC = 2.5V, TA = 25°C.; RLoad = 50Ω to VCC; Typical Operating Characteristics VCC = 2.5 ± 5%; TA = –40°C to +85°C, typical values at VCC = 2.5V, TA = 25°C.; RLoad = 50Ω to VCC; LOS Assert/De-Assert Levels LOS Hysteresis 6 1000 Hysteresis (dB) Amplitude (mV) 5 100 10 4 3 2 1 1 0.1 1 0.1 10 January 2011 1 10 LOSLVL Resistor (KOhm) LOSLVL Resistor (KOhm) 5 M9999-011711-A [email protected] or (408) 955-1690 Micrel, Inc. SY84113BU Functional Block Diagram Detailed Description The SY84113BU is a high-sensitivity limiting post amplifier that operates from a single +2.5V 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 SY84113BU generates a LOS output signal that can be fed back to /EN for output stability in the absence of a signal at the input. LOSLVL sets the sensitivity of the input amplitude detection. SY84113BU offers ultra wide LOS detection range. This allows the device to be used in multiple AC-coupled applications. Input Amplifier/Buffer Figure 2 shows a simplified schematic of the input stage. The high-sensitivity of the input amplifier can detect and amplify AC-coupled signals as small as 5mVpp to full CML output level. The input stage also can allow signals as large as 1800mVpp. Input signals are amplified with a typically 38dB differential voltage gain until they reach the limiting mode of the amplifier. SY84113BU outputs in standard 400mV CML output levels. Loss-of-Signal The SY84113BU generates a chatter-free loss-of-signal (LOS) open-collector TTL output as shown in Figure 4. LOS is used to determine that the input amplitude is too small to be considered as a valid input. LOS asserts high if the input amplitude falls below the threshold set by LOSLVL and de-asserts low otherwise. LOS can be fed back to the enable (/EN) input to maintain output stability under a loss of signal condition. /EN de-asserts low the true output signal without removing the input signals. Typically, 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. Output Buffer The SY84113BU’s CML output buffer is designed to drive 50Ω lines and is internally terminated with 50Ω to VCC. Figure 3 shows a schematic of the output stage. Hysteresis The SY84113BU provides typically 3dB LOS electrical hysteresis, which is defined as 20log (VINLOS-Assert / VINLOS-De-Assert). Since the relationship between the voltage out of the ROSA to optical power at its input is linear, the optical hysteresis will be typically half of the electrical hysteresis reported in the datasheet, but in practice the ratio between electrical and optical hysteresis is found to be within the range 1.5-1.8. Thus 3dB electrical hysteresis will correspond to an optical hysteresis within the range 1.7dB - 2dB. January 2011 6 M9999-011711-A [email protected] or (408) 955-1690 Micrel, Inc. SY84113BU Figure 1. VIS and VID Definition Figure 2. Input Structure Figure 3. Output Structure Figure 4. LOS Output Structure Figure 5. LOSLVL Setting Circuit Note: Recommended value for RLOSLVL is 15kΩ or less. January 2011 7 M9999-011711-A [email protected] or (408) 955-1690 Micrel, Inc. SY84113BU Package Information 16-Pin (3mm x 3mm) QFN (QFN-16) 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 Micrel makes no representations or warranties with respect to the accuracy or completeness of the information furnished in this data sheet. This information is not intended as a warranty and Micrel does not assume responsibility for its use. Micrel reserves the right to change circuitry, specifications and descriptions at any time without notice. No license, whether express, implied, arising by estoppel or otherwise, to any intellectual property rights is granted by this document. Except as provided in Micrel’s terms and conditions of sale for such products, Micrel assumes no liability whatsoever, and Micrel disclaims any express or implied warranty relating to the sale and/or use of Micrel products including liability or warranties relating to fitness for a particular purpose, merchantability, or infringement of any patent, copyright or other intellectual property right. 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. © 2010 Micrel, Incorporated. January 2011 8 M9999-011711-A [email protected] or (408) 955-1690