Micrel, Inc. SY88953L DESCRIPTION FEATURES ■ ■ ■ ■ ■ ■ Single 3.3V power supply Up to 10.7Gbps operation 800mVp-p output swing with 30ps edge rates 28dB voltage gain with 5mVp-p input sensitivity On chip 50Ω Ω I/O termination Programmable signal detect (SD and /SD) with 6dB hysteresis ■ Chatter-free OC-TTL SD and /SD outputs with internal Ω pull-up resistors can feedback to TTL enable 5kΩ (/EN) input ■ Available in a tiny (3mm × 3mm) 16-pin MLF® package or die The SY88953L high-speed 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 SY88953L quantizes these signals and outputs CML level waveforms. The SY88953L operates from a single +3.3V power supply, over temperatures ranging from –40°C to +85°C. With its wide bandwidth and high gain, signals with data rates up to 10.7Gbps and as small as 5mVp-p can be amplified to drive devices with CML inputs. The SY88953L outputs TTL signal-detect (SD and /SD) signals. 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 deasserts low otherwise. /SD is the complementary output of SD. /SD can be fedback to the enable (/EN) input to maintain output stability under a loss of signal condition. /EN deasserts the true output signal without removing the input signal. Typically 6dB SD hysteresis is provided to prevent chattering. The SY88953L also includes an input threshold adjustment to correct pulsewidth distortion. APPLICATIONS ■ ■ ■ ■ ■ SY88953L 3.3V 10.7Gbps CML LIMITING POST AMPLIFIER W/ TTL SD AND /SD OC-192 SDH/SONET 10G Ethernet/Fibre Channel receivers Upto 10.7Gbps proprietary link XFP transceivers Line driver/receiver TYPICAL APPLICATIONS CIRCUIT SD 0.1µF VCC /SD VTHP /EN DOUT From Transimpedance Amp. DIN 0.1µF SY88953L 0.1µF To CDR /DOUT /DIN SDLVL VTHN GND VCC 0.1µF 200kΩ MicroLeadFrame and MLF are registered trademarks of Amkor Technology, Inc. M9999-081506 [email protected] or (408) 955-1690 Rev.: C 1 Amendment: /0 Issue Date: August 2006 Micrel, Inc. SY88953L 16 15 14 Ordering Information GND SDLVL /EN VTHP PACKAGE/ORDERING INFORMATION 13 DIN 1 12 DOUT VCC 2 11 VCC VCC 3 10 VCC /DIN 4 9 Package Type Operating Range Package Marking Lead Finish SY88953LMI MLF-16 Industrial 953L Sn-Pb SY88953LMITR(1) MLF-16 Industrial 953L Sn-Pb SY88953LMG MLF-16 Industrial 953L with Pb-Free bar-line indicator Pb-Free NiPdAu SY88953LMGTR(1) MLF-16 Industrial 953L with Pb-Free bar-line indicator Pb-Free NiPdAu 8 GND 7 /SD 6 SD VTHN 5 /DOUT Part Number Note: 1. Tape and Reel. 16-Pin MLF® PIN DESCRIPTION Pin Number Pin Name Type 1 DIN Data Input 2, 3, 10, 11 VCC Power Supply 4 /DIN Data Input 5 VTHN Input 6 SD Open-collector TTL output w/ internal 5kΩ pull-up resistor Signal-Detect: Asserts high when the data input amplitude rises above the threshold set by SDLVL. 7 /SD Open-collector TTL output w/ internal 5kΩ pull-up resistor Inverted Signal-Detect: Asserts low when the data input amplitude rises above the threshold set by SDLVL. 8, 13, EP GND Ground 9 /DOUT CML Output Complementary data output. 12 DOUT CML Output True data output. 14 SDLVL Input 15 /EN TTL Input: Default is high. 16 VTHP Input M9999-081506 [email protected] or (408) 955-1690 Pin Function True data input w/50Ω resistor to VCC. Positive power supply. Complementary data input w/50Ω resistor to VCC. /DIN DC threshold adjustment pin. Device ground. Exposed pad must be soldered to PCB ground for proper electrical and thermal performance. 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. Enable: Deasserts true data output when high. DIN DC threshold adjustement pin. 2 Micrel, Inc. SY88953L Absolute Maximum Ratings(1) Operating Ratings(2) Supply Voltage (VCC) ................................... -0.5V to +4.0V Data Input Voltage (DIN, /DIN) ... (VCC–1.0V) to (VCC+0.5V) Data Output Voltage (DOUT, /DOUT) .................................... .......................................... (VCC–1.0V) to (VCC+0.5V) Data Output Current (DOUT, /DOUT) ........................... 22mA /EN Voltage ............................................................ 0 to VCC SD, /SD Current ........................................................... 5mA SDLVL Voltage ...................................... (VCC–1.3V) to VCC 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 Package Thermal Resistance(3) MLF® (θJA) Still-Air ..................................................... 59°C/W (ψJB) Still-Air .................................................... 32°C/W DC ELECTRICAL CHARACTERISTICS VCC = 3.0V to 3.6V; RLOAD = 50Ω to VCC; TA = –40°C to +85°C; typical values at VCC = 3.3V, TA = 25°C Symbol Parameter Condition Min Typ Max Units ICC Power Supply Current no output load 110 170 mA VSDLVL SDLVL Voltage VCC V 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 SD, /SD Output HIGH Level VOL SD, /SD Output LOW Level IOL = +2mA VOH Output HIGH Voltage 50Ω to VCC output load VOL Output LOW Voltage 50Ω to VCC output load VOFFSET Differential Output Offset ZO Single-Ended Output Impedance 40 50 60 Ω ZO Single-Ended Input Impedance 40 50 60 Ω VCC–1.3 2.0 V 0.8 V 20 µA –0.3 mA 2.4 V 0.5 VCC–0.020 VCC–0.005 VCC VCC–0.560 VCC–0.400 VCC–0.240 ±80 Note s: 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 ratlng 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. Exposed pad must be soldrered to PCB's ground plane. M9999-081506 [email protected] or (408) 955-1690 3 V V V mV Micrel, Inc. SY88953L AC ELECTRICAL CHARACTERISTICS VCC = 3.0V to 3.6V; RLOAD = 50Ω to VCC; TA = –40°C to +85°C; typical values at VCC = 3.3V, TA = 25°C Symbol Parameter Condition HYS SD Hysteresis electrical signal PSRR Power Supply Rejection Ratio 35 tOFF SD, /SD Release Time 0.1 0.5 µs tON SD, /SD Assert Time 0.2 0.5 µs tr,tf Output Rise/Fall Time 30 35 ps VID Differential Input Voltage Swing 1800 mVPP VOD Differential Output Voltage Swing 1120 mVPP VSR SD Sensitivity Range 5 50 mVPP AV(Diff) Differential Voltage Gain 22 28 dB S21 Single-Ended Small-Signal Gain 16 22 dB B–3dB 3dB Bandwidth 7.5 GHz M9999-081506 [email protected] or (408) 955-1690 Min Typ Max Units 2 6 8 dB VID ≥ 50mVPP 5 480 4 800 dB Micrel, Inc. SY88953L TYPICAL OPERATING CHARACTERISTICS SD Assert and Deassert Levels vs. SDLVL 120 INPUT (mVp-p) 80 DIN OFFSET (VCC – mV) 3.3V TA = 25°C 10Gbps Pattern 223-1 100 Assert 60 40 Deassert 20 -1 -0.8 -0.6 -0.4 -0.2 SDLVL=VCC – V -50 -100 -150 -200 -250 -300 0.0 0 1.0 2.0 VTH (V) 3.0 4.0 (5mV/div.) 0 DIN OFFSET vs. VTH 0 23ns TIME (20ps/div.) 23.15ns (3.3V, 27°C, 10Gbps) 30mVPP Differential Input Example of Using VTH to Cancel Effect of Pulse Width Distortion M9999-081506 [email protected] or (408) 955-1690 5 Micrel, Inc. SY88953L DETAILED DESCRIPTION Signal-Detect The SY88953L generates chatter-free signal-detect (SD and /SD) open-collector TTL outputs with internal 5kΩ pullup resistors as shown in Figure 4. SD is used to determine that the input amplitude is large enough to be considered a valid input. SD asserts high if the input amplitude rises above the threshold set by SDLVL and deasserts low otherwise. /SD is the complementary output of SD. /SD asserts low if the input amplitude rises above the threshold set by SDLVL and deasserts high otherwise. /SD can be fed back to the enable (/EN) input to maintain output stability under a loss of signal condition. /EN deasserts the true output signal without removing the input signals. Typically 6dB SD hysteresis is provided to prevent chattering. The SY88953L high-speed 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 10.7Gbps and as small as 5mVp-p can be amplified. Figure 1 shows the allowed input voltage swing. The SY88953L generates SD and /SD outputs. SDLVL sets the sensitivity of the input amplitude detection. The SY88953L also includes an input threshold adjustment to correct pulsewidth distortion Input Amplifier/Buffer Figure 2 shows a simplified schematic of the SY88953L's input stage. The high-sensitivity of the input amplifier allows signals as small as 5mVp-p to be detected and amplified. The input amplifier allows input signals as large as 1800mVpp. Input signals are linearly amplified with a typically 28dB differential voltage gain. Since it is a limiting amplifier, the SY88953L outputs typically 800mV PP voltage-limited waveforms for input signals that are greater than 32mVp-p. Applications requiring the SY88953L to operate with highgain should have the upstream TIA placed as close as possible to the SY88953L’s input pins to ensure the best performance of the device. Signal-Detect Level Set A programmable signal-detect 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 voltages ranges from VCC to VCC-1.3V. The external resistor creates a voltage divider between VCC and VCC-1.3V as shown in Figure 5. If desired, an appropriate external voltage may be applied rather than using a resistor. The smaller the external resistor, implying a smaller voltage difference from SDLVL to VCC, the smaller the SD sensitivity. Hence, larger input amplitude is required to assert SD. “Typical Operating Characteristics” shows the relationship between the input amplitude detection sensitivity and the SDLVL voltage. Threshold Adjustment The SY88953L’s duty cycle can be controlled by forcing an offset at either input using VTHP or VTHN. Typically, only one of the inputs is required to be adjusted, depending on the required direction of the pulse width adjustment. The SY88953L implements current source based offset control of the inputs. “Typical Operating Characteristics” shows the offset applied to the input for a given VTH voltage. This feature is disabled by simply setting VTH to GND. Hysteresis The SY88953L provides typically 6dB 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 datasheet. The SY88953L provides typically 3dB SD optical hysteresis. As the SY88953L is an electrical device, this datasheet refers to hysteresis in electrical terms. With 6dB SD hysteresis, a voltage factor of two is required to assert or deassert SD. Output Buffer The SY88953L’s CML output buffer is designed to drive 50Ω lines. The output buffer requires appropriate termination for proper operation. An external 50Ω resistor to VCC for each output pin provides this. Figure 3 shows a simplified schematic of the output stage and includes an appropriate termination method. Of course, driving a downstream device that is internally terminated with 50Ω to VCC eliminates the need for external termination. As noted in the previous section, the amplifier outputs typically 800mVp-p waveforms across 25Ω total loads. The output buffer thus switches typically 16mA tail-current. M9999-081506 [email protected] or (408) 955-1690 6 Micrel, Inc. SY88953L DATA+ 2.5mV (Min.) VIS(mVp-p) 900mV (Max.) DATA- (DATA+) - (DATA-) 5mVp-p (Min.) VID(mVp-p) 1800mVp-p (Max.) Figure 1. VIS and VID Definitions VCC VCC RLOAD VCC 50Ω 50Ω 50Ω Q 50Ω AC-coupling capacitors DIN 50Ω Z0 = 50Ω /Q 50Ω Z0 = 50Ω ESD STRUCTURE AC-coupling capacitors 0.1µF /DIN 0.1µF VTHP VTHN GND GND Figure 2. Input Structure ESD STRUCTURE Figure 3. Output Structure VCC RSDLVL SDLVL VCC 5kΩ SD 3kΩ VCC -1.3V Figure 5. SDLVL Setting Circuit Figure 4. SD, /SD Output Structure M9999-081506 [email protected] or (408) 955-1690 7 Micrel, Inc. SY88953L FUNCTIONAL BLOCK DIAGRAM VTHP VCC GND VCC VCC 50½ 50½ DOUT /DOUT DIN 50½ Amplifier Amplifier /DIN VCC 50½ TTL Buffer /EN Level Detect Amplifier TTL Buffer SD /SD VTHN SDLVL DESIGN PROCEDURE Layout and PCB Design Since the SY88953L is a high-frequency component, performance can be largely determined by the board layout and design. A common problem with high-gain amplifiers is the feedback from the large swing outputs to the input via the power supply. M9999-081506 [email protected] or (408) 955-1690 The SY88953L’s ground pins should be connected to the circuit board ground. Use multiple PCB vias close to the part to connect to ground. Avoid long, inductive runs which can degrade performance. 8 Micrel, Inc. SY88953L 16-PIN MicroLeadFrame® (MLF-16) Package EP- Exposed Pad Die CompSide Island Heat Dissipation Heat Dissipation VEE Heavy Copper Plane VEE Heavy Copper Plane PCB Thermal Consideration for 16-Pin MLF® Package (Always solder, or equivalent, the exposed pad to the PCB) Package Notes: 1. Package meets Level 2 qualification. 2. All parts are 100% baked and dry-packaged before shipment. 3. Exposed pads must be soldered to a ground for proper thermal management. 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 datasheet 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 at Purchaser’s own risk and Purchaser agrees to fully indemnify Micrel for any damages resulting from such use or sale. © 2005 Micrel, Incorporated. M9999-081506 [email protected] or (408) 955-1690 9