5V/3.3V 1.25Gbps HIGH-SPEED LIMITING POST AMPLIFIER FEATURES DESCRIPTION ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ 3.3V and 5V power supply options Up to 1.5Gbps operation Low power Low noise Chatter-Free /LOS Generation PECL /LOS Output TTL /EN Input Differential PECL inputs for data /EN input is TTL with internal 27K pull up Single power supply Designed for use with Micrel-Synergy laser diode driver and controller ■ Available in a tiny 10-pin (3mm) MSOP The SY88913V limiting post amplifier with its high gain and wide bandwidth is ideal for use as a post amplifier in fiber-optic receivers with data rates up to 1.5Gbps. Signals as small as 5mVp-p can be amplified to drive devices with PECL inputs. The SY88913V generates a chatter-free PECL Loss of Signal (/LOS) output. The SY88913V incorporates a programmble 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 2. Figure 3 and 4 show the relationship between input level sensitivity and the voltage set on LOSLVL. APPLICATIONS PIN CONFIGURATION /EN 1 ■ ■ ■ ■ 10 VCC DIN 2 /DIN 3 SY88913V 9 DOUT MSOP K10-1 8 /DOUT VREF 4 7 /LOS LOSLVL 5 6 GND 1.25Gbps Gigabit Ethernet 531Mbps and 1062Mbps Fibre Channel 622Mbps SONET Gigabit Interface Converter BLOCK DIAGRAM DIN DOUT ECL Buffer Limiting Amplifer /DIN /DOUT VREF Enable /EN VCC Level Detect GND LOS LOSLVL Rev.: B 1 Amendment: /0 Issue Date: August 2000 Micrel SY88913V PIN NAMES Pin GENERAL DESCRIPTION Type General The SY88913V is an integrated limiting amplifier intended for high-frequency fiber-optic applications. The circuit connects to typical transimpedance amplifiers found within a fiber-optics link. The linear signal output from a transimpedance amplifier can contain significant amounts of noise, and may vary in amplitude over time. The SY88913V limiting amplifier quantizes the signal and outputs a voltage-limited waveform. The TTL /EN pin allows the user to disable the signal without removing the input signal. Function DIN Data Input Data Input /DIN Data Input Inverting Data Input LOSLVL Input Loss of Signal Level Set /EN TTL Input Output Enable (active Low) /LOS PECL Output Loss of Signal Indicator (active Low) GND Ground Ground DOUT PECL Output Data Output /DOUT PECL Output Inverting Data Output VCC Power Supply Positive Power Supply VREF Output Reference Voltage Output for LOS Level Set (see Fig. 2) ABSOLUTE MAXIMUM RATINGS(1) Symbol Rating Value Unit VCC Power Supply Voltage 0 to +7.0 V DIN, /DIN Input Voltage 0 to VCC V DOUT, /DOUT, /LOS Output Voltage (with 50Ω load) VCC –2.5 to VCC +0.3 V LOSLVL Input Voltage 0 to VCC V VREF Output Voltage VCC –2.0 to VCC V TA Operating Temperature Range –40 to +85 °C Tstore Storage Temperature Range –55 to +125 °C NOTE: 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 Micrel SY88913V DC ELECTRICAL CHARACTERISTICS VCC = +3.3V ±10% or +5V ±10%, RLOAD = 50Ω to VCC –2V TA = –40°C Symbol Parameter TA = 0°C TA = +25°C TA = +85°C Min. Max. Min. Max. Min. Typ. Max. Min. Max. Unit — — 35 35 — — 35 35 — — 21 23 35 35 — — 40 40 mA ICC Power Supply Current(1) 5V 3.3V IIL /EN Input LOW Current –0.3(5) — –0.3(5) — –0.3(5) — — –0.3(5) — mA IIH /EN Input HIGH Current — — 20(2) 100(3) — — 20(2) 100(3) — — — — 20(2) 100(3) — — 20(2) 100(3) µA VCMR Common Mode Range Voffset Differential Output Offset LOSLVL LOSLVL Level VOH DOUT and /DOUT HIGH Output VCC –1085 VCC –880 VCC –1025 VCC –880 VCC –1025 VCC –955 VCC –880 VCC –1025 VOL GND +2.0 VCC –1.0 GND +2.0 VCC –1.0 GND +2.0 — VCC –1.0 GND +2.0 VCC –1.0 V — ±100 — ±100 — ±40 ±100 — ±100 mV VREF VCC VREF VCC VREF — VCC VREF VCC V VCC –880 mV DOUT and /DOUT LOW Output VCC –1830 VCC –1555 VCC –1810 VCC –1620 VCC –1810 VCC –1705 VCC –1620 VCC –1810 VCC –1620 mV VREF Reference Supply(4) VCC –1.38 VCC –1.26 VCC –1.38 VCC –1.26 VCC –1.38 VCC –1.32 VCC –1.26 VCC –1.38 VIH /EN Input HIGH Voltage 2.0 — 2.0 — 2.0 — — VIL /EN Input LOW Voltage — 0.8 — 0.8 — — 0.8 VCC –1.26 V 2.0 — V — 0.8 V 4. IREF must be limited to be within –0.8mA (source) and 0.5mA (sink). 5. VIN = 0.5V. NOTES: 1. No Output Load. 2. VIN = 2.7V. 3. VIN = VCC. AC ELECTRICAL CHARACTERISTICS VCC = +3.3V ±10% or +5V ±10%, RLOAD = 50Ω to VCC –2V TA = –40°C Symbol Parameter TA = 0°C TA = +25°C TA = +85°C Min. Max. Min. Max. Min. Typ. Max. Min. Max. Unit — dB PSRR Power Supply(1) Rejection Ratio — — — — — 35 — — VID Input Voltage Range 5 1800 5 1800 5 — 1800 5 VOD Differential Output Voltage Swing(2) — 200 — — — 200 — — — 200 700 250 — — — 200 — — mV mV tOFFL /LOS Release Time(3) Minimum Input — 0.5 — 0.5 — 0.1 0.5 — 0.5 µs tONL /LOS Assert Time(3) — 0.5 — 0.5 — 0.2 0.5 — 0.5 µs — 0.1 0.5 — 0.5 µs Time(4) Input referred, 55MHz 1800 mVp-p tOFFH /LOS Release Maximum Input — 0.5 — 0.5 VSR /LOS Sensitivity Range 5 50 5 50 5 — 50 5 50 mVp-p HYS /LOS Hysteresis 2 8 2 8 2 4.6 8 2 8 dB tr, tf Output Rise/Fall Time — — 260 — — — 260 — — — 170 trin,tfin 260 — — — 260 — ps NOTES: 1. Input referred noise = RMS output noise/low frequency gain. 2. Input is 622MHz square wave. Conditions VID = 15mVp-p VID = 5mVp-p VID > 100mVp-p VID < 100mVp-p 3. Input is a 200MHz square wave, tr < 300ps, 8mVp-p. 4. Input is a 200MHz square wave, tr < 300ps, 1.8Vp-p. 3 Micrel SY88913V APPLICATION NOTE Output Termination The SY88913V outputs must be terminated with a 50Ω load to VCC –2V (or Thevenin equivalent). The SY88913V ground pin 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. Layout and PCB Design Since the SY88913V is a high-frequency component, performance can largely be determined by board layout and design. A common problem with high-gain amplifiers is feedback from the large swing outputs to the input via the power supply. VCC 0.1µF 0.1µF DIN+ R1 DIN– LOSLVL 50Ω 50Ω R2 VREF VREF 0.1µF Figure 1. Differential Input Configuration Figure 2. LOSLVL Circuit NOTES: LOSLVL = VCC –1.32 + R2 × 1.32 R1 + R2 R1 + R2 ≥ 5kΩ PRODUCT ORDERING CODE 4 Ordering Code Package Type Operating Range SY88913VKC K10-1 Commercial Micrel SY88913V PERFORMANCE CURVE LOS Assert and Deassert Levels vs LOSLVL 3.3V TA = 25°C 1.25Gbps Pattern 27-1 90 80 70 60 50 40 30 20 10 0 0 LOS Assert and Deassert Levels vs LOSLVL 100 INPUT LEVEL (mVp-p) INPUT LEVEL (mVp-p) 100 70 60 50 40 30 20 10 0 -0.2 -0.4 -0.6 -0.8 -1.0 -1.2 LOSLVL = VCC – V (V) 5.0V TA = 25°C 1.25Gbps Pattern 27-1 90 80 0 -0.2 -0.4 -0.6 -0.8 -1.0 -1.2 LOSLVL = VCC – V (V) Figure 4. 5.0V LOS Assert and Deassert Levels vs. LOSLVL Figure 3. 3.3V LOS Assert and Deassert Levels vs. LOSLVL 5 Micrel SY88913V 10 LEAD MSOP (K10-1) Rev. 00 MICREL-SYNERGY TEL + 1 (408) 980-9191 FAX 3250 SCOTT BOULEVARD SANTA CLARA CA 95054 USA + 1 (408) 914-7878 WEB http://www.synergysemi.com http://www.micrel.com This information is believed to be accurate and reliable, however no responsibility is assumed by Micrel for its use nor for any infringement of patents or other rights of third parties resulting from its use. No license is granted by implication or otherwise under any patent or patent right of Micrel Inc. © 2000 Micrel Incorporated 6