HFD3031 Schmitt Input, Inverting TTL Output Receiver FEATURES • Converts fiber optic input signals to TTL totem pole outputs • Sensitivity is 1.5 µW peak (-28.2 dBm) • Single 5 V supply requirement • Schmitt circuitry gives 17 dB dynamic range and low Pulse Width Distortion • Operates up to 200K bps NRZ • Plastic TO-18 style cap • Designed to operate with Honeywell 850 nm LEDs and integrated transmitters FIBER106.TIF DESCRIPTION The HFD3031 is a sensitive Schmitt optical receiver designed for use in short distance, 850 nm fiber optic systems. It uses a bipolar integrated receiver circuit with internal voltage regulation and internal photodiode. The TTL inverting output allows the HFD3031 to be directly interfaced with standard digital TTL circuits. The plastic package with a TO-18 collar can be mounted in several types of fiber optic connectors. APPLICATION The HFD3031 fiber optic receiver converts the optical signal in a point to point data communications fiber optic link to a TTL output. It is designed to be mounted in a fiber optic connector that aligns the optical axis of the component to the axis of the optical fiber. Its photodiode is mechanically centered within the TO-18 package. Electrical isolation is important in obtaining the maximum performance of this high sensitivity receiver. Shielding can reduce coupled noise and obtain maximum sensitivity. This can include the use of ground planes in the PCB, shielding around the device, and shielding around the leads. An internal voltage regulator allows operation with a 5 volt supply. An external bypass capacitor (0.1 µF) between VÙÙ (pin 1) and ground (pin 3) is recommended for maximum power supply noise rejection. Honeywell also offers companion transmitters designed to operate in conjunction with the HFD3031. Honeywell reserves the right to make changes in order to improve design and supply the best products possible. OUTLINE DIMENSIONS in inches (mm) WINDOW .047 (1.19) DIA. CRUSH RING .229 (5.82) .220 (5.59) .210 (5.33) .081 (2.06) .176 (4.47) .165 (4.19) .500 MIN (12.7) 1 3 2 FIBER202.DIM Pinout 1. VÙÙ 2. Output (TTL) 3. Case (ground) h 285 HFD3031 Schmitt Input, Inverting TTL Output Receiver APPLICATION (continued) Optical power (photons) from the fiber strikes the photodiode and is converted to electrical current which is then converted into voltage in the transimpedance preamplifier. The comparator stage incorporates the Schmitt trigger circuitry which ensures proper output signals. The Schmitt detection circuit monitors the input preamplifier, and triggers when its output exceeds preset levels. These levels are established sufficiently above the worst case RMS noise level to allow an excellent BER (bit error rate), while low enought to give enough sensitivity to permit operation over long links. This circuitry recognizes the positive and negative going input signals. When optical input goes from high to low, electrical output changes to "1" (high). The output changes to "0" (low) when optical input goes from low to high. Limited bandwidth minimizes noise problems. The Schmitt trigger detector stage output is designed to ensure good pulse width distortion (PWD). 286 h Honeywell reserves the right to make changes in order to improve design and supply the best products possible. HFD3031 Schmitt Input, Inverting TTL Output Receiver ELECTRO-OPTICAL CHARACTERISTICS (VÙÙ = 5 VDC unless otherwise stated) PARAMETER SYMBOL Input Sensitivity [À] MIN PÛÜ (peak) High Level Logic Output Voltage Low Level Logic Output Voltage VÏÝ VÏÚ Rise Time Fall Time Supply Current Pulse Width Distortion [À] tß t¸ IÙÙ PWD 2.4 TYP MAX UNITS TEST CONDITIONS 0.5 1.5 µW 3.3 0.3 0.4 V V æÎ = 850 nm into 100/140 micron fiber cable, Duty cycle = 50%, square wave PÛÜ – 0.1 µW, VÙÙ = 5.0 VDC PÛÜ — 1.5 µW, VÙÙ = 5.0 VDC IÏ – 16 mA PÛÜ – 0.1 µW, VÏ = 0.4 to 2.4 V PÛÜ — 1.5 µW, VÏ = 2.4 to 0.4 V VÙÙ = 5 VDC f = 20 kHz, Duty Cycle = 50% PÛÜ = 1.5 µW PÛÜ = 100 µW PÛÜ —1.0µW, Duty Cycle = 50% 12 3 6 5 5 Bandwidth Output Impedance BW IÞ 12 10 10 200 20 ns ns mA % kHz í Notes 1. TÙ = +25¡C ABSOLUTE MAXIMUM RATINGS (25¡C Free-Air Temperature unless otherwise noted) Storage temperature -40 to 85¡C RECOMMENDED OPERATING CONDITIONS Operating temperature 0 to +85¡C (heat sinked) Operating temperature -40 to +85¡C Supply voltage +4.5 to +7 V Lead solder temperature 260¡C, 10 s Optical input power 1.5 to 100 µW Junction temperature 150¡C Optical signal pulse width > 4 µs Supply voltage +7 V Stresses greater than those listed under "Absolute Maximum Ratings" may cause permanent damage to the device. This is a stress rating only and functional operation of the device at these or any other conditions above those indicated in the operational section of this specification is not implied. Exposure to absolute maximum rating conditions for extended periods of time may affect reliability. Honeywell reserves the right to make changes in order to improve design and supply the best products possible. h 287 HFD3031 Schmitt Input, Inverting TTL Output Receiver ORDER GUIDE Description Catalog Listing Standard screening, plastic package HFD3031-002 This package is also available in special interface receptacles for interfacing to standard fiber optic cables. CAUTION The inherent design of this component causes it to be sensitive to electrostatic discharge (ESD). To prevent ESD-induced damage and/or degradation to equipment, take normal ESD precautions when handling this product. BLOCK DIAGRAM FIBER INTERFACE Honeywell detectors are designed to interface with multimode fibers with sizes (core/cladding diameters) ranging from 50/125 to 200/230 microns. Honeywell performs final tests using 100/140 micron core fiber. The fiber chosen by the end user will depend upon a number of application issues (distance, link budget, cable attenuation, splice attenuation, and safety margin). The 50/125 and 62.5/125 micron fibers have the advantages of high bandwidth and low cost, making them ideal for higher bandwidth installations. The use of 100/140 and 200/230 micron core fibers results in greater power being coupled by the transmitter, making it easier to splice or connect in bulkhead areas. Optical cables can be purchased from a number of sources. SWITCHING WAVEFORM FIBER003.SCH Fig. 1 Pulse Width Distortion vs Temperature FIBER202.CIR Fig. 2 Pulse Width Distortion vs Frequency FIBER038.GRA 288 h FIBER039.GR Honeywell reserves the right to make changes in order to improve design and supply the best products possible. HFD3031 Schmitt Input, Inverting TTL Output Receiver Fig. 3 Pulse Width Distortion vs Optical Input Power Fig. 4 Propagation Delay vs Optical Input Power FIBER041.GR FIBER040.GRA Honeywell reserves the right to make changes in order to improve design and supply the best products possible. h 289