Silicon Schottky Barrier Detector Diodes Features 3 Both P-Type and N-Type Low Barrier Silicon Available Low 1/f Noise Bonded Junctions for Reliability Planar Passivated Beam-Lead and Chip Construction See Also Zero Bias Silicon Schottky Barrier Detector Diodes Description Alpha packaged, beam-lead and chip Schottky barrier detector diodes are designed for applications through 40 GHz in Ka-band. They are made by the deposition of a suitable barrier metal on an epitaxial silicon substrate to form the junction. The process and choice of materials result in low series resistance along with a narrow spread of capacitance values for close impedance control. P-type silicon is used to obtain superior 1/f noise characteristics. N-type silicon is also available. The packaged diodes are suitable for use in waveguide, coaxial, and stripline applications. The beam-lead and chip diodes can also be mounted in a variety of packages or on special customer substrates. Unmounted beam-lead diodes are especially well suited for use in MIC applications. Mounted beam-lead diodes can be easily used in MIC, stripline or other such circuitry. The "Universal Chips" are designed for a high degree of device reliability in both commercial and industrial uses. The offset bond pad assures that no mechanical damage will occur at the junction during the wire bonding. Additionally the 4 mil bond pad eliminates performance variation due to bonding and is ideal for automated assembly, and improves efficiency during manual operations as well. The choice on "N" and "P" type silicon allows for the designer to optimize the silicon material for the intended application. Doppler mixers, high sensitivity detectors will benefit from using the low noise characteristics of the "P" type silicon. Low conversion loss mixers and biased detectors can be designed using standard "N" type material. Alpha Industries * * Fax * E-mail * Visit our web site: 3-33 Silicon Schottky Barrier Detector Diodes Applications These diodes are categorized by TSS (Tangential Signal Sensitivity) for detector applications in four frequency ranges: S, X, Ku, and Ka-band. However, they can also be used as modulators, high speed switches and low power limiters. RF parameters on chips and beam-lead diodes are tested on a sample basis, while breakdown voltage and capacitance measurements are 100% tested. Packaged diodes are 100% RF tested. Bias does, however, increase noise, particularly in the 1/f region. Therefore, it should be kept at as low a level as possible (typically 5-50 microamps). Voltage output versus power input as a function of load resistance and bias is shown in Figures 1a and 1b. Assembly and Handling Procedure TSS is the one parameter that best describes a diode's use as a video detector. It is defined as the amount of signal power, below a one milliwatt reference level, required to produce an output pulse whose amplitude is sufficient to raise the noise fluctuations by an amount equal to the average noise level. TSS is approximately 4 dB above the Minimum Detectable Signal. The Schottky barrier diodes in this data sheet are of P-type construction and are optimized for low noise, particularly in the 1/f region. They require a small forward bias (to overcome the barrier potential) if efficient operation is required, especially at power levels below -20 dBm. Bias not only increases sensitivity but also greatly reduces parameter variation due to temperature change. Video impedance is a direct function of bias and closely follows the 28/l (mA) relationship. This is important to pulse fidelity, since the video impedance in conjunction with the detector output capacitance affects the effective amplifier bandwidth. 3-34 Die Attach Methods All universal chips are compatible with both eutectic and conductive epoxy die attach methods. Eutectic composition preforms of Au/Sn or Au/Ge are useful when soldering devices in circuit. Gold/silicon eutectic die attach can be accomplished by scrubbing the chip directly to the gold plated bonding area. Epoxy die attach with silver or gold filled conductive epoxies, can also be used where thermal heat sinking is not a requirement. Wire Bonding Two methods can be used to connect wire, ribbon, or wire mesh to the chips: Thermocompression Ballbonding Alpha recommends use of pure gold wire (0.7 - 1.25 mil diameter). Alpha Industries * * Fax * E-mail * Visit our web site: Silicon Schottky Barrier Detector Diodes Electrical Specifications at 25C "P" Type Detectors Beam-Lead 207 220 Electrical Characteristics TSS - dBm1,2 ZIF (Ohms) Gamma () 250 Test Conditions VB @ 10 A (V) Frequency GHz Outline Drawing Number 200-350 2 10 491-006 200-350 2 16 491-006 0.10 300-450 3 24.15 491-006 CJ @ 0V (pF) Frequency Band Part Number Min. Min. Max. Max. X DDB2503-000 50 500 700 0.15 Ku DDB2504-000 48 500 700 0.10 K DDB2265-000 503 8003 12003 VF @ 1 mA (mv) RT @ 10 mA (Ohms) Chip Ku CDB7620-000 40 500 700 8000 0.15 250-350 30 2 16 526-006 K CDB7619-000 503 500 700 5000 0.10 300-450 40 3 24.15 526-006 Packaged Diodes Ku CDB7620-207 40 500 700 8000 0.15 300-350 30 2 16 207 K CDB7619-207 50 500 700 5000 0.10 300-450 40 3 24.15 207 X DDB2503-250 50 500 700 0.15 200-350 2 10 250 Ku DDB2504-250 48 500 700 0.10 200-350 2 16 250 K DDB2265-250 503 8003 12003 0.10 300-450 40 3 24.15 250 K DDB2265-220 503 8003 12003 0.10 300-450 40 3 24.15 220 "N" Type Detectors Electrical Characteristics Frequency Band Part Number Drive Level VF @ 1 mA (mv) CJ @ 0V (pF) RT @ 10 mA (Ohms) VB @ 10 uA (V) Max. X CDF7623-000 Low 240-300 0.30 10 2 K CDF7621-000 Low 270-350 0.10 20 2 Ku CME7660-000 Med 350-450 0.15 10 3 K CDE7618-000 Med 375-500 0.10 20 3 Ku CDP7624-000 Med/High 450-575 0.15 15 3 1. Bias = 50 A. 2. Video Bandwidth = 10 MHz. 3. Bias = 30 A. 4. RV = 2800 Ohms. Alpha Industries * * Fax * E-mail * Visit our web site: 3-35 3 Silicon Schottky Barrier Dector Diodes Spice Model Parameters 10-1 10-2 Parameter Unit CDF7621-000 CDC7630-000 CDB7619-000 IS A 8E-08 3E-06 3E-09 RS Ohm 6 26 26 n - 1.04 1.04 1.04 TD s 1E-11 1E-11 1E-11 CJ 0 pF 0.11 0.1 0.11 m - 0.3 0.25 0.32 EG eV 0.69 0.69 0.69 VJ - 0.51 0.34 0.54 XTI - 2 2 2 FC - 0.5 0.5 0.5 BV V 2.5 2 3 IBV A 1E-05 0.001 1E-05 I F (Amps) Part Number 10-3 10-4 10-5 10-6 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 VF (Volts) CDC7630-000 10-1 Typical I-V Characteristics I F (Amps) 10-1 10-2 I F (Amps) 10-2 10-3 10-4 10-3 10-5 10-4 10-6 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 VF (Volts) 10-5 CDB7619-000 10-6 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 VF (Volts) Shipping Information CDF7621-000 Individual Chips Standard packaging procedures at Alpha are for "wafflepack" delivery. Devices can also be packaged on "GelPack" carriers. Wafer Shipment for Whole Wafer Packaging options include delivery for devices on film frame where wafer is sawn on wafer gel pack for uncut, unsawn wafer. 3-36 Alpha Industries * * Fax * E-mail * Visit our web site: Silicon Schottky Barrier Detector Diodes Typical Performance Data a) Unbiased RL = 10K 10000.00 RL = 100K Video Output RL = 1K 1000.00 Load Resistor RL = 100 Voltage Output, mV RF Bypass Input RL = 1M DC Return 100.00 RL = 10 Bias Supply 10.00 1.00 -20 -10 0 10 RF Bypass Input Test Conditions: F=9.375 GHz DC Bias = 0 0.10 -30 3 a) Biased RL = 1 Video Output Load Resistor 20 DC Return Power Input, dBm Multi Octave-High Sensitivity Figure 1a. Voltage Output vs. Power Input as a Function of Load Resistance a) Unbiased RL = 1M 10000.00 Input RF Bypass Video Output RL = 1K Voltage Output, mV 1000.00 100.00 Load Resistor 50 A 5 A RL = 10 Bias Supply 50 A 10.00 a) Biased 5 A Input 1.00 -20 Video Output Test Conditions: F=9.375 GHz 5 A 0.10 -30 RF Bypass Load Resistor -10 0 10 20 50 Power Input, dBm Figure 1b. Voltage Output vs. Power Input as a Function of Load Resistance and Bias Broadband-Low Sensitivity Figure 2. Typical Video Detector Circuits Frequency Table Band UHF L S C X Ku K Ka mm Frequencies (GHz) Up to 1 1-2 2-4 4-8 8.2 - 12.4 12.4 - 18 18.0 - 26.5 26.5 - 40 40 - 100 Alpha Industries * * Fax * E-mail * Visit our web site: 3-37 Silicon Schottky Barrier Detector Diodes Outline Drawings 491-006 526-006, 526-011 526-006 = Cathode Bond Pad 526-011 = Anode Bond Pad 0.015 (0.38 mm) 0.013 (0.33 mm) 0.015 (0.38 mm) 0.013 (0.33 mm) Bonding Pad (526-006 Cathode) 526-011 Anode) Diameter 0.0035 - 0.004 0.0085 (0.216 mm) 0.0065 (0.165 mm) 3-38 Alpha Industries * * Fax * E-mail * Visit our web site: