MASW-000834-001SMB

MASW-000834-000SMB Sample Board Application Note on Sample Board Operation of the MASW-000834-13560T T/R Switch M/A-COM Products REV.3 The following is an application guide for utilization of the MASW-000834-13560T in conjunction with a supplied sample board from M/ ACOM. The guide will review the operation of the T/R using a single positive supply as well as other optional dual polarity supplies. The MASW-000834-13560T is a T/R switch with two PIN diodes in series in a common anode configuration and one PIN diode in shunt on the Rx path. The switch die along with select matching components are mounted in a standard 4mm MLP 16 lead package (Figure 1). The switch die utilizes M/ACOM’s patented HMIC process. The backside of the switch die is thermally grounded while electrically isolated. The excellent power handling of the die is achieved through specific techniques using unique thermal conductive epoxy embedded in the die. This allows the heat to be transferred from the series connected device to ground while maintaining electrical isolation. The large backside of the pad of the package is both thermal and electrical ground. Figure 2 shows the electrical/ thermal schematic of the device. The sample board is made of Rogers RO4350 material 10mils thick dielectric with added layers to increase the board thickness to 62mils for handling, rigidity and connector mounting. There are on-board bias networks incorporated to accommodate biasing the device without the use of expensive external bias tees. Figure 3 shows the standard board layout with component selection for optimized performance up to 6 GHz. Figure 1. Package Outline Drawing Figure 2. Electrical/Thermal Schematic 1 M/A-COM Inc. and its affiliates reserve the right to make changes to the product(s) or information contained herein without notice. M/A-COM makes no warranty, representation or guarantee regarding the suitability of its products for any particular purpose, nor does M/A-COM assume any liability whatsoever arising out of the use or application of any product(s) or information. • North America Tel: 800.366.2266 / Fax: 978.366.2266 • Europe Tel: 44.1908.574.200 / Fax: 44.1908.574.300 • Asia/Pacific Tel: 81.44.844.8296 / Fax: 81.44.844.8298 Visit www.macom.com for additional data sheets and product information. MASW-000834-000SMB Sample Board Application Note on Sample Board Operation of the MASW-000834-13560T T/R Switch C1 M/A-COM Products REV.3 R L C1: 27pF C1 C1 L L C2: 12pF L: 68nH R: 100 Ohm C2 L C2 R Figure 3. Sample Board Assembly Drawing The diagram in Figure 4 is a schematic depiction of the Figure 3 sample board drawing. There are 100 Ohm resistors on the ANT path and the DC2 path. This topology allows for either an all-positive bias scheme or a positive and negative bias scheme. Figure 4. Sample Board Schematic 2 M/A-COM Inc. and its affiliates reserve the right to make changes to the product(s) or information contained herein without notice. M/A-COM makes no warranty, representation or guarantee regarding the suitability of its products for any particular purpose, nor does M/A-COM assume any liability whatsoever arising out of the use or application of any product(s) or information. • North America Tel: 800.366.2266 / Fax: 978.366.2266 • Europe Tel: 44.1908.574.200 / Fax: 44.1908.574.300 • Asia/Pacific Tel: 81.44.844.8296 / Fax: 81.44.844.8298 Visit www.macom.com for additional data sheets and product information. MASW-000834-000SMB Sample Board Application Note on Sample Board Operation of the MASW-000834-13560T T/R Switch M/A-COM Products REV.3 Positive Voltage Supply To accommodate biasing with a single positive supply, DC voltage must be applied to the Antenna, RX, TX, and DC2 ports. The resistor on the Antenna path will limit the current drawn when this voltage is applied. The resistor present on the DC2 bias path limits the current when the RX shunt diode is turned on. To achieve optimum performance, 50mA of DC bias current to the diodes is necessary. M/A-COM Tech supplies 100 Ohm resistors on these sample boards. In order to achieve proper isolation in the “OFF” arm, the back bias (Vr) on the diodes should be large enough to sustain higher power levels. The voltage levels can range from +5V to +25V, as shown in the Figure. Minimum back bias requirements will change depending on incident peak RF Voltage and frequency of operation. Please contact M/A-COM Technology Solutions for additional guidance on required reverse bias voltages for specific application environments. Figure 5. Transmit On, Receive Off DC BIAS 3 Figure 6. Transmit Off, Receive On Example Positive Bias Scheme Tx - Antenna RF Condition Rx - Antenna RF Condition IDC = +20 or +50 mA [ANT to TX Path ON] VANT = Voltage in which ANT resistor limits current to IDC VTX = 0V VRX = Voltage in which DC2 resistor limits current to IDC Must be greater than VANT [RX Path OFF / DC2 Path On] DC2 = 0 IDC = +50mA VANT = +5V VTX = 0V VRX = +25V DC2 = 0V Insertion Loss Isolation IDC = +20 or +50 mA [ANT to RX Path ON] VANT = Voltages in which resistors limit current to IDC VRX = 0V VTX = Must be greater than VANT [TX Path OFF] DC2 = Equal or higher than VRX [DC2 Path OFF] IDC = +50mA VANT = +5V VTX = +25V VRX = +0V DC2 = +5V Isolation Insertion Loss Figure 7. Single Positive Supply Biasing M/A-COM Inc. and its affiliates reserve the right to make changes to the product(s) or information contained herein without notice. M/A-COM makes no warranty, representation or guarantee regarding the suitability of its products for any particular purpose, nor does M/A-COM assume any liability whatsoever arising out of the use or application of any product(s) or information. • North America Tel: 800.366.2266 / Fax: 978.366.2266 • Europe Tel: 44.1908.574.200 / Fax: 44.1908.574.300 • Asia/Pacific Tel: 81.44.844.8296 / Fax: 81.44.844.8298 Visit www.macom.com for additional data sheets and product information. MASW-000834-000SMB Sample Board Application Note on Sample Board Operation of the MASW-000834-13560T T/R Switch M/A-COM Products REV.3 Dual Positive and Negative Voltage The sample board can accommodate dual polarity supplies as shown in Figures 8 through 10. In this scheme, bias is applied to the Rx , Tx, and DC2 path. Unlike the single positive polarity bias scheme, bias to the ANT port is not used. A series resistor on the ANT arm and second resistor on the DC2 path will limit the current when a negative voltage is applied to the TX or RX Port. M/A-COM Tech supplies 100 Ohm resistors on these sample boards. In order to achieve proper isolation in the “OFF” arm, the back bias (Vr) on the diodes should be large enough to sustain higher power levels. The voltage levels can range from +5V to +25V, as shown in the Figure. Minimum back bias requirements will change depending on incident peak RF Voltage and frequency of operation. Please contact M/A-COM Technology Solutions for additional guidance on required reverse bias voltages for specific application environments. Figure 8. Transmit On, Receive Off Example Dual Bias Scheme Tx - Antenna RF Condition Rx - Antenna RF Condition VTX = Negative voltage in which ANT resistor limits current to IDC [ANT to TX Path ON] VRX = Positive voltage level, greater than 0V in which DC2 resistor limits current to IDC [RX Path OFF / DC2 Path On] VANT = 0V VTX = -5V VRX = +25V DC2 = 0V IDC = +/- 50mA Low Loss Isolation VRX = Negative Voltage in which ANT resistor limits current to IDC [ANT to RX Path ON] VTX = Positive voltage level, greater than 0V in which DC2 resistor limits current to IDC [RX Path OFF / DC2 Path On] VANT = 0V VRX = -5V VTX = +25V DC2 = 0V IDC = +/- 50mA Isolation Low Loss DC BIAS 4 Figure 9. Transmit Off, Receive On Figure 10. Dual Positive and Negative Voltage Source Bias Truth Table M/A-COM Inc. and its affiliates reserve the right to make changes to the product(s) or information contained herein without notice. M/A-COM makes no warranty, representation or guarantee regarding the suitability of its products for any particular purpose, nor does M/A-COM assume any liability whatsoever arising out of the use or application of any product(s) or information. • North America Tel: 800.366.2266 / Fax: 978.366.2266 • Europe Tel: 44.1908.574.200 / Fax: 44.1908.574.300 • Asia/Pacific Tel: 81.44.844.8296 / Fax: 81.44.844.8298 Visit www.macom.com for additional data sheets and product information.