Aeroflex / Metelics has introduced a family of RoHS compliant, silicon PIN diode surface-mount high power switches, ideal for high volume, high performance manufacturing in the military and commercial-industrial markets. These switches are ideal for higher power, higher linearity RF and microwave applications for the military radio, IED defeat, MRI and WiMAX markets.
The MSW2000 Series of surface-mount PIN diode SP2T switches is manufactured using Aeroflex / Metelics’ proven hybrid manufacturing process incorporating high voltage PIN diodes and passive devices integrated within a ceramic substrate. This low profile, compact, surface-mount component (8 X 5 X 2.5 mm) offers superior low and high signal performance compared to MMIC devices in QFN packages. The RF cover provides a suitable degree of EMI shielding, moisture protection, and a flat surface suitable for high volume, surface-mount manufacturing and test equipment.
The SP2T switches are designed in both asymmetrical and symmetrical topologies. The asymmetrical SP2T’s are available as either having the Tx RF port on either the left side of the device (CS200: case style 200) or the right side (CS201: case style 201) for design versatility. The symmetrical configuration consists of a series and shunt PIN diode in both RF ports for improved RF isolation in both ports.
The asymmetrical SP2T design consists of a unique geometry Tx series PIN diode that provides a lower Rs (< 0.7 at 100 mA) for improved power dissipation and higher IIP3 values. The thermal resistance of the Tx PIN diode is on the order of 6° C/W, allowing it to safely handle CW incident power levels exceeding 100 W at +85°C. The Rx port incorporates a series PIN diode in addition to a shunt PIN diode floated on a RF bypass capacitor, allowing for positive voltage only operation. This arrangement provides improved Tx-Rx isolation in excess of 40 dB, or allows less than +10 dBm leakage to the receiver port with a +50 dBm Tx applied signal.
The switches are capable of operating in either a high signal 100 W CW cold switched mode or in a hot switched condition where the RF power state change commutation period from Tx-Ant to Ant-Rx is less than 100 ns. The switches are capable of operating at higher peak RF power levels than comparable surface-mount MMIC switches, since the breakdown voltages of the PIN diodes exceed 1,000 V. Rated RF peak power levels for the SP2T family is 500 W peak power at 50 µS RF pulse width at 5 percent duty cycle at +85°C. This type of high signal switch performance is extremely advantageous in applications where the peak to average power ratio is greater than 12 dB.
Figure 1 MSW2000-200 SP2T insertion loss vs. frequency.
Figure 2 MSW2000-200 SP2T return loss vs. frequency.
Figure 3 MSW2000-200 SP2T isolation vs. frequency.
These SP2T switches are optimized in design to function in two frequency bands of interest: Band 1: 10 to 1,000 MHz and band 2: 400 to 4,000 MHz. Typical RF performance for the asymmetrical SP2T switch in band 1 provides Tx-Ant insertion loss of 0.2 dB, with better than 20 dB return loss and 45 dB Tx-Rx isolation. Ant-Rx loss is similar at 0.3 dB with greater than 20 dB return loss and better than 20 dB Rx-Tx isolation. See Figures 1, 2 and 3 for graphs of insertion loss, return loss and isolation, respectively, versus frequency.
Typical RF performance for the asymmetrical SP2T switch in band 2 provides Tx-Ant insertion loss of 0.3 dB, with better than 17 dB return loss and 40 dB Tx-Rx isolation. Ant-Rx loss is similar at 0.6 dB with 15 dB return loss and greater than 13 dB Rx-Tx isolation. IIP3 is better than +90 dBm. The SP2T switches are capable of operating from positive voltage only: +5, +28 and +50 V DC. Design work is in progress to complete a similar SP2T for the 2 to 6 GHz band.
These SP2T switches are designed to be used in higher power switch applications, operating from 10 MHz to 4 GHz, requiring high volume, surface-mount, solder re-flow manufacturing.
The SP2T ceramic package metallization scheme is compatible with either Sn63/Pb37 or RoHS type solders. They are durable, reliable and capable of meeting all military, commercial and industrial environments. The devices are fully RoHS compliant and are available in high volume tape-reel and tube packaging.
RS No. 302