Silicon Drivers for Commercial IC Products APN2018 Silicon Driver Chips for the GaAs IC Switch and Digital Attenuator A very important feature of the GaAs IC switch is the low current flow during either the “on” or “off” state. The current that flows when a FET is reversed biased at -5 V (series FET in the “off” state and shunt FET in the “on” state) is the leakage across the FET (gate to source and gate to drain). This current is typically < 25 µA. Therefore, taking advantage of this feature, it is desirable to use drivers that are primarily voltage devices with very little current consumption for their operation. Consequently CMOS logic devices are ideal for this application. of the control device applications. To fully obtain the very fast FET response, 3–10 ns, discrete hybrid silicon or GaAs drivers are required. Skywork Solution Inc. offers a limited number of special CMOS silicon decoder chips to simplify control of our multithrow switches. Contact factory for availability for large volume applications. In the table below are listed a few of the many CMOS chips that may be utilized with the GaAs IC switches and digital attenuators. These chips are moderately fast, 15–100 ns switching time and can satisfy a large percent Commercial GaAs IC Driver Chips Transition Time 10/90% or 90/10% RF Switching Speed 50% CTL to 90/10% RF Current Draw (Static) Typ. Typ. Typ. 54S04 5 ns 15 ns 54LS04 10 ns 30 ns 54F04 5 ns 54HCT04 54ACT11004 TTL Compatibility Power Supply1 25 mA Yes +5 V 8 mA Yes +5 V 15 ns 10 mA Yes +5 V 10 ns 25 ns 50 µA Yes (CMOS) +5 V 8 ns 20 ns 100 µA Yes (CMOS) +5 V 10 ns 50 ns 50 µA No (CMOS) +5 V 54HCT139 10 ns 25 ns 25 µA Yes +5 V Zener/Hex3 5 ns 20 ns 2 mA Yes ±5 V or +5 V, -12 V DG403 Analog Switch 10 ns 100 ns 4 mA Yes +5 to +15, -5 to -15 Driver Chips Logic Function Hex Inverters2 Quad Complementary Inverter2 CD4041UB Two to Four Line Decoder 1. Refer to the “Positive Voltage Operation” application note. 2. Both the 54 series inverters and the quad complementary inverter can be driven by -5 V by tying VCC to GND and GND to -5 V; however, the input pulse must be negative going. Single chip is capable of driving an SP4T switch or 4 bit digital attenuator. 3. Refer to the “A Fast TTL Input Compatible Driver Circuit for Commercial IC Switches” application note. Skyworks Solutions, Inc. [781] 376-3000 • Fax [781] 376-3100 • Email [email protected] • www.skyworksinc.com Specifications subject to change without notice. 9/03A 1