An Ultradynamic Range GaAs Amplifier

Watkins-Johnson Co.
Palo Alto, CA

Fig.1 An IP3 and third-order intermodulation vs. output power comparison at 900 MHz using two tones separated by 10 MHz The model AH11 GaAs amplifier has been introduced to supplement the company’s line of linear GaAs components. Operating from a +5 V DC supply in a push-pull configuration, the new IC amplifier extends the linear efficiency advantages of the existing AH1 device to higher power levels and delivers +17 dBm of linear output power with an output third-order intercept point (OIP3) of greater than 50 dBm. Figure 1 shows the AH11 device’s IP3 and third-order intermodulation products vs. output power compared to other AH-series devices.

Fig. 2 The AH11 device's functional diagram The AH11 is a dual version of the company’s AH1 device suitable for base station receivers and broadband wireless distribution applications where ultra-high dynamic range is required. Specifications for the amplifier include a 600 to 2100 MHz frequency range and a single +5 V DC supply. The device has a typical gain of 11.4 dB in the balanced configuration and 12 dB in the push-pull configuration. For the balanced configuration, S11 /S22 is -15 dB, OIP3 is 44 dBm, noise figure is 4.2 dB and output 1 dB compression point (P1dB) is 24 dBm with a typical operating current of 300 mA. For the push-pull configuration, S11 /S22 is -12 dB, OIP3 is 47 dBm, noise figure is 3.7 dB and output P1dB is 27 dBm with a 600 mA operating current. Absolute ratings for the device include an operating case temperature of -40° to +85°C and a storage temperature of -40° to +125°C. Maximum junction temperature is +155°C, supply voltage is +6 V (max) and input RF power is +13 dBm (max). Figure 2 shows a functional diagram of the AH11 device, including pin designations and locations.

The new device is produced using GaAs MESFET technology and is targeted at applications where higher power and exceptional linearity are required. Features include surface-mounting capability and a mean time to failure in excess of 100 years. The AH11 is available in an industry-standard, thermally enhanced SOIC-8 package and is 100 percent RF and DC tested prior to shipment. Devices are available for immediate delivery and are priced at less than $6.75 each in 10,000-piece quantities.

Watkins-Johnson Co., Palo Alto, CA (800) 951-4401.