Amplifier delivers +51dBm OIP3 & 2.9dB noise

17th October 2014

Siobhan O'Gorman

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Datasheet

Offering linearity of +51dBm OIP3 (Output Third Order Intercept), a 20MHz-2GHz differential input and output 20dB gain amplifier has been released by Linear Technology. The LTC6430-20, which provides 2.9dB noise figure at 240MHz, features an OP1dB (Output 1dB Compression Point) of +23.9dBm.

Guaranteed to a minimum OIP3 of +44.8dBm, typically +48.3dBm at 380MHz, the A-grade version is 100% tested. At a minimum of 19.6 and a maximum of 22.1dB, gain is also guaranteed. A typical OIP3 of +46.3dBm at the same frequency is offered by the B-grade version. IF and RF signals in low distortion, high dynamic range transmitters or receivers at frequencies to 1.5GHz can be amplified using the LTC6430-20. With appropriate impedance matching, higher frequencies up to 2GHz can be achieved.

When the device is used as an IF amplifier driving differential inputs of high speed ADC in main receivers, high linearity is provided. The same linearity is provided when the amplifier is used for driving differential inputs of high speed ADC in digital predistortion receivers, which rely on low distortion and high dynamic range. For broadband and narrowband radios that operate in the VHF/UHF bands, the device can be used as a low noise amplifier. Such radios include broadcast equipment, cable networks, white space broadband data services and low-band LTE/LTE-Advanced wireless base stations.

From 20MHz to 1.2GHz, both inputs and outputs of the LTC6430-20 are internally 100Ω matched differential. Over the same frequency range, the inputs and outputs have a 20.5dB power gain with a frequency response flatness of better than 0.5dB. Due to the internal 100Ω matching, minimal external components are required as both design and cascading for higher gains is simplified. Low 2nd order harmonic distortion is also produced by the differential configuration. For example, at 380MHz, the 2nd order harmonic spur is -70dBc down from the fundamental.

To enable stable performance, the LTC6430-20 is manufactured using a SiGe BiCMOS process, allowing it to tolerate wide variations in power supply voltage and temperature. The device, which operates from -40 to 85°C, is offered in a 4x4mm QFN package. At 170mA supply current, the amplifier is powered from a single 5V supply. Both versions are sold in 1,000-pieces quantities, with the A-grade priced from $6.44 and the B-grade from $3.69.