100M-500M低噪放设计方案
A 100 MHz to 500 MHz Low Noise Feedback Amplifier using ATF-54143
Application Note 5057
Introduction
In the last few years the leading technology in the area of low noise amplifier design has been gallium arsenide (GaAs) devices, MESFET, and pHEMT. Power amplifiers based on GaAs can achieve high efficiency and linearity, as well as ity, with a second feature offering a means of reducing the overall stage gain to the specified 20 dB level. The amplifier design specification includes operation from a 5V supply with current consumption of less than 65 mA.
provide high output power. Recently, Enhancement Mode pHEMT technology has demonstrated industry leading power added efficiency (PAE) and linearity performance for amplifier applications. The E-pHEMT technology provides high gain and very low noise. The high gain at low frequen-cies enables the use of feedback to linearize the E-pHEMT device. This application note shows why E-pHEMT technology can provide superior electrical performance for low noise and high linearity amplifier design in UHF and VHF wireless communications bands.
Design GoalsThe goal of the amplifier design is to produce a 100 to 500 MHz LNA, with an output third order intercept point (OIPof +36 dBm, a noise figure below 2.0 dB, and 20 dB gain with 3) a flat gain response. RC feedback was used to provide good input and output match and to ensure unconditional stabil-The Avago Technologies’ ATF-54143 is one of a family of high dynamic range, low noise enhancement mode PHEMT discrete transistors designed for use in low cost commercial applications in the VHF through 6 GHz fre-quency range. It is housed in a 4-lead SC-70 (SOT-343) surface mount plastic package, and operates from a single regulated supply. If an active bias is desirable for r
epeatability of the bias setting—particularly desirable in h igh-volume production—the ATF-54143 requires only the addition of a single PNP bipolar junction transistor. Compared to amplifiers using depletion mode devices,
the E-pHEMT design has a lower part count and a more compact layout. Besides having a very low typical noise figure (0.5 dB), the Avago Technologies’ ATF-54143 is specified at 2 GHz and 3-volt bias to provide a +36 dBm intercept point at 60 mA drain current. A data sheet for this http://www.77cn.com.cn/litweb/pdf/5989-0034EN.pdf
device may be downloaded from: http://literature.