基于LT5517 40MHZ到90NHZ 积分解调器的设计

字数:4475.页数:19

摘要

LT5517 是一个40MHZ到900MHZ的 积分解调器为高线性接收器应用最佳化在高的动态范围很重要的地方。 它是适用于通信接收机一个射频或中频信号是可以用高达130MHZ的基带信号直接修改进入I和 Q的 基带信号。LT5517 合并平衡I/Q混合器，LO缓冲放大器提高精密度，宽带积分发生器由二分频电路产生。
LT5517高质量的线性和低噪音性能那完全达成它的频率范围。一个良好的二分频电路产生高精密度的积分LO载波可以驱动I混合器与Q混合器。最终, 输出I 频段和Q频段有很好的振幅匹配, 并且相位差为90度。LT5517同样能提供50欧
阻抗来匹配2XLO的整个频率范围。
关键词：积分解调器  I/Q混合器 LO缓冲放大器

The LT 5517 is a 40MHz to 900MHz quadrature demodulator optimized for high linearity receiver applications where high dynamic range is important.
It is suitable for communications receivers where an RF or IF signal is directly converted into I and Q baseband signals with a bandwidth up to 130MHz.
The LT5517 incorporates balanced I and Q mixers, LO buffer amplifiers and
a precision, broadband quadrature generator derived from an on-chip
divide-by-two circuit.
The superior linearity and low noise performance of the LT5517 is achieved across its full frequency range. A wellbalanced divide-by-two
circuit generates precision quadrature LO carriers to drive the I mixer and
the Q mixer. Consequently, the outputs of the I-channel and the Q-channel
are well matched in amplitude, and their phases are 90° apart. The LT5517 also provides excellent 50W impedance matching at the 2XLO port across
its entire  frequency range
key: quadrature demodulator  I/Qmixers  LO buffer amplifiers

目 录

LT5517芯片简介.........................................................................4
LT5517的主要电气特性...................................................................4
2.1典型性能特征........................................................................6
3. LT5517芯片封装与引脚功能...........................................................12
LT5572内部结构与工作原理..............................................................13
5. LT5517的应用电路设计...............................................................13
 5．1 应用电路图......................................................................13
 5．2 功能描述........................................................................14
  5．2．1 RF输入端....................................................................16
  5．2．2 2XLO输入端..................................................................16
  5．2．3 I-频段和Q-频段的输出........................................................17
5. 2. 4. 基于LT5517积分解调器的应用信息...............................................18
6. 总结...............................................................................19
参考文献..............................................................................19

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