基于LT5500f 的1.8~2.7 GHzLNA/混频器电路设计

字数:4900,页数:20

摘      要

LT5500是linear 公司开发的一款1.8~2.7GHz混频器芯片，该芯片包含一个低噪声放大器（LNA）、一个混频器和一个LO缓冲器。它是一个接收器前端IC，与LTC系列的WLAN产品兼容。LT5500可应用于IEEE802.11和802.11bDSSS及FHSS、高速无线LAN和区域性环路。

LT5500的工作电压为1.8~2.5V。LT5500的LAN可任意设置为高增益模式或低增益模式。在2.5GHz频段，高增益模式产生13.5dB的增益和4dB的噪声系数（NF），低增益模式产生—14dB的增益和一个+8dBm的IIP3。在2.5Gh频段和—10dB的LO输入功率下，混频器有5dBm的IIP3。

The LT5500 consists of an LNA, a Mixer, an LO buffer and the associated bias circuitry. The chip is designed to be compatible with IEEE802.11b wireless local area network(WLAN), MMDS and other wireless applications.

The LNA and Mixer are designed to operate over an input frequency range of 1.8GHz to 2.7GHz with a supply voltage of 1.8V to 5.25V.The LT 5500 is a receiver front end IC designed for low voltage operation. The chip contains a low noise amplifier(LNA), a Mixer and an LO buffer. The IC is designed to operate over a power supply voltage range from 1.8V to 5.25V.The LNA can be set to either high gain or low gain mode.At 2.5GHz, the high gain mode provides 13.5dB gain and a

noise figure (NF) of 4dB. The LNA in low gain mode provides –14dB gain and an IIP3 of +8dBm at 2.5GHz.The mixer has 5dB of conversion gain and an IIP3 of.

关键词：    增益    匹配   噪声系数    回波损耗    耦合      使能

key words：  
gain                               Matching

Noise Figure                        Return Loss

coupled                              Enable

目      录

LT5500简介.............................................................................5
LT5500的主要电气性能...................................................................5
LT5500的芯片封装与引脚功能.............................................................7
3.1、LT5500的芯片封装形式..............................................................7
3.2、LT5500的芯片引脚功能..............................................................8
LT5500的内部结构与工作原理.............................................................9
LT5500的应用电路设计..................................................................10
5.1、LT5500的测试电路.................................................................10
5.2、LT5500输入端和IF输出端的匹配元件参数.............................................11
5.3、LT5500混频器中频输出匹配.........................................................11
5.4、基于变压器原理的差分LO驱动器.....................................................12
5.5、2.5GHz频段的应用电路.............................................................13
5.6、2.5GHz频段应用电路的元器件布局图.................................................14
5.7、2.5GHz频段应用电路的印制板图.....................................................14
６、LT５５００的典型特性..............................................................15
结论..................................................................................20
参考文献..............................................................................20