ADI应用笔记：最佳噪声性能_低噪声放大器选择指南 AN-940 One Technology Way t P.O. B ox 9106 t Norwood, MA 02062-9106 t Tel: 781/329-4700 t Fax: 781/326-8703 t www.analog.com ǖ ǖPaul Lee 4kTB In = (2 ) R ǖ ……