- 您現(xiàn)在的位置：買賣IC網(wǎng) > PDF目錄374585 > RF2870 (RF MICRO DEVICES INC) CDMA LOW NOISE AMPLIFIER/MIXER 900MHz DOWNCONVERTER PDF資料下載
8-10
RF2870
Rev A8 030507
Differential IF Matching
L1 and C1 are chosen to resonate at the desired IF frequency. C1 can be omitted and the value of L1 increased and uti-
lized solely as a choke to provide V
CC
to the open-collector outputs, but it is strongly recommended that at least some
small-valued C1 (a few pF) be retained for better mixer linearity performance. R is normally selected to match the input
impedance of the IF filter. However, mixer performance can be modified by selecting an R value that is different from the
IF filter input impedance, and inserting a conjugate matching network between the Resistive Output Network and the IF
filter.
C2 serve dual purposes. C2 serves as a series DC block when a DC path to ground is present in the IF filter. In addition,
C2 may be chosen to improve the combine performance of the mixer and IF filter. L2 should choose to resonate with the
internal capacitance of the SAW filter. Usually, SAW filter has some capacitance. Otherwise, L2 could be eliminated.
A practical approach to obtain the differential matching is to tune the mixer to the correct load point for gain, IIP3, and NF
using the single-end current combiner method. Second, use the component values found in the single-end approach as
starting point for the differential matching. The two-shunt capacitors in the single-end could be converted in a parallel
capacitor and the parallel inductor in the single-end need to be converted in two-choke inductor. Third, set the DC block
capacitors (C2) in the differential-end matching to a high value (i.e., 100pF) and retune the resonate circuit (C1 & L1)
and the resistor (R) for optimal performance. After optimal performance is achieved and if performance is not satisfac-
tory, decrease the series capacitors until optimal performance is achieved.
C1
R
L1
L1
V
CC
100 pF
C2
C2
CDMA IF+
CDMA IF-
L2
CDMA
IF Saw
4
5
9
10
IF-
IF+
相關(guān)PDF資料 |
PDF描述 |
|---|---|
| RF2870PCBA | CDMA LOW NOISE AMPLIFIER/MIXER 900MHz DOWNCONVERTER |
| RF2890 | DUAL-BAND CDMA CELLULAR/GPS LOW NOISE AMPLIFIER/MIXER |
| RF2905 | 433/868/915MHZ FM/FSK/ASK/OOK TRANSCEIVER |
| RF2908 | 915MHZ SPREAD SPECTRUM RECEIVER WITH PLL FREQUENCY SYNTHESIZER |
| RF340 | 10A, 400V, 0.550 Ohm, N-Channel Power MOSFET |
相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| RF2870PCBA | 制造商:RFMD 制造商全稱:RF Micro Devices 功能描述:CDMA LOW NOISE AMPLIFIER/MIXER 900MHz DOWNCONVERTER |
| RF2872-000 | 制造商:TE Connectivity 功能描述:GDT - Trays |
| RF2873-000 | 功能描述:POLYSWITCH 1.25A RESET FUSE RAD RoHS:是 類別:過電壓，電流，溫度裝置 >> PTC 可復(fù)位保險(xiǎn)絲 系列:LVB125 標(biāo)準(zhǔn)包裝:500 系列:PFRA 電流 - 維持(Ih):750mA 電流 - 跳閘(It):1.5A 電流 - 最大:40A 電壓 - 最大:60V R最小/最大:0.180 ~ 0.400 歐姆 跳閘時(shí)間:6.3s 封裝/外殼:徑向 - 圓盤形 包裝:散裝 |
| RF2877-000 | 制造商:TE Connectivity 功能描述:GDT - Trays |
| RF2878 | 制造商:RFMD 制造商全稱:RF Micro Devices 功能描述:3V LOW NOISE AMPLIFIER/ 3V PA DRIVER AMPLIFIER |
發(fā)布緊急采購，3分鐘左右您將得到回復(fù)。