- 您現(xiàn)在的位置：買賣IC網(wǎng) > PDF目錄364678 > AN3100 (飛思卡爾半導體(中國)有限公司) General Purpose Amplifier Biasing PDF資料下載
參數(shù)資料
| 型號： | AN3100 |
| 廠商： | 飛思卡爾半導體(中國)有限公司 |
| 英文描述： | General Purpose Amplifier Biasing |
| 中文描述： | 通用放大器偏置 |
| 文件頁數(shù)： | 2/4頁 |
| 文件大?。?/td> | 71K |
| 代理商： | AN3100 |
2
RF Application Information
Freescale Semiconductor
AN3100
The second circuit method is used on the intermediate
power amplifiers (P1dB ranging from 27 to 34 dBm). These
are designed with a MMIC that contains a discrete device, Q1,
with an integrated current mirror to drive the base (Fig. 3).
This active bias approach means that the bias current has
minimal shift with normal supply voltage deviations over the
specified operating temperature range. R6 in Fig. 3 is an
external dropping resistor that is required to establish the
reference voltage on the current mirror that drives the bias of
Q1.
R3
C6
C3
RF
INPUT
V
CC
Q3
C2
C1
R1
R2
Q1
Q2
R4
R5
RF
OUTPUT
C4
L1
R6
V
ref
C5
PACKAGED DEVICE
Figure 3. Intermediate Power InGaP HBT Bias Scheme
The reference voltage (V
ref
) is different for each device
based on its size. The data sheets for each device list the
specific reference voltage required for optimal bias current. L1
is required to prevent the DC supply line from improperly
loading the RF output. RF coupling capacitors (C3 and C4 in
Fig. 3) are also required.
The third circuit approach in GPAs is used for the HFET
devices. Bias of this type of device is very similar to the
Darlington circuit technology.
The HFETs are discrete devices that operate directly from
a 5 Volt supply voltage (Fig. 4). The DC blocking capacitor that
is integrated in the feedback loop prevents the gate voltage
from being established with R1 and R2; therefore, the HFET
devices operate at I
DSS
when 5 Volts are applied to the drain.
L1 is again required as an RF choke as well as the RF coupling
capacitors, C2 and C3.
C4
C2
R1
RF
INPUT
RF
OUTPUT
R2
Q1
C3
V
SUPPLY
L1
PACKAGED DEVICE
C1
Figure 4. HFET Bias Scheme
SUMMARY
The GPA lineup from Freescale is designed to operate from
a single positive voltage supply, which makes them easy to
use. Designers using these devices should be careful to bias
the devices correctly using the appropriate method for the type
of device used. If the current is set too low, linearity and power
will degrade. If the current is set too high, there is some risk
of compromising reliability.
The techniques outlined here are a guide to the bias
approaches for the different technologies and products
available from Freescale. The data sheets for each device
should be followed to achieve optimal performance from all
GPAs.
相關PDF資料 |
PDF描述 |
|---|---|
| AN3129S | Analog IC |
| AN313 | |
| AN3248NK | Consumer IC |
| AN32502A | For Information·Communication - PDA |
| AN3294K | VCR， Other/Special/Miscellaneous |
相關代理商/技術參數(shù) |
參數(shù)描述 |
|---|---|
| AN3100A-18-1S | 制造商:Amphenol Corporation 功能描述:CONN 5015 CIRC SKT 10 POS SLDR ST WALL MNT - Bulk |
| AN3100A-18-1SW | 制造商:Amphenol Corporation 功能描述:CONN 5015 CIRC SKT 10 POS SLDR ST WALL MNT - Bulk |
| AN3100A-18-1SX | 制造商:Amphenol Corporation 功能描述:CONN 5015 CIRC SKT 10 POS SLDR ST WALL MNT - Bulk |
| AN3100A-18-1SY | 制造商:Amphenol Corporation 功能描述:CONN 5015 CIRC SKT 10 POS SLDR ST WALL MNT - Bulk |
| AN3100A-18-1SZ | 制造商:Amphenol Corporation 功能描述:CONN 5015 CIRC SKT 10 POS SLDR ST WALL MNT - Bulk |
發(fā)布緊急采購，3分鐘左右您將得到回復。