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参数资料
| 型号： | ATF-55143-TR1G |
| 元件分类： | 小信号晶体管 |
| 英文描述： | C BAND, Si, N-CHANNEL, RF SMALL SIGNAL, HEMFET |
| 封装： | LEAD FREE, PLASTIC, SC-70, 4 PIN |
| 文件页数： | 7/21页 |
| 文件大小： | 338K |
| 代理商： | ATF-55143-TR1G |
15
The values of resistors R1 and R2 are calculated with the
following formulas
R1 =
V
gs
(2)
p
I
BB
R2 =
(V
ds – Vgs) R1
(3)
p
V
gs
Example Circuit
V
DD = 3V
V
ds = 2.7 V
I
ds = 10 mA
V
gs = 0.47 V
Choose I
BB to be at least 10X the normal expected gate
leakage current. I
BB was conservatively chosen to be
0.5 mA for this example. Using equations (1), (2), and (3)
the resistors are calculated as follows
R1 = 940
R2 = 4460
R3 = 28.6
Active Biasing
Active biasing provides a means of keeping the quies
cent bias point constant over temperature and constant
over lot to lot variations in device dc performance. The
advantage of the active biasing of an enhancement
mode PHEMT versus a depletion mode PHEMT is that a
negative power source is not required. The techniques
of active biasing an enhancement mode device are very
similar to those used to bias a bipolar junction transis
tor.
INPUT
C1
C2
C3
C7
L1
R5
R6
R7
R3
R2
R1
Q2
Vdd
R4
L2
L3
L4
Q1
Zo
C4
C5
C6
OUTPUT
Figure 34. Typical ATF-55143 LNA with Active Biasing.
An active bias scheme is shown in Figure 34. R1 and R2
provide a constant voltage source at the base of a PNP
transistor at Q2. The constant voltage at the base of Q2
is raised by 0.7 volts at the emitter. The constant emitter
voltage plus the regulated V
DD supply are present across
resistor R3. Constant voltage across R3 provides a con
stant current supply for the drain current. Resistors R1
and R2 are used to set the desired Vds. The combined
series value of these resistors also sets the amount of
extra current consumed by the bias network. The equa
tions that describe the circuit’s operation are as follows.
V
E = Vds + (Ids R4)
(1)
R3 =
V
DD – VE
(2)
p
I
ds
V
B = VE – VBE
(3)
V
B =
R1
V
DD
(4)
p
R1 + R2
V
DD = IBB (R1 + R2)
(5)
Rearranging equation (4) provides the following for
mula
R2 =
R
1 (VDD – VB)
(4A)
V
B
and rearranging equation (5) provides the following
formula
R1 =
V
DD
(5A)
9
I
BB
(1+ V
DD – VB
)
p
V
B
Example Circuit
V
DD = 3 V
I
BB = 0.5 mA
V
ds = 2.7V
I
ds = 10 mA
R4 = 10
V
BE = 0.7 V
Equation (1) calculates the required voltage at the emit
ter of the PNP transistor based on desired V
ds and Ids
through resistor R4 to be 2.8V. Equation (2) calculates
the value of resistor R3 which determines the drain cur
rent I
ds. In the example R3 = 20. Equation (3) calculates
the voltage required at the junction of resistors R1 and
R2. This voltage plus the stepup of the base emitter
junction determines the regulated V
ds. Equations (4) and
(5) are solved simultaneously to determine the value
of resistors R1 and R2. In the example R1=4200 and
R2=1800. R7 is chosen to be 1k. This resistor keeps
a small amount of current flowing through Q2 to help
maintain bias stability. R6 is chosen to be 10k. This
value of resistance is necessary to limit Q1 gate current
in the presence of high RF drive levels (especially when
Q1 is driven to the P
1dB gain compression point). C7
provides a low frequency bypass to keep noise from Q2
effecting the operation of Q1. C7 is typically 0.1 F.
相关PDF资料 |
PDF描述 |
|---|---|
| ATF-55143-TR2 | C BAND, Si, N-CHANNEL, RF SMALL SIGNAL, HEMFET |
| ATF-55143-BLK | C BAND, Si, N-CHANNEL, RF SMALL SIGNAL, HEMFET |
| ATF-55143-TR1 | C BAND, Si, N-CHANNEL, RF SMALL SIGNAL, HEMFET |
| ATF-551M4-TR2G | X BAND, Si, N-CHANNEL, RF SMALL SIGNAL, HEMFET |
| ATF-551M4-BLK | X BAND, Si, N-CHANNEL, RF SMALL SIGNAL, HEMFET |
相关代理商/技术参数 |
参数描述 |
|---|---|
| ATF-55143-TR2 | 制造商:AGILENT 制造商全称:AGILENT 功能描述:Agilent ATF-55143 Low Noise Enhancement Mode Pseudomorphic HEMT in a Surface Mount Plastic Package |
| ATF-55143-TR2G | 功能描述:射频GaAs晶体管 Transistor GaAs Single Voltage RoHS:否 制造商:TriQuint Semiconductor 技术类型:pHEMT 频率:500 MHz to 3 GHz 增益:10 dB 噪声系数: 正向跨导 gFS（最大值/最小值）:4 S 漏源电压 VDS: 闸/源击穿电压:- 8 V 漏极连续电流:3 A 最大工作温度:+ 150 C 功率耗散:10 W 安装风格: 封装 / 箱体: |
| ATF-551M4 | 制造商:AGILENT 制造商全称:AGILENT 功能描述:Low Noise Enhancement Mode Pseudomorphic HEMT in a Miniature Leadless Package |
| ATF-551M4-BLK | 功能描述:射频GaAs晶体管 Transistor GaAs Single Voltage RoHS:否 制造商:TriQuint Semiconductor 技术类型:pHEMT 频率:500 MHz to 3 GHz 增益:10 dB 噪声系数: 正向跨导 gFS（最大值/最小值）:4 S 漏源电压 VDS: 闸/源击穿电压:- 8 V 漏极连续电流:3 A 最大工作温度:+ 150 C 功率耗散:10 W 安装风格: 封装 / 箱体: |
| ATF-551M4-BLK | 制造商:Avago Technologies 功能描述:Transistor |
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