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參數(shù)資料
| 型號(hào)： | ATF-541M4-TR2 |
| 元件分類： | 小信號(hào)晶體管 |
| 英文描述： | C BAND, Si, N-CHANNEL, RF SMALL SIGNAL, HEMFET |
| 封裝： | 1.40 X 1.20 MM, 0.70 MM HEIGHT, LEAD FREE, LEADLESS, MINIPAK-4 |
| 文件頁數(shù)： | 4/17頁 |
| 文件大?。?/td> | 731K |
| 代理商： | ATF-541M4-TR2 |
1
INPUT
C1
C
L1
R4
R1
R
Vdd
R
L
L4
Q1
Zo
C4
C5
C6
OUTPUT
R5
Figure . Typical ATF-541M4 LNA with Passive Biasing.
Bias Networks
One of the major advantages of the enhancement
mode technology is that it allows the designer to be
able to dc ground the source leads and then merely
apply a positive voltage on the gate to set the desired
amount of quiescent drain current Id.
Whereas a depletion mode PHEMT pulls maximum
drain current when V
gs= 0 V, an enhancement mode
PHEMT pulls only a small amount of leakage current
when V
gs= 0 V. Only when Vgs is increased above Vto, the
device threshold voltage, will drain current start to
flow. At a V
ds of 3V and a nominal Vgs of 0.58V, the drain
current I
d will be approximately 60 mA. The data sheet
suggests a minimum and maximum V
gs over which the
desired amount of drain current will be achieved. It is
also important to note that if the gate terminal is left
open circuited, the device will pull some amount of
drain current due to leakage current creating a voltage
differential between the gate and source terminals.
Passive Biasing
Passive biasing of the ATF541M4 is accomplished by the
use of a voltage divider consisting of R1 and R2 connect
ed to the gate of the device. The voltage for the divider
is derived from the drain voltage. This provides a form of
voltage feedback (through the use of R3) to help keep
drain current constant. Resistor R5 (approximately 10K)
is added to limit the gate current of enhancement mode
devices such as the ATF541M4. This is especially impor
tant when the device is driven to P1dB or Psat.
ATF-541M4 Applications Information
Introduction
Avago Technologies’s ATF541M4 is a low noise
enhancement mode PHEMT designed for use in low cost
commercial applications in the VHF through 6 GHz fre
quency range. As opposed to a typical depletion mode
PHEMT where the gate must be made negative with
respect to the source for proper operation, an enhance
ment mode PHEMT requires that the gate be made more
positive than the source for normal operation. Therefore
a negative power supply voltage is not required for an
enhancement mode device. Biasing an enhancement
mode PHEMT is much like biasing the typical bipolar
junction transistor. Instead of a 0.7V base to emitter
voltage, the ATF541M4 enhancement mode PHEMT re
quires a nominal 0.58V potential between the gate and
source for a nominal drain current of 60 mA.
Matching Networks
The techniques for impedance matching an enhancement
mode device are very similar to those for matching a deple
tion mode device. The only difference is in the method of
supplying gate bias. S and Noise Parameters for various bias
conditions are listed in this data sheet. The circuit shown
in Figure 23 shows a typical LNA circuit normally used for
900 and 1900 MHz applications. (Consult the Avago Tech
nologies web site for application notes covering specific
designs and applications). High pass impedance matching
networks consisting of L1/C1 and L4/C4 provide the appro
priate match for noise figure, gain, S11 and S22. The high
pass structure also provides low frequency gain reduction
which can be beneficial from the standpoint of improving
outofband rejection.
Capacitors C2 and C5 provide a low impedance inband
RF bypass for the matching networks. Resistors R3 and
R4 provide a very important low frequency termination
for the device. The resistive termination improves low
frequency stability. Capacitors C3 and C6 provide the RF
bypass for resistors R3 and R4. Their value should be cho
sen carefully as C3 and C6 also provide a termination for
low frequency mixing products. These mixing products
are as a result of two or more inband signals mixing and
producing third order inband distortion products. The
low frequency or difference mixing products are termi
nated by C3 and C6. For best suppression of third order
distortion products based on the CDMA 1.25 MHz signal
spacing, C3 and C6 should be 0.1 uF in value. Smaller val
ues of capacitance will not suppress the generation of
the 1.25 MHz difference signal and as a result will show
up as poorer two tone IP3 results.
相關(guān)PDF資料 |
PDF描述 |
|---|---|
| ATF-541M4-BLK | C BAND, Si, N-CHANNEL, RF SMALL SIGNAL, HEMFET |
| ATF-541M4-TR1 | C BAND, Si, N-CHANNEL, RF SMALL SIGNAL, HEMFET |
| ATF-55143-BLKG | C BAND, Si, N-CHANNEL, RF SMALL SIGNAL, HEMFET |
| ATF-55143-TR1 | C BAND, Si, N-CHANNEL, RF SMALL SIGNAL, HEMFET |
| ATF-55143-TR2 | C BAND, Si, N-CHANNEL, RF SMALL SIGNAL, HEMFET |
相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| ATF55143 | 制造商:AGILENT 制造商全稱:AGILENT 功能描述:Agilent ATF-55143 Low Noise Enhancement Mode Pseudomorphic HEMT in a Surface Mount Plastic Package |
| ATF-55143 | 制造商:Avago Technologies 功能描述:MOSFET RF HEMT SOT-343 |
| ATF-55143-BLK | 制造商:AGILENT 制造商全稱:AGILENT 功能描述:Agilent ATF-55143 Low Noise Enhancement Mode Pseudomorphic HEMT in a Surface Mount Plastic Package |
| ATF-55143-BLKG | 功能描述:射頻GaAs晶體管 Transistor GaAs Single Voltage RoHS:否 制造商:TriQuint Semiconductor 技術(shù)類型:pHEMT 頻率:500 MHz to 3 GHz 增益:10 dB 噪聲系數(shù): 正向跨導(dǎo) gFS（最大值/最小值）:4 S 漏源電壓 VDS: 閘/源擊穿電壓:- 8 V 漏極連續(xù)電流:3 A 最大工作溫度:+ 150 C 功率耗散:10 W 安裝風(fēng)格: 封裝 / 箱體: |
| ATF-55143-BLKG | 制造商:Avago Technologies 功能描述:RF BIPOLAR TRANSISTOR |
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