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参数资料
| 型号： | ATF-541M4-TR2 |
| 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： | 1.40 X 1.20 MM, 0.70 MM HEIGHT, LEAD FREE, LEADLESS, MINIPAK-4 |
| 文件页数： | 2/17页 |
| 文件大小： | 731K |
| 代理商： | ATF-541M4-TR2 |
10
Noise Parameter Applications Information
The Fmin values are based on a set of 16 noise figure
measurements made at 16 different impedances using
an ATN NP5 test system. From these measurements, a
true Fmin is calculated. Fmin represents the true mini
mum noise figure of the device when the device is
presented with an impedance matching network that
transforms the source impedance, typically 50, to an
impedance represented by the reflection coefficient
Γ
o.
The designer must design a matching network that will
present
Γ
o to the device with minimal associated circuit
losses. The noise figure of the completed amplifier is
equal to the noise figure of the device plus the losses of
the matching network preceding the device. The noise
figure of the device is equal to Fmin only when the de
vice is presented with
Γ
o. If the reflection coefficient of
Gate
Pin
Source
Pin
Drain
Pin 4
Source
Pin 1
Reference
Plane
Microstrip
Transmission Lines
Sx
the matching network is other than
Γ
o, then the noise
figure of the device will be greater than Fmin based on
the following equation.
NF = F
min + 4 Rn
|
Γ
s – Γo |
2
Zo
(|1 +
Γ
o|
2
)(1
|Γ
s|
2
)
Where Rn/Zo is the normalized noise resistance,
Γ
o is the
optimum reflection coefficient required to produce Fmin
and
Γ
s is the reflection coefficient of the source imped
ance actually presented to the device.
The losses of the matching networks are nonzero and
they will also add to the noise figure of the device cre
ating a higher amplifier noise figure. The losses of the
matching networks are related to the Q of the compo
nents and associated printed circuit board loss.
Γ
o is
typically fairly low at higher frequencies and increases
as frequency is lowered. Larger gate width devices will
typically have a lower Γo as compared to narrower gate
width devices. Typically for FETs , the higher
Γ
o usually
infers that an impedance much higher than 50
is re
quired for the device to produce Fmin. At VHF frequen
cies and even lower L Band frequencies, the required im
pedance can be in the vicinity of several thousand ohms.
Matching to such a high impedance requires very hiQ
components in order to minimize circuit losses. As an
example at 900 MHz, when airwwound coils (Q>100)are
used for matching networks, the loss can still be up to
0.25 dB which will add directly to the noise figure of the
device. Using muiltilayer molded inductors with Qs in
the 30 to 50 range results in additional loss over the air
wound coil. Losses as high as 0.5 dB or greater add to the
typical 0.15 dB Fmin of the device creating an amplifier
noise figure of nearly 0.65 dB.
SMT Assembly
The package can be soldered using either leadbearing
or leadfree alloys (higher peak temperatures). Reliable
assembly of surface mount components is a complex
process that involves many material, process, and equip
ment factors, including: method of heating (e.g. IR or
vapor phase reflow, wave soldering, etc) circuit board
material, conductor thickness and pattern, type of solder
alloy, and the thermal conductivity and thermal mass of
components. Components with a low mass, such as the
Minipak 1412 package, will reach solder reflow tempera
tures faster than those with a greater mass.
The recommended leaded solder timetemperature pro
file is shown in Figure 20. This profile is representative of
an IR reflow type of surface mount assembly process. Af
ter ramping up from room temperature, the circuit board
with components attached to it (held in place with sol
der paste) passes through one or more preheat zones.
S and Noise Parameter Measurements
The position of the reference planes used for the meas
urement of both S and Noise Parameter measurements
is shown in Figure 19. The reference plane can be de
scribed as being at the center of both the gate and drain
pads.
S and noise parameters are measured with a 50 ohm mi
crostrip test fixture made with a 0.010" thickness alumi
num substrate. Both source leads are connected directly
to ground via a 0.010" thickness metal rib which provides
a very low inductance path to ground for both source
leads. The inductance associated with the addition of
printed circuit board plated through holes and source
bypass capacitors must be added to the computer cir
cuit simulation to properly model the effect of ground
ing the source leads in a typical amplifier design.
Figure 1.
相关PDF资料 |
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 |
相关代理商/技术参数 |
参数描述 |
|---|---|
| ATF55143 | 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 | 制造商:Avago Technologies 功能描述:MOSFET RF HEMT SOT-343 |
| ATF-55143-BLK | 制造商:AGILENT 制造商全称: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-55143-BLKG | 制造商:Avago Technologies 功能描述:RF BIPOLAR TRANSISTOR |
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