參數(shù)資料
型號(hào)： ATF-521P8-TR1
元件分類(lèi)： 小信號(hào)晶體管
英文描述： L BAND, Si, N-CHANNEL, RF SMALL SIGNAL, HEMFET, MO-229
封裝： 2 x 2 MM, 0.75 MM HEIGHT,LEAD FREE, PLASTIC,LPCC-8
文件頁(yè)數(shù)： 8/23頁(yè)
文件大?。?/td> 319K
代理商： ATF-521P8-TR1
16
Figure 8. Passive Biasing.
Active Bias[2]
Due to very high DC power dissipation and small
package constraints, it is recommended that ATF521P8
use active biasing. The main advantage of an active
biasing scheme is the ability to hold the drain to source
current constant over a wide range of temperature
variations.
A very inexpensive method of accomplishing this
is to use two PNP bipolar transistors arranged in a
current mirror configuration as shown in Figure 9. Due
to resistors R1 and R3, this circuit is not acting as a
true current mirror, but if the voltage drop across R1
and R3 is kept identical then it still displays some of
the more useful characteristics of a current mirror. For
example, transistor Q1 is configured with its base and
collector tied together. This acts as a simple PN junction,
which helps temperature compensate the EmitterBase
junction of Q2.
To calculate the values of R1, R2, R3, and R4 the
following parameters must be know or chosen first:
I
ds is the device draintosource current;
I
R is the Reference current for active bias;
V
dd is the power supply voltage available;
V
ds is the device draintosource voltage;
V
g is the typical gate bias;
V
be1 is the typical BaseEmitter turn on voltage for Q1 &
Q2;
Therefore, resistor R3, which sets the desired device
drain current, is calculated as follows:
R3 = Vdd – Vds
(4)
p
I
ds + IC2
where,
I
C2 is chosen for stability to be 10 times the typical gate
current and also equal to the reference current I
R.
The next three equations are used to calculate the
rest of the biasing resistors for Figure 9. Note that the
voltage drop across R1 must be set equal to the voltage
drop across R3, but with a current of I
R.
R1 = Vdd – Vds
(5)
I
R
R2 sets the bias current through Q1.
R2 = Vds – Vbe1
(6)
p
I
R
R4 sets the gate voltage for ATF521P8.
R4 = Vg
(7)
p
I
C2
Thus, by forcing the emitter voltage (V
E) of transistor
Q1 equal to V
ds, this circuit regulates the drain current
similar to a current mirror. As long as Q2 operates in the
forward active mode, this holds true. In other words, the
CollectorBase junction of Q2 must be kept reversed
biased.
C1
RFin
RFout
L4
L1
L2
L3
R6
R5
R3
R4
C4
C3
C7
C8
C6
C5
Q2
C2
R1
R2
Q1
VE
Vg
Vds
Vdd
2
7
ATF-521P8
2PL
Figure 9. Active Bias Circuit.
INPUT
OUTPUT
Zo
C1
C4
Zo
C5
C6
Vdd
R3
L4
L1
R4
R5
C3
C2
R1
R2
Q1
Ib
相關(guān)PDF資料
PDF描述
ATF-521P8-BLK L BAND, Si, N-CHANNEL, RF SMALL SIGNAL, HEMFET, MO-229
ATF-53189-TR1 C BAND, Si, N-CHANNEL, RF SMALL SIGNAL, HEMFET
ATF-53189-BLK C BAND, Si, N-CHANNEL, RF SMALL SIGNAL, HEMFET
ATF-531P8-BLK C BAND, Si, N-CHANNEL, RF SMALL SIGNAL, HEMFET, MO-229
ATF-531P8-TR1G C BAND, Si, N-CHANNEL, RF SMALL SIGNAL, HEMFET, MO-229
相關(guān)代理商/技術(shù)參數(shù)
參數(shù)描述
ATF-521P8-TR2 功能描述:射頻GaAs晶體管 Transistor GaAs High Linearity RoHS:否 制造商:TriQuint Semiconductor 技術(shù)類(lèi)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:
ATF524S16M 制造商:n/a 功能描述:Inverter Semiconductor
ATF-53189 制造商:AGILENT 制造商全稱(chēng):AGILENT 功能描述:Enhancement Mode Pseudomorphic HEMT in SOT 89 Package
ATF-53189-BLK 功能描述:射頻GaAs晶體管 Transistor GaAs High Linearity RoHS:否 制造商:TriQuint Semiconductor 技術(shù)類(lèi)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-53189-TR1 功能描述:射頻GaAs晶體管 Transistor GaAs High Linearity RoHS:否 制造商:TriQuint Semiconductor 技術(shù)類(lèi)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:
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