- 您現(xiàn)在的位置：買賣IC網(wǎng) > PDF目錄375316 > AN105 (Vishay Intertechnology,Inc.) FETS AS VOLTAGE-CONTROLLED RESISTORS PDF資料下載
參數(shù)資料
| 型號(hào)： | AN105 |
| 廠商： | Vishay Intertechnology,Inc. |
| 英文描述： | FETS AS VOLTAGE-CONTROLLED RESISTORS |
| 中文描述： | 場效應(yīng)管的電壓，控制電阻 |
| 文件頁數(shù)： | 3/7頁 |
| 文件大?。?/td> | 106K |
| 代理商： | AN105 |
AN105
Siliconix
10-Mar-97
3
V
OUT
V
IN
VCR
V
GS
R
+
–
G
Diode
Anode
Diode
Cathode
when Signal
Swings Negative
+V
–V
0
Figure 5.
Simple Attenuator Circuit
V
OUT
V
IN
VCR
V
GG
R
1
+
–
R
3
R
2
VCR Linearization
R
2
= R
3
// 10(r
DS
//R
load
//R
1
)
Figure 6.
V
OUT
V
IN
VCR
R
1
R
3
R
2
+
V
CONTROL
Figure 7.
Reducing Signal Distortion
The majority of VCR applications require that signal
distortion be kept to a minimum. Also, numerous
applications require large signal handling capability. A
simple feedback technique may be used to reduce
distortion while permitting large signal handling
capability; a small amount of drain signal is coupled to the
gate through a resistor divider network, as shown in
Figure 6.
The application of a part of the positive drain signal to the
gate causes the channel depletion layer to decrease, with
a corresponding increase in drain current. Increasing the
drain current for a given drain voltage tends to linearize
the V
GS
bias curves. On the negative half-cycle, a small
negative voltage is coupled to the gate to reduce the
amount of drain-gate forward bias. This in turn reduces
the drain current and linearizes the bias lines. Now the
channel resistance is dependent on the dc gate control
voltage and not on the drain signal, unless the V
DS
= V
GS
– V
GS(off)
locus is approached. Resistors R
2
and R
3
in
Figure 6 couple the drain signal to the gate; the resistor
values are equal, so that symmetrical voltage-current
characteristics are produced in both quadrants. The
resistors must be sufficiently large to provide minimum
loading to the circuit:
R
2
= R
3
10 [R
1
r
DS
(max) R
L
]
(3)
Typically, 470-k resistors will work well for most ap-
plications. R
1
is selected so that the ratio of r
DS(on)
R
L
to
[(r
DS(on)
R
L
) + R
1
] give the desired output voltage, or:
V
O
V
I
r
DS(on)
R
L
(r
DS(on)
R
L
)
R
1
(4)
The feedback technique used in Figure 6 requires that the
gate control voltage, V
GG
, be twice as large as V
GS
in Fig-
ure 5 for the same r
DS
value. Use of a floating supply be-
tween the resistor junction and the FET gate will over-
come this problem. The circuit is shown in Figure 7 and
allows the gate control voltage to be the same value as that
voltage used without a feedback circuit, while preserving
the advantages to be gained through the feedback tech-
nique.
相關(guān)PDF資料 |
PDF描述 |
|---|---|
| AN1201SM | Polarity inverting charge pump DC/DC converter IC |
| AN1324 | Circular Connector; No. of Contacts:4; Series:MS27508; Body Material:Aluminum; Connecting Termination:Crimp; Connector Shell Size:8; Circular Contact Gender:Socket; Circular Shell Style:Box Mount Receptacle; Insert Arrangement:8-44 RoHS Compliant: No |
| AN1324NS | Circular Connector; No. of Contacts:6; Series:MS27508; Body Material:Aluminum; Connecting Termination:Crimp; Connector Shell Size:8; Circular Contact Gender:Socket; Circular Shell Style:Box Mount Receptacle; Insert Arrangement:8-6 RoHS Compliant: No |
| AN6564 | Quadruple Operational Amplifiers |
| AN6564NS | Quadruple Operational Amplifiers |
相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| AN-1050 | 制造商:CYMBET 制造商全稱:CYMBET 功能描述:Using the EnerChip Energy Harvesters with the TI LaunchPad |
| AN-1052 | 制造商:CYMBET 制造商全稱:CYMBET 功能描述:Operating the EnerChip in High Temperature Environments |
| AN-1053 | 制造商:CYMBET 制造商全稱:CYMBET 功能描述:Silicon Labs RF-to-USB2 Cymbet EH Demos |
| AN106 | 制造商:未知廠家 制造商全稱:未知廠家 功能描述:Optoelectronic |
| AN1062 | 制造商:MOTOROLA 制造商全稱:Motorola, Inc 功能描述:Using the QSPI for Analog Data Acquisition |
發(fā)布緊急采購，3分鐘左右您將得到回復(fù)。