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參數(shù)資料
| 型號： | VCA810 |
| 英文描述： | High Gain Adjust Range, Wideband, Voltage-Controlled Amplifier |
| 中文描述： | 高增益調整范圍，寬帶，電壓控制放大器 |
| 文件頁數(shù)： | 19/25頁 |
| 文件大?。?/td> | 417K |
| 代理商： | VCA810 |
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SBOS275C JUNE 2003 REVISED OCTOBER 2004
www.ti.com
19
DESIGN-IN TOOLS
DEMONSTRATION BOARDS
A PC board is available to assist in the initial evaluation of
circuit performance using the VCA810. This evaluation
board (EVM) is available free, as an unpopulated PC
board delivered with descriptive documentation. The
summary information for this board is shown in Table 1
below:
PRODUCT
PACKAGE
BOARD PART
NUMBER
LITERATURE
REQUEST
NUMBER
VCA810ID
SO8
DEM-VCA81xD
SBOU025
Table 1. EVM Ordering Information
Go to the TI web site (
www.ti.com
) to request evaluation
boards through the VCA810 product folder.
MACROMODELS AND APPLICATIONS
SUPPORT
Computer simulation of circuit performance using SPICE
is often useful when analyzing the performance of analog
circuits and systems. This is particularly true for video and
RF amplifier circuits where parasitic capacitance and
inductance can play a major role in circuit performance. A
SPICE model for the VCA810 is available through the TI
web page. The applications group is also available for
design assistance. The models available from TI predict
typical small signal AC performance, transient steps, DC
performance, and noise under a wide variety of operating
conditions. The models include the noise terms found in
the electrical specifications of the relevant product data
sheet.
OPERATING SUGGESTIONS
INPUT/OUTPUT RANGE
The VCA810’s 80dB gain range allows the user to handle
an exceptionally wide range of input signal levels. If the
input and output voltage range specifications are
exceeded, however, signal distortion and amplifier
overdrive will occur. The VCA810 maximum input and
output voltage range is best illustrated in the Typical
Characteristics plot,
Input/Output Range vs Gain
. This
chart plots input and output voltages versus gain in dB.
The maximum input voltage range is the largest at full
attenuation (40dB) and decrease as the gain increases.
Similarly, the maximum useful output voltage range
increases as the input decreases. We can distinguish
three overloading issues as a result of the operating mode:
high attenuation, mid-range gain-attenuation, and high
gain.
From –40dB to –10dB, gain overdriving the input stage is
the only method to overdrive the VCA810. Preventing this
type of overdrive is achieved by limiting the input voltage
range.
From –10dB to +40dB, overdriving can be prevented by
limiting the output voltage range. There are two limiting
mechanisms operating in this situation. From –10dB to
+10dB, an internal stage is the limiting factor; from +10dB
to +40dB, the output stage is the limiting factor.
Output overdriving occurs when either the maximum
output voltage swing or output current is exceeded. The
VCA810 high output current of
±
60mA insures that
virtually all output overdrives will be limited by voltage
swing rather than by current limiting. Table 2 summarizes
these overdrive conditions.
GAIN RANGE
LIMITING
MECHANISM
TO PREVENT,
OPERATE DEVICE
WITHIN:
40dB < G < 10dB
Input Stage Overdrive
Input Voltage Range
10dB < G < +10dB
Internal Stage Overdrive
Output Voltage Range
+5dB < G < +40dB
Output Stage
Overdrive
Output Voltage Range
Table 2. Output Signal Compression
OVERDRIVE RECOVERY
As shown in the Typical Characteristics plot,
Input/Output
Range vs Gain
, the onset of overdrive occurs whenever
the actual output begins to deviate from the ideal expected
output. If possible, the user should operate the VCA810
within the linear regions shown in order to minimize signal
distortion and overdrive delay time. However, instances of
amplifier overdrive are quite common in Automatic Gain
Control (AGC) circuits, which involve the application of
variable gain to input signals of varying levels. The
VCA810 design incorporates circuitry that allows it to
recover from most overdrive conditions in 200ns or less.
Overdrive recovery time is defined as the time required for
the output to return from overdrive to linear operation,
following the removal of either an input or gain-control
overdrive signal. The overdrive plots for maximum gain
and maximum attenuation are shown in the Typical
Characteristics plots.
相關PDF資料 |
PDF描述 |
|---|---|
| VCA810AID | High Gain Adjust Range, Wideband, Voltage-Controlled Amplifier |
| VCA810AIDR | High Gain Adjust Range, Wideband, Voltage-Controlled Amplifier |
| VCA810ID | High Gain Adjust Range, Wideband, Voltage-Controlled Amplifier |
| VCA810IDR | High Gain Adjust Range, Wideband, Voltage-Controlled Amplifier |
| VCA822IDGS | Wideband, > 40dB Gain Adjust Range, Linear in V/V VARIABLE GAIN AMPLIFIER |
相關代理商/技術參數(shù) |
參數(shù)描述 |
|---|---|
| VCA810_12 | 制造商:TI 制造商全稱:Texas Instruments 功能描述:High Gain Adjust Range, Wideband, VARIABLE GAIN AMPLIFIER |
| VCA-8103 | 制造商:Quest Technology International Inc 功能描述: |
| VCA810AID | 功能描述:特殊用途放大器 High-Gain Adj Range Wideband Vltg-Cntrl RoHS:否 制造商:Texas Instruments 通道數(shù)量:Single 共模抑制比（最小值）: 輸入補償電壓: 工作電源電壓:3 V to 5.5 V 電源電流:5 mA 最大功率耗散: 最大工作溫度:+ 70 C 最小工作溫度:- 40 C 安裝風格:SMD/SMT 封裝 / 箱體:QFN-20 封裝:Reel |
| VCA810AIDG4 | 功能描述:特殊用途放大器 High-Gain Adj Range Wideband Vltg-Cntrl RoHS:否 制造商:Texas Instruments 通道數(shù)量:Single 共模抑制比（最小值）: 輸入補償電壓: 工作電源電壓:3 V to 5.5 V 電源電流:5 mA 最大功率耗散: 最大工作溫度:+ 70 C 最小工作溫度:- 40 C 安裝風格:SMD/SMT 封裝 / 箱體:QFN-20 封裝:Reel |
| VCA810AIDR | 功能描述:特殊用途放大器 High-Gain Adj Range Wideband Vltg-Cntrl RoHS:否 制造商:Texas Instruments 通道數(shù)量:Single 共模抑制比（最小值）: 輸入補償電壓: 工作電源電壓:3 V to 5.5 V 電源電流:5 mA 最大功率耗散: 最大工作溫度:+ 70 C 最小工作溫度:- 40 C 安裝風格:SMD/SMT 封裝 / 箱體:QFN-20 封裝:Reel |
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