- 您現(xiàn)在的位置：買賣IC網(wǎng) > PDF目錄383947 > THS4502CDGKR (Texas Instruments, Inc.) WIDEBAND, LOW-DISTORTION FULLY DIFFERENTIAL AMPLIFIERS PDF資料下載
參數(shù)資料
| 型號(hào)： | THS4502CDGKR |
| 廠商： | Texas Instruments, Inc. |
| 元件分類： | 運(yùn)動(dòng)控制電子 |
| 英文描述： | WIDEBAND, LOW-DISTORTION FULLY DIFFERENTIAL AMPLIFIERS |
| 中文描述： | 寬帶，低失真全差動(dòng)放大器 |
| 文件頁數(shù)： | 26/40頁 |
| 文件大?。?/td> | 609K |
| 代理商： | THS4502CDGKR |
第1頁第2頁第3頁第4頁第5頁第6頁第7頁第8頁第9頁第10頁第11頁第12頁第13頁第14頁第15頁第16頁第17頁第18頁第19頁第20頁第21頁第22頁第23頁第24頁第25頁當(dāng)前第26頁第27頁第28頁第29頁第30頁第31頁第32頁第33頁第34頁第35頁第36頁第37頁第38頁第39頁第40頁
THS4502
THS4503
SLOS352D
APRIL 2002
REVISED JANUARY 2004
www.ti.com
26
LINEARITY: DEFINITIONS, TERMINOLOGY,
CIRCUIT TECHNIQUES, AND DESIGN
TRADEOFFS
The THS4500 family of devices features unprecedented
distortion performance for monolithic fully differential
amplifiers. This section focuses on the fundamentals of
distortion, circuit techniques for reducing nonlinearity,
and methods for equating distortion of fully differential
amplifiers to desired linearity specifications in RF receiver
chains.
Amplifiers are generally thought of as
linear
devices. In
other words, the output of an amplifier is a linearly scaled
version of the input signal applied to it. In reality, however,
amplifier transfer functions are nonlinear. Minimizing
amplifier nonlinearity is a primary design goal in many
applications.
Intercept points are specifications that have long been
used as key design criteria in the RF communications
world as a metric for the intermodulation distortion
performance of a device in the signal chain (e.g.,
amplifiers, mixers, etc.). Use of the intercept point, rather
than strictly the intermodulation distortion, allows for
simpler system-level calculations. Intercept points, like
noise figures, can be easily cascaded back and forth
through a signal chain to determine the overall receiver
chain
’
s intermodulation distortion performance. The
relationship between intermodulation distortion and
intercept point is depicted in Figure 103 and Figure 104.
Figure 103
IMD
3
= P
S
P
O
P
S
P
O
P
O
f
c
= f
c
f1
f
c
= f2
f
c
P
S
f
c
3
f
f1 f
c
f2
f
c
+ 3
f
P
f
Frequency
MHz
Figure 104
IMD
3
OIP
3
IIP
3
3X
P
IN
(dBm)
1X
P
OUT
(dBm)
P
O
P
S
Due to the intercept point
’
s ease of use in system level
calculations for receiver chains, it has become the
specification of choice for guiding distortion-related design
decisions. Traditionally, these systems use primarily
class-A, single-ended RF amplifiers as gain blocks. These
RF amplifiers are typically designed to operate in a 50-
environment, just like the rest of the receiver chain. Since
intercept points are given in dBm, this implies an
associated impedance (50
).
However, with a fully differential amplifier, the output does
not require termination as an RF amplifier would. Because
closed-loop amplifiers deliver signals to their outputs
regardless of the impedance present, it is important to
comprehend this when evaluating the intercept point of a
fully differential amplifier. The THS4500 series of devices
yields optimum distortion performance when loaded with
200
to 1 k
, very similar to the input impedance of an
analog-to-digital converter over its input frequency band.
As a result, terminating the input of the ADC to 50
can
actually be detrimental to system performance.
This discontinuity between open-loop, class-A amplifiers
and closed-loop, class-AB amplifiers becomes apparent
when comparing the intercept points of the two types of
devices. Equation 10 gives the definition of an intercept
point, relative to the intermodulation distortion.
OIP
3
P
O
IMD
3
2
where
P
O
10 log
V
2
Pdiff
0.001
2R
L
(10)
(11)
NOTE
:
P
o
is the output power of a single tone, R
L
is the differential load
resistance, and V
P(diff)
is the differential peak voltage for a
single tone.
相關(guān)PDF資料 |
PDF描述 |
|---|---|
| THS4502CDGKRG4 | WIDEBAND, LOW-DISTORTION FULLY DIFFERENTIAL AMPLIFIERS |
| THS4502CDGKT | WIDEBAND, LOW-DISTORTION FULLY DIFFERENTIAL AMPLIFIERS |
| THS4502CDGNT | WIDEBAND, LOW-DISTORTION FULLY DIFFERENTIAL AMPLIFIERS |
| THS4502CDR | WIDEBAND, LOW-DISTORTION FULLY DIFFERENTIAL AMPLIFIERS |
| THS4502CDRG4 | WIDEBAND, LOW-DISTORTION FULLY DIFFERENTIAL AMPLIFIERS |
相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| THS4502CDGKRG4 | 功能描述:特殊用途放大器 Hi-Sp Fully-Diff Amp RoHS:否 制造商:Texas Instruments 通道數(shù)量:Single 共模抑制比（最小值）: 輸入補(bǔ)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(fēng)格:SMD/SMT 封裝 / 箱體:QFN-20 封裝:Reel |
| THS4502CDGKT | 制造商:TI 制造商全稱:Texas Instruments 功能描述:WIDEBAND, LOW-DISTORTION FULLY DIFFERENTIAL AMPLIFIERS |
| THS4502CDGN | 功能描述:特殊用途放大器 HS Full Diff RoHS:否 制造商:Texas Instruments 通道數(shù)量:Single 共模抑制比（最小值）: 輸入補(bǔ)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(fēng)格:SMD/SMT 封裝 / 箱體:QFN-20 封裝:Reel |
| THS4502CDGNDT | 制造商:TI 制造商全稱:Texas Instruments 功能描述:WIDEBAND, LOW-DISTORTION FULLY DIFFERENTIAL AMPLIFIERS |
| THS4502CDGNG4 | 功能描述:特殊用途放大器 HS Full Diff RoHS:否 制造商:Texas Instruments 通道數(shù)量:Single 共模抑制比（最小值）: 輸入補(bǔ)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(fēng)格:SMD/SMT 封裝 / 箱體:QFN-20 封裝:Reel |
發(fā)布緊急采購，3分鐘左右您將得到回復(fù)。