參數(shù)資料
型號: TL054CNSRG4
廠商: TEXAS INSTRUMENTS INC
元件分類: 運算放大器
英文描述: QUAD OP-AMP, 7700 uV OFFSET-MAX, 2.7 MHz BAND WIDTH, PDSO14
封裝: GREEN, PLASTIC, SOP-14
文件頁數(shù): 41/68頁
文件大?。?/td> 1554K
代理商: TL054CNSRG4
TL05x, TL05xA
ENHANCED-JFET LOW-OFFSET
OPERATIONAL AMPLIFIERS
SLOS178A – FEBRUARY 1997 - REVISED FEBRUARY 2003
46
POST OFFICE BOX 655303
DALLAS, TEXAS 75265
APPLICATION INFORMATION
voltage-ratio-to-dB converter
The application in Figure 90 measures the amplitude ratio of two signals, then converts the ratio to decibels (see
Figure 91). The output voltage provides a resolution of 100 mV/dB. The two inputs can be either dc or sinusoidal
ac signals. When using ac signals, both signals should be the same frequency or output glitches will occur. For
measuring two input signals of different frequencies, extra filtering should be added after the rectifiers.
The circuit contains three low-offset TL05xA devices. Two of these devices provide the rectification and
logarithmic conversion of the inputs. The third TL05xA forms an instrumentation amplifier. The stage performing
the logarithmic conversion also requires two well-matched npn transistors.
The input signal first passes through a high-impedance unity-gain buffer U1A (U2A). Then U1B (U2B) rectifies
the input signal at a gain of 0.5, and U1C (U2C) provides a noninverting gain of 2, so that the system gain is
still one. U1D (U2D), R6 (R13), and Q1 (Q2) perform the logarithmic conversion of the rectified input signal. The
instrumentation amplifier formed by U3A, U3B, U3D scales the difference of the two logarithmic voltages by a
gain of 33.6. As a result, the output voltage equals 100 mV/dB. The 1-k
potentiometer on the input of U3C
calibrates the zero-dB reference level. The following equations are used to derive the relationship between the
input voltage ratio, expressed in decibels, and the output voltage.
XdB
+ 20 log
V
A
V
B
+ 20
In V
A
– V
B
In (10)
XdB
+ 8.686 In V
A
– In V
B
V
BE(Q1) +
kT
q In
V
A
R
I
S
V
BE(Q2) +
kT
q In
V
B
R
I
S
DV
BE +
V
BE(Q1)
–V
BE(Q2) +
kT
q
In V
A
– In V
B
XdB
+ 8.686
kT q
V
BE(Q1)
–V
BE(Q2) +
336
V
BE(Q1)
–V
BE(Q2)
at 25
°C
where
k
+ 1.38
10–23,q
+ 1.602
10–19, and T is Kelvin temperature
This gives a resolution of 1 V/dB. Therefore, the gain of the instrumentation amplifier is set at 33.6 to obtain
100 mV/dB.
相關PDF資料
PDF描述
TL072ACPSRG4 DUAL OP-AMP, 7500 uV OFFSET-MAX, 3 MHz BAND WIDTH, PDSO8
TL072CPSRG4 DUAL OP-AMP, 13000 uV OFFSET-MAX, 3 MHz BAND WIDTH, PDSO8
TL072CPWRG4 DUAL OP-AMP, 13000 uV OFFSET-MAX, 3 MHz BAND WIDTH, PDSO8
TL1431CPK 1-OUTPUT TWO TERM VOLTAGE REFERENCE, PSSO3
TL431CN 1-OUTPUT TWO TERM VOLTAGE REFERENCE, PDIP8
相關代理商/技術參數(shù)
參數(shù)描述
TL054I 制造商:TI 制造商全稱:Texas Instruments 功能描述:ENHANCED-JFET LOW-OFFSET OPERATIONAL AMPLIFIERS
TL054ID 功能描述:運算放大器 - 運放 Quad Enhanced JFET Precision RoHS:否 制造商:STMicroelectronics 通道數(shù)量:4 共模抑制比(最小值):63 dB 輸入補償電壓:1 mV 輸入偏流(最大值):10 pA 工作電源電壓:2.7 V to 5.5 V 安裝風格:SMD/SMT 封裝 / 箱體:QFN-16 轉換速度:0.89 V/us 關閉:No 輸出電流:55 mA 最大工作溫度:+ 125 C 封裝:Reel
TL054IDE4 功能描述:運算放大器 - 運放 Quad Enhanced JFET Precision RoHS:否 制造商:STMicroelectronics 通道數(shù)量:4 共模抑制比(最小值):63 dB 輸入補償電壓:1 mV 輸入偏流(最大值):10 pA 工作電源電壓:2.7 V to 5.5 V 安裝風格:SMD/SMT 封裝 / 箱體:QFN-16 轉換速度:0.89 V/us 關閉:No 輸出電流:55 mA 最大工作溫度:+ 125 C 封裝:Reel
TL054IDG4 功能描述:運算放大器 - 運放 Quad Enh JFET Prec Op Amp RoHS:否 制造商:STMicroelectronics 通道數(shù)量:4 共模抑制比(最小值):63 dB 輸入補償電壓:1 mV 輸入偏流(最大值):10 pA 工作電源電壓:2.7 V to 5.5 V 安裝風格:SMD/SMT 封裝 / 箱體:QFN-16 轉換速度:0.89 V/us 關閉:No 輸出電流:55 mA 最大工作溫度:+ 125 C 封裝:Reel
TL054IDR 功能描述:運算放大器 - 運放 Quad Enhanced JFET Precision RoHS:否 制造商:STMicroelectronics 通道數(shù)量:4 共模抑制比(最小值):63 dB 輸入補償電壓:1 mV 輸入偏流(最大值):10 pA 工作電源電壓:2.7 V to 5.5 V 安裝風格:SMD/SMT 封裝 / 箱體:QFN-16 轉換速度:0.89 V/us 關閉:No 輸出電流:55 mA 最大工作溫度:+ 125 C 封裝:Reel