參數(shù)資料
型號: 052AI
廠商: Texas Instruments, Inc.
英文描述: ENHANCED-JFET LOW-OFFSET OPERATIONAL AMPLIFIERS
中文描述: 增強(qiáng)型場效應(yīng)低失調(diào)運算放大器
文件頁數(shù): 41/68頁
文件大?。?/td> 1336K
代理商: 052AI
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(guān)PDF資料
PDF描述
92HD71B8X3NLGXYYX8 PCM CODEC, QCC48
92HD71B8X3NLGXYYX PCM CODEC, QCC48
92HD71B8X3PRGXYYX8 PCM CODEC, PQFP48
92HD71B8X3PRGXYYX PCM CODEC, PQFP48
92HD71B8X5NLGXYYX8 PCM CODEC, QCC48
相關(guān)代理商/技術(shù)參數(shù)
參數(shù)描述
052-ALMOND 功能描述:罩類、盒類及殼類產(chǎn)品 3.26X5.63X1.41 AL RoHS:否 制造商:Bud Industries 產(chǎn)品:Boxes 外部深度:6.35 mm 外部寬度:6.35 mm 外部高度:2.56 mm NEMA 額定值: IP 等級: 材料:Acrylonitrile Butadiene Styrene (ABS) 顏色:Red
052-BLACK 功能描述:罩類、盒類及殼類產(chǎn)品 3.26X5.63X1.41 BK RoHS:否 制造商:Bud Industries 產(chǎn)品:Boxes 外部深度:6.35 mm 外部寬度:6.35 mm 外部高度:2.56 mm NEMA 額定值: IP 等級: 材料:Acrylonitrile Butadiene Styrene (ABS) 顏色:Red
052C GRAY 功能描述:罩類、盒類及殼類產(chǎn)品 5.62 x 3.25 x 1.4 GRAY BOTTOM RoHS:否 制造商:Bud Industries 產(chǎn)品:Boxes 外部深度:6.35 mm 外部寬度:6.35 mm 外部高度:2.56 mm NEMA 額定值: IP 等級: 材料:Acrylonitrile Butadiene Styrene (ABS) 顏色:Red
052C,AL 功能描述:BOX 5.62X3.25X1.40 CLR TOP; ALMD RoHS:是 類別:盒,外殼,支架 >> 箱 系列:S 特色產(chǎn)品:Customize Your Enclosure 3D 型號:1591UFL.dwg 1591UFL.(igs,stp) 標(biāo)準(zhǔn)包裝:1 系列:1591FL 容器 - 類型:帶安裝法蘭的盒子 尺寸/尺寸:4.724" L x 4.724" W(119.99mm x 119.99mm) 高度:2.322"(58.98mm) 面積 (L x W):22.3"(144cm) 設(shè)計:包含蓋 材質(zhì):塑料 - ABS 顏色:灰 厚度:0.079"(2.01mm) 特點:卡導(dǎo)軌,阻燃 額定值:IP54 材料可燃性額定值:UL94 V-0 裝運信息:從 Digi-Key 運送 重量:0.375 磅(170.1g) 相關(guān)產(chǎn)品:1599CLIPGY-ND - BELT/POCKET CLIP HANDHELD GRAY1599CLIP-ND - BELT/POCKET CLIP HANDHELD BLACK1591Z50-ND - ADAPTER PC BOARD CARD 1=501591Z100-ND - ADAPTER PC BOARD CARD 1=1001591UC-ND - LID CLEAR POLY USE W/1591U SERIE1591MS100-ND - SCREW MACHINE TYPE M3-0.5X10MM1591F2BK-10-ND - FLANGE ABS 1.0X3.0X0.1 BLACKHM204-ND - ADAPTER CARD PCB FOR 1591SER 6PK
052C,BK 功能描述:BOX 5.62X3.25X1.40 CLR TOP; BLK RoHS:是 類別:盒,外殼,支架 >> 箱 系列:S 特色產(chǎn)品:Customize Your Enclosure 3D 型號:1591UFL.dwg 1591UFL.(igs,stp) 標(biāo)準(zhǔn)包裝:1 系列:1591FL 容器 - 類型:帶安裝法蘭的盒子 尺寸/尺寸:4.724" L x 4.724" W(119.99mm x 119.99mm) 高度:2.322"(58.98mm) 面積 (L x W):22.3"(144cm) 設(shè)計:包含蓋 材質(zhì):塑料 - ABS 顏色:灰 厚度:0.079"(2.01mm) 特點:卡導(dǎo)軌,阻燃 額定值:IP54 材料可燃性額定值:UL94 V-0 裝運信息:從 Digi-Key 運送 重量:0.375 磅(170.1g) 相關(guān)產(chǎn)品:1599CLIPGY-ND - BELT/POCKET CLIP HANDHELD GRAY1599CLIP-ND - BELT/POCKET CLIP HANDHELD BLACK1591Z50-ND - ADAPTER PC BOARD CARD 1=501591Z100-ND - ADAPTER PC BOARD CARD 1=1001591UC-ND - LID CLEAR POLY USE W/1591U SERIE1591MS100-ND - SCREW MACHINE TYPE M3-0.5X10MM1591F2BK-10-ND - FLANGE ABS 1.0X3.0X0.1 BLACKHM204-ND - ADAPTER CARD PCB FOR 1591SER 6PK