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參數資料
| 型號： | AD536AKQ |
| 廠商： | Analog Devices Inc |
| 文件頁數： | 9/17頁 |
| 文件大?。?/td> | 552K |
| 描述： | IC TRUE RMS/DC CONV 14CDIP |
| 產品變化通告： | Product Discontinuance 27/Oct/2011 |
| 標準包裝： | 25 |
| 電流 - 電源： | 1.2mA |
| 電源電壓： | 5.0V ~ 36V，±3.0V ~ 18V |
| 安裝類型： | 通孔 |
| 封裝/外殼： | 14-CDIP（0.300"，7.62mm） |
| 供應商設備封裝： | 14-CERDIP |
| 包裝： | 管件 |
AD536A
Data Sheet
Rev. E | Page 8 of 16
THEORY OF OPERATION
The AD536A embodies an implicit solution of the rms equation
that overcomes the dynamic range as well as other limitations
inherent in a straightforward computation of rms. The actual
computation performed by the AD536A follows the equation
?/DIV>
?/DIV>
?/DIV>
?/DIV>
?/DIV>
?/DIV>
=
rms
V
V
Avg
rms
V
IN
2
Figure 6 is a simplified schematic of the AD536A. Note that it is
subdivided into four major sections: absolute value circuit
(active rectifier), squarer/divider, current mirror, and buffer
amplifier. The input voltage (V
IN
), which can be ac or dc, is
converted to a unipolar current (I
1
) by the active rectifiers
(A
1
, A
2
). I
1
drives one input of the squarer/divider, which has
the transfer function
I
4
= I
I
2
/I
3
The output current, I
4
, of the squarer/divider drives the current
mirror through a low-pass filter formed by R1 and the exter-
nally connected capacitor, C
AV
. If the R1 C
AV
time constant is
much greater than the longest period of the input signal, then
I
4
is effectively averaged. The current mirror returns a current
I
3
, which equals Avg[I
4
], back to the squarer/divider to complete
the implicit rms computation. Thus,
I
4
= Avg[I
I
2
/I
4
] = I
I
rms
14
+V
S
V
S
I
3
I
2
I
1
I
OUT
R
L
IN
|V
IN
|R
1
ABSOLUTEVALUE;
VOLTAGE-CURRENT
CONVERTER
ONE-QUADRANT
SQUARER/DIVIDER
CURRENT MIRROR
Q1
Q2
Q3
Q4
Q5
COM
4
9
dB
OUT
5
BUF
OUT
6
3
8
1
BUF
IN
BUFFER
7
10
0.4mA
FS
A3
OTES
. PINOUTSARE FOR 14-LEAD DIP.
0.2mA
FS
R1
25k&
R2
25k&
12k&
25k&
12k&
R4
50k&
R3
25k&
80k&
A4
A2
A1
Figure 6. Simplified Schematic
The current mirror also produces the output current, I
OUT
, which
equals 2I
4
. I
OUT
can be used directly or can be converted to a
voltage with R2 and buffered by A4 to provide a low impedance
voltage output. The transfer function of the AD536A results in
the following:
V
OUT
= 2R2 ?I rms = V
IN
rms
The dB output is derived from the emitter of Q3 because the
voltage at this point is proportional to log V
IN
. The emitter
follower, Q5, buffers and level shifts this voltage so that the dB
output voltage is zero when the externally supplied emitter
current (I
REF
) to Q5 approximates I
3
.
CONNECTIONS FOR dB OPERATION
The logarithmic (or decibel) output of the AD536A is one of
its most powerful features. The internal circuit computing dB
works accurately over a 60 dB range. The connections for dB
measurements are shown in Figure 7.
Select the 0 dB level by adjusting R1 for the proper 0 dB reference
current (which is set to cancel the log output current from the
squarer/divider at the desired 0 dB point). The external op amp
provides a more convenient scale and allows compensation of
the +0.33%/癈 scale factor drift of the dB output pin.
The temperature-compensating resistor, R2, is available online
in several styles from Precision Resistor Company, Inc., (Part
Number AT35 and Part Number ST35). The average temperature
coefficients of R2 and R3 result in the +3300 ppm required to
compensate for the dB output. The linear rms output is available
at Pin 8 on the DIP or Pin 10 on the header device with an output
impedance of 25 k&. Some applications require an additional
buffer amplifier if this output is desired.
For dB calibration,
1. Set V
IN
= 1.00 V dc or 1.00 V rms.
2. Adjust R1 for dB output = 0.00 V.
3. Set V
IN
= +0.1 V dc or 0.10 V rms.
4. Adjust R5 for dB output = 2.00 V.
Any other desired 0 dB reference level can be used by setting
V
IN
and adjusting R1 accordingly. Note that adjusting R5 for the
proper gain automatically provides the correct temperature
compensation.
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相關代理商/技術參數 |
參數描述 |
|---|---|
| AD536ASCHIPS | 制造商:AD 制造商全稱:Analog Devices 功能描述:Integrated Circuit True RMS-to-DC Converter |
| AD536ASD | 功能描述:IC TRUE RMS/DC CONV 14-CDIP RoHS:否 類別:集成電路 (IC) >> PMIC - RMS 至 DC 轉換器 系列:- 標準包裝:46 系列:- 電流 - 電源:1.2mA 電源電壓:±18 V，36 V 安裝類型:表面貼裝 封裝/外殼:16-SOIC（0.295"，7.50mm 寬） 供應商設備封裝:16-SOIC W 包裝:管件 |
| AD536ASD/883B | 功能描述:直流/直流開關轉換器 RMS/DC CONVERTER IC RoHS:否 制造商:STMicroelectronics 最大輸入電壓:4.5 V 開關頻率:1.5 MHz 輸出電壓:4.6 V 輸出電流:250 mA 輸出端數量:2 最大工作溫度:+ 85 C 安裝風格:SMD/SMT |
| AD536ASD883B | 制造商:ANALOG DEV 功能描述:DIP-14PIN GOLD |
| AD536ASE | 制造商:Rochester Electronics LLC 功能描述: 制造商:Rochester Electronics LLC 功能描述:- Bulk 制造商:Analog Devices 功能描述: |
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