AD536AKD Analog Devices Inc, AD536AKD Datasheet - Page 8

• Manufacturer Part Number: AD536AKD
• Description: IC TRUE RMS/DC CONV 14-CDIP
• Manufacturer: Analog Devices Inc

Specifications of AD536AKD

• Rohs Status: RoHS non-compliant
• Current - Supply: 1.2mA
• Voltage - Supply: 5.0V ~ 36V, ±3.0V ~ 18V
• Mounting Type: Through Hole
• Package / Case: 14-CDIP (0.300", 7.62mm)
• Accuracy %: 0.2%
• Bandwidth: 450kHz
• Supply Current: 1.2mA
• Power Dissipation Pd: 500mW
• Supply Voltage Range: 5V To 36V
• Digital Ic Case Style: DIP
• No. Of Pins: 14
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant

AD536A
APPLICATIONS INFORMATION
TYPICAL CONNECTIONS
The AD536A is simple to connect to for the majority of high
accuracy rms measurements, requiring only an external capaci-
tor to set the averaging time constant. The standard connection
is shown in Figure 6 through Figure 8. In this configuration, the
AD536A measures the rms of the ac and dc levels present at the
input, but shows an error for low frequency input as a function
of the filter capacitor, C
capacitor is used, the additional average error at 10 Hz is 0.1%;
at 3 Hz, the additional average error is 1%.
The accuracy at higher frequencies is according to specification.
To reject the dc input, add a capacitor in series with the input,
as shown in Figure 10. Note that the capacitor must be nonpolar.
If the AD536A supply rails contain a considerable amount of
high frequency ripple, it is advisable to bypass both supply pins
to ground with 0.1 μF ceramic capacitors, located as close to the
device as possible.
V
+V
OUT
Figure 6. 14-Lead Standard RMS Connection
COM
Figure 7. 10-Pin Standard RMS Connection
–V
S
V
IN
BUF IN
S
BUF OUT
+V
S
V
C
–V
IN
V
NC
dB
AV
C
IN
S
AV
R
AV
AD536A
L
1
2
3
4
5
6
7
, as shown in Figure 12. Thus, if a 4 μF
AD536A
CURRENT
MIRROR
SQUARER/
I
DIVIDER
25kΩ
OUT
ABSOLUTE
BUF
VALUE
ABSOLUTE
SQUARER/
25kΩ
–V
CURRENT
DIVIDER
MIRROR
VALUE
C
S
AV
25kΩ
25kΩ
BUF
BUF IN
C
14
13
12
11
10
9
8
AV
+V
BUF OUT
NC
NC
NC
COM
R
I
OUT
S
L
dB
V
+V
OUT
S
Rev. D | Page 8 of 16
The input and output signal ranges are a function of the supply
voltages; these ranges are shown in Figure 21 and Figure 22.
The AD536A can also be used in an unbuffered voltage output
mode by disconnecting the input to the buffer. The output then
appears unbuffered across the 25 kΩ resistor. The buffer ampli-
fier can then be used for other purposes. Further, the AD536A
can be used in a current output mode by disconnecting the
25 kΩ resistor from ground. The output current is available at
Pin 8 (I
40 μA per V rms input positive output.
OPTIONAL EXTERNAL TRIMS FOR HIGH
ACCURACY
The accuracy and offset voltage of the AD536A is adjustable
with external trims, as shown in Figure 9. R4 trims the offset.
Note that the offset trim circuit adds 365 Ω in series with the
internal 25 kΩ resistor. This causes a 1.5% increase in scale factor,
which is compensated for by R1. The scale factor adjustment
range is ±1.5%.
The trimming procedure is as follows:
1.
2.
3.
The major advantage of external trimming is to optimize device
performance for a reduced signal range; the AD536A is
internally trimmed for a 7 V rms full-scale range.
Ground the input signal, V
output from Pin 6. Alternatively, adjust R4 to provide the
correct output with the lowest expected value of V
Connect the desired full-scale input level to V
or a calibrated ac signal (1 kHz is the optimum frequency).
Trim R1 to provide the correct output at Pin 6. For example,
1.000 V dc input provides 1.000 V dc output. A ±1.000 V
peak-to-peak sine wave should provide a 0.707 V dc output.
Any residual errors are caused by device nonlinearity.
OUT
, Pin 10 on the H-10 package) with a nominal scale of
Figure 8. 20-Terminal Standard RMS Connection
–V
S
C
–V
NC
NC
dB
V
AV
OUT
S
C
4
5
6
7
8
AV
AD536A
NC
3
9
BUF
25kΩ
V
10
2
IN
IN
NC
11
ABSOLUTE
SQUARER/
1
, and adjust R4 to provide 0 V
DIVIDER
CURRENT
VALUE
MIRROR
+V
12
20
S
25kΩ
NC
19
13
18
17
16
15
14
NC
NC
NC
NC
COM
IN
, either dc
IN
.