RC4200N Fairchild Semiconductor, RC4200N Datasheet - Page 15

• Manufacturer Part Number: RC4200N
• Description: Multipliers / Dividers DIP-8
• Manufacturer: Fairchild Semiconductor

Specifications of RC4200N

• Package / Case: PDIP-8
• Maximum Operating Temperature: + 70 C
• Minimum Operating Temperature: 0 C
• Mounting Style: Through Hole
• Product: Multiplier & Divider
• Lead Free Status / Rohs Status: No

PRODUCT SPECIFICATION
Appendix 2—Applications
Design Considerations for RMS-to-DC Circuits
Average Value
Consider V
Where T = Period
RMS Value
Again, consider V
REV. 1.2.1 6/14/01
V
V
V
V
V
V
V
V
V
AG
AG
rms
rms
rms
= 2 f
rms
rms
rms
rms
=
Average Value of Asin t is
2
----- -
=
T
for Asin tdt:
=
=
=
=
=
=
=
=
=
2A
------ -
-- -
T
T
2
2A
------ -
2
T
-- -
0
V
2
in
-- -
T
A
------
1
A
------
A
------
A
------
V
IN
V
0
2
T
2
2
T
-- -
2
–
2
2
2
2
AVG
= Asin
–
A
IN
0
T
0
--- -
1
cos
A
T
0
T
-- -
2
T
-- -
2
sin
t d
cos
2
–
IN
1
-- -
2
sin
=
------ - sin2
4
–
1
t
= Asin t
2
1
-- - cos 2 cos 2
2
t d
t
. By definition,
+
-- -
T
1
t dt
T
-- -
2
0
cos
T
2
A
T
0
V
0
t
IN
0
T
2
-- - A
2
t d
t
T
dt
65-1873
t
Therefore, the rms value of Asin t becomes:
RMS Value for Rectified Sine Waves
Consider V
integrate of each half cycle.
Practical Consideration: |Asin t| has high-order harmonics;
Asin t does not. Therefore, non-ideal integrators may cause
different errors for two approaches.
V
i.e.
This is the same as
so, |Asin t|
V
Avg
implies V
1
-- -
T
(a)
(b)
rms
V
V
0
IN
IN
1
-- - TV
T
=
0
T
-- -
2
=
0
A
V
--------- -
V
Absolute
a
2
IN
Avg V
Value
2
------ -
0
sin
A
2
0
in
2
in
2
rms
2
=
= |A sin t|, a rectified wave. To solve,
dt =
=
t dt+
IN
V
=
Avg V
Low Pass
V
IN
2
Filter
0
Asin t
1
-- - TA
1
0
a
b
T
T
-- -
2
2
Figure 14.
IN
–
2
Asin t
rms
V
sin
V
2
IN
O
2
2
Low Pass
t t d
Filter
2
dt
V = V
O
IN
V =
O
rms
65-4200-09
A
RC4200
VG
V
IN
15
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