Full Wave Rectifier Circuit

The use of a diode rectifierintroduces significant distortion

for signals that are small compared to the diode forward bias

voltage. Therefore, when low distortion performance is

needed, standard diode based circuits do not work well. The

CLC532 can be configured to provide a very low distortion

full wave rectifier. The circuit in

Figure 9 is used to select

between an analog input signal and an inverted version of

the input signal. The resulting output exhibits very little dis-

tortion for small scale signals up to several hundred

kilohertz.

Use of the CLC532 as a Mixer

A double balanced diode bridge mixer, as shown in

Figure

10, operates by multiplying the RFsignal input by the LO

input signal . This is done by using the LO signal phase to

select either the forward or reverse path through the diode

the CLC532 circuit shown in

Figure 11. The CLC532 based

circuit uses a digital LO making system design easier in

those cases where the LO is digitally derived. Another ad-

vantage of the CLC532 based approach is excellent isolation

between all three ports. (See the RF design awards article

by Thomas Hack in January 1993 of RF Design.)

CLC532

µ

F

Gain

SELECT

0.1 F

F

µ

R

48.7

5

IN

B

8

10

6

9

IN

A

4

3

2

1

7

13

14

12

DGND

-5.2V

0.1

µF

+5V

D

REF

11

µ

+6.8

+6.8

10pF

10pF

50

Ω

50

Ω

OUT

Ω

50

Ω

To

Load

50

Ω

To

Source

Ω

200

Ω

66.6

0

Ω

To

Source

Input

R7

R6

R

INB

DS012716-44

FIGURE 8. Selectable Gain Stage Improves ADC Dynamic Range

10114

50

Ω

50

Ω

50

Ω

50

Ω

-2V

R

L

IN

B

IN

A

V

OUT

CLC532

V

BB

0.1

µF

+1

-1

+20

RECTIFIER

INPUT

Zero Crossing

Tr eshold

Detector

DS012716-45

FIGURE 9. Low Distortion Full Wave Rectifier

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