Philips Semiconductors Linear Products

Product specification

NE/SE567

Tone decoder/phase-locked loop

April 15, 1992

411

C

130

f

O

m F

C

260

f

O

m F

In cases where turn-off time can be sacrificed to achieve fast

turn-on, the optional sensitivity adjustment circuit can be used to

voltage). However, sensitivity to beat frequencies, noise and

extraneous signals will be increased.

The 567 has been designed so that, for most applications, no

external adjustments are required. Certain applications, however,

will be greatly facilitated if full advantage is taken of the added

control possibilities available through the use of additional external

components. In the diagrams given, typical

values are suggested where applicable. For best results the

resistors used, except where noted, should have the same

temperature coefficient. Ideally, silicon diodes would be

low-resistivity types, such as forward-biased transistor base-emitter

junctions. However, ordinary low-voltage diodes should be adequate

for most applications.

DETECTION BAND — % OF fO

Figure 6. BW Reduction

NOTE:

130

f

O

10k

)

R

R

t

C

2 t

1300

f

O

10k

)

R

R

Adjust control for symmetry of detection band edges

about fO.

250

200

150

100

50

0

0

2

4

6

8

10

12

14

16

0.5k 0.9k 1.4k

1.9k

2.5k 3.2k

4.0k

10k

20k

100k

R

OPTIONAL SILICON

DIODES FOR

TEMPERATURE

COMPENSATION

PIN 2

567

V+

C2

RA

RB

RC

R

+ R

A )

R

B

R

C

R

B )

R

C

50k

When operated as a very narrow-band detector (less than 8

noise and out-band signal rejection. This will inevitably slow the

response time. If, however, the output stage is biased closer to the

threshold level, the turn-on time can be

improved. This is accomplished by drawing additional current to

terminal 1. Under this condition, the 567 will also give an output for

lower-level signals (10mV or lower).

By adding current to terminal 1, the output stage is biased further

away from the threshold voltage. This is most useful when, to obtain

Normally, frequencies just outside the detection band could cause

false outputs under this condition. By desensitizing the output stage,

the out-band beat notes do not feed through to the output stage.

Since the input level must

Figure 7. Output Latching

NOTE:

CA prevents latch-up when power supply is turned on.

V+

C3

RL

V+

CA

RA

10k

567 8

1

UNLATCH

20k

Rf

V+

567 8

1

20k

C3

RL

Rf

UNLATCH

V+