Overview

The LA75691 is a PAL/NTSC multichannel audio
VIF/SIF signal-processing IC that makes the minimum
number of adjustments possible. The system is designed
so that VCO adjustment makes AFT adjustment
unnecessary, thus simplifying the adjustment steps in end-
product manufacturing. PLL detection is adopted in the
FM detector, allowing the LA75691 to support
multichannel detection for the audio signal. In addition, it
also incorporates a buzz canceller that suppresses Nyquist
buzz for improved audio quality.

Functions

[VIF Block]
· PLL detector with minimum number of adjustments
· AFT
· Equalizer amplifier
· RF AGC
[First SIF BLOCK]
· First SIF detector
· HPF
[SIF Block]
· PLL-based FM detector
[Muting Block]
· AV muting

Features

· Excellent buzz and buzz/beating characteristics provided

by a PLL detection technique that includes a buzz
canceller.

· The second IF AGC filter is built in.
· No coils are used in the AFT and SIF circuits, making

them adjustment free.

Package Dimensions

unit: mm

3067-DIP24S

Monolithic Linear IC

90898RM (OT) No. 5734-1/13

SANYO: DIP24S

[LA75691]

SANYO Electric Co.,Ltd. Semiconductor Bussiness Headquarters

TOKYO OFFICE Tokyo Bldg., 1-10, 1 Chome, Ueno, Taito-ku, TOKYO, 110-8534 JAPAN

IF Signal-Processing IC for PAL/NTSC Multichannel

Audio TV and VCR Systems

LA75691

Ordering number : EN5734

Ambient temperature, Ta -- °C

Allowable power dissipation, Pd max -- W

Any and all SANYO products described or contained herein do not have specifications that can handle
applications that require extremely high levels of reliability, such as life-support systems, aircraft's
control systems, or other applications whose failure can be reasonably expected to result in serious
physical and/or material damage. Consult with your SANYO representative nearest you before using
any SANYO products described or contained herein in such applications.

SANYO assumes no responsibility for equipment failures that result from using products at values that
exceed, even momentarily, rated values (such as maximum ratings, operating condition ranges, or other
parameters) listed in products specifications of any and all SANYO products described or contained
herein.

No. 5734-2/13

LA75691

Parameter

Symbol

Conditions

Ratings

Unit

Maximum supply voltage

max

13.2

Circuit voltage

V13, V17

Circuit current

I10

I24

Allowable power dissipation

Pd max

68°C

720

Operating temperature

Topr

20 to +70

°C

Storage temperature

Tstg

55 to +150

°C

Note: When mounted on a 65

1.6 mm laminated paper phenolic resin printed circuit board.

Specifications

Maximum Ratings

at Ta = 25°C

Parameter

Symbol

Conditions

Ratings

Unit

min

typ

max

[VIF Block]

Circuit current

35.5

42.0

48.5

Maximum RF AGC voltage

14H

7.5

8.1

Minimum RF AGC voltage

14L

0.5

Input sensitivity

S1 = Off

dBµV

AGC range

Maximum allowable input

max

dBµV

No-signal video output voltage

3.5

3.8

4.2

Synchronizing signal tip voltage

tip

1.15

1.45

1.74

Video output level

1.7

2.0

2.3

Vp-p

Black noise threshold voltage

BTH

0.5

0.8

1.1

Black noise clamp voltage

BCL

2.5

2.8

3.1

Video signal-to-noise ratio

S/N

C-S beating

IC-S

Frequency characteristics

6 MHz

3.0

1.5

Differential gain

3.0

6.5

Differential phase

deg

Maximum AFT voltage

13H

8.5

8.7

9.0

Minimum AFT voltage

13L

0.18

0.5

AFT detection sensitivity

22.4

28.0

33.6

mV/kHz

VIF input resistance

38.9 MHz

1.5

VIF input capacitance

38.9 MHz

APC pull-in range (U)

0.8

1.3

MHz

APC pull-in range (L)

1.5

0.8

MHz

AFT frequency tolerances 1

dfa 1

300

+300

kHz

VCO1 maximum variability range (U)

dfu

1.0

1.3

MHz

VCO1 maximum variability range (L)

dfl

1.5

1.0

MHz

VCO control sensitivity

1.4

2.8

5.6

kHz/mV

5.5 MHZ output level

P/S = 14 dB

mVrms

[SIF Block]

Limiting voltage

Vi (lim)

5.5 MHz ± 30 kHz

dBµV

FM detector output voltage

(FM)

5.5 MHz ± 30 kHz

720

900

1100

mVrms

AM rejection ratio

AMR

AM = 30 %

Total harmonic distortion

THD

0.3

0.8

SIF signal-to-noise ratio

S/N (FM)

Operating Characteristics

at Ta = 25°C, V

= 9 V, f

= 38.9 MHz

Parameter

Symbol

Conditions

Ratings

Unit

Recommended supply voltage

Operating supply voltage range

8.5 to 12.5

Operating Conditions

No. 5734-7/13

LA75691

Pin Descriptions

Pin No.

Function

Equivalent circuit

SIF input

The input impedance is about 1 k

. The pattern layout for

the input circuit for this pin must be designed carefully, since
buzzing and/or beating can be caused by interference
signals. Video signals, the chrominance signal, and the VIF
carrier signal can cause interference in the audio signal.

SIF INPUT

The FM detector signal-to-noise ratio can be improved by
inserting a filter in the FM detector bias line.

C1 must be at least 0.47 µF, and 1 µF is recommended.

If the FM detector is not used, insert a 2-k

resistor between

pin 2 and ground. This stops the FM detector VCO.

FM power supply filter

Pin 3 is the first SIF output.

This is the output pin for the audio carrier to which P/S
separate detection has been applied. This is an emitter-
follower output with a 200

series resistor inserted.

First SIF output

Continued on next page.

No. 5734-8/13

LA75691

Continued from preceding page.

Pin No.

Function

Equivalent circuit

The V

to ground decoupling capacitors must be placed as

close to the IC as possible.

Equalizer circuit. This circuit corrects the frequency
characteristics of the video signal.

Pin 17 is the equalizer amplifier input. A 1.5-V p-p signal is
input to pin 17, and that signal is amplified to be a 2-V p-p
signal by the equalizer amplifier.

Equalizer amplifier design:

The equalizer amplifier is designed as a voltage-follower
amplifier with a gain of about 2.3 dB. Connect an inductor, a
capacitor, and a resistor in series between pin 7 and ground
if the frequency characteristics require correction.

Notes on the equalizer amplifier:

If the input signal is vi and the output signal is vo, then:

---- +1 (vi + vin) = Vo

G: The voltage-follower amplifier gain.

vin: Imaginary short

G: About 2.3 dB

Assuming that vin is 0, then:

VoG

AV = ------ = ---- +1

R1 is the IC internal resistance of 1 k

. Simply select Z to

match the desired characteristics. However, note that Z must
be chosen carefully in order not to cause distortion, since the
equalizer amplifier gain will be maximum at the resonance
determined by Z.

EQ amp

PLL detector APC filter

The APC time constant is switched internally in the IC. When
locked, the VCO is controlled by loop A, and the gain is
reduced. When unlocked and in weak field reception, the
VCO is controlled by loop B, and the gain is increased.

For this APC filter the recommended values are:

R should be between 150 and 390

C should be 0.47 µF.

APC FILTER

Continued on next page.

No. 5734-9/13

LA75691

Continued from preceding page.

Pin No.

Function

Equivalent circuit

Output for the video signal that includes the SIF carrier

A resistor must be inserted between pin 10 and ground to
assure adequate drive capabilities.

300

Conposite video output

Connections for the VCO tank circuit used by the video
detector. See the coil specifications for the tank circuit
provided separately. This VCO is a vector synthesis VCO.

VCO tank

AFT output

The AFT center voltage is created by an external bleeder
resistor. The AFT gain increases as the value of this bleeder
resistor increases. This resistor must not exceed 390 k

This circuit includes a function that controls the AFT voltage
to naturally approach the center voltage during weak field
reception.

AFT OUTPUT

RF AGC output

This signal controls the tuner RF AGC.

This is an emitter output with a 200

protective resistor

inserted in series. Determine the value of the external
bleeder resistor according to the specifications of the tuner.

RF AGC OUTPUT

Continued on next page.

No. 5734-11/13

LA75691

Pin No.

Function

Equivalent circuit

This filter is used to hold the FM detector output DC voltage
fixed.

Normally, a 1-µF electrolytic capacitor should be used.

The value of this capacitor can be increased to improve the
low band (around 50 Hz) frequency characteristics.

FM filter

Audio FM detector output

This is an emitter follower output with a 200-

resistor

inserted in series.

· Stereo applications

Some applications may find that the stereo decoder input has
a low input impedance, and that the left and right signals are
distorted, i.e. that the stereo characteristics are degraded. If
that is a problem, add the resistor R1 shown in the figure
between pin 24 and ground.

5.1 k

· Mono applications

Use an external deemphasis circuit with the following time
constant:

t = 2RC

FM Detector output

Continued from preceding page.

Notes on Sanyo SAW Filters

There are two types of SAW filter that differ in the piezoelectric substrate material used.

· Lithium-tantalum (LiTaO3) SAW filters

TSF11

s s

... Japan

TSF12

s s

... US

Although lithium tantalate SAW filters have the low temperature coefficient of -18 ppm/°C, they suffer from a large
insertion loss. However, it is possible, at the cost of increasing the number of external components required, to minimize
this insertion loss by using a matching circuit consisting of coils and other components at the SAW filter output. At the
same time as minimizing insertion loss, this technique also allows the frequency characteristics, level, and other aspects
to be varied, and thus provides increased circuit design flexibility. Also, since the SAW filter reflected wave level is
minimal, the circuit can be designed with a small in-band ripple level.

· Lithium niobate (LiNbO3) SAW filter

TSF52

s s

... US

TSF53

s s

... PAL

Although lithium niobate SAW filters have the high temperature coefficient of -72 ppm/°C, they feature an insertion loss
about 10 dB lower than that of lithium tantalate SAW filters. Accordingly, there is no need for a matching circuit at the
SAW filter output. Although the in-band ripple is somewhat larger than with lithium tantalate SAW filters, since they
have a low impedance and a small field slew, they are relatively immune to influences from peripheral circuit
components and the geometry of the printed circuit board pattern. This allows stable out-of-band trap characteristics to be
acquired. Due to the above considerations, lithium tantalate SAW filters are used in applications for the US and Japan
that have a high IF frequency, and lithium niobate SAW filters are used in PAL and US applications that have a low IF
frequency.

Notes on SAW Filter Matching

In SAW filter input circuit matching, rather than matching the IF frequency, flatter video band characteristics can be
acquired by designing the tuning point to be in the vicinity of the audio carrier rather than the chrominance carrier. The
situation shown in figure on the right makes it easier to acquire flat band characteristics than that in figure on the left.

No. 5734-12/13

LA75691

When tuned to the IF frequency

When tuned near S or C

The high-band frequency

response is reduced

SAW filter

characteristics

The high-band frequency response is extended

Frequency

PS No. 5734-13/13

LA75691

Notes on VCO Tank Circuits
· Built-in capacitor VCO tank circuits

When power is applied to the IC, the heat generated by the IC is transmitted through the printed circuit board to the
VCO tank circuit. At this point, the VCO coil frame functions as a heat sink and the IC heat is dissipated. As a result,
this heat is not transmitted readily to the VCO tank circuit's built-in capacitor, and drift at power on is reduced.
Therefore, it suffices to design the circuit so that the coil and capacitor thermal characteristics cancel. Ideally, it is
better to use a coil with a core material that has low temperature coefficient characteristics.

· External capacitor VCO tank circuits

When an external capacitor is used, heat generated by the IC is transmitted through the printed circuit board directly to
the VCO tank circuit external capacitor. While this capacitor is heated relatively early after the power is turned on, the
coil is not influenced as much by this heat, and as a result the power-on drift is larger. Accordingly, a coil whose core
material has low temperature coefficient characteristics must be used. It is also desirable to use a capacitor with
similarly low temperature coefficient characteristics.

Note: Applications that use an external capacitor here must use a chip capacitor. If an ordinary capacitor is used,

problems such as the oscillator frequency changing with the capacitor orientation may occur.

This catalog provides information as of June, 1998. Specifications and information herein are subject to
change without notice.

Specifications of any and all SANYO products described or contained herein stipulate the performance,
characteristics, and functions of the described products in the independent state, and are not guarantees
of the performance, characteristics, and functions of the described products as mounted in the customer's
products or equipment. To verify symptoms and states that cannot be evaluated in an independent device,
the customer should always evaluate and test devices mounted in the customer's products or equipment.

SANYO Electric Co., Ltd. strives to supply high-quality high-reliability products. However, any and all
semiconductor products fail with some probability. It is possible that these probabilistic failures could
give rise to accidents or events that could endanger human lives, that could give rise to smoke or fire,
or that could cause damage to other property. When designing equipment, adopt safety measures so
that these kinds of accidents or events cannot occur. Such measures include but are not limited to protective
circuits and error prevention circuits for safe design, redundant design, and structural design.

In the event that any or all SANYO products (including technical data, services) described or contained
herein are controlled under any of applicable local export control laws and regulations, such products must
not be exported without obtaining the export license from the authorities concerned in accordance with the
above law.

No part of this publication may be reproduced or transmitted in any form or by any means, electronic or
mechanical, including photocopying and recording, or any information storage or retrieval system,
or otherwise, without the prior written permission of SANYO Electric Co., Ltd.

Any and all information described or contained herein are subject to change without notice due to
product/technology improvement, etc. When designing equipment, refer to the "Delivery Specification"
for the SANYO product that you intend to use.

Information (including circuit diagrams and circuit parameters) herein is for example only; it is not
guaranteed for volume production. SANYO believes information herein is accurate and reliable, but
no guarantees are made or implied regarding its use or any infringements of intellectual property rights
or other rights of third parties.

Coil Specifications

JAPAN

PAL

f = 58.75 MHz

f = 45.75 MHz

f = 38.9 MHz

VCO coils

Test production no. 16991B

Test production no. 16687B

Test production no. 16686B

Tokyo Parts Industrial Co., Ltd.

SAW filters (split)

Picture

TSF1137U

TSF1241

TSF5315

Sound

SAW filters (inter)

TSF5220

TSF5321

TSF5221

TSF5344

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