la7567b Sanyo Semiconductor Corporation, la7567b Datasheet - Page 15

• Manufacturer Part Number: la7567b
• Description: Tv And Vcr Vif/sif If Signal-processing Circuit With Pal/ntsc Multi-format Audio Support
• Manufacturer: Sanyo Semiconductor Corporation

Notes on VCO Tank Circuits
• Built-in capacitor VCO tank circuits
• External capacitor VCO tank circuits
When the power is turned on, 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, it
becomes more difficult to transmit heat to the VCO tank circuit's built-in capacitor, and the influence of 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.
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 so influenced as much by this heat, and as a result the power-on drift is increased. 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 April 2003. 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.
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semiconductor products fail with some probability. It is possible that these probabilistic failures could
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or that could cause damage to other property. When designing equipment, adopt safety measures so
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circuits and error prevention circuits for safe design, redundant design, and structural design.
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for the SANYO product that you intend to use.
Information (including circuit diagrams and circuit parameters) herein is for example only; it is not
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LA7567B, 7567BM
PS No. 6099-15/15