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Ordering number: EN3994B
Monolithic Linear IC
LA7975 PAL SIF Converter Circuit for TV and VCR Multi-system
Overview
The LA7975 is an IC that converts PAL SIF signals (5.5 MHz, 6 MHz, and 6.5 MHz) to 6 MHz. For the sake of high sound quality, this IC uses a unique mixer technique to supress interference from NICAM signals.
Package Dimensions
unit : mm
3042C-SIP5
[LA7975]
Functions
. Mixer, amplifier, oscillator, oscillator mute
Features
. Resistant to interference by NICAM signals . Small SIP-5 package . Wide range of usage voltage (5 V to 12 V)
Specifications
Maximum Ratings at Ta = 25°C
Parameter Maximum supply voltage Maximum feed current Allowable power dissipation Operating temperature Storage temperature Symbol VCC max I5 max I4 max Pd max Topr Tstg Ta % 70°C Conditions
SANYO : SIP5
Ratings 13.2 3 1 200 20 to +70 40 to +150
Unit V mA mA mW °C °C
Operating Conditions at Ta = 25°C
Parameter Recommended supply voltage Operating voltage range Symbol VCC VCC op Conditions Ratings 9 5 to 12 Unit V V
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73096HA(II)/8282TS No.3994-1/6
LA7975
Operating Characteristics at Ta = 25°C, VCC = 9 V
Parameter Current drain Conversion gain 5.5 MHz 6.5 MHz 6.0 MHz Oscillation level Maximum output level Input impedance Pin voltages 500 kHz level difference relative to 6 MHz Maximum input level Oscillation stop current Symbol ICC G5.5 G6.5 G6.0 VOSC VO max Ri V1 V4 V5 OSC leak VIN max I4 Conditions 80 dB/µV input 80 dB/µV input 80 dB/µV input, Pin 4 grounded with 10 k 5.5 MHz 100 dB/µV input 5.5 MHz input Test point Pin 2 Pin 5 Pin 5 Pin 5 Pin 4 Pin 5 Pin 1 Pin 4 Pin 5 Pin 5 Pin 4 min 5 10 10 18.5 15 109 2.6 7.6 7.2 30 90 300 typ 6.5 13.5 13.5 22 36 112 4.8 3 8 7.6 44 max 9 17 17 25.5 80 115 3.4 8.4 8 Unit mA dB dB dB mVp-p dB/µV k V V V dB dB/µV µA
Sample Application Circuit
Oscillator 500 kHz CSB503E5 Murata Industries, Ltd. 1.5 MHz CSA1.500MK2 Murata Industries, Ltd. 500 kHz EFOA500K04S Matsushita Electric, Ltd.
Unit (resistance: , capacitance: F)
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LA7975
Reference Example 1
Reference Example 2
Unit (resistance: , capacitance: F)
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LA7975
. Pin 1 is the SIF input pin.
The filter in Figure 2 can be connected to the input section to improve the buzz characteristic. Figure 3 shows the characteristics for the filter in Figure 2. If C1 is too small, the buzz characteristic improves for normal input, but the filter cuts into the sound carrier and the buzz characteristic deteriorates for the P/S (picture/sound carrier) ratio. Use C1 6 20 pF to 47 pF.
Filter characteristic Figure 1 Unit (resistance: , capacitance: F) Attenuation dB Figure 2
Unit (resistance: , capacitance: F)
From video output section
Frequency Hz Figure 3
. Pin 4 is the ceramic oscillator pin.
To make the oscillation waveform approach a sine wave,the oscillation level is controlled internally. Oscillation levels of 15 to 80 mVp-p at Pin 4 give the waveform shown in Figure 5. To stop oscillation, attach an external resistor as in Figure 6 and switch S1 on. Here are the conditions for handling multiple systems.
Input frequency 5.5 MHz 6.0 MHz 6.5 MHz 4.5 MHz Oscillator 500 kHz Oscillation stop 500 kHz 1.5 MHz Pin 5 output 6 MHz 6 MHz (pass through) 6 MHz 6 MHz
Figure 4
Unit (resistance: )
Figure 5 (Pin 4 oscillation waveform)
Figure 7 Figure 8 shows a proposed multi-system
(Multi-system implementation)
Figure 6
Figure 8 Unit (resistance: )
Unit (resistance: )
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LA7975
. Pin 5 is the output pin. The output from Pin 5 is input to the
SIF via a 6 MHz bandpass filter (BPF). When 5.5 MHz is input to Pin 1, the spectrum shown in Figure 10 is obtained at Pin 5. Even if there is a 5.85 MHz NICAM signal, the D/U (desirable/undesirable) ratio at Pin 5 increases and the buzz characteristic does not deteriorate. When 6 MHz is input at Pin 1 and there is a 6.552 MHz NICAM signal, then 6.552 MHz is mixed with 500 kHz to make 6.052 MHz. This becomes an interference signal and is within the band for 6 MHz. Therefore,for 6 MHz input, Pin 4 is grounded with 10 k to stop the oscillation and pass through the input signal 6 MHz as is. Unit (resistance: ) Ceramic BPF chracteristic
Figure 9 Output level
D/U ratio
Figure 10 (5.5 MHz input) Output level
Interference obtained with LA7975 mixer 6.552 MHz 500 kHz = 6.052 MHz
D/U ratio
Figure 11 (6 MHz input)
Reference Characteristic Diagram
Input/output characteristic VO VCC
Output level, VO dB/µV
* S1 on for 6 MHz measurement
Output level, VO dB/µV
Unit (resistance: , capacitance: F)
* Input level 80 dB/µV S1 on for 6 MHz measurement
Input level dB/µV
Supply voltage, VCC V No.3994-5/6
LA7975
f VCC Oscillation frequency, f kHz Oscillation level VCC
Oscillation stop voltage 3.7 V
Supply voltage, VCC V Oscillation level R
Oscillation level mVp-p
Supply voltage, VCC V
Oscollation level mVp-p
FET probe
Series resistance, R
No products described or contained herein are intended for use in surgical implants, life-support systems, aerospace equipment, nuclear power control systems, vehicles, disaster/crime-prevention equipment and the like, the failure of which may directly or indirectly cause injury, death or property loss. Anyone purchasing any products described or contained herein for an above-mentioned use shall: 1 Accept full responsibility and indemnify and defend SANYO ELECTRIC CO., LTD., its affiliates, subsidiaries and distributors and all their officers and employees, jointly and severally, against any and all claims and litigation and all damages, cost and expenses associated with such use: 2 Not impose any responsibility for any fault or negligence which may be cited in any such claim or litigation on SANYO ELECTRIC CO., LTD., its affiliates, subsidiaries and distributors or any of their officers and employees jointly or severally. 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. This catalog provides information as of July, 1996. Specifications and information herein are subject to change without notice.
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