SANYO LA1266 Datasheet

LA1266

Ordering number : EN2291B

AM/FM Tuner System Of

Electronic Tuning Type

Monolithic Linear IC

SANYO Electric Co.,Ltd. Semiconductor Bussiness Headquarters

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

N3097HA (KT)/41594HK/9047AT/7256KI, TS No.2291-1/11

Functions

FM : IF amplifier, quadrature detector, AF

preamplifier, signal meter, IF count outputlifier, tuning indicator drive output (common with stop signal, muting drive output)

AM : RF amplifier, MIX, OSC (with ALC), IF

amplifier, detector, AGC, signal meter, tuning indicator drive output (common with stop signal), IF count output, local OSC buffer.

Features

• Minimum number of external parts required.

• Excellent S/N

• Local OSC with ALC

• Local OSC buffer

• Tuning indicator pin (common with narrow-band stop signal and muting drive output)

• Variable stop sensitivity (variable separately for FM, AM)

• Less tweet interference

• Signal meter pin

• IF count output

Specifications Maximum Ratings

at Ta=25°C

Parameter Symbol Conditions Ratings Unit Maximum supply voltage VCCmax Pins 7,8,20 16 V Flow-in current I

Pin 8 20 mA

Flow-out current I

Pin 22 1 mA

Pin 24 2 mA Allowable power dissipation Pd max Ta≤60°C 700 mW Operating temperature Topr –20 to +70 °C Storage temperature Tstg –40 to +125 °C

Operating Conditions at Ta=25°C

Parameter Symbol Conditions Ratings Unit

Recommended supply voltage V

8.5 V

Operating voltage range V

op 6 to 14 V

Package Dimensions

unit : mm

3067-DIP24S

[LA1266]

SANYO : DIP24S

Operating Characteristics at Ta=25°C, V

=8.5V, See Test Circuit.

Parameter Symbol Conditions

Ratings

min typ max

Unit

[AM : fc=1MHz, fm=1kHz] Quiescent current Icco No input 22 30 mA Detection output VO1 VIN=20dBµ, 30% mod. 30 60 110 mV

VO2 VIN=80dBµ, 30% mod. 90 150 210 mV

Signal to noise ratio S/N1 VIN=20dBµ 15 19 dB

S/N2 VIN=80dBµ 49 54 dB

Total harmonic distortion THD1 VIN=80dBµ, 30% mod. 0.3 1.0 %

THD2 VIN=107dBµ, 30% mod. 0.3 1.0 %

Signal meter output VSM1 No input 0 0 0.2 V

VSM2 VIN=80dBµ 1.8 2.8 3.5 V

LED drive sensitivity LED-ON I

LED

=1mA 13 23 33 dBm

Local OSC buffer output V

OSC

fosc=1.45MHz 220 280 340 mV

IF buffer output V

VIN=20dBµ 120 180 250 mV [FM : fc=10.7MHz, fm=1kHz] Quiescent current Icco No input 29 40 mA Input limiting sensitivity –3dBL.S. 3dB down, 100% mod. 31 37 dBµ Demodulation output V

VIN=100dBµ, 100% mod. 270 390 540 mV S/N ratio S/N VIN=100dBµ 78 84 dB Total harmonic distortion THD VIN=100dBµ, 100% mod. 0.03 0.3 % Signal meter output VSM1 No input 0 0 0.2 V

VSM2 VIN=100dBµ 1.7 2.3 3.1 V

LED drive sensitivity LED-ON I

LED

=1mA 46 61 76 dBµ

LED drive bandwidth LED-BW VIN=100dBµ, I

LED

=1mA 70 105 140 kHz

AM rejection ratio AMR V

=100dBµ, 100% mod. 45 58 dB

AM-1kHz, 30% mod. IF buffer output V

VIN=50dBµ 110 160 230 mV

Equivalent Circuit Block Diagram

LA1266

No.2291-2/11

LA1266

No.2291-3/11

How to use LA1266

1. LED driver, muting drive output, stop signal(SD).

• For LED drive, muting drive output, stop signal, the output at pin 8 is used.

• Voltage on pin 8, when tuned, turns from "H" to "L" . (Active-low)

• Signal bandwidth at pin 8 – For AM, the bandwidth depends on the C.F(BFU450CN) at pin 14.

If a capacitor is connected in place of the C.F, the bandwidth will get wider.

– For FM, the bandwidth depends on the resistance across pins 9 and 22.

If the resistance is increased, the bandwidth will get narrower. R=15kΩ makes the bandwidth approximately 110kHz.

• Sensitivity adjustment of LED, muting, stop signal – For FM, the semifixed variable resistor across pin 16 and GND is used. – For AM, the semifixed variable resistor across pin 17 and GND is used.

The relation (for AM,FM) between signal meter voltage and input voltage with the resistance of the semifixed variable resistor as a parameter is shown below.

LED Drive Bandwidth

–

Resistance across Pins 9 and 22

FM S Meter Voltage AM S Meter Voltage

Unit (capacitance : F)

Resisitance across Pins 9 and 22 – kΩ

IF input voltage – dBµ

LED drive bandwidth – kHz

S meter voltage – V

Antenna input voltage – dB/m

LA1266

No.2291-4/11

2. AM/FM changeover

• AM/FM changeover is made using pin 20 as shown right.

• However, the voltage on pin 20 relative to V

(pin 7) must be within

the range of +0.1V to – 0.8V. If not within this range, distortion and selectivity will get worse. A resistance of 68kΩ at the IFT cold terminal, which is used to prevent the changeover circuit from malfunctioning, must be connected.

3. Local OSC buffer output

• When local OSC buffer output waveform is saw-toothed at the SW mode, connect a reistance of 1.2kΩ or thereabouts across pin 24 and GND.

4. Capacitance across pin 9 and GND A large capacitance across pin 9 and GND may cause a misstop at an adjacent channel when the channel select speed is made faster at the autmatic channel select mode. In thes case, decrease the capacitance across pin 9 and GND. However, if too decreased, the LED will flutter at low modulation frequencies at the time of detuning. Therefore, it is recommended to fix the capacitance across pin 9 and GND to be 3.3µF to 10µF. The relation between modulation frequency and demodulation output voltage on pin 9 with the capacitance across pin 9 and GND as a parameter is shown right.

5. If the coupling coefficient of the local OSC coil is small and an antiresonance point of approximately 100MHz is present or the stray capacitance across pin 24 and pin 23 is large, a parasitic oscillation of approximately 100MHz may occur in the buffer output (pin 24). In this case, connect a capacitance of approximately 30pF across pin 24 and GND.

6. AM OSC coil Generally speaking, the following should be noted. Avoid winding with loose coupling between primary side and secondary side (especially SW1, SW2). To be concrete, the pot core type is better than the screw type which is loose in coupling. This prevents the local OSC frequency from turning third resonance frequency related to the coupling coefficient.

7. Resistance across pin 8 and V

If pin 8 is used for stop signal (SD) only, without using LED, it is recommended to fix resistance RLacross pin 8 and VDDto be 51kΩ to 100kΩ.

8. To prevent whistle from worsening, make the pattern of AM output pin 15 as short as possible.

9. AM, FM IF buffer output Application of a voltage to pin 13 (STRQ) causes AM IF(455kHz) signal (at AM mode) and FM IF(10.7MHz) signal (at FM mode) to be delivered at pin 11 and pin 10, respectively. It is recommended that the voltage to be applied to

68kΩ

V9 – Modulation Frequency

V9 – mVrms

Modulatin frequency – Hz

Ω

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