SANYO LA1265 Datasheet

LA1265

Ordering number : EN1820C

FM/AM Tuner 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

N2897HA (KT)/40194HK/O077KI/D095KI/2255KI, TS No.1820-1/15

Functions

FM : IF amplifier, quadrature detector, AF preamplifier,

signal meter, 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).

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).

Package Dimensions

unit : mm

3059-DIP22S

[LA1265]

SANYO : DIP22S

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

• Low whistle.

• Signal meter pin.

Specifications Maximum Ratings

at Ta=25°C, See specified Test Circuit.

Parameter Symbol Conditions Ratings Unit

Maximum supply voltage V

max Pins 7, 8, 17 16 V

Flow-in current I

Pin 8 20 mA

Flow-out current I

Pin 20 1 mA

Pin 22 2 mA Allowable power dissipation Pd max Ta≤60°C 650 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 operating voltage V

8.5 V

Operating voltage range V

op 6 to 14 V

Operating Characteristics at Ta=25°C, V

=8.5V, See specified Test Circuit

Parameter Symbol Conditions

Ratings

min typ max

Unit

[AM : f=1MHz] Quiescent current Icco No input 18 26 mA Detection output VO1 VIN=20dBµ, 400Hz, 30% mod. 30 50 90 mV

VO2 VIN=80dBµ, 400Hz, 30% mod. 110 160 220 mV

S/N S/N1 VIN=20dBµ 16 20 dB

S/N2 VIN=80dBµ 49 54 dB

Total harmonic distortion THD1 VIN=80dBµ, 400Hz, 30% mod. 0.3 1.0 %

THD2 VIN=107dBµ, 400Hz, 30% mod. 0.5 2.0 %

Signal meter output VSM1 No input 0 0 0.2 V

VSM2 VIN=80dBµ 2.4 2.8 3.1 V

LED lighting sensitivity VLED on I

LED

=1mA 15 24 33 dBµ

Local OSC buffer output V

OSC

=1.45MHz 220 275 330 mV [FM : f=10.7MHz] Quiescent current Icco No input 20 28 mA Input limiting sensitivity –3dBL.S. 3dB down, 400Hz, 100% mod. 31 37 dBµ Demodulation output V

VIN=10dBµ, 400Hz, 100% mod. 240 330 460 mV S/N S/N VIN=100dBµ 78 84 dB Total harmonic distortion THD VIN=100%dBµ, 400Hz, 100% mod. 0.03 0.3 % Signal meter output VSM1 No input 0 0 0.2 V

VSM2 VIN=100dBµ 1.5 2.7 3.1 V

LED lighting sensitivity LED-on I

LED

=1mA 35 50 65 dBµ

LED lighting bandwidth LED-BW VIN=100dB, I

LED

=1mA 90 120 160 kHz

AM rejection ratio AMR V

=100dBµ, FM=400Hz 45 60 dB

100% mod. AM=1kHz 30% mod.

LA1265

No.1820-2/15

Ambient temperature, Ta – °C

Allowable power dissipation, Pd max – mW

LA1265

No.1820-3/15

How to use the LA1265

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

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

• The 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 CF (BFU450CN) at

pin 11. If a capacitor is connected in place of the CF, the bandwidth will get wider.

– For FM, the bandwidth depends on the resistance across pins

9 and 20. If the resistance is increased, the bandwidth will get narrower. R=15kΩ makes the bandwidth approximately 120kHz.

• Sensitivity adjustment of LED, muting, stop signal.

– For FM, the semifixed variable resistor across pin 13 and GND is used. – For AM, the semifixed variable resistor across pins 13 and 14 is used. Be sure to start adjustment for FM, and then

make adjustment for AM. For the stop signal sensitivity and FM stop signal bandwidth, the variations should be considered and it is recommended to use the semifixed variable resistor for adjustment.

• LED lighting sensitivity setting for AM. For the LED lighting sensitivity setting for AM, it is desirable that the IC input be 30dBµ (antenna input : approximately 50dB/m). In this case, the value of VR1 is 30kΩ.

Equivalent Circuit Block Diagram

Resistance across pins 9 and 20 – kΩ

LED Lighting Bandwidth – Resistance across pins 9 and 20

LED lighting bandwidth – kHz

S Carve

S meter

LA1265

No.1820-4/15

3. Local OSC buffer output

• When local OSC buffer output wave form is saw-toothed at the SW mode, connect a resistance of 1.2kΩ or

thereabouts across pin 22 and GND.

4. AM input pin

• It is desirable that the AM input pin (pin 19) be L-coupled to pin 18.

• Inputting to pin 19 can be done by DC-cutting with a capacitor. However, an unbalance in the RF amplifier (differential amplifier) causes gain drop and whistle worsening.

5. 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 automatic channel select mode. In this 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.

• LED lighting sensitivity setting for FM.

– For the LED lighting sensitivity setting for FM, the IC

input may be 45dBµ to 60dBµ. With the variations in the front end considered, it is ideal that the IC input in a standard receiving set be 51dBµ to 54dBµ. The lower value of VR2 for the LED lighting sensitivity setting is as illustrated right. Since the variations in the front end cause the IC input setting sensitivity to vary, it is recommended to use a value of VR2 at an input voltage lower than a standard setting by 6dB or greater. For example, if IC input 53dBµ is taken as a standard, use VR2≤100kΩ at IC input 47dBµ.

2. AM/FM changeover

• Two selections are available for changeover as shown below

: (A) pin 17-used method and (B) pin 18-used method.

• For (A), the voltage on pin 17 relative to VCC(pin 7) must be within the range of –0.8V to +0.1V. If not within this

range, distortion and selectivity will get worse.

• For (A), a resistance of 68kΩ at the IFT cold terminal, which is used to prevent the changeover circuit from

malfunctioning, must be connected.

(A) pin 17-use method for AM/FM changeover (B) Pin 18-used method for AM/FM changeover

IC input – dBµ

Semifixed Variable Resistor for FM

VR2 semifixed variable resistor value – kΩ

LED lighting sensitivity setting for FM

Ideal setting range

Modulation frequency – Hz

V9 – Modulation Frequency

LA1265

No.1820-5/15

– Parameter Frequency – Admittance Unit

IF γi1 10.7MHz

330 Ω

20 pF

– Parameter Frequency –

RF γi19 1MHz

Admittance

Unit

kΩ pF

AGC-off (V16=1.4V) AGC-on (V16=2.5V)

15 16

4 4

MIX γo17 500kHz

kΩ pF

– – 3 3

IF γi15 500kHz

kΩ pF

2 2

10 8

6. 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 pins 22 and 21 is large, a parasitic oscillation of approximately 100MHz may occur in the buffer output (pin 22). In this case, connect a capacitance of approximately 30pF across pin 22 and GND.

7. 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 put it concretely, the pot core type is better than the screw core type which is loose in coupling. This prevents the local OSC frequency from turning third resonance frequency related to the coupling coefficient.

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

9. To prevent whistle from worsening, make the pattern of AM output pin 12 as short as possible.

Input/Output Admittance

Test Circuit : FM, AM-MW

T1 4147-1457-177 (Sumida) T2 HW-40174 (Mitsumi) T3a HW-40130, T3b HW-40131 (Mitsumi)

Unit (resistance : Ω, capacitance : F)

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