SANYO LA1260 Datasheet

LA1260

Ordering number : EN1506D

FM/AM Tuner System

for Radio-Casette Recorders, Music Centers

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)/33194HO/O067KI/8225MW/4045KI/8084KI, TS No.1506-1/14

Functions

FM : IF amplifier, quadrature detector, AF preamplifier,

tuning indicator drive output.

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

Detector, AGC, tuning indicator drive.

Features

• Minimum number of external parts required (No AM detection coil required).

• High S/N :FM 81dB

AM 53dB

• Low-level AM oscillator with ALC : Pin 16 OSC output MW 130mV SW 70 mV to 90 mV

(7MHz) (24MHz)

Package Dimensions

unit : mm

3006B-DIP16

[LA1260]

SANYO : DIP16

• Less AM whistle interference : Whistle 1% at input 100dB/m.

• On-chip LED tuning indicator driver.

• On-chip FM/AM selector.

• Independent FM/AM output pins : Possible to set FM/AM frequency characteristic independently.

Specifications Maximum Ratings

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

Parameter Symbol Conditions Ratings Unit

Maximum supply voltage V

max Pins 6, 12 9 V

Maximum current drain I

max Pins 6+7+12 50 mA

Flow-in current I

Pin 7 20 mA

Flow-out current I

Pin 15 0.1 mA Allowable power dissipation Pd max Ta≤70°C 450 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

4.5 V

Operating voltage range V

op 3.0 to 8.0 V

Operating Characteristics at Ta=25°C, V

=4.5V, See specified Test Circuit

Parameter Symbol Conditions

Ratings

min typ max

Unit

[AM Characteristics : f=1MHz] Quiescent current Icco AM VIN=No input 7.5 10.5 mA Detection output VO1 VIN=23dBµ, 400Hz-30% mod. –33 –28 –23 dBm

17.3 31 55 mV S/N ratio S/N1 VIN=23dBµ, 400Hz-30% mod. 18.0 21.5 dB Detection output VO2 VIN=60dBµ, 400Hz-30% mod. –19.0 –16.0 –13.0 dBm

87 122 174 mV S/N ratio S/N2 VIN=60dBµ, 400Hz-30% mod. 48 53 dB Total harmonic distortion THD1 VIN=60dBµ, 400Hz-30% mod. 0.45 1.3 %

THD2 VIN=100dBµ, 400Hz-30% mod. 1.5 3.0 %

LED lighting voltage V

LEDAM

IC=1mA 22 30 38 dBm

Oscillation output (24MHz) V

OSC24M

60 86 120 mV [FM Characteristics : f=10.7MHz] Quiescent current IccoFM VIN=No input 8.5 12.0 mA –3dB sensitivity VINlim –3dB down, 400Hz-100% mod. 35 42 dBµ Demodulation output VO3 VIN=80dBµ, 400Hz-100% mod. –12.5 –9.5 –6.5 dBm

183 260 367 mV

S/N ratio S/N3 VIN=80dBµ, 400Hz-100% mod. 77 81 dB

S/N4 VIN=80dBµ, 400Hz-30% mod. 71 dB

Total harmonic distortion THD3 VIN=80dBµ, 400Hz-100% mod. 0.55 1.2 %

THD4 VIN=80dBµ, 400Hz-30% mod. 0.05 %

LED lighting voltage V

LEDFM

IL=1mA 39 49 dBµ

AM rejection ratio AMR V

=80dBµ, 400Hz-100% FM mod. 60 dB

1kHz-30% AM mod.

Equivalent Circuit Block Diagram

LA1260

No.1506-2/14

LA1260

No.1506-3/14

Unit (resistance : Ω, capacitance : F)

T1 Mitsumi YT30194 (56pF tuning) T2 Mitsumi KW30011 T3 Mitsumi YT30105 T4 Mitsumi YT30112

Proper Cares in Using the IC

External parts placement and pattern

• The AM local oscillation parts, AM local oscillation coil, and antenna circuit parts such as bar antenna must be separated from each other as far as possible to prevent Qs from worsening.

• Pin 16 (AM oscillation injection pin) and pin 14 (RF input pin) must be separated from each other on the pattern as shown in Figure. A below. Care should be taken not to make unwanted coupling by parallel wiring as shown in Figure B to prevent Qs from worsening.

FM quadrature detection coil

• The values recommended for the detection coil are shown below. (See Figure 1.)

Tuning capacitance : 56pF Damping resistance : 6.8kΩ

• Values other than recommended provide the LED drive characteristic as shown below.

Figure A Good example Figure B Bad example

Value increased Value decreased

Tuning capacitance • Lighting is delayed.

• No lighting may occur at low temperature.

• Lighting is advanced.

• Mislighting may occur in the absence of signal.

Damping resistance • Lighting is advanced.

• Mislighting may occur in the absence of signal.

• Lighting is delayed.

• No lighting may occur at low temperature.

If the product of tuning capacitance and damping resistance is equal to that of values recommended above (e. g. tuning capacitance=82pF, damping resistance=4.7kΩ), other characteristics (demodulation output, S/N, THD, etc.) than the LED drive characteristic remain almost unaffected.

• For applications where a double tuning coil is used, refer to "Applications where a double coil is used" on page 13.

Test Circuit

LA1260

No.1506-4/14

How to apply FM AFC

The S curve at the FM output pin (pin 8) is as shown in Figure 1. Therefore, the domestic (Japan) band (lower local oscillation) use and foreign band (upper local oscillation) use differ as shown in Figures 2 and 3.

AM local oscillation

Since the LA1260 contains an ALC circuit, the oscillation level at pin 16 can be limited to 60 to 150mV in the following applications where a coil is used.

Stable oscillation occurs at a coil impedance of 5kΩ or greater viewed from across pins 16 and 15. Turn ratio n and QOmust be determined so that the oscillation level at pin 16 becomes 75mV or greater for MW use and 60mV or greater for SW use.

If turn ratio n is increased more than needed, the oscillation level at pin 16 drops, thereby lowering the maximum sensitivity as shown in Figure 5 and 6. Figure 7 shows the relation between turn ratio n and oscillation level at pin 16 in the MW band.

Unit (capacitance : F)

Figure 1 Figure 2 Domestic (lower local

oscillation) band

Figure 3 Foreign (upper local

oscillation) band

Unit (resistance : Ω, capacitance : F)

Unit (capacitance : F)

OSC injection voltage at pin 16 – mV

Maximum sensitivity, V

Usable sensitivity, Q

– dB/m

Maximum sensitivity, V

Usable sensitivity, Q

– dB/m

OSC injection voltage at pin 16 – mV

21MHz reception mode

fr=1000kHz reception

Maximum sensitivity (input at detection

output –30dBm)

Maximum sensitivity (input at detection

output –30dBm)

Usable sensitivity (S/N=20dB)

Figure 5 Figure 6

Figure 4

LA1260

No.1506-5/14

AM oscillation coil

Generally speaking, the following should be noted. Winding with loose coupling between 1 and 2 and between 1 and 3 must be avoided. (Particularly SW1, SW2). To put in concretely, the pot core type is better than the screw core type which is loose in coupling. This prevents the local oscillation frequency from turning third resonance frequency related to the coupling coefficient.

LED unlighted time and distortion in AM (MW)

By increasing the value of the electrolytic capacitor for AGC at pin 11 (Figure 8), the distortion in the AM mode can be improved, but the LED unlighted time is made longer. 10µF is recommended for obtaining the optimum LED unlighted time and distortion. The LED unlighted time is 200ms at this value (Approximately 400ms at 22µF).

FM-AM selection and dc level at pin 12

(1) Pin 12-used method=recommended circuit

The FM mode is entered with pin 12 open. When pin 12 and pin 6 are at the same potential in terms of DC, the AM circuit is turned on by the internal switch. It should be noted that the dynamic range is narrowed whether the potential at pin 12 is lower or high than that at pin 6.

(2) Pin 13-used method

The AM mode is entered with pin 13 open. When pin 13 is grounded, the FM circuit is turned on and the AM circuit is turned off by the internal switch. In this case, pin 12 and pin 6 (VCC) are at the same potential.

Unit (capacitance : F)

Receiving frequency, fr– Hz

OSC voltage at coil end, V

OSC

– mV

V16 OSC voltage – mV

Figure 7

MW OSC characteristic

Modulation degree – %

Total harmonic distortion, THD – %

Figure 8

Input 100dBm VCC=4.5V AM mod. char. and electrolytic capacitor at pin 11.

100Hz, capacitor across pin 11 and Gnd : 10

µF

V16 OSC voltage

OSC voltage at coil end

Relation between turn ration n and OSC level

Unit (capacitance : F)

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