SANYO LA1805 Datasheet
LA1805
Ordering number : EN2887B
AM/FM-IF/MPX 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
12798HA (KT)/D0994JN/4030MO/N148YT, TS No.2887-1/13
Overview
The LA1805 is a characteristics-improved version of the
LA1810, with the same pin assignment and package as
those of the LA1810. Improvements are made on the
following point :
• Separation (35dB→48dB) and its dependence on free-
running frequency (Sep – fFCharacteristic on page 4).
• FM main distortion (0.8%→0.45%).
• AM detection output (approximately 5dB increased).
The constants on five external parts are changed as shown
on page 10.
Functions
• FM-IF : IF amp, quadrature detector, soft muting, tuning
indicator.
• MPX :PLL stereo decoder, stereo indicator, forced
monaural, VCO stop.
• AM : RF amp, MIX, OSC (with ALC), IF amp, detector,
AGC, tuning indicator.
Features
• FM/AM/MPX functions contained on a single chip.
• Minimum number of external parts required.
• On-chip FM muting function.
• High sensitivity.
• Less carrier leak of MPX.
Specifications
Maximum Ratings
at Ta=25°C, See specified Test Circuit.
Parameter Symbol Conditions Ratings Unit
Maximum supply voltage VCCmax Pins 3, 7, 8, 11, 20, 21 9 V
Maximum supply current ICCmax Pins 3+20+21 50 mA
Flow-in current I
LED
Pins 7, 8 20 mA
(Indicator drive current)
Flow-out current I
23
Pin 23 0.1 mA
Allowable power dissipation Pd max Ta≤70°C 500 mW
Operating temperature Topr –20 to +70 °C
Storage temperature Tstg –40 to +125 °C
Package Dimensions
unit : mm
3067-DIP24S
[LA1805]
SANYO : DIP24S
0.48
3.25
3.3
3.9max
0.51min
21.2
0.81 1.78
0.25
7.62
6.4
112
24
13
0.95
LA1805
No.2887-2/13
Operating Conditions at Ta=25°C
Parameter Symbol Conditions Ratings Unit
Recommended operating voltage V
CC
4.5 V
Operating voltage range V
CC
op 3.0 to 8.0 V
Note : The FM output level forms an N curve (LA1805) and an S curve (LA1806).
LA1805 : N curve (for US band)
LA1806 : S curve (for Japanese band). Your desired output level can be set by varying the output resistance.
Operating Characteristics at Ta=25°C, V
CC
=4.5V, See Test Circuit
Parameter Symbol Conditions
Ratings
min typ max
Unit
[FM characteristics (Mono) : fc=10.7MHz, fm=1kHz]
Quiescent current Icco No input 13 20 mA
–3dB sensitivity –3dBL.S. Referenced to V
IN
=100dBµ, 28 35 dBµ
100%, down 3dB
Demodulation output V
O
VIN=100dBµ, 100% mod. 140 205 280 mV
Channel balance C.B. VIN=100dBµ, 100% mod. 0 0 1.5 dB
Total harmonic distortion THD VIN=100dBµ, 100% mod. 0.45 1.2 %
Signal to noise ratio S/N VIN=100dBµ, 100% mod. 70 80 dB
LED ON sensitivity V
LED
IL=1mA 23 33 43 dBµ
[FM characteristics (Stereo) : fc=10.7MHz, fm=1kHz, L+R=90%, pilot=10%, VIN=100dBµ]
Separation Sep 32 48 dB
Stereo distortion THD (Main) 0.45 1.2 %
LED ON level V
LED
-on 2.4 3.9 5.4 %
LED OFF level V
LED
-off 2.7 %
[AM characteristics : fc=1000kHz, fm=1kHz]
Quiescent current Icco No input 9.5 14.5 mA
Demodulation output VO1 VIN=23dBµ, 30% mod. 27 50 90 mV
VO2 VIN=80dBµ, 30% mod. 70 113 173 mV
Signal to noise ratio S/N1 VIN=23dBµ, 30% mod. 17 21 dB
S/N2 VIN=80dBµ, 30% mod. 50 55 dB
Total harmonic distortion THD1 VIN=80dBµ, 30% mod. 0.45 1.2 %
THD2 VIN=100dBµ, 30% mod. 0.6 1.5 %
LED on sensitivity V
LED
IL=1mA 16 24 32 dBµ
Note : Be fully careful of dielectric breakdown.
Equivalent Circuit Block Diagram
LA1805
No.2887-3/13
Test Circuit
Polystyrene film capacitor
Differs from the application circuit
where a front end is used.
(See Sample Application Circuit
on page 10.)
How to use the LA1805
1. Forced monaural mode.
Figures 1 and 2 show how to cause the forced monaural mode to be entered.
(1) Connect pin 14 to VCCthrough a resistor of 100kΩ. (Turn ON the SW1 in Figure 1.)
(2) Connect pin 15 to GND through a resistor of 47kΩ. (Turn ON the SW2 in Figure 2.)
Figure 1 Forced Monaural Mode Setting Method Figure 2 Forced Monaural Mode Setting Method
Unit (resistance : Ω, capacitance : F)
Either above-mentioned (1) or (2) causes the forced
monaural mode to be entered. In this case, the VCO
does not stop operating. If the resistance of R1 and
R2 are decreased, internal bias will vary when the S1
or S2 is turned ON. This data is shown in Figure 3.
Forced Monaural Mode Setting Resistance FreeRunning Frequency
Free-running frequency – kHz
Figure 3
LA1805
No.2887-4/13
2. VCO Stop
The VCO is so designed as to stop automatically at the
AM mode.
(when pin 11 and pin 21 are at the same potential)
There is no pin available for stopping the VCO at the
FM mode. However, the method shown right can be
used to stop the VCO at the FM mode, causing the
forced monaural mode to be entered.
3. Free-running frequency measurement and adjustment
Either of the following two methods is used to measure the
free-running frequency.
(1) Connect pin 13 to a frequency counter through the high
input impedance amplifier.
(2) Connect the connection point of the semifixed resistor
connected to pin 13 and the fixed resistor to a frequency
counter through the resistor of 240kΩ or greater.
Make the wiring as
short as possible.
Figure 4
Figure 5
Figure 6
How the error changes with the resistor value is
shown in Figure 7.
Resistor value, RX– kΩ
Measured error, ∆f – %
Free-running frequency, fF– kHz
IF input 100dBµ
Nonmodulation
• When setting the free-running frequency, the following must be noted.
Apply a 10.7MHz 100dBµ nonmodulation carrier as IF input signal and set to 76kHz±50Hz with the tuning indicator
lighted.
4. Separation setting capacitor Cs
The separation characteristic for the LA1805 alone
(IF input) differs from that for the antenna input
with a front end. This difference is caused by the
characteristics of the front end and ceramic filter.
Shown right is how the separation characteristic
changes with the separation setting capacitor value
when the LA1186N is used as front end. Referring
to this separation characteristic, choose the
optimum separation for your set model.
Figure 7
Figure 8
Separation, Sep – dB
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