SANYO LA1140 Datasheet

Ordering number: EN 729E

Monalithic Linear IC

LA1140

FM IF System for Car Radio

Overview

The LA1140 is an IF system IC designed for FM car stereo
receivers. It features versatile muting characteristics and allows
receiver designers to realize the muting performance according
to their design concept. Since the muting characteristics can be
varied with a switch or a semi-fixed resistor, DX-Local
switching will be accomplished with ease.

Functions

.

IF amplification/limiter

.

Quadrature detector

.

AF preamplifier

.

AFC output

.

Signal meter output

.

AGC output

.

Muting bandwidth

.

Muting under weak signal strength

Features

.

Versatile muting

a) When muting operation is performed under a weak signal

strength, an attenuation slope of the audio output against
the input signal strength variations can be set at any given
value.

b) Maximum muting attenuation can be selected to be

approximately 6 to 40 dB.

c) Input signal strength level which actuates the muting

circuit can be set freely.

.

High limiting sensitivity (25 dBµ typ. with muting off)
provides a fine quieting characteristic.

.

High S/N (78 dB typ.)

.

Low distortion (0.05% typ.) avaiable if used with
double-tuned circuits.

.

Good AMR (63 dB typ. with 6 stages of differential IF
amplifiers).

.

Signal meter drive output proportional to the input signal
strength in dB (suitable to control multiplex IC LA3370).

.

Clamped (±VBE) AFC output, bandwidth adjustable.

.

Delayed AGC output for front end circuit.

.

Small space factor due to single-ended package employed.

.

3 mm pitch of pin terminals permitting ease-to-write PC
board pattern.

Package Dimensions

unit : mm

3020A-SIP16

[LA1140]

SANYO : SIP16

SANYO Electric Co.,Ltd. Semiconductor Bussiness Headquarters

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

93097HA(II)/D0994JN/N257TA/4105MW/3233KI,TS O090KI No.729-1/15

LA1140

Specifications

Maximum Ratings at Ta = 25°C

Parameter Symbol Conditions Ratings Unit
Maximum supply voltage V
Maximum supply current I
Allowable power

dissipation
Input voltage V

Flow-in current I2 Pin 2 ±0.2 mA

Flow-out current I5 Pin 5 1 mA

Operating temperature Topr –20 to +70 °C
Storage temperature Tstg –40 to +125 °C

max Pin 12 16 V

CC

max Pin 12 40 mA

CC

Pd max Ta = 25°C 640 mW

Ta = 70°C 460 mW

IN

Pin1to2 ±1 Vp-p

I3 Pin 3 ±0.2 mA
I6 Pin 6 2 mA

I13 Pin 13 2 mA
I14 Pin 14 2 mA
I15 Pin 15 1 mA
I16 Pin 16 1 mA

Operating Conditions at Ta = 25°C

Parameter Symbol Conditions Ratings Unit
Recommended supply

voltage
Operating voltage range V

V

CC

op 7.5to16 V

CC

8V

Operating Characteristics at Ta = 25°C, VCC= 8 V, f = 10.7 MHz, See specified Test Circuit

Parameter Symbol Conditions min typ max Unit
Quiescent current I
Current drain I

CCO

CC

Demodulation output V
Total harmonic distortion THD V
Signal-to-noise ratio S/N V
Input limiting voltage V
Muting sensitivity V

IN

(Mute) V14 = 2.0 V 22 26 32 dBµ

IN

Muting attenuation (1) Mute (A

Muting attenuation (2) Mute (A
Muting bandwidth BW (Mute) V
AM rejection ratio AMR
Muting drive output V14-0 Quiescent 3.5 4.2 5.0 V

Muting drive output V14-100 V
Signal meter output (1) V15-0 Quiescent 0 0.1 0.3 V
Signal meter output (2) V15-50 V
Signal meter output (3) V15-70 V
Signal meter output (4) V15-100 V
AGC output (1) V16-0 Quiescent 3.5 4.1 4.5 V
AGC output (2) V16-100 V
Offset voltage (1) V7-13 Quiescent, pin 7 to 13 –0.25 0 +0.25 V
Offset voltage (2) V8-13 Quiescent, pin 8 to 13 –0.5 0 +0.5 V

Quiescent 15 21 27 mA
VIN= 100 dBµ 20 25 30 mA
VIN= 100 dBµ, 400 Hz 100% mod. 200 260 320 mVrms

O

= 100 dBµ, 400 Hz 100% mod. 0.05 0.2 %

IN

= 100 dBµ, 400 Hz 100% mod. 72 78 dB

IN

(lim) VO: 3 dB down, 400 Hz 100% mod. 25 29 dBµ

V6 = 2.0 V (22 kΩ), V

)

CC

400 Hz 100% mod.
V6 = 5.0 V (22 kΩ), V

)

CC

400 Hz 100% mod.

= 100 dBµ, V14 = 2.0 V 140 210 370 kHz

IN

= 100 dBµ, FM 400 Hz

V

IN

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

= 100 dBµ 0 0 0.3 V

IN

= 50 dBµ 0.8 1.4 2.0 V

IN

= 70 dBµ 1.6 2.4 3.2 V

IN

= 100 dBµ 4.5 5.3 6.0 V

IN

= 100 dBµ 0 0.02 0.3 V

IN

= 100 dBµ,

IN

= 100 dBµ,

IN

10 15 20 dB

24 28 32 dB

50 63 dB

No. 729-2/15

Equivalent Circuit Block Diagram

AC Test Circuit

LA1140

T1: CBTKAC-24782 AUO (Toko Co.)
T2: CBTKAE-24783X (Toko Co.)
22µH: S-220J (Korin Co.)
Input signal strength is an actual input at pin 1

Signal

strength

Ind.

Unit (resistance: Ω, capacitance: F)

Muting Characteristic

The muting operation in the LA1140 is performed by an AF preamplifier, the gain of which varies continuously with control
current, and a muting drive output circuit which supplies the control current.
The gain of the AF preamplifier decreases with increasing gain control current applied to pin 6. However, the gain does not
decrease further when the control current reaches approximately 120 µA or greater. The lower limit of the gain under this
condition depends upon a resistor connected between pin 5 and GND, and the higher the resistance the lower the gain (the higher
the attenuation). Thus the maximum muting attenuation will be set by connecting the resistor between pin 5 and GND.

AF output

R5-G (lower) 20 kΩ

AF output

R5-G (higher) 100 kΩ

No. 729-3/15

LA1140

Since the muting control input pin 6 is connected to the base of the emitter grounded transistor (through a protection resistor of
500 Ω in series), the voltage between pin 6 and GND is about 0.6 V when the control current is applied. In actual cases, the
muting operation is accomplished by applying a voltage drive type muting drive output (pin 14 to pin 6 through a high resistance
(up to 20 kΩ)).

The muting drive output comes in three types:

1) Hole detector output which develops a voltage when C/N (carrier-to-noise
ratio) lowers under weak signal input conditions.

2) A reversed output of the signal strength indicating output (output at pin

15)

Unit (resistance: Ω)

All these outputs are led to an OR circuit and the processed output is developed at pin 14. Of the above muting drive outputs,
descriptions on the hole detector output and the bandwidth limited muting drive output will be omitted, since they are the same as
those used in conventional quadrature detector ICs (such as LA1230, LA1231N).

The inverted output of the signal strength indication output is obtained as illustrated below.

3) A bandwidth limited muting drive output which develops a voltage when
the AFC output becomes higher than ±V

during tuning-off operation.

BE

Inverter

Inverter

(AGC output) (Signal meter output)

By referring to the illustration, V14 is given by the formula: V14 = V
Conditions are: V

≅ 4.9 V, IO≅ 0.2 mA, a ≅ 2, RL=22kΩ,VBE≅ 0.6 V, I1 = V15/R15-G, I2 = V16/R16-G where V16 is a

r

Inverter

(Offset)

–(IO+ I1 – aI2)RL–VBE.

r

(Muting drive output)

constant equal to 4.1 V (typ) for medium or lower signal input levels, where the muting drive output is required. Since the V15
increases proportionally to the increase of the input signal strength, I1 will also increase. Therefore the V14 will decrease with
increasing signal strength. Thus the required muting drive output can be obtained by selecting proper values of R15-G and R16-G.
For example, the muting drive output moves toward strong input signal level
if the R16-G is decreased, or the muting drive output becomes zero due to the
offset current I

under a weak signal input condition, if the R16-G is

O

increased to infinity (namely pin 16 is opened). However the muting drive
output caused by a whole detector still exists in this case. Increasing R15-G
decreases the slope of the curve for the muting drive output vs. antenna signal
input level, or decreasing the R15-G increases the slope of the curve.
Furthermore, varying the value of a resistor connected between the muting
drive output (pin 14) and the muting control input (pin 6) changes the value of
the muting control current required to obtain the same muting drive output,

ANT Input

accordingly the slope of the curve for muting attenuation vs. antenna signal
input level is also changed. These characteristics investigated by using an
actual receiver are shown on the curves below.

The general method to adjust the muting circuit of the LA1140 is: to set the signal input level required to actuate the muting
circuit with the R16-G, to adjust the slope of the curve for the muting attenuation vs. antenna signal input with the R15-G, and to
adjust the maximum muting attenuation (determined by setting the noise level at no signal) with the R5-G. The slope of the curve
for the muting attenuation vs. antenna signal input level can also be adjusted by the resistor connected between pins 14 and 6 in
addition to R15-G, however, selecting a resistor too high does not allow the muting control current flowing into pin 6 to reach
120 µA even through the maximum muting drive output (V14) is applied, namely the muting attenuation does not reach its
maximum value. Accordingly a recommended value of the resistor between pins 14 and 6 is about 22 kΩ.

No. 729-4/15

LA1140

AF Output

R15-G higher

Muting by varying R15-G

AF Output

Muting by varying R14-6

–dB

O

, distortion THD,

O

Demodulation output V

AM rejection AMR, Noise N

ANT Input

R14-6 lower

ANT Input

Allowable power dissipation, Pd max – mW

Ambient temperature, Ta – °C

f = 10.7 MHz, non-modulation

Pin voltage V14, V15, V16 – V

Noise

–dB

Demodulation output, V

Input voltage, V

Muting = OFF

O

(pin 1) – dBµ

IN

Input voltage, VIN(pin 1) – dBµ

VCC=8V
Resistance
between pin 5 and
GND is 100 kΩ

Muting attenuation, Mute (Att) – dB

Resistance between pin 5 and GND – Ω

fO= 10.7 MHz
VIN= 100 dBµ
Pins7–13=5.1kΩ

1 Tuned, muting OFF
2 – 200 kHz detuned, muting OFF
3 – 200 kHz detuned, muting ON

–mA

CC

V6 through 22 kΩ –V

Current drain, I

Bandwidth muting drive output, V14 – V

Frequency detuned, ∆f – kHz

Input voltage, VIN(Pin 1) – dBµ

No. 729-5/15