Ordering number : EN3044A
Monolithic Linear IC
LA1061M
Antenna Switching Controller
Overview
The LA1061M is an antenna switching controller for
mobile radio equipment.
The LA1061M uses a number of inputs from the receiver
circuitry to select the main antenna or sub-antenna
according to signal strength and quality. Weak and strong
signals are detected with the S-meter DC voltage and F.E.
AGC voltage, respectively. Multi-path distortion is
detected from the AC component of the IF output, using
the same high-sensitivity counter circuit as in Sanyo's
earlier LA1060 device. An auxiliary circuit keeps the main
antenna selected for a fixed time period when reception
conditions outside a moving vehicle are changing rapidly.
The LA1061M is available in surface-mount 8-pin DIPs,
facilitating construction of compact equipment. It operates
from a single 7 to 12V power supply.
Package Dimensions
unit: mm
3111-MFP14S
[LA1061M]
SANYO: MFP14S
Features
• Uses Sanyo's proprietary AGC amplifier and detector, providing accurate detection of multi-path distortion.
• High-current Main and Sub-antenna switching outputs.
• Antenna switching frequency limiting circuit.
• On-board comparators for F.E AGC (strong signal) and S-meter DC (weak signal) detection.
• Surface-mount 14-pin MFP.
Specifications
Maximum Ratings
at Ta=25°C
Parameter
Maximum supply voltage
Allowable power dissipation
Operating temperature
Storage temperature
Maximum flow-out current
Symbol
VCC max
Pd max
Topr
Tstg
I4
I5
I6
I9
I10
I12
Maximum apply voltage
V13
V14
Pin 4
Pin 5
Pin 6
Pin 9
Pin 10
Pin 12
Pin 13
Pin 14
Conditions
Ratings
14
182
–30 to +80
–40 to +125
1
10
10
2
5
2
VCC
VCC
Unit
V
mW
°C
°C
mA
mA
mA
mA
mA
mA
V
V
SANYO Electric Co.,Ltd. Semiconductor Bussiness Headquarters
TOKYO OFFICE Tokyo Bldg., 1-10, 1 Chome, Ueno, Taito-ku, TOKYO, 110 JAPAN
82997HA (KT)/9070TA/6019TA, TS No.3044-1/8
LA1061M
Operating Conditions
at Ta=25°C
Parameter
Recommended supply voltage
Operating voltage range
Symbol
VCC
VCC op
Conditions
Ratings
8
7 to 12
Unit
V
V
Operation Characteristics
at Ta=25°C, VCC=8V, f=100kHz sine wave
Parameter
Current drain
Pin 5 ‘H’-level voltage
Pin 6 ‘H’-level voltage
Noise amp gain
Noise detection sensitivity
Noise count number
Gate time 1
Pin 9 voltage
Strong signal comparator
threshold
Weak signal comparator
threshold
Gate time 2
Gate time3
Switching frequency
limit maximum count
tG2
tG3
HCN
2
13
4
23
15
6
40
ms
ms
Vth13
1.8
2.0
2.2
V
Symbol
ICC
V5
V6
Gv1
Gv2
NDS
NCN
tG1
V9
Vth14
Conditions
No input, I5 and I6 are not included.
1kΩ to ground
1kΩ to ground
VIN=3mVrms, f=100kHz
VIN=100mVrms, f=100kHz
Noise AGC off
VIN=30mVrms, f=100kHz, sine wave
Noise AGC off
VIN=100mVrms, f=100kHz,
R9=300kΩ
0.8
1.0
1.2
V
120
7.0
Ratings
min
4.5
5.0
5.0
33
10
9
typ
7
6.0
6.0
36
13
12
10
150
7.7
180
8.0
µs
V
max
12
7.0
7.0
39
16
Unit
mA
V
V
dB
dB
15 mVrms
Equivalent Circuit Block Diagram
Unit (resistance :
Ω)
No.3044-2/8
LA1061M
Functional Description
General Operation
The LA1061M has two inputs for weak and strong
signal detection, and one for multi-path distortion
detection. It has two outputs for Main and Sub-antenna
selection, one of which is selected according to the state
of the inputs. Both outputs can directly drive an antenna
switching pin diode.
Signal Strength Detection
Each signal strength detection input has a built-in
comparator. The weak signal comparator (pin 13) is
driven by the S-meter DC voltage and has a threshold of
approximately 2V. The antenna switching logic selects
the Main antenna when the voltage on this pin is lower
than the threshold, regardless of the state of the other
inputs.
The strong signal detector (pin 14) is driven by the F.E.
AGC voltage and has a threshold of approximately 1V.
The antenna switching logic selects the Sub-antenna if
the voltage on this pin is lower than the threshold, the
weak signal comparator is off, and the multi-path
distortion detector is not already on.
Multi-path Distortion Detection
The IF output signal is high-pass filtered and the
resulting noise signal input through a coupling capacitor
to pin 1, the LA1061M amplifies this signal and applies
AGC to it. The AGC amplifier is designed to detect
multi-path distortion without amplifying noise due to a
weak IF signal. The number of noise pulses within the
period set by the time constant on pin 4 is counted. If it
exceeds a certain limit, and the strong signal detector is
not already on, the antenna switching logic selects the
Main antenna.
Switching Frequency Detection
The LA1061M counts the number of antenna changes
within the time interval set by the time constant on pin
12. The internal D/A converter outputs a current on pin
11, which is converted to a voltage by the resistor
connected to this pin. If this voltage exceeds a certain
value, that is, the switching frequency is too high, the
Main antenna is selected for the period set by the time
constant on pin 10. The Main antenna is selected for this
time regardless of the state of the other inputs.
Unit (resistance :
Ω,
capacitance : F)
External circuits
Isolate noise components present in the IF output signal
with a high-pass filter, and input via a decoupling
capacitor.
Notes
The input impedance of the
LA 1061M varies with input
level. The minimum value is
10kΩ.
Pin Description
Pin No.
Function
1
Noise input
Continued on next page.
No.3044-4/8
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