UTC TA31142
LINEAR INTEGRATED CIRCUIT
LOW POWER IF RECEIVER IC
DESCRIPTION
The UTC TA31142 is a low power IF receiver IC
and is suitable for use as the second IF
downconverter in double-conversion paging systems.
It is well-suited for POCSAG paging applications and
incorporates a 2-level FSK demodulator consisting of
a quadrature FM demodulator, on-chip bit-rate filter,
and 1-bit comparator. An on-chip 1V regulator is
provided for convenient biasing of off-chip circuitry.
FEATURES
*Extremely low power operation with power-down
feature
*Built-in crystal oscillator for mixer local oscillator
*Mixer input frequency: 10-50 MHz
*Quadrature detector
*On-chip bit-rate filter
*Audio output
*1-bit comparator with open collector output
*1V regulator
*1.1V low battery alarm
TSSOP-20
PIN CONFIGURATIONS
OSCIN
1
OSCOUT
2
MIXOUT
3
VCC
IFIN
DEC
FSKREF
IFOUT
QUAD
AFOUT
4
5
6
7
8
9
10
11
LPFIN
12
LPFOUT
13
BS
14
CHARGE
15
FSKOUT
16
ALM
17
REGCON
18
REGOUT
19
VSS
20
MIXIN
UTC
UNISONIC TECHNOLOGIES
CO., LTD.
1
QW-R103-015,A
UTC TA31142
NUMBER SYMBOL
1
2
3
LINEAR INTEGRATED CIRCUIT
DESCRIPTION
NUMBER SYMBOL
11
12
13
DESCRIPTION
OSCIN Oscillator input (base)
OSCOUT Oscillator output (emitter)
MIXOUT Mixer output (2KΩ output
impedance)
4
VCC
Nominal 1.4V supply
14
5
6
7
8
IFIN
DEC
FSKREF
IFOUT
IF amplifier input (2KΩ input
impedance)
IF amplifier de-coupling capacitor
connection
1-bit comparator reference input
(requires external capacitor)
IF amplifier output
15
16
17
18
9
10
QUAD
AFOUT
Quadrature FM demodulator input
Quadrature FM demodulator
output
19
20
LPFIN LPF operational amplifier input
LPFOUT LPF operational amplifier output
BS
Two-state logic input to control
receiver power up/down.
(BS=high=normal operation;
BS=low=stand-by mode)
CHARGE Two-state logic input to control
charge-discharge circuit.
(CHARGE=high=fast charge;
CHARGE=low=slow charge)
FSKOUT Open collector NRZ comparator
output (requires pull-up resistor)
ALM
Open collector low battery alarm
output (requires pull-up resistor)
BEGCON 1.0V regulator control output for
connection to external PNP base
REGOUT 1.0V regulator input for
connection to external PNP
collector
VSS
Ground
MIXIN Mixer input (5KΩ input
impedance)
ABSOLUTE MAXIMUM RATINGS
(Vss=0V )
PARAMETER
Supply Voltage
Operating temperature range
Storage temperature range
Soldering temperature range
Soldering time range
SYMBOL
Vcc
T
OPR
T
STG
T
SLD
t
SLD
VALUE
Vss-0.3 to Vss+3.5
-30 to 85
-55 to 150
255
10
UNIT
V
°C
°C
°C
s
RECOMMENDED OPERATING CONDITIONS
(Vss=0V)
PARAMETER
Supply voltage range
MIXIN input frequency
Operating temperature
SYMBOL
Vcc
f
MIXIN
T
A
Min.
1.1
-10
VALUE
Typ.
1.35
25
Max.
1.6
50
60
UNIT
V
MHz
°C
UTC
UNISONIC TECHNOLOGIES
CO., LTD.
2
QW-R103-015,A
UTC TA31142
PARAMETER
Quiescent current consumption
Standby current consumption
Mixer conversion gain
Mixer output intermodulation
intercept point
Mixer input resistance
Mixer output resistance
IF amplifier input resistance
S/N ratio I
S/N ratio 2
S/N ratio 3
Demodulation output level
AM rejection ratio
FSK output duty ratio
Low battery alarm threshold
voltage
Regulator output voltage
Charging / discharging current
ALM logic HIGH output current
ALM logic LOW output voltage
FSKOUT logic HIGH output
current
FSKOUT logic LOW output
vlotage
LINEAR INTEGRATED CIRCUIT
SYMBOL
Icc,
total
Icc,
modby
Gc
OIP3
R
in,MIX
R
out,MIX
R
in,IF
SNI
SN2
SN3
VOD
AMR
DR
V
ALM
V
REGOUT
I
CH
I
OH,ALM
I
OL,ALM
I
OH.FSK.OUT
V
OL,PSK,
OUT
ELECTRICAL CHARACTERISTICS
(Ta=25
°C
, Vcc=1.4V,Vss=0V, BS=high unless otherwise noted)
TEST CONDITIONS
V
BS
=0V
Measured after 455 KHz
ceramic filter
MIN
TYP
1.1
MAX
1.6
5
16
UNIT
mA
µA
dB
dBm
kΩ
kΩ
kΩ
dB
dB
dB
mVrms
dB
%
V
V
µA
µA
V
µA
V
9
12.5
-10
5
2
2
63
63
25
45
50
50
1.1
1.0
70
-53 dBm at MIXIN
-53 dBm at IFIN
-91 dBm at IFIN
-53 dBm at IF|N
-53 dBm at IFIN AM=30%
40
1.05
430Ω load resistor
V
FSKREF
=0V, V
LPFOUT
=0.18V
0.95
35
60
1.15
1.05
110
2
0.4
2
0.4
UTC
UNISONIC TECHNOLOGIES
CO., LTD.
3
QW-R103-015,A
UTC TA31142
LINEAR INTEGRATED CIRCUIT
FUNCTIONAL DESCRIPTION
The UTC TA31142 IF receiver IC incorporates a mixer, crystal-based local oscillator, IF amplifier, quadrature FM
demodulator, bit-rate filter, and 1–bit comparator and is capable of demodulating 2-level FSK input signals. In
addition, 1.0V regulator and 1.1V low battery alarm functions are provided.
POWER-DOWN FUNCTION
The entire receiver IC may be powered up and down through the control of the BS input (pin13). During power
down operation, the quiescent current consumption of the IC drops to approximately 0µA. The high input impedance
of the BS pin allows for direct interfacing with the CMOS output of an off-chip micro controller.
CHARGE / DISCHARGE CIRCUITRY
The function of the charge / discharge circuitry is for both fast and slow charging / discharging of the capacitor
used for storing the voltage reference level of the FSKREF pin. The CHARGE input (pin14) should be enabled
(CHARGE=high=fast charge) immediately after transition of the receiver IC from power-down to normal operation in
order to reduce the charging / discharging time for coarse adjustment of the FSKREF voltage to the appropriate dc
level (i.e. dc level of LPFOUT pin) and consequently to minimize the erroneous output of the 1-bit comparator.
During actual data reception, the CHARGE pin should be set to low (CHARGE=low=slow charge) for fine adjustment
of the FSKREF voltage.
1-bit COMPARATOR
The integrated 1-bit comparator operates as a data slicer and “squares up” the bit-rate filtered output from the
quadrature demodulator. The decision threshold voltage level for the 1-bit comparator is stored on an external
capacitor connected to the FSKREF pin.
REGULATOR
The on-chip 1.0V regulator requires a suitable off-chip PNP transistor to achievc regulation. The external PNP
transistor should have an hFE>200 for V
CE
>=0.1V.
LOW BATTERY ALARM
The low battery alarm output, ALM, is normally low, but rises to 1.1V (=VCC) when the VCC voltage falls below
approximately 1.1V.
UTC
UNISONIC TECHNOLOGIES
CO., LTD.
4
QW-R103-015,A
UTC TA31142
LINEAR INTEGRATED CIRCUIT
TYPICAL CHARACTERISTICS
UTC
UNISONIC TECHNOLOGIES
CO., LTD.
5
QW-R103-015,A
Microcontroller MCU
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