UTC TA31142

LINEAR INTEGRATED CIRCUIT

UTC

UNISONIC TECHNOLOGIES CO., LTD.

QW-R103-015,A

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
2
3
4
5
6
7
8
9

OSCOUT

MIXOUT

VCC

IFIN

DEC

FSKREF

QUAD

IFOUT

AFOUT

LPFIN

11
12
13
14
15
16
17
18
19
20

LPFOUT

CHARGE

FSKOUT

ALM

REGCON

VSS

REGOUT

MIXIN

UTC TA31142

LINEAR INTEGRATED CIRCUIT

UTC

UNISONIC TECHNOLOGIES CO., LTD.

QW-R103-015,A

NUMBER SYMBOL

DESCRIPTION

NUMBER SYMBOL

DESCRIPTION

OSCIN

Oscillator input (base)

LPFIN

LPF operational amplifier input

OSCOUT Oscillator output (emitter)

LPFOUT LPF operational amplifier output

3 MIXOUT Mixer output (2K

output

impedance)

Two-state logic input to control
receiver power up/down.
(BS=high=normal operation;
BS=low=stand-by mode)

VCC

Nominal 1.4V supply

CHARGE Two-state logic input to control

charge-discharge circuit.
(CHARGE=high=fast charge;
CHARGE=low=slow charge)

5 IFIN

IF amplifier input (2K

input

impedance)

FSKOUT Open collector NRZ comparator

output (requires pull-up resistor)

DEC

IF amplifier de-coupling capacitor
connection

ALM

Open collector low battery alarm
output (requires pull-up resistor)

FSKREF 1-bit comparator reference input

(requires external capacitor)

BEGCON 1.0V regulator control output for

connection to external PNP base

IFOUT

IF amplifier output

REGOUT 1.0V regulator input for

connection to external PNP
collector

QUAD

Quadrature FM demodulator input

VSS

Ground

AFOUT Quadrature FM demodulator

output

20 MIXIN

Mixer input (5K

input

impedance)

ABSOLUTE MAXIMUM RATINGS

(Vss=0V )

PARAMETER

SYMBOL

VALUE

UNIT

Supply Voltage

Vcc

Vss-0.3 to Vss+3.5

Operating temperature range

OPR

-30 to 85

�

Storage temperature range

STG

-55 to 150

�

Soldering temperature range

SLD

255

�

Soldering time range

SLD

RECOMMENDED OPERATING CONDITIONS

(Vss=0V)

PARAMETER

SYMBOL

VALUE

UNIT

Min.

Typ.

Max.

Supply voltage range

Vcc

1.1

1.35

1.6

MIXIN input frequency

MIXIN

50 MHz

Operating temperature

-10

�

UTC TA31142

LINEAR INTEGRATED CIRCUIT

UTC

UNISONIC TECHNOLOGIES CO., LTD.

QW-R103-015,A

ELECTRICAL CHARACTERISTICS

(Ta=25

�

, Vcc=1.4V,Vss=0V, BS=high unless otherwise noted)

PARAMETER SYMBOL

TEST

CONDITIONS

MIN

TYP

MAX

UNIT

Quiescent current consumption Icc,

total

1.1

1.6

Standby current consumption

Icc,

modby

=0V

�

Mixer conversion gain

Measured after 455 KHz

ceramic filter

9 12.5 16 dB

Mixer output intermodulation
intercept point

OIP3

-10

dBm

Mixer input resistance

in,MIX

Mixer output resistance

out,MIX

IF amplifier input resistance

in,IF

S/N ratio I

SNI

-53 dBm at MIXIN

S/N ratio 2

SN2

-53 dBm at IFIN

S/N ratio 3

SN3

-91 dBm at IFIN

Demodulation output level

VOD

-53 dBm at IF|N

mVrms

AM rejection ratio

AMR

-53 dBm at IFIN AM=30%

FSK output duty ratio

Low battery alarm threshold
voltage

ALM

1.05

1.1

1.15

Regulator output voltage

REGOUT

430

load resistor

0.95

1.0 1.05 V

Charging / discharging current

FSKREF

=0V, V

LPFOUT

=0.18V

35 70 110

�

ALM logic HIGH output current

OH,ALM

�

ALM logic LOW output voltage

OL,ALM

0.4

FSKOUT logic HIGH output
current

OH.FSK.OUT

�

FSKOUT logic LOW output
vlotage

OL,PSK,

OUT

0.4

UTC TA31142

LINEAR INTEGRATED CIRCUIT

UTC

UNISONIC TECHNOLOGIES CO., LTD.

QW-R103-015,A

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 0

�

A. 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

>=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.

Электронный компонент: TA31142