1996 Oct 08

2

Philips Semiconductors

Objective specification

Quadrature demodulator

TDA8040T

FEATURES

• +5 V supply voltage

• Bandgap internal reference voltage

• Low crosstalk between I (in-phase) and Q (quadrature)

channel outputs

• High operating input sensitivity

• High Carrier-to-Noise Ratio (CNR) of the VCO.

APPLICATIONS

• Quadrature Phase Shift Keying (QPSK) demodulation.

GENERAL DESCRIPTION

The TDA8040T is a monolitic bipolar IC dedicated for

quadrature demodulation.

It has been designed to operate in conjunction with the

TDA8041H to provide a complete QPSK demodulator.

The design of this circuit has been optimized to provide the

best quadrature accuracy necessary for digital receiver

applications and particularly for digital television.

The TDA8040T includes two matched mixers, an

RF amplifier, a symmetrical Voltage Controlled Oscillator

(VCO), a frequency divider and two matched amplifiers.

Two external filters are required for the baseband filtering.

The VCO requires an external LC tank circuit with two

varicap diodes. This oscillator operates at twice the

IF carrier frequency and can be used in a carrier recovery

AFC loop.

QUICK REFERENCE DATA

ORDERING INFORMATION

SYMBOL

PARAMETER

CONDITIONS

MIN.

TYP.

MAX.

UNIT

supply voltage

4.5

5.0

5.5

V

total supply current

70

79

90

mA

operating input voltage level

64

67

70

dB

µV

RF input signal frequency

10.7

−

150

MHz

I and Q output voltage

(peak-to-peak value)

−

0.5

−

V

E

phase error between the

I and Q channels

−−

3

deg

gain error between the

I and Q channels

−−

1dB

gain tilt error in the I and Q channels

−−

1dB

α

ct(IQ)

crosstalk between the

I and Q channels

30

−−

dB

IM3

intermodulation distortion in the

I and Q channels

40

−−

dB

TYPE NUMBER

PACKAGE

NAME

DESCRIPTION

VERSION

TDA8040T

SO16

plastic small outline package; 16 leads; body width 3.9 mm

SOT109-1