Philips TDA8040T Datasheet
INTEGRATED CIRCUITS
DATA SH EET
TDA8040T
Quadrature demodulator
Objective specification
Supersedes data of 1995 Feb 07
File under Integrated Circuits, IC02
1996 Oct 08
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.
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.
APPLICATIONS
• Quadrature Phase Shift Keying (QPSK) demodulation.
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.
GENERAL DESCRIPTION
The TDA8040T is a monolitic bipolar IC dedicated for
quadrature demodulation.
QUICK REFERENCE DATA
SYMBOL PARAMETER CONDITIONS MIN. TYP. MAX. UNIT
V
CC
I
CC(tot)
V
i(RF)
f
i(RF)
V
olQ(p-p)
supply voltage 4.5 5.0 5.5 V
total supply current VCC= 5 V 70 79 90 mA
operating input voltage level 64 67 70 dBµV
RF input signal frequency 10.7 − 150 MHz
I and Q output voltage
− 0.5 − V
(peak-to-peak value)
Eφ
(IQ)
phase error between the
−−3 deg
I and Q channels
E
G(IQ)
gain error between the
−−1dB
I and Q channels
E
G(tilt)
α
ct(IQ)
gain tilt error in the I and Q channels −−1dB
crosstalk between the
30 −−dB
I and Q channels
IM3 intermodulation distortion in the
40 −−dB
I and Q channels
ORDERING INFORMATION
PACKAGE
TYPE NUMBER
NAME DESCRIPTION VERSION
TDA8040T SO16 plastic small outline package; 16 leads; body width 3.9 mm SOT109-1
1996 Oct 08 2
Philips Semiconductors Objective specification
Quadrature demodulator TDA8040T
BLOCK DIAGRAM
handbook, full pagewidth
V
CC(A)
GND(D)
RF A
RF B
V
CC(D)
GND(A)
1
2
I
Q
AMP
3
4
AMP
5
6
7
AMP
89
TDA8040T
VOLTAGE
REFERENCE
0
2
÷
90
AMP
VCO
AMP
16
15
14
13
12
11
10
MGE511
I
in
I
out
V
CC(V)
VCOB
VCOA
GND(V)
Q
out
Q
in
Fig.1 Block diagram.
1996 Oct 08 3
Philips Semiconductors Objective specification
Quadrature demodulator TDA8040T
PINNING
SYMBOL PIN DESCRIPTION
V
CC(A)
I 2 I channel buffer output
GND(D) 3 demodulator ground
RF A 4 RF input A
RF B 5 RF input B
V
CC(D)
Q 7 Q channel buffer output
GND(A) 8 I and Q amplifiers ground
Q
in
Q
out
GND(V) 11 VCO ground
VCOA 12 VCO tank circuit A
VCOB 13 VCO tank circuit B
V
CC(V)
I
out
I
in
1 supply voltage for I and Q amplifiers
6 supply voltage for demodulator
9 Q channel amplifier input
10 Q channel amplifier output
14 supply voltage for VCO
15 I channel amplifier output
16 I channel amplifier input
handbook, halfpage
V
GND(D)
V
GND(A)
CC(A)
RF A
RF B
CC(D)
I
Q
1
2
3
4
TDA8040T
5
6
7
8
MGE510
Fig.2 Pin configuration.
16
15
14
13
12
11
10
9
I
in
I
out
V
CC(V)
VCOB
VCOA
GND(V)
Q
out
Q
in
FUNCTIONAL DESCRIPTION
The QPSK modulated RF signal is applied at the input of a
high gain RF amplifier. The amplified signal is then mixed
in a pair of mixers with two LO signals, which are
90 degrees out of phase, to produce the in-phase (I) and
quadrature (Q) signals. These two signals are separately
buffered to drive the external low-pass filters used for the
baseband filtering. The I and Q signals are then amplified
by two matched amplifiers designed to avoid crosstalk
between channels.
The VCO operates at twice the carrier frequency. Its output
signal is applied to a frequency divider (divide-by-2) to
produce the two LO signals which are 90 degrees out of
phase. The VCO is powered from the internal voltage
stabilizer to ensure good shift performance.
1996 Oct 08 4
Philips Semiconductors Objective specification
Quadrature demodulator TDA8040T
LIMITING VALUES
In accordance with the Absolute Maximum Rating System (IEC 134).
SYMBOL PARAMETER CONDITIONS MIN. MAX. UNIT
V
CC(A)
V
CC(D)
V
CC(V)
V
n(max)
I
max
t
sc(max)
Z
L(IQ)
Z
LA(IQ)
V
VCO(p-p)
P
tot
T
stg
T
j
T
amb
supply voltage for I and Q amplifiers −0.3 +6.0 V
supply voltage for demodulator −0.3 +6.0 V
supply voltage for VCO −0.3 +6.0 V
maximum voltage on all pins −0.3 V
CC
V
maximum sink or source current − 10 mA
maximum short-circuit time on outputs − 10 s
AC load impedance for
fi= 15 MHz 35 −Ω
I and Q channels
AC load impedance for
fi= 15 MHz 300 −Ω
I and Q output amplifiers
voltage drive level for external oscillator
− 0.6 V
signal (peak-to-peak value)
total power dissipation T
=70°C − 500 mW
amb
storage temperature −55 +150 °C
junction temperature − 150 °C
operating ambient temperature 0 70 °C
HANDLING
Inputs and outputs are protected against electrostatic discharge in normal handling. However, to be totally safe, it is
desirable to take normal precautions appropriate to handling MOS devices.
THERMAL CHARACTERISTICS
SYMBOL PARAMETER VALUE UNIT
R
th j-a
thermal resistance from junction to ambient in free air 110 K/W
1996 Oct 08 5
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