Philips TDA3858 Datasheet

INTEGRATED CIRCUITS

DATA SH EET

TDA3858

Quasi-split sound processor for all
standards

Product specification
File under Integrated Circuits, IC02

June 1994

Philips Semiconductors Product specification

Quasi-split sound processor for all standards TDA3858

FEATURES

• Quasi-split sound processor for all standards e. g. B/G
(FM sound) and L (AM sound)

• Reducing of spurious video signals by tracking function
and AFC for the vision carrier reference circuit;
(recommended for NICAM)

• Automatic muting of the AF2 signal (at B/G) by the input
level

• AM signal processing for L standard and switching over
the audio signal

• Stereo matrix correction

• Layout-compatible with TDA3856 (24 pins) and

GENERAL DESCRIPTION

Separate symmetrical IF inputs for FM or AM sound.
Gain controlled wideband IF amplifier, input select switch.

AGC generation due to peak sync for FM or mean signal
level for AM. Reference amplifier for the regeneration of
the vision carrier. Optimized limiting amplifier for AM
suppression in the regenerated vision carrier signal and
90° phase shifter.

Intercarrier mixer for FM sound, output with low-pass filter.
Separate signal processing for 5.5 and 5.74 MHz
intercarriers. Wide supply voltage range, only 300 mW
power dissipation at 5 V.

TDA3857 (20 pins).

QUICK REFERENCE DATA

SYMBOL PARAMETER MIN. TYP. MAX. UNIT

V

P1

V

P2

Data at V

I

P

V

i IF

V

O (RMS)

V

O (RMS)

P1

supply voltage (pin 27) 4.5 5 8.8 V
alternative supply voltage (pin 28) 10.8 12 13.2 V

=5 V

supply current (pin 27) − 60 72 mA
IF input sensitivity (−3 dB) − 70 100 µV
audio output signal for FM (B/G) − 1 − V
audio output signal for AM (L) − 0.6 − V

THD total harmonic distortion

for FM − 0.5 − %
for AM − 1 − %

S/N (W) weighted signal-to-noise ratio

for FM − 68 − dB
for AM − 56 − dB

ORDERING INFORMATION

PACKAGE

EXTENDED

TYPE NUMBER

PINS

PIN

POSITION

MATERIAL CODE

TDA3858 32 shrink DIL plastic SOT232

Note

1. SOT 232-1; 1996 November 21.

June 1994 2

(1)

Philips Semiconductors Product specification

Quasi-split sound processor for all standards TDA3858

Fig.1 Block diagram (B/G and L).

June 1994 3

Philips Semiconductors Product specification

Quasi-split sound processor for all standards TDA3858

PINNING

SYMBOL PIN DESCRIPTION

AMIF1 1 AM IF difference input 1 for L standard (32.4 MHz)
AMIF2 2 AM IF difference input 2 for L standard (32.4 MHz)
n.c. 3 not connected
C

AGC

C

AM

MODE 6 3-state input for standard select
MATR 7 input for stereo matrix correction
FM2R1 8 reference circuit for FM2 (5.74 MHz)
FM2R2 9 reference circuit for FM2 (5.74 MHz)
AF2 10 AF2 output (AF out of 5.74 MHz)
AF1 11 AF1 output (AF out of 5.5 MHz or AM)
FM1R1 12 reference circuit for FM1 (5.5 MHz)
FM1R2 13 reference circuit for FM1 (5.5 MHz)
n.c. 14 not connected
n.c. 15 not connected
VC-R1 16 reference circuit for the vision carrier (38.9 MHz)
VC-R2 17 reference circuit for the vision carrier (38.9 MHz)
n.c. 18 not connected
TRACK 19 DC output level for tracking
C

AFAM

FM1l 21 intercarrier input for FM1 (5.5. MHz)
C

AF1

ICO 23 intercarrier output signal (5.5/5.74 MHz)
C

AF2

FM2I 25 intercarrier input for FM2 (5.74 MHz)
GND 26 ground (0 V)
V

P1

V

P2

C

REF

n.c. 30 not connected
FMIF1 31 IF difference input 1 for B/G standard (38.9 MHz)
FMIF2 32 IF difference input 2 for B/G standard (38.9 MHz)

4 charge capacitor for AGC (FM and AM)
5 charge capacitor for AM AGC

20 DC decoupling capacitor for AM demodulator (AF-AM)

22 DC decoupling capacitor for FM1 demodulator (AF1)

24 DC decoupling capacitor for FM2 demodulator (AF2)

27 +5 to +8 V supply voltage (pin 28 not connected)
28 + 12 V supply voltage (pin 27 not connected)
29 charge capacitor for reference voltage

Fig.2 Pin configuration.

June 1994 4

Philips Semiconductors Product specification

Quasi-split sound processor for all standards TDA3858

FUNCTIONAL DESCRIPTION

The quasi-split sound processor is
suitable for all standards. Dependent
on the voltage at pin 6 either FM
mode (B/G) or AM mode (L) is
selected.

B/G standard (FM mode)

Pins 31 and 32 are active, AGC
detector uses peak sync level. Sound
carrier SC1 (5.5 MHz) provides AF1,
sound carrier SC2 (5.74 MHz)
provides AF2.

Muting

With no sound carrier SC2 at pin 25,
AF2 output is muted (in mid-position
of the standard select switch FM
mode without muting of AF2 is
selected).
The mute circuit prevents false signal
recognition in the stereo decoder at
high IF signal levels when no second
sound carrier exists (mono) and an
AF signal is present in the
identification signal frequency range.
With 1 mV at pin 25, under
measurement conditions, AF2 is
switched on (see limiting amplifier).
Weak input signals at pins 31 and 32
generate noise at pin 25, which is
present in the intercarrier signal and
passes through the 5.74 MHz filter.
Noise at pin 25 inhibits muting. No
misinterpretation due to white noise
occurs in the stereo decoder, when
non-correlated noise masks the
identification signal frequencies,
which may be present in sustained
tone signals. The stereo decoder
remains switched to mono.

L standard (AM mode)

Pins 1 and 2 are active, AGC detector
uses mean signal level. The audio
signal from the AM demodulator is
output on AF1, with AF2 output
muted.

Sound carrier notch filter for an
improved intercarrier buzz

The series capacitor Csin the

38.9 MHz resonant circuit provides a
notch at the sound carrier frequency
in order to provide more attenuation
for the sound carrier in the vision
carrier reference channel. The ratio of
parallel/series capacitor depends on
the ratio of VC/SC frequency and has
to be adapted to other TV
transmission standards if necessary,
according to the formula
CS=CP(fVC/fSC)2− CP.

The result is an improved intercarrier
buzz (up to 10 dB improvement in
sound channel 2 with 250 kHz video
modulation for B/G stereo) or
suppression of 350 kHz video
modulated beat frequency in the
digitally-modulated NICAM
subcarrier.

Intercarrier buzz fine tuning with
250 kHz square wave video
modulation

The picture carrier for quadrature
demodulation in the intercarrier mixer
is not exactly 90 degrees due to the
shift variation in the integrated phase
shift network. The tuning of the LC
reference circuit to provide optimal
video suppression at the intercarrier
output is not the same as that to
provide optimal intercarrier buzz
suppression. In order to optimize the
AF signal performance, a fine tuning
for the optimal S/N at the sound
channel 2 (from 5.74 MHz) may be
performed with a 250 kHz square
wave video modulation.

Measurements at the demodulators

For all signal-to-noise measurements
the generator must meet the following
specifications:

phase modulation errors < 0.5°for
B/W-jumps

intercarrier signal-to-noise ratio as
measured with ‘TV-demodulator
AMF2’ (weighted S/N) must
be > 60 dB at 6 kHz sine wave
modulation of the B/W-signal.

Signal-to-noise ratios are measured
with ∆f = ±50 kHz deviation and
f

= 1 kHz; with a deviation of

mod

±30 kHz the S/N ratio is deteriorated
by 4.5 dB.
.

June 1994 5

Philips Semiconductors Product specification

Quasi-split sound processor for all standards TDA3858

LIMITING VALUES

In accordance with the Absolute Maximum Rating System (IEC 134).

SYMBOL PARAMETER MIN. MAX. UNIT

V

P1

V

P2

V

I

V

I(12 V)

P

tot

T

stg

T

amb

V

ESD

supply voltage (pin 27) − 8.8 V
supply voltage (pin 28) − 13.2 V
voltage (pins 1, 2, 6, 10, 11, 21, 23, 25, 31and 32) 0 V

V

P

voltage at 12 V supply (pin 6) 0 5.5 V
total power dissipation 0 950 mW
storage temperature −25 +150 °C
operating ambient temperature 0 +70 °C
electrostatic handling (note 1)

all pins except pins 1, 2, 31 and 32 ±500 − V
pins 1, 2, 31 and 32 +400 − V

−500 − V

Note to the Limiting Values

1. Equivalent to discharging a 200 pF capacitor through a 0 Ω series resistor.

June 1994 6