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

Data at V

i IF

O (RMS)

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

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).

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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

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

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. .

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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

I(12 V)

tot

stg

amb

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

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

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