Philips TDA3866 Datasheet

INTEGRATED CIRCUITS

DATA SH EET

TDA3866

Quasi-split sound processor for all standards

Preliminary speciﬁcation File under Integrated Circuits, IC02

January 1992

Philips Semiconductors Preliminary speciﬁcation

Quasi-split sound processor for all standards TDA3866

FEATURES

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

• AF2 signal automatically muted (at B/G) by the input signal level

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

• Stereo-matrix correction

• Layout-compatible with TDA3858 (32 pins) and

TDA3857 (20 pins)

• AM output level typically 500 mV at m = 0.54 (+2.5 dB in comparison to TDA3856)

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.

QUICK REFERENCE DATA

SYMBOL PARAMETER MIN. TYP. MAX. UNIT

iIF

supply voltage (pin 21) 4.5 5 8.8 V supply current − 60 72 mA IF input sensitivity (−3 dB) − 70 100 µV audio output signal for FM standard B/G (RMS value) − 1 − V audio output signal for AM standard L (RMS value) − 0.5 − 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 AND PACKAGE INFORMATION

EXTENDED TYPE

NUMBER

PINS PIN POSITION MATERIAL CODE

PACKAGE

TDA3866 24 shrink DIL plastic SOT234

Note

1. SOT234-1; 1997 January 8.

January 1992 2

(1)

Philips Semiconductors Preliminary speciﬁcation

Quasi-split sound processor for all standards TDA3866

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

January 1992 3

Philips Semiconductors Preliminary speciﬁcation

Quasi-split sound processor for all standards TDA3866

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 C C

AGC AM

3 charge capacitor for AGC (FM and AM)

4 charge capacitor for AM AGC MODE 5 3-state input for standard select FM2R1 6 reference circuit for FM2 (5.74 MHz) FM2R2 7 reference circuit for FM2 (5,74 MHz) AF2 8 AF2 output (AF out of 5.74 MHz) AF1 9 AF1 output (AF out of 5.5 MHz or AM) FM1R1 10 reference circuit for FM1 (5.5 MHz) FM1R2 11 reference circuit for FM1 (5.5 MHz) VC-R1 12 reference circuit for the vision carrier (38.9 MHz) VC-R2 13 reference circuit for the vision carrier (38.9 MHz) C

AFAM

14 DC-decoupling capacitor for AM demodulator (AF-AM) FM1I 15 intercarrier input for FM1 (5.5 MHz) C

AF1

16 DC-decoupling capacitor for FM1 demodulator (AF1) ICO 17 intercarrier output signal (5.5/5.74 MHz) C

AF2

18 DC-decoupling capacitor for FM2 demodulator (AF2) FM2I 19 intercarrier input for FM2 (5.74 MHz) GND 20 ground (0 V) V

ref

21 +5 ... +8 V supply voltage

22 charge capacitor for reference voltage FMIF1 23 IF difference input 1 for B/G standard (38.9 MHz) FMIF2 24 IF difference input 2 for B/G standard (38.9 MHz)

PIN CONFIGURATION

Fig.2 Pin configuration.

January 1992 4

Philips Semiconductors Preliminary speciﬁcation

Quasi-split sound processor for all standards TDA3866

FUNCTIONAL DESCRIPTION

The quasi-split sound processor is for all standards. Dependent on the voltage on pin 5 either FM mode (B/G) or AM mode (L) is selected.

B/G standard (FM mode): Pins 23 and 24 are active, AGC detector uses peak sync level. Sound carrier SC1 (5.5 MHz) provides AF1, sound carrier SC2 (5.74 MHz) provides AF2. With no sound carrier SC2 on pin 19, 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 on pin 19, under measurement conditions, AF2 is switched on (see limiting amplifier). Weak input signals at pins 23 and 24 generate noise on pin 19, which is present in the intercarrier signal and passes through the 5.74 MHz filter. Noise on pin 19 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.

The series capacitor C 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. 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.

in 38.9 MHz

Measurements at the demodulators: For all signal-to-noise measurements the generator must meet the following specifications; phase modulation errors < 0.5 degree 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

mod

of ±27 kHz the S/N ratio is deteriorated by 5.3 dB.

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.

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