Philips TDA1592T Datasheet

INTEGRATED CIRCUITS

TDA1592

PLL stereo decoder and noise blanker

Preliminary specification

1996 May 31

Supersedes data of June 1993

File under Integrated Circuits, IC01

Philips Semiconductors	Preliminary specification
PLL stereo decoder and noise blanker	TDA1592

FEATURES

∙Adjustment-free voltage controlled PLL oscillator for ceramic resonator (f = 456 kHz)

∙Pilot signal dependent mono/stereo switching

∙Analog control of mono/stereo change over [stereo blend, Stereo Noise Controller (SNC)]

∙Adjacent channel noise suppression (114 kHz)

∙Pilot canceller

∙Analog control of de-emphasis; High Cut Control (HCC)

∙Reduced and controlled de-emphasis for AM operation (pin 7 to GND)

∙Applicable as source selector for AM/FM/cassette switching

∙Soft mute for silent tuning

∙Separate interference noise detector

∙Integrated input low-pass filter for delayed noise blanking

∙Noise blanking at MPX-demodulator outputs.

QUICK REFERENCE DATA

GENERAL DESCRIPTION

The TDA1592 is a monolithic bipolar integrated circuit providing the stereo decoder function and noise blanking for FM car radio applications.

The device operates in a power supply range of 7.5 to 12 V.

SYMBOL	PARAMETER	MIN.	TYP.	MAX.	UNIT
VP	supply voltage (pin 5)	7.5	10	12	V
IP	supply current	−	15	20	mA
Vo(rms)	audio output signal (RMS value)	800	900	1000	mV
THD	total harmonic distortion	−	0.1	0.3	%
S/N	signal-to-noise ratio	−	82	−	dB
αcs	channel separation	30	40	−	dB
Vtrigg	interference voltage trigger level	−	10	−	mV

ORDERING INFORMATION

TYPE		PACKAGE
NUMBER	NAME	DESCRIPTION	VERSION
TDA1592	DIP20	plastic dual in-line package; 20 leads (300 mil)	SOT146-1
TDA1592T	SO20	plastic small outline package; 20 leads; body width 7.5 mm	SOT163-1

1996 May 31

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31 May 1996

3

pilot

andbook,

auxiliary

full

Vref

VSNC

VHCC

Rout

MPX input

indicator

input

pagewidth

100 nF

750

100 nF

kΩ

mono

Rout R

164 kΩ

Rin

6.8

6.8

47 kΩ

nF

nF

20

19

18

17

16

15

14

13

12

11

Vref

PILOT

SNC

SWITCH

TDA1592

75

DETECTOR

6.8

kΩ

kΩ

7.4 kΩ

Vref

4-POLE

2-POLE

GATE

PILOT

FILTER

MUTE

FILTER

7.4 kΩ

AND

CANCEL

(80 kHz)

(30 kHz)

HCC

PHASE

INTERFERENCE

DETECTOR

Vref

DETECTOR

6.8 kΩ

19

19

19

38

LOGIC

HIGH-PASS

PULSE

AMPLIFIER

FORMER

Vref

(120 kHz)

VCO

POWER

Iref

AGC

NOISE AND AGC

Vref

SUPPLY

DETECTOR

47 kΩ

1

2

3

4

5

6

7

8

9

10

VCO

BC548

47 kΩ

27 kΩ

33 kΩ

68 kΩ

CSB

off

68

Rout L

100 kΩ

10 nF

456 F11

100 nF

33 pF

pF

47

820

100 nF

nF

kΩ

27 kΩ

VP

interference

mute

auxiliary

Lout

input

input

MED724

Fig.1 Block diagram with external components, also used as test circuit.

DIAGRAM BLOCK

blanker noise and decoder stereo PLL

TDA1592

Semiconductors Philips

specification Preliminary

Philips Semiconductors	Preliminary specification
PLL stereo decoder and noise blanker	TDA1592

PINNING

SYMBOL	PIN	DESCRIPTION
PLL	1	phase locked loop filter
OSC	2	oscillator input/output pin for
		ceramic resonator
GND	3	ground (0 V)
Iref	4	reference current
VP	5	supply voltage (+10 V)
INFI	6	interference signal input
PUFO	7	pulse former time constant; VCO
		off
NDET	8	noise detector time constant; mute
		on
FB-L	9	AF feedback input for left audio
		signal
VoL	10	AF output signal left
VoR	11	AF output signal right
FB-R	12	AF feedback input for right audio
		signal
CDEEL	13	de-emphasis capacitor for left
		channel
CDEER	14	de-emphasis capacitor for right
		channel
HCC	15	HCC input for de-emphasis control
SNC	16	stereo blend input
Vref	17	externally applied reference
		voltage of 1 to 5 V
IDENT	18	identification output (HIGH = pilot
		existing; stereo)
PILOT	19	pilot detector level (forced mono
		input)
Vi MPX	20	MPX input signal from IF
		demodulator

handbook, halfpage

PLL	1		20			Vi MPX
OSC	2		19			PILOT
GND	3		18			IDENT
Iref	4		17			Vref
VP	5		16			SNC
INFI			TDA1592			HCC
	6		15
PUFO						CDEER
	7		14
NDET	8		13			CDEEL
FB-L						FB-R
	9		12
VoL						VoR
	10		11
			MED726

Fig.2 Pin configuration.

1996 May 31

4

Philips Semiconductors	Preliminary specification
PLL stereo decoder and noise blanker	TDA1592

FUNCTIONAL DESCRIPTION

The MPX input of the TDA1592 (pin 20) is the null-node of an operational amplifier with internal feedback resistor. Adapting the stereo decoder input to the level of the FM demodulator output is realized by the value of input resistor Rin (see Fig.3). The total gain of the stereo decoder is applicable by varying the feedback resistors

Rout (pins 9, 10, 11 and 12) of the output operational amplifiers (see Fig.4).

The input amplifier is followed by an integrated 4th order Bessel low-pass filter with a cut-off frequency of 80 kHz. It provides necessary signal delay for noise blanking and damping of high frequency interferences at the stereo decoder input.

The soft mute facility (pin 8) provides silent tuning for RDS processing. The mute time constant may be adjusted from pin 8. In mute position and the VCO switched off (pin 7), the output amplifiers can be used for cassette playback, AM stereo purpose or other signal sources.

The voltage to current converted MPX signal is fed to phase detector, pilot detector and pilot canceller circuits. The oscillator is alignment-free with an external ceramic resonator at 456 kHz as reference (pin 2). The required 19 kHz and 38 kHz signals are generated by division of the oscillator output signal in a logical circuit. For regeneration of the 38 kHz subcarrier, a PLL is used. The 19 kHz quadrature phase signal is fed to the 19 kHz

phase detector, where it is compared with the incoming pilot tone. The DC output signal of the phase detector (pin 1) controls the oscillator (PLL).

The pilot presence detector is driven by internally generated in-phase 19 kHz. Its pilot-dependent DC output voltage (pin 19) is fed to a threshold switch, which activates the pilot indicator logic output (pin 18) and turns the stereo decoder to stereo operation. The same

DC voltage is used to control the amplitude of an anti-phase internally generated 19 kHz signal. In the pilot canceller, the pilot tone is compensated by this anti-phase 19 kHz signal.

The pilot cancelled signal is fed to the multiplex decoder. There, the side signal is demodulated and combined with the main signal in a matrix to left and right audio channel.

Compensation for roll-off in the incoming MPX signal caused by IF filters and FM demodulator is realized by corresponding side signal amplification.

A smooth mono to stereo take-over, which is controlled by the level detector voltage of the IF part, is achieved by the SNC (pins 16 and 17; see Fig.6).

From the output of the MPX demodulator the signals are fed to 2-pole low-pass filters with a cut-off frequency of 30 kHz to provide additional signal delay for noise blanking and attenuation of the subcarrier and its harmonics.

These filters are followed by the noise suppression gates, which are combined with de-emphasis and HCC. The de-emphasis is defined by internal resistors (aligned by an external current) and external capacitors (pins 13 and 14). For HCC, the de-emphasis time constant can be changed to higher values (pins 15 and 17; see Figs 7 to 9). This function is controlled by an analog input signal, derived from the level detector voltage of the IF part. When the VCO is turned off (pin 7 to GND), de-emphasis is reduced to 20 μs for full frequency response when AM-AF is fed through the stereo decoder. De-emphasis remains controllable.

From the gate circuits audio is fed through internal series resistors to the inverting inputs of the output operational amplifiers (pins 9 and 12), which can also be used as signal inputs for cassette playback or other sources when the mute is activated. The gain of these amplifiers is defined by external feedback resistors Rout

(pins 9, 10, 11 and 12).

The input of the ignition noise blanker is the null node of an operational amplifier (pin 6). It can be driven by the level detector output of the FM-IF limiter and/or the MPX signal. Its sensitivity is dependent on the value of the series input resistor at pin 6.

The operational amplifier output signal is fed through an integrated 120 kHz high-pass filter, becomes amplified and is then fed in parallel to the noise detector and the interference detector. The noise detector is a negative peak detector. Its output (pin 8) controls the trigger sensitivity (prevention to false triggering at noisy input signals) and the attenuation of the input operational amplifier. The output of the interference detector, when receiving a steep pulse, triggers a mono flip-flop, which is a part of the pulse former circuit. The time constant of the mono flip-flop is defined by an external capacitor (pin 7) and its output activates the blanking gates in the audio.

1996 May 31

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Philips Semiconductors			Preliminary specification
PLL stereo decoder and noise blanker				TDA1592
LIMITING VALUES
In accordance with the Absolute Maximum Rating System (IEC 134).
SYMBOL	PARAMETER	MIN.	MAX.		UNIT
VP	supply voltage (pin 5)	0	13.2		V
Ptot	total power dissipation	0	0.25		W
Tstg	storage temperature	−55	+150		°C
Tamb	operating ambient temperature	−40	+85		°C
Ves	electrostatic handling for all pins; note 1	−400	+400		V

Note

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

CHARACTERISTICS

VP = 10 V; Tamb = 25 °C; input signal Vi MPX(p-p) = 1.7 V; m = 100% ( f = ±75 kHz, fmod = 1 kHz); de-emphasis of 50 μs and series resistor at input R1 = 164 kΩ; measurements taken in Fig.1; unless otherwise specified.

SYMBOL	PARAMETER	CONDITIONS	MIN.	TYP.	MAX.	UNIT
VP	supply voltage (pin 5)		7.5	10	12	V
IP	supply current		−	15	20	mA
Stereo decoder
Vi MPX(p-p)	MPX input signal		−	1.7	−	V
Vi MPX(p-p)	overdrive margin of MPX input signal	THD = 1%	6	−	−	dB
Vo(rms)	AF mono output signal at pins 10 and 11	without pilot	800	900	1000	mV
	(RMS value)
Vo	overdrive margin of output signal	THD = 1%	6	−	−	dB
V10-11/Vo	difference of output voltage levels		−	−	1	dB
Vo 10,11	DC output voltage (pins 10 and 11)		3.2	3.7	4.2	V
Ro 10,11	output resistance		−	150	−	Ω
Io	output current		330	400	−	μA
R2,3	maximum feedback resistor		−	−	68	kΩ
V4,3	reference voltage		3.7	3.8	3.9	V
αcs	channel separation	pin 16 open-circuit;	30	40	−	dB
		see Fig.6
THD	total harmonic distortion		−	0.1	0.3	%
S/N	signal-to-noise ratio	f = 20 to 16000 Hz	77	82	−	dB
α19	pilot signal suppression	f = 19 kHz	40	50	−	dB
α38	subcarrier suppression	f = 38 kHz	35	50	−	dB
α57		f = 57 kHz	46	−	−	dB
α76		f = 76 kHz	−	60	−	dB
IM2	intermodulation for fspur = 1 kHz	fmod = 10 kHz; note 1	−	60	−	dB
IM3		fmod = 13 kHz	−	58	−	dB
α57 VF	traffic radio (VWF)	f = 57 kHz; note 2	−	70	−	dB
α67	SCA (Subsidiary Communications	f = 67 kHz; note 3	70	−	−	dB
	Authorization)

1996 May 31

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