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TDA9814

Multistandard VIF-PLL with QSS-IF and dual FM-PLL/AM demodulator

Philips Electronics 

Philips Semiconductors

Multistandard VIF-PLL with QSS-IF

and dual FM-PLL/AM demodulator

Product specification

TDA9814T

The FM-PLL consists of an integrated relaxation oscillator,

an integrated loop filter and a phase detector. The

oscillator is locked to the FM intercarrier signal, output

from the limiter. As a result of locking, the oscillator

frequency tracks with the modulation of the input signal

and the oscillator control voltage is superimposed by the

AF voltage. The FM-PLL operates as an FM-demodulator.

The AF amplifier consists of two parts:

1. The AF preamplifier for FM sound is an operational

amplifier with internal feedback, high gain and high

common mode rejection. The AF voltage from the PLL

demodulator, by principle a small output signal, is

amplified by approximately 33 dB. The low-pass

characteristic of the amplifier reduces the harmonics of

the intercarrier signal at the sound output terminal. An

additional DC control circuit is implemented to keep

the DC level constant, independent of process spread.

2. The AF output amplifier (10 dB) provides the required

output level by a rail-to-rail output stage. This amplifier

makes use of an input selector for switching to AM/FM

or mute state, controlled by the standard switching

voltage and the mute switching voltage.

Internal voltage stabilizer and 1⁄2VP-reference

The bandgap circuit internally generates a voltage of

approximately 1.25 V, independent of supply voltage and

temperature. A voltage regulator circuit, connected to this

voltage, produces a constant voltage of 3.6 V which is

used as an internal reference voltage.

For all audio output signals the constant reference voltage

cannot be used because large output signals are required.

Therefore these signals refer to half the supply voltage to

achieve a symmetrical headroom, especially for the

rail-to-rail output stage. For ripple and noise attenuation

the 1⁄2VP voltage has to be filtered via a low-pass filter by

using an external capacitor together with an integrated

resistor (fg = 5 Hz). For a fast setting to 1⁄2VP an internal

start-up circuit is added.

LIMITING VALUES

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

SYMBOL

PARAMETER

CONDITIONS

VP

Vn

ts(max)

V16

Tstg

Tamb

Ves

supply voltage (pin 26)

voltage at pins 1 to 7, 9 to 16, 19, 20 and

23 to 28

maximum short-circuit time

tuner AGC output voltage

storage temperature

operating ambient temperature

electrostatic handling voltage

maximum chip temperature

of 125 °C; note 1

note 2

Notes

1. IP = 125 mA; Tamb = 70 °C; Rth(j-a) = 80 K/W.

2. Machine model class B (L = 2.5 µH).

MIN.

0

0

−

0

−25

−20

−300

MAX. UNIT

5.5

V

VP

V

10

s

13.2 V

+150 °C

+70

°C

+300 V

THERMAL CHARACTERISTICS

SYMBOL

PARAMETER

CONDITIONS

Rth(j-a)

thermal resistance from junction to ambient in free air

VALUE

80

UNIT

K/W

1998 Feb 09

8

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