tda9870ah NXP Semiconductors, tda9870ah Datasheet - Page 28

• Manufacturer Part Number: tda9870ah
• Description: Digital Tv Sound Processor Dtvsp
• Manufacturer: NXP Semiconductors

Philips Semiconductors
Notes
1. Definitions of levels and level setting:
2. All analog and digital supply ground pins are connected internally.
3. Set demodulator to AM mode. Apply an AM carrier (with 1 kHz and 100%) to one channel. Check AGC step. Switch
4. FM source; in dual mode only A (respectively B) signal modulated; measured at B (respectively A) channel output;
5. FM source; in stereo mode only L (respectively R) signal modulated; measured at R (respectively L) channel output;
6. If the supply voltage for the TDA9870A is switched off, because of the ESD protection circuitry, all audio input pins
7. The SCART specification allows a signal level of up to 2 V (RMS). Because of signal handling limitations due to the
8. ADC level adjust is 6 dB, all other level adjusts are 0 dB. If an external 3 dB divider is used set output buffer gain
1999 Dec 20
X
X
X
J
D
A
Digital TV Sound Processor (DTVSP)
SYMBOL
a) The full-scale level for analog audio signals is 1.4 V (RMS).
b) The nominal level at the digital crossbar switch is defined at 15 dB (full-scale).
c) Nominal audio input levels for external and mono: 500 mV (RMS) at 9 dB (full-scale).
d) See also Tables 6 and 7.
AGC off and set AGC to the gain step found. Measure the 1 kHz signal level of this channel and take it as a reference.
Switch to the other SIF input to which no signal is connected and which is terminated with 50 . Now measure the
1 kHz crosstalk signal level. The SIF source resistance should be low (50 ).
V
V
the transmitter.
are short-circuited. To avoid a short-circuit at the SCART inputs a 15 k resistor ( 3 dB divider) has to be used.
5 V supply voltage for the TDA9870A, there is a need for fixed 3 dB attenuators at the SCART inputs. To achieve
SCART-to-SCART copies with 0 dB gain, there are 3 and 0 dB amplifiers at the outputs of SCART 1 and SCART 2
and at the line output. The attenuator is realized by an internal resistor that works together with an external series
resistor as a voltage divider. With this voltage divider the maximum SCART input signal level of 2 V (RMS) is scaled
down to 1.4 V (RMS) at the input pin. To avoid clipping, the 3 dB gain must not be used if the SCART input signal is
larger than 1.4 V (RMS).
to 3 dB, tone control to 0 dB, AVL off and volume control to 0 dB.
o
o
= 1 V (RMS) of modulated channel.
= 1 V (RMS) of modulated channel. The stereo channel separation may be limited by adjustment tolerances of
adjustment tolerance
drift
ageing
PARAMETER
across temperature range
CONDITIONS
28
MIN.
TYP.
Product specification
TDA9870A
30
30
5
MAX.
10
10
10
-----------
year
UNIT
–
6
6
6