TDA9881TS/V2,518 NXP Semiconductors, TDA9881TS/V2,518 Datasheet - Page 7

• Manufacturer Part Number: TDA9881TS/V2,518
• Description: IC IF-PLL DEMOD 24-SSOP
• Manufacturer: NXP Semiconductors
• Type: Demodulatorr

Specifications of TDA9881TS/V2,518

• Package / Case: 24-SSOP
• Applications: Set-Top Boxes
• Mounting Type: Surface Mount
• Mounting Style: SMD/SMT
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Other names: 935275699518; TDA9881TS/V2-T; TDA9881TS/V2-T

Philips Semiconductors
8. Functional description
9397 750 13417
Product data sheet
8.1 VIF amplifier
8.2 Tuner AGC and VIF AGC
8.3 VIF AGC detector
A simplified block diagram of the device is illustrated in
following functional blocks:
The VIF amplifier consists of three AC-coupled differential stages. Gain control is
performed by emitter degeneration. The total gain control range is typical 66 dB. The
differential input impedance is typical 2 k in parallel with 3 pF.
This block adapts the voltage, generated at the VIF AGC detector, to the internal signal
processing at the VIF amplifier and performs the tuner AGC control current generation.
The onset of the tuner AGC control current generation can be set by a potentiometer at
pin TOP.
Gain control is performed using sync level detection.
The sync level voltage is stored in an integrated capacitor by means of a fast peak
detector. This voltage is compared with a reference voltage (nominal sync level) by a
comparator which charges or discharges the integrated AGC capacitor to generate the
VIF gain. The time constants for decreasing or increasing the gain are nearly equal and
the total AGC reaction time is fast, to cope with ‘aeroplane fluttering’.
1. VIF amplifier
2. Tuner AGC and VIF AGC
3. VIF AGC detector
4. Frequency Phase-Locked Loop (FPLL) detector
5. VCO and divider
6. AFC and digital acquisition help circuit
7. Video demodulator and amplifier
8. Sound carrier trap
9. SIF amplifier
10.SIF AGC detector
11.Single reference QSS mixer
12.FM demodulator and acquisition help circuit
13.Audio amplifier and mute time constant
14.Internal voltage stabilizer
15.Logic.
Rev. 01 — 16 November 2004
Alignment-free vision and FM sound IF PLL demodulator
Figure
© Koninklijke Philips Electronics N.V. 2004. All rights reserved.
1. The device contains the
TDA9881
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