TEA5777 NXP Semiconductors, TEA5777 Datasheet - Page 13

• Manufacturer Part Number: TEA5777
• Manufacturer: NXP Semiconductors

Specifications of TEA5777

• Lead Free Status / Rohs Status: Supplier Unconfirmed

Philips Semiconductors
TEA5777_1
Product data sheet
8.2.3 FM VCO
8.2.4 FM IF filter
8.2.5 FM demodulator
8.3.1 MPX decoder
8.3.2 Signal strength depending mono/stereo blend
8.3.3 Pilot detector
8.3.4 De-emphasis
8.3 Stereo decoder
8.4 Tuning function
The symmetrical LC, varactor tuned VCO provides the oscillator signals for the FM
quadrature mixers (pins VCOTANK1 and VCOTANK2). The VCO operates at double the
RF frequency f
guarantee good start-up behavior and carrier-to-noise ratio (C/N) even with low Q coils
(Q > 40). High-side injection (+f
via the bus control.
The FM signal path incorporates an I and Q orthogonal FM channel with fully integrated
polyphase IF filter. All FM IF filtering is done inside the IC, therefore no external filter
components are required. The center frequency of the filter matches the chosen IF
(f
The FM demodulator is fully integrated and needs no external components. In order to
remove undesired IF and or RF input related components, a 80 kHz low-pass filter has
been integrated.
The PLL stereo decoder is alignment free and incorporates a fully integrated PLL loop
filter. The stereo decoder can be switched to forced mono via bus control bit FOMO.
When decreasing the RF input level, the MPX decoder blends from stereo to mono to limit
the output noise. The control signal is obtained from the low-pass filtered level information
at pin TMUTE. This blend function, called SDS, can also be switched off via bus control bit
SDSOFF and a RF level related sudden change from stereo to mono transition will result.
A pilot detector, with external filter capacitor at pin PILDET/AMRFAGC, is used to detect
the presence of a stereo signal. Mono or stereo reception can be read via the bus control,
but can also be passed to pin DATA in the Dbus mode (see
DBUS has to be programmed. In this case, no bus action is required (silent readout) to
read the status of the pilot detector and the information is continuously available.
In FM mode, the de-emphasis is switchable between 50 s and 75 s (bit DEEM). In AM
mode, bit DEEM selects a low-pass filter with the time constant 50 s or 75 s in order to
limit the noise bandwidth.
The tuning concept of the TEA5777 is based on a PLL and programming of the required
frequency takes place via the bus control.
IF
= 133.333 kHz or 150 kHz) and has a 3 dB bandwidth of approximately 110 kHz.
VCO
= 2
Rev. 01 — 11 April 2006
(f
RF
Low-power AM/FM stereo radio for handheld applications
f
IF
IF
) or low-side injection ( f
) and has an internal AGC control circuit in order to
IF
© Koninklijke Philips Electronics N.V. 2006. All rights reserved.
) of the VCO can be chosen
Section
9). For this option, bit
TEA5777
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