ATR2733-PLQW Atmel, ATR2733-PLQW Datasheet - Page 4

• Manufacturer Part Number: ATR2733-PLQW
• Description: RF Wireless Misc COM.RADIO-Frontend; VHF Band
• Manufacturer: Atmel

Specifications of ATR2733-PLQW

• Package / Case: QFN-48
• Mounting Style: SMD/SMT
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

3. Functional Description
3.1
4
Main Functions
ATR2733 [Preliminary]
The ATR2733 front-end IC was developed as a tuner IC for DAB reception. It was designed for
operation in VHF BIII (174 MHz to 240 MHz). The front end contains gain-controlled LNAs and a
VHF-band mixer with a fractional PLL. The IF path contains three gain-controlled amplifiers. The
front-end IC allows the use of automatic tuning, which contains an adjustable input filter for VHF
BIII and an adjustable preselection filter for VHF reception.
The high dynamic range of the RF inputs, the use of gain-controlled amplifiers and gain-con-
trolled mixers in the RF and IF path (VHF band) offer the possibility of handling even strong RF
input signals.
The RF and IF parts include AGC functional blocks, which are needed for proper operation. The
thresholds are programmable via a simple serial bus.
The SPI bus is used to adjust and control all functional blocks.
The following sections briefly describe the major functions and features.
The following description gives a short overview of the general signal flow using the ATR2733
front-end IC for reception of DAB signals. Numbers in the text refer to the numbers in
on page
A DAB signal in the antenna. the signal is band-pass filtered using a filter with low insertion loss.
The internal variable gain LNA for Band III (3)) amplifies the signal. The signal leaves the IC at
point (4), followed by an external preselection filter. This filter has an automatic tuner adjust-
ment; that is, the tuning-voltage-generation block adjusts the pass band of this filter to the
desired frequency. After passing this filter, the RF signal is down-mixed to a fixed IF frequency of
38.912 MHz. The IF signal is amplified and passed to a SAW filter (5). The first IF variable-gain
amplifier is followed by an IF filter at position (6). This filter is used as an anti-alias-filter. Finally,
the DAB signal is amplified using the 2nd IF amplifier. The signal leaves the front-end IC at (7),
giving the signal to the DAB baseband IC.
Figure 3-1.
4:
1)
Functional Block Diagram with Labelled Inputs and Outputs
Vtune
Gain
Gen.
Cntl
VCO
2)
A
Frac.PLL
A
D
VHF
Control Unit
RSSI
3)
PWR
Cntl
4)
4926BS–DAB–05/06
5)
Figure 3-1