uaa2062 NXP Semiconductors, uaa2062 Datasheet - Page 9

• Manufacturer Part Number: uaa2062
• Description: Analog Cordless Telephone Ic
• Manufacturer: NXP Semiconductors

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Philips Semiconductors
The synthesizer
The synthesizer has been designed to support most
country channel frequencies between 25 and 50 MHz
(see Chapter “Channel frequencies”).
The local oscillator LO2 and the reference divider provide
the reference frequency for the RX and TX PLL loops.
A single bit programmes the divider value for the reference
divider. A 5 kHz reference frequency (respectively
12.5 kHz) is used with a 10.24 MHz crystal frequency
(respectively 11.15 MHz). The clock divider ratio can be
programmed to 2.5 or to 80. The ratio 80 can be chosen
when the IC is in sleep mode to obtain current saving in the
microcontroller. The clock output is a CMOS output
inverter, supplied by V
The 14-bit TX counter is programmed for the desired
transmit channel frequency. The 14-bit RX counter is
programmed for the desired RX VCO frequency.
2000 Aug 10
Analog cordless telephone IC
C1
C2
C3
R2
R3
RXPD
CLKO
RXLF
22
47
43
PROGRAMMABLE
ref(PLL)
RX COUNTER
DIVIDER
CLOCK
14-BIT
.
RX VCO
DETECTOR
RX PHASE
Fig.5 Synthesizer schematic diagram.
REFERENCE COUNTER
1-BIT PROGRAMMABLE
/2048 or /892
DETECTOR
TX PHASE
9
All counters power-up in the proper default state and for a
10.24 MHz reference crystal. Both RX and TX phase
detectors have current drive type outputs of 400 A.
The RX VCO is connected to an external capacitor and
inductor as illustrated in Fig.5. The varicaps are integrated.
Operating in the 25 US channels, there is a large
frequency difference between the minimum and the
maximum channel frequencies. The sensitivity of the
RX VCO is not large enough to accommodate this large
frequency range. Internal programmable capacitors can
be connected across the RX VCO tank circuit to change
the RX VCO sensitivity. The TX VCO also has internal
programmable capacitors to accommodate a large
frequency range. Chapter “Channel frequencies” shows
the frequency selection for all countries.
crystal oscillator
PROGRAMMABLE
TX COUNTER
14-BIT
VCO
TX
FCA123
24
23
44 LO1I
45 LO1O
9 LO3I
3
2 TXPD
LO2I
LO2O
TXLF
R6
Product specification
UAA2062
R5
C6
C5
C4