uaa2068ahl NXP Semiconductors, uaa2068ahl Datasheet - Page 6

• Manufacturer Part Number: uaa2068ahl
• Description: Transmit Chain And Synthesizer With Integrated Vco For Dect
• Manufacturer: NXP Semiconductors

Philips Semiconductors
FUNCTIONAL DESCRIPTION
Transmit chain
VCO,
The VCO operates at a nominal centre frequency of
950 MHz. The VCO is fully integrated apart from two
inductors which complete the resonator network. The VCO
operates from an on-chip regulated power supply (V
which minimizes frequency disturbances due to variations
in supply voltage. The buffered VCO signal is fed into a
frequency doubler. The large difference between the
transmitted and VCO frequencies reduces transmitter
oscillator coupling problems.
The output of the doubler is used to drive the synthesizer
main divider and can also be switched to either the TX
preamplifier or the RX LO output buffer. The high isolation
obtained from the VCO buffer and the frequency doubler
ensures that very small frequency changes occur when
turning on the TX preamplifier or the RX LO output buffer.
In TX mode, the oscillator can be directly modulated with
GMSK filtered data at pin V
1999 Jun 04
handbook, full pagewidth
Transmit chain and synthesizer with
integrated VCO for DECT
BUFFER AND FREQUENCY DOUBLER
MOD
V CC(SYD)
V CC(SYA)
SYDGND
SYAGND
CPGND
.
DATA
XTAL
CP
1
2
3
4
5
6
7
8
Fig.2 Pin configuration.
REG
UAA2068AHL
),
6
RF
The RF switch passes the doubled VCO signal to either
the TX preamplifier (when T_EN is HIGH) or to the RX LO
buffer (when T_EN is LOW). In TX mode, the difference in
the RF power levels, observed at the TX output when
T_EN is switched from LOW-to-HIGH, is typically 40 dB.
TX
The TX preamplifier amplifies the RF signal up to a level of
3 dBm which is suitable for use with Philips
Semiconductors DECT power amplifiers such as the
CGY20xx series. It is powered-up when both R_OFF and
VCO_ON are HIGH.
RX LO
The RX LO buffer outputs the frequency doubled VCO
signal at a level of 14 dBm. This signal can then be used
as the local oscillator drive for the receive mixers of
devices such as the UAA3540TS. The buffer is
powered-up when R_OFF is LOW and VCO_ON is HIGH.
PREAMPLIFIER
SWITCH
BUFFER
24
23
22
21
20
19
18
17
FCA070
V REG
V TUNE
VCGND
VCOB
VCOA
VCOGND
V MOD
V CC(VCO)
UAA2068AHL
Product specification