uaa2068g NXP Semiconductors, uaa2068g Datasheet - Page 6

• Manufacturer Part Number: uaa2068g
• 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. It is fully integrated apart from two inductors
which complete the resonator network. This VCO operates
from an on-chip regulated power supply (V
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 very small frequency changes 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
1998 Nov 19
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
REG
), which
Fig.2 Pin configuration.
UAA2068G
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 UAA2078. The buffer is powered-up
when R_OFF is LOW and VCO_ON is HIGH.
PREAMPLIFIER
SWITCH
BUFFER
19
18
17
24
23
22
21
20
MGK382
V REG
V TUNE
VCGND
VCOB
VCOA
VCOGND
V MOD
V CC(VCO)
Product specification
UAA2068G