UAA2068 Ver la hoja de datos (PDF) - Philips Electronics

Número de pieza

componentes Descripción

Lista de partido

UAA2068

Transmit chain and synthesizer with integrated VCO for DECT

Philips Electronics 

Philips Semiconductors

Transmit chain and synthesizer with

integrated VCO for DECT

handbook, full pagewidth

Product specification

UAA2068G

DATA 1

VCC(SYD) 2

SYDGND 3

XTAL 4

VCC(SYA) 5

SYAGND 6

CPGND 7

CP 8

UAA2068G

24 VREG

23 VTUNE

22 VCGND

21 VCOB

20 VCOA

19 VCOGND

18 VMOD

17 VCC(VCO)

MGK382

Fig.2 Pin configuration.

FUNCTIONAL DESCRIPTION

Transmit chain

VCO, BUFFER AND FREQUENCY DOUBLER

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 (VREG), 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 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 VMOD.

RF SWITCH

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 PREAMPLIFIER

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 BUFFER

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.

1998 Nov 19

6

Share Link: