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UAA2067G

Image reject 1800 MHz transceiver for DECT applications

Philips Electronics 

Philips Semiconductors

Image reject 1800 MHz transceiver

for DECT applications

Product specification

UAA2067G

FEATURES

• Receiver with:

– low noise amplifier

– dual quadrature mixers for image rejection

(lower sideband)

– I and Q combining networks at a fixed IF

• Both high-frequency and low-frequency VCOs including

buffers with good isolation for low pulling

• Transmitter with:

– dual quadrature mixers for image rejection

(lower sideband)

– amplitude ramping circuit

– amplifier with high output power.

APPLICATIONS

• 1800 MHz transceiver for DECT hand-portable

equipment

• TDMA systems.

GENERAL DESCRIPTION

The UAA2067G is a low-power transceiver intended for

use in portable and base station transceivers complying

with the DECT system. The IC performs in accordance

with specifications in the −30 to +85°C temperature range.

The UAA2067G contains a front-end receiver for the

1800 to 1900 MHz frequency range, a high-frequency

VCO for the 1650 to 1850 MHz range, a low-frequency

VCO for the 100 to 140 MHz frequency range and a

transmitter with a high-output power amplifier driver stage

for the 1800 to 1900 MHz frequency range. Designed in

an advanced BiCMOS process, it combines high

performance with low-power consumption and a high

degree of integration, thus reducing external component

costs and total radio size.

Its first advantage is to provide typically 34 dB of image

rejection in the receiver path. Thus, the image filter

between the LNA and the mixer is redundant and

consequently can be removed. The receive section

consists of a low-noise amplifier that drives a quadrature

mixer pair. Image rejection is achieved by this RF mixer

pair and the two phase shifters in the I and Q channels that

phase shift the IF by 45° and 135° respectively. The two

phase shifted IFs are recombined and buffered to furnish

the IF output signal.

Signals presented at the RF input at LO − IF frequency are

rejected through this signal processing while signals at

LO + IF frequency can form the IF signal.

Its second advantage is to provide a good buffered

high-frequency VCO signal to the RX and TX mixers and

to the synthesizer-prescaler. Switching the receive or

transmit section on gives a very small change in VCO

frequency.

Its third advantage is to provide a good buffered

low-frequency VCO signal to the TX mixers, to the

synthesizer-prescaler and the second down conversion

mixer in a double conversion receiver. Switching the

transmit section on gives a very small change in

VCO frequency.

The frequency of each VCO is determined by a resonator

network that is external to the IC. Each VCO has a

regulated power supply voltage that has been designed

specifically for minimizing a change in frequency due to

changes in the power supply voltage, which may be

caused for instance by switching on the power amplifier.

Its fourth advantage is to provide typically 33 dBc of image

rejection in the single-sideband up-conversion mixer. Thus

the image filter between the power amplifier and the

antenna is redundant and may consequently be removed.

Image rejection is achieved in the internal architecture by

two RF mixers in quadrature and two phase shifters in the

low-frequency VCO signal that shifts the phase to

0° and 90°. The output signals of the mixers are summed

to form the single-upper-sideband output signal.

The output stage is a high-level output buffer with an

output power of approximately 4 dBm. The output level is

sufficient to drive a three-stage bipolar preamplifier

for DECT.

ORDERING INFORMATION

TYPE NUMBER

UAA2067G

NAME

LQFP32

PACKAGE

DESCRIPTION

plastic low profile quad flat package; 32 leads; body 5 × 5 × 1.4 mm

VERSION

SOT401-1

1996 Oct 22

2

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