Wave Issue 0301 1/17/03 Article 4-02

***Zarlink Announces Single-Chip Radio Transceiver for Multi-Mode
2.5G Networks
(January 14)

Zarlink Semiconductor today unveiled a single-chip radio
transceiver (transmitter/receiver) for cell phones used in multi
band, multi-mode, 2G and 2.5G digital cellular networks. The new
ZL20250 chip is targeted primarily at handsets for GAIT overlay
networks that add GSM capability and mobile Internet data
services to existing TDMA/AMPS wireless infrastructure. Multi
mode GAIT cellular networks are currently being deployed across
North America.

Zarlink estimates that the new transceiver eliminates about 60
separate components from GAIT cell phones, shrinking the size of
the radio by more than half, and reducing BOM (bill of material)
costs by up to 40%. The device supports reception of all GAIT
voice services, as well as data services based on the 2.5G GPRS
and EDGE platforms, at a two-way rate of 384 Kb/s (kilobits per
second) - the top EDGE rate - without using external circuitry.

Zarlink's ZL20250 transceiver provides two-way compatibility for
8PSK (8-level phase shift keying), the digital modulation scheme
that gives EDGE its 384 Kb/s data rate. In addition, Zarlink's
transceiver supports the normal GMSK (Gaussian minimum shift
keying) modulation technique used by GSM and GPRS applications.

The ZL20250 is a commercial single-chip, 2.5G cell phone radio
transceiver. This is possible because of a two-stage receiver
design, that allows the chip to overcome the isolation issues
typical to cellular receiving and transmitting. Cellular receive
and transmit functions are usually implemented on two or more
chips to ensure that RF front-end receive circuits are isolated
from transmit signals.

The chip's receive circuitry has two IF (intermediate frequency)
inputs, one for GSM/GPRS/EDGE, the other for TDMA/AMPS. Incoming
signals are mixed with synthesized LO (local oscillator) signals
from an on-chip VHF VCO (very high frequency, voltage-controlled
oscillator), amplified, and downconverted to the baseband
frequency. The ZL20250 receiver also has integrated channel
filters that allow the chip to connect directly to most baseband
processors.

The transmitter on the ZL20250 is a linear circuit with a
quadrature modulator, IF gain control, and a single-ended output.
The single- ended output delivers enough power to directly drive
a two-stage power amplifier, eliminating the need for an external
balun (balanced/unbalanced) transformer.

The ZL20250 uses a fractional-N synthesizer to control its UHF
(ultra high frequency) VCO, allowing it to switch rapidly between
frequencies. The radio is designed to give designers control over
power consumption, with programmable features to adjust receive
and transmit currents to accommodate different operating
requirements.

Zarlink's multi-mode ZL20250 transceiver operates in four key
cellular frequency bands: 850 MHz (megahertz), 900 MHz, 1800 MHz,
and 1900 MHz. This quad-band capability allows the transceiver to
support TDMA/AMPS/GSM/GPRS/EDGE services in North America, as
well as many GSM/GPRS/EDGE operating environments in Europe and
other regions. The chip is compliant with the TIA/EIA IS (interim
standard)-136 specification, and with protocols for GSM, EDGE,
and GPRS defined by ETSI.

The ZL20250 is entering volume production, in a SiGe (silicon
germanium) BiCMOS (bipolar complementary metal oxide silicon)
process, and offered in a 56-pin MLP (micro-lead frame package)
with dimensions of 8 mm x 8 mm. An evaluation board and API
software support the chip. In high volumes, the ZL20250 is priced
at less than US$7.00.

www.zarlink.com