June 2002

1

MICRF103

MICRF103

Micrel

MICRF103

QwikRadio™ UHF ASK Transmitter

Final

General Description

The MICRF103 is a single chip Transmitter IC for remote

wireless applications. The device employs Micrel’s latest

QwikRadio™ technology. This device is a true ”data-in,

antenna-out” monolithic device. All antenna tuning is accom-

plished automatically within the IC which eliminates manual

tuning, and reduces production costs. The result is a highly

reliable yet extremely low cost solution for high volume

wireless applications. Because the MICRF103 is a true

single-chip radio transmitter, it is easy to apply, minimizing

design and production costs, and improving time to market.

The MICRF103 uses a novel architecture where the external

antenna is tuned by the internal UHF synthesizer. This

transmitter is designed to comply worldwide UHF unlicensed

band international radio regulations. The IC is compatible

with virtually all ASK/OOK (Amplitude Shift Keying/On-Off

Keyed) UHF receiver types from wide-band super-regenera-

tive radios to narrow-band, high performance super-hetero-

dyne receivers. The transmitter is designed to work with

transmitter data rates up to 115k bits per second.

The automatic tuning in conjunction with an external resistor,

insures that the transmitter output power stays constant at

maximum regulatory transmit power limits for the life of the

battery.

When coupled with Micrel’s family of QwikRadio™ receivers,

the MICRF103 provides the lowest cost and most reliable

remote actuator and RF link system available.

Typical Application

PC

VDD

VSS

REFOSC

ASK

MICRF103

Note: Example for 868MHz

ASK DATA INPUT

RP2

6.8k

0.1

µF

4.7

µF

RP1

100k

+5V

+5V

Y1

8.2pF

100pF

1.0pF

10nH

1.0pF

27nH

27nH

ANTP

ANTM

STBY

100k

SAW Filter

50

Ω

Monopole

PCB Antenna

Figure 1

Features

• Complete UHF transmitter on a monolithic chip

• Frequency range 800MHz to 1GHz

• Data rates to 115kbps

• Automatic antenna alignment, no manual adjustment

• Low external part count

• Low standby current <1

µA

Applications

• Remote keyless entry systems (RKE)

• Remote fan/light control

• Garage door opener transmitters

• Remote sensor data links

Ordering Information

Part Number

Temperature Range

Package

MICRF103BM

–40

°C to +85°C

8-Pin SOIC

Micrel, Inc. • 1849 Fortune Drive • San Jose, CA 95131 • USA • tel + 1 (408) 944-0800 • fax + 1 (408) 944-0970 • http://www.micrel.com

QwikRadio is a trademark of Micrel, Inc. The QwikRadio ICs were developed under a partnership agreement with AIT of Orlando, Florida.