MICRF221

3.3V, QwikRadio

QwikRadio is a registered trademark of Micrel, Inc.

Micrel Inc. • 2180 Fortune Drive • San Jose, CA 95131 • USA • tel +1 (408) 944-0800 • fax + 1 (408) 474-1000 • http://www.micrel.com

General Description

The MICRF221 is a third generation QwikRadio

®

receiver, offering all the benefits of Micrel's earlier

QwikRadio

®

products with significant improvements,

including: enhanced sensitivity, automatic duty-cycle

feature and RSSI output.

The MICRF221, Figure 1, is a super-heterodyne

receiver, designed for OOK and ASK modulation. The

down-conversion mixer also provides image rejection.

The MICRF221 receiver provides a SLEEP Mode for

duty-cycle operation and an enhanced, customer

programmable "WAKE" function. These features are

further combined into a wholly integrated "self-polling"

scheme that is ideal for low and ultra-low power

applications, such as RKE and RFID

All post-detection data filtering is provided on the

MICRF221 receiver. Any one of four filter bandwidths

may be selected externally by the user in binary steps,

from 1.25 kHz to 10 kHz. The user needs only to

program the device with a set of easily determined

values based on data rate, code modulation format, and

desired duty-cycle operation.

Features

• Complete Receiver on a Chip

• -109dBm sensitivity, 1 kbps and BER 10E-02

• Image Rejection Mixer

• 850 MHz to 950 MHz frequency range

• Low Power, 9mA @ 868 MHz, continuous on

• Data Rates to 10kbps (Manchester Encoded)

• Auto polling (sleep mode, current < 0.1 mA)

• Analog RSSI Output

• Programmable “Low Sensitivity” mode

• No IF filter required

• Excellent selectivity and noise rejection

• Low external part count

• Additional Functions Programmed through serial

interface

Ordering Information

Part Number

Temperature Range

Package

MICRF221AYQS

–40° to +105°C

16-Pin QSOP

Typical Application

Figure 1: MICRF221 Receiver 915.0 MHz, 1kHz Baud Rate Example

October 2008

M9999-100108

(408) 955-1690