High Performance Narrowband

ISM Transceiver IC

Preliminary Technical Data

ADF7021

FEATURES

Low power, low IF transceiver

Frequency bands

80 MHz to 650 MHz

862 MHz to 940 MHz

Modulation schemes

2FSK, 3FSK, 4FSK

Spectral shaping

Gaussian and raised-cosine filtering

Data rates supported

0.05 kbps to 25 kbps

2.3 V to 3.6 V power supply

Programmable output power

−16 dBm to +13 dBm in 63 steps

Automatic PA ramp control

Receiver sensitivity

−125 dBm at 1 kbps, 2 FSK

On-chip VCO and fractional-N PLL

On-chip 7-bit ADC and temperature sensor

Fully automatic frequency control loop (AFC)

Digital RSSI

Integrated Tx/Rx switch

Leakage current <1 μA in power-down mode

APPLICATIONS

Narrow-band standards

ETSI EN 300-220, FCC Part 90, FCC Part 15, FCC Part 95,

ARIB STD-T67

Low cost, wireless data transfer

Remote control/security systems

Wireless metering

Private mobile radio

Wireless medical telemetry service (WMTS)

Keyless entry

Home automation

Process and building control

Pagers

FUNCTIONAL BLOCK DIAGRAM

05876-001

Tx/Rx

CONTROL

AFC

CONTROL

2FSK

3FSK

4FSK

DEMODULATOR

CLOCK

AND DATA

RECOVERY

RSSI/

OFFSET

CORRECTION

7-BIT ADC

GAIN

DIV R

RFOUT

LNA

PFD

OSC1 OSC2

DIVIDERS/

MUXING

N/N + 1

DIV P

TEMP

SENSOR

RING OSC

CLK

DIV

CLKOUT

TEST MUX

VCOIN CPOUT

POLARIZATION

LDO(1:4)

MUXOUTRSET

CREG(1:4)

LNA

FIN

FINB

DATA CLK | TxDATA

SWD

DATA I/O | RxDATA

SERIAL

PORT

SLE

SDATA

SREAD

SCLK

IF FILTER

Σ-Δ

MODULATOR

PA RAMP

L1 L2

VCO

MUX

2FSK

3FSK

4FSK

MOD CONTROL

GAUSSIAN/

RAISED COSINE

FILTER

3FSK

ENCODING

AGC

CONTROL

MUX

Figure 1.

Rev. PrI

Information furnished by Analog Devices is believed to be accurate and reliable. However, no

responsibility is assumed by Analog Devices for its use, nor for any infringements of patents or other

rights of third parties that may result from its use. Specifications subject to change without notice. No

license is granted by implication or otherwise under any patent or patent rights of Analog Devices.

Trademarks and registered trademarks are the property of their respective owners.

One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A.

Tel: 781.329.4700 www.analog.com

ADF7021 Preliminary Technical Data

Rev. PrI | Page 2 of 44

TABLE OF CONTENTS

Features .............................................................................................. 1

Applications....................................................................................... 1

Functional Block Diagram .............................................................. 1

General Description......................................................................... 3

Specifications..................................................................................... 4

Timing Characteristics..................................................................... 7

Absolute Maximum Ratings............................................................ 9

ESD Caution.................................................................................. 9

Pin Configuration and Function Descriptions........................... 10

Frequency Synthesizer ................................................................... 12

Reference Input........................................................................... 12

MUXOUT.................................................................................... 13

Voltage Controlled Oscillator (VCO) ...................................... 14

Choosing Channels for Best System Performance................. 14

Transmitter ...................................................................................... 15

RF Output Stage.......................................................................... 15

Modulation Schemes.................................................................. 15

Spectral Shaping ......................................................................... 17

Modulation and Filtering Options........................................... 17

Receiver Section.............................................................................. 18

RF Front End............................................................................... 18

RSSI/AGC.................................................................................... 19

FSK Demodulators on the ADF7021....................................... 19

FSK Correlator/Demodulator................................................... 19

Linear 2FSK Demodulator ........................................................ 21

3FSK Demodulator..................................................................... 21

4FSK Demodulator..................................................................... 21

AFC Section ................................................................................ 21

Automatic Sync Word Recognition ......................................... 22

Applications..................................................................................... 23

LNA/PA Matching...................................................................... 23

Transmit Protocol and Coding Considerations ..................... 24

Device Programming after Initial Power-Up ........................... 24

Interfacing to Microcontroller/DSP ........................................ 26

Serial Interface ................................................................................ 27

Readback Format........................................................................ 27

Outline Dimensions....................................................................... 44

Ordering Guide .......................................................................... 44

Preliminary Technical Data ADF7021

Rev. PrI | Page 3 of 44

GENERAL DESCRIPTION

The ADF7021 is a low power, highly integrated 2FSK/3FSK/4FSK

transceiver. It is designed to operate in the narrow-band,

license-free ISM bands and licensed bands in the 80 MHz to

650 MHz and 862 MHz to 940 MHz frequency ranges. It has

both Gaussian and raised cosine data filtering options to

improve spectral efficiency for narrow-band applications.

It is suitable for circuit applications targeted at European

ETSI-EN 300-220, the Japanese ARIB STD-T67, the Chinese

Short Range Device regulations, and the North American FCC

Part 15, Part 90, and Part 95 regulatory standards. A complete

transceiver can be built using a small number of external

discrete components, making the ADF7021 very suitable for

price-sensitive and area-sensitive applications.

The transmit section contains a voltage controlled oscillator

(VCO) and a low noise fractional-N PLL with output resolution

of <1 ppm. This frequency-agile PLL allows the ADF7021 to be

used in frequency hopping spread spectrum (FHSS) systems.

The VCO operates at twice the fundamental frequency to

reduce spurious emissions and frequency pulling problems.

The transmitter output power is programmable in 63 steps from

−16 dBm to +13 dBm and has an automatic power ramp control

to prevent spectral splatter and help meet regulatory standards.

The transceiver RF frequency, channel spacing, and modulation

are programmable using a simple 3-wire interface. The device

operates with a power supply range of 2.3 V to 3.6 V and can be

powered down when not in use.

A low IF architecture is used in the receiver (100 kHz),

minimizing power consumption and the external component

count while avoiding interference problems at low frequencies.

The IF filter has programmable bandwidths of 12.5 kHz,

18.75 kHz, and 25 kHz. The ADF7021 supports a wide variety

of programmable features including Rx linearity, sensitivity, and

IF bandwidth, allowing the user to trade off receiver sensitivity

and selectivity against current consumption, depending on the

application. The receiver also features a patent-pending

automatic frequency control (AFC) loop with programmable

pull-in range, allowing the PLL to track out the frequency error

in the incoming signal.

An on-chip ADC provides readback of an integrated tempera-

ture sensor, an external analog input, the battery voltage, and

the RSSI signal, which provides savings on an ADC in some

applications. The temperature sensor is accurate to ±10°C over

the full operating temperature range of −40°C to +85°C. This

accuracy can be improved by doing a 1-point calibration at

room temperature and storing the result in memory.

Part #	ADF7021BCPZ
Description	RF TRNSCVR MSK/FSK 2.5V/3.3V48LFCSP EP - Trays
Category	IC
Availability	In Stock
Qty	119

Qty	Price
1 - 24	$4.54612
25 - 49	$3.61623
50 - 74	$3.40959
75 - 99	$3.16851
100 +	$2.82410

Manufacturer	Available	Qty
Analog Devices Date Code: 1048	Freelance Stock: 19 Ships Immediately
Analog Devices Date Code: 1203	Freelance Stock: 100 Ships Immediately

ADF7021BCPZ

Related Items

Technical Document