1
Features
•RF Frequency Range of 250 – 450 MHz
•6 dBm RF Output into Matched Antenna
•RF Output Power Adjustable in 1 dB Steps
•Phase-Locked Loop (PLL) Based Frequency Synthesizer
•Data Bandwidth of up to 20 Kb/s
•Operates Down to 2V from a CR2032/CR2016 LiMnO2 Battery
•8-bit AVR® RISC Microcontroller Core Compatible with ATmega163
•Minimal External Components
•Space-saving 20-lead TSSOP
•2 KB (1K x 16b) of Flash Program Memory
•128 Bytes of EEPROM
•In-System Programmable Data and Program Memory
•6 I/O (Serial I/F, LED Drive Outputs, Button Input Interrupts)
•Low Battery Detect and Brownout Protection
Applications
•Remote Keyless Entry (RKE) Transmitters
•Wireless Security Systems
•Home appliance control (Gas Fireplace, Ceiling Fans)
•Radio Remote Control (Hobby, Toys)
•Garage Door Openers
•Wireless PC Peripherals (Keyboard, Mouse)
•Telemetry (Tire Pressure, Utility Meter, Asset Tracking)
Description
The Atmel AT86RF401 SmartRF™ MicroTransmitter™ is a highly-integrated, low-cost
RF transmitter, combined with an AVR® RISC microcontroller. It requires only an inex-
pensive crystal, a single LiMnO2 coin cell (CR2032 or similar), an inductor, and a
tuned loop antenna to implement a complete On-Off Keyed (OOK) wireless RF data
transmitter.
Block Diagram
PHASE
DETECTOR
OSCILLATOR LOOP
FILTER VCO
PRESCALER
÷
24
RF
AMP
LOOP FIL
CLOCK
RESET
WATCHDOG
LOW-VOLTAGE DETECT
BROWN-OUT PROTECT
AVR RISC Microcontroller
2 KB Flash Program Memory
128 Bytes EEPROM Data Memory
L1
L2
DATA GAIN
TRIM
POWER
SUPPLY
SUPERVISOR
XTAL
XTALB
AVDD
AGND
ANT
ANTB
B+
DVDD
DGND
IO5
IO4
IO3
SCK/IO2
SDO/IO1
SDI/IO0
RESETB
CFIL
SmartRF™
Wireless Data
Transmitter
AT86RF401
Preliminary
Rev. 1424A–10/00
AT86RF401
2
In-system, programmable, nonvolatile Flash program mem-
ory and EEPROM data storage makes possible rapid time
to market and lower inventory costs.
Static current consumption is kept to a minimum with an
ultra low current shutdown mode. Normal operation
resumes when a button is pressed. This activates the crys-
tal oscillator circuit which serves as the clock for the AVR®
microcontroller. The RF carrier is synthesized utilizing an
on-board voltage controlled oscillator (VCO). Its accuracy
is maintained with a phase-locked loop detector which
compares the crystal oscillator to a frequency-scaled ver-
sion (divided by 24) of the RF carrier. The resulting error
signal adjusts the VCO to produce a very stable RF carrier.
An interrupt-based bit-timer structure, integral to the AVR®
microcontroller, simplifies the implementation of user spe-
cific, data bit encoding routines, such as PWM or
Manchester, for modulating the RF carrier. The RF signal
output is placed differentially on a tuned loop antenna,
which may be realized as a counterspread copper trace on
a PCB.
The AT86RF401 is fabricated in Atmel’s 0.6 µm mixed sig-
nal CMOS + EEPROM process enabling true system-level
integration (SLI).
A masked ROM version of this part is planned for high-
volume OEM applications.
Pin Configuration
20-lead TSSOP
1
2
3
4
5
6
7
8
9
10
ANTB
LOOPFIL
L1
L2
RESETB
NC
SDI/IO0
SDO/IO1
SCK/IO2
XTAL
20
19
18
17
16
15
14
13
12
11
ANT
CFIL
AVDD
DVDD
AGND
DGND
IO5
IO4
IO3
XTALB/CLK
© Atmel Corporation 2000.
Atmel Corporation makes no warranty for the use of its products, other than those expressly contained in the Company’s standard war-
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not authorized for use as critical components in life support devices or systems.
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1424A–10/00/xM
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