MICRF620
434MHz ISM Band Transceiver Module
General Description
The MICRF620 is a self-contained frequency shift keying
(FSK) transceiver module, intended for use in half-duplex,
bidirectional RF links. The multi-channeled FSK
transceiver module is intended for UHF radio equipment in
compliance with the European Telecommunication
Standard Institute (ETSI) specification, EN300 220.
The transmitter consists of a fully programmable PLL
frequency synthesizer and power amplifier. The frequency
synthesizer consists of a voltage-controlled oscillator
(VCO), a crystal oscillator, dual modulus prescaler,
programmable frequency dividers, and a phase-detector.
The output power of the power amplifier can be
programmed to seven levels. A lock-detect circuit detects
when the PLL is in lock.
In receive mode, the PLL synthesizer generates the local
oscillator (LO) signal. The N, M, and A values that give the
LO frequency are stored in the N0, M0, and A0 registers.
The receiver is a zero intermediate frequency (IF) type that
makes channel filtering possible with low-power, integrated
low-pass filters. The receiver consists of a low noise
amplifier (LNA) that drives a quadrature mix pair. The
mixer outputs feed two identical signal channels in phase
quadrature. Each channel includes a pre-amplifier, a third
order Sallen-Key RC low-pass filter that protects the
following switched-capacitor filter from strong adjacent
channel signals, and a limiter. The main channel filter is a
switched-capacitor implementation of a six-pole elliptic low
pass filter. The cut-off frequency of the Sallen-Key RC filter
can be programmed to four different frequencies: 100kHz,
150kHz, 230kHz, and 350kHz. The I and Q channel
outputs are demodulated and produce a digital data
output. The demodulator detects the relative phase of the I
and the Q channel signal. If the I channel signal lags
behind the Q channel, the FSK tone frequency is above
the LO frequency (data “1”). If the I channel leads the Q
channel, then the FSK tone is below the LO frequency
(data “0”). The output of the receiver is available on the
DataIXO pin. A receive signal strength indicator (RSSI)
circuit indicates the received signal level. All support
documentation can be found on Micrel’s web site at:
www.micrel.com.
RadioWire® Module
Features
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“Drop in” RF solution
Small size: 11.5x14.1mm
RF tested
Low Power
Surface Mountable
Tape & Reel
Digital Bit Synchronizer
Received Signal Strength Indicator (RSSI)
RX and TX power management
Power down function
Register read back function
Applications
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Telemetry
Remote metering
Wireless controller
Remote data repeater
Remote control systems
Wireless modem
Wireless security system
RadioWire® is a 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
July 2006
M9999-120205
Micrel, Inc.
MICRF620/MICRF620Z
Contents
General Description ................................................................................................................................................................ 1
Features .................................................................................................................................................................................. 1
Applications ............................................................................................................................................................................. 1
Contents .................................................................................................................................................................................. 2
RadioWire® RF Module Selection Guide................................................................................................................................. 3
Ordering Information ............................................................................................................................................................... 3
Block Diagram ......................................................................................................................................................................... 3
Pin Configuration..................................................................................................................................................................... 4
Pin Description ........................................................................................................................................................................ 4
Absolute Maximum Ratings(1) ................................................................................................................................................. 5
Operating Ratings(2) ................................................................................................................................................................ 5
Electrical Characteristics......................................................................................................................................................... 5
Programming........................................................................................................................................................................... 7
General ............................................................................................................................................................................... 7
Writing to the Control Registers in MICRF620 ................................................................................................................... 8
Writing to a Single Register ................................................................................................................................................ 8
Writing to All Registers ....................................................................................................................................................... 8
Writing to n Registers Having Incremental Addresses ....................................................................................................... 9
Reading from the Control Registers in MICRF620 ............................................................................................................. 9
Reading n Registers from MICRF620................................................................................................................................. 9
Programming Interface Timing.............................................................................................................................................. 10
Power on Reset ................................................................................................................................................................ 11
Programming Summary.................................................................................................................................................... 11
Frequency Synthesizer ......................................................................................................................................................... 12
Crystal Oscillator (XCO) ................................................................................................................................................... 12
VCO .................................................................................................................................................................................. 12
Lock Detect ....................................................................................................................................................................... 13
Modes of Operation............................................................................................................................................................... 13
Transceiver Sync/Non-Synchronous Mode ...................................................................................................................... 14
Data Interface ................................................................................................................................................................... 14
Receiver ................................................................................................................................................................................ 14
Front End .......................................................................................................................................................................... 15
Sallen-Key Filters.............................................................................................................................................................. 15
Switched Capacitor Filter.................................................................................................................................................. 15
RSSI.................................................................................................................................................................................. 16
FEE ................................................................................................................................................................................... 16
Bit Synchronizer................................................................................................................................................................ 17
Transmitter ............................................................................................................................................................................ 17
Power Amplifier................................................................................................................................................................. 17
Frequency Modulation ...................................................................................................................................................... 17
Using the XCO-tune Bits ....................................................................................................................................................... 17
Application Circuit Illustration ................................................................................................................................................ 18
Assembling the MICRF620 ................................................................................................................................................... 19
Recommended Reflow Temperature Profile .................................................................................................................... 19
Shock/Vibration during Reflow.......................................................................................................................................... 19
Handassembling the MICRF620....................................................................................................................................... 19
Layout.................................................................................................................................................................................... 19
Recommended Land Pattern............................................................................................................................................ 19
Layout Considerations ...................................................................................................................................................... 20
Package Dimensions ............................................................................................................................................................ 21
Tape Dimensions .................................................................................................................................................................. 21
July 2006
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Micrel, Inc.
MICRF620/MICRF620Z
RadioWire® RF Module Selection Guide
Device
MICRF600
Frequency
Range
Data Rate
Receive
Supply
Voltage
Transmit
Modulation
Type
Package
902-928 MHz
-129 = +127
CS
2) 126
CS
18k
3) 125
3k3
SCLK
To avoid this situation, always make sure max count is
between limits.
SCLK
18k
3k3
Application Circuit Illustration
IO
IO
18k
15k
DATAIXO
DATAIXO
DATACLK
DATACLK
LD
RSSI
LD
RSSI
Figure 12. How to connect MICRF620 (2.5V) and MCU (3.0V)
Figure 11. Circuit illustration of MICRF620, LDO and MCU
Figure 12 shows a typical set-up with the MICRF620, a
Low-Drop-Out voltage regulator (LDO) and a mikrocontroller (MCU). When the MICRF620 and the MCU runs
on the same power supply (min 2.0, max. 2.5V), the IO
can be connected directly to the MCU. If the MCU needs a
higher VDD than the max. specified VDD of the MICRF620
(2.5V), voltage dividers need to be added on the IO lines
not to override the max. input voltage.
Figure 11 shows a recommended voltage divider circuit for
a MCU running at 3.0V and the MICRF620 at 2.5V.
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Micrel, Inc.
MICRF620/MICRF620Z
Assembling the MICRF620
Layout
Recommended Reflow Temperature Profile
When the MICRF620 module is being automatically
assembled to a PCB, care must be taken not to expose
the module for temperature above the maximum specified.
Figure 13 shows the recommended reflow temperature
profile.
Recommended Land Pattern
Figure 14 shows a recommended land pattern that
facilitates both automatic and hand assembling.
Figure 14. Recommended Land Pattern (TOP VIEW)
Figure 13. Recommended Reflow Temperature Reflow
Shock/Vibration during Reflow
The module has several components inside which are
assembled in a reflow process. These components may
reflow again when the module is assembled onto a PCB. It
is therefore important that the module is not subjected to
any mechanical shock or vibration during this process.
Handassembling the MICRF620
It is recommended to use solder paste also during hand
assembling of the module. Because of the module ground
pad on the bottom side, the module will be assembled
most efficient if the heat is being subjected to the bottom
side of the PCB. The heat will be transferred trough the
PCB due the ground vias under the module (see Layout
Considerations). In addition, it is recommended to use a
solder tip on the signal and power pads, to make sure the
solder points are properly melted.
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Micrel, Inc.
MICRF620/MICRF620Z
low noise LDO’s with high PSSR should be
chosen. What is present on the voltage supply will
be directly modulated to the RF spectrum causing
degradation and regulatory issues. To make sure
you have the right selection, please contact local
sales for the latest Micrel offerings in power
management and guidance. To avoid “pickup”
from other circuitry on the VDD lines, it is
recommended to route the VDD in a star
configuration with decoupling at each circuitry and
at the common connection point (see above
layout). If there are noisy circuitry in the design, it
is strongly recommended to use a separate power
supply and/or place low value resistors (10ohms),
inductors in series with the power supply line into
these circuitry.
Layout Considerations
Except for the antenna input/output signal, only digital and
low frequency signals need to interface with the module.
There is therefore no need of years of RF expertise to do a
successful layout, as long as the following few points are
being followed:
•
Proper ground is needed. If the PCB is 2-layer, the
bottom layer should be kept only for ground. Avoid
signal traces that split the ground plane. For a 4layer PCB, it is recommended to keep the second
layer only for ground.
•
A ground via should be placed close to all the
ground pins. The bottom ground pad should be
penetrated with 4-16 ground vias.
•
The antenna has an impedance of ~50 ohm. The
antenna trace should be kept to 50 ohm to avoid
signal reflection and loss of performance. Any
transmission line calculator can be used to find the
needed trace width given a board build up. Ex: A
trace width of 44 mil (1.12 mm) gives 50
impedance on a FR4 board (dielectric cons=4.4)
with copper thickness of 35µm and height (layer 1layer 2 spacing) of 0.61 mm.
•
RF circuitry is sensitive to voltage supply and
therefore caution should be taken when choosing
power circuitry. To achieve the best performance,
July 2006
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Digital high speed logic or noisy circuitry
should/must be at a safe distance from RF
circuitry or RF VDD as this might/will cause
degradation of sensitivity and create spurious
emissions. Example of such circuitry is LCD
display, charge pumps, RS232, clock / data bus
etc.
M9999-120205
Micrel, Inc.
MICRF620/MICRF620Z
Package Dimensions
Figure 15. Package Dimensions
Tape Dimensions
Figure 16. Tape Dimensions
MICREL, INC. 2180 FORTUNE DRIVE SAN JOSE, CA 95131 USA
TEL +1 (408) 944-0800 FAX +1 (408) 474-1000 WEB http:/www.micrel.com
The information furnished by Micrel in this data sheet is believed to be accurate and reliable. However, no responsibility is assumed by Micrel for its
use. Micrel reserves the right to change circuitry and specifications at any time without notification to the customer.
Micrel Products are not designed or authorized for use as components in life support appliances, devices or systems where malfunction of a product
can reasonably be expected to result in personal injury. Life support devices or systems are devices or systems that (a) are intended for surgical implant
into the body or (b) support or sustain life, and whose failure to perform can be reasonably expected to result in a significant injury to the user. A
Purchaser’s use or sale of Micrel Products for use in life support appliances, devices or systems is a Purchaser’s own risk and Purchaser agrees to fully
indemnify Micrel for any damages resulting from such use or sale.
© 2005 Micrel, Incorporated.
July 2006
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