Micrel MICRF211AYQS 3v, qwikradioâ® 433.92 mhz receiver Datasheet

MICRF211
3V, QwikRadio® 433.92 MHz Receiver
General Description
Features
The MICRF211 is a general purpose, 3V QwikRadio
Receiver that operates at 433.92MHz with typical
sensitivity of -110dBm.
The MICRF211 functions as a super-heterodyne
receiver for OOK and ASK modulation up to 10kbps.
The down-conversion mixer also provides image
rejection. All post-detection data filtering is provided on
the MICRF211. Any one-of-four filter bandwidths may
be selected externally by the user in binary steps, from
1.25kHz to 10kHz. The user need only configure the
device with a set of easily determined values, based
upon data rate, code modulation format, and desired
duty-cycle operation.
•
•
•
•
•
•
•
•
–110 dBm sensitivity, 1kbps and BER 10E-02
Image Rejection Mixer
Frequency from 380MHz to 450MHz
Low power, 6.0mA @ 433.92MHz, continuous on
data rates to 10kbps (Manchester Encoded)
Analog RSSI Output
No IF filter required
Excellent selectivity and noise rejection
Low external part count
Ordering Information
Part Number
Temperature Range
Package
MICRF211AYQS
–40° to +105°C
16-Pin QSOP
_______________________________________________________________________________________________
Typical Application
433.92 MHz, 1kHz Baud Rate Example
QwikRadio is a registered trademark of Micrel, Inc.
Certain of the QwikRadio ICs were developed under a development agreement with AIT of Orlando, FL.
Micrel Inc. • 2180 Fortune Drive • San Jose, CA 95131 • USA • tel +1 (408) 944-0800 • fax + 1 (408) 474-1000 • http://www.micrel.com
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MICRF211
Pin Configuration
MICRF211AYQS
Pin Description
16-Pin
QSOP
Pin
Name
1
RO1
2
GNDRF
3
ANT
4
GNDRF
5
VDD
Pin Function
Reference resonator input connection to Colpitts oscillator stage. May also be driven by external reference
signal of 1.5V p-p amplitude maximum.
Negative supply connection associated with ANT RF input.
RF signal input from antenna. Internally AC coupled. It is recommended that a matching network with an
inductor -to-RF ground is used to improve ESD protection.
Negative supply connection associated with ANT RF input.
Positive supply connection for all chip functions.
6
SQ
7
SEL0
Logic control input with active internal pull-up. Used in conjunction with SEL1 to control the demodulator low
pass filter bandwidth. (See filter table for SEL0 and SEL1 in application section)
8
SHDN
Shutdown logic control input. Active internal pull-up.
9
GND
10
DO
11
SEL1
Logic control input with active internal pull-up. Used in conjunction with SEL0 to control the demodulator low
pass filter bandwidth. (See filter table for SEL0 and SEL1 in application section)
12
CTH
Demodulation threshold voltage integration capacitor connection. Tie an external capacitor across CTH pin
and GND to set the settling time for the demodulation data slicing level. Values above 1nF are
recommended and should be optimized for data rate and data profile.
13
CAGC
AGC filter capacitor connection. CAGC capacitor, normally greater than 0.47µF, is connected from this pin to
GND
14
RSSI
Received signal strength indication output. Output is from a buffer with 200Ω typical output impedance.
15
NC
16
RO2
March 2007
Squelch control logic input with an active internal pull-up when not shut down.
Negative supply connection for all chip functions except RF input.
Demodulated data output.
Not Connected (Connect to Ground)
Reference resonator input connection to Colpitts oscillator stage, 7pF, in parallel with low resistance MOS
switch-to-GND, during normal operation. Driven by startup excitation circuit during the internal startup control
sequence.
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MICRF211
Absolute Maximum Ratings(1)
Operating Ratings(2)
Supply Voltage (VDD) .................................................+5V
Input Voltage .............................................................+5V
Junction Temperature ......................................... +150ºC
Lead Temperature (soldering, 10sec.) .................. 260°C
Storage Temperature (TS) .....................-65ºC to +150°C
Maximum Receiver Input Power ........................+10dBm
ESD Rating(3) .................................................. 2KV CDM
...................................................200V HBM
................................ 100V Machine Model
Supply voltage (VDD) ..............................+3.0V to +3.6V
Ambient Temperature (TA) ................. –40°C to +105°C
Input Voltage (VIN)........................................ 3.6V (Max)
Maximum Input RF Power................................ –20dBm
Electrical Characteristics(4)
Specifications apply for 3.0V < VDD < 3.6V, VSS = 0V, CAGC = 4.7µF, CTH = 0.1µF, fRX = 433.92 MHz, unless otherwise
noted. Bold values indicate –40°C – TA – 105°C. 1kbps data rate (Manchester encoded), reference oscillator
frequency = 13.52127MHz.
Symbol
ISS
ISHUT
Parameter
Condition
Min
Operating Supply
Current
Continuous Operation, fRX = 433.92MHz
Typ
Max
Units
6.0
mA
0.5
µA
20
dB
1.2
MHz
fRX = 433.92MHz (matched to 50 Ω)
BER=10-2
-110
dBm
fRX = 433.92MHz
330
kHz
fRX = 433.92MHz
19 –
j174
Ω
Shut down Current
RF/IF Section
Image Rejection
st
1 IF Center
Frequency
Receiver Sensitivity @
1kbps
IF Bandwidth
Antenna Input
Impedance
Receive Modulation
Duty Cycle
AGC Attack / Decay
Ratio
AGC pin leakage
current
AGC Dynamic Range
fRX = 433.92MHz
Note 5
20
tATTACK / tDECAY
80
%
0.1
TA = 25ºC
TA = +105ºC
RFIN @ -40dBm
RFIN @ -100dBm
±2
± 800
1.15
1.70
nA
nA
V
V
13.52127
MHz
300
kΩ
Reference Oscillator
Reference Oscillator
Frequency
Reference Oscillator
Input Impedance
Reference Oscillator
Input Range
Reference Oscillator
Source Current
March 2007
fRX = 433.92 MHz
Crystal Load Cap = 10pF
0.2
V(REFOSC) = 0V
1.5
3.5
3
Vp-p
µA
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MICRF211
Demodulator
Symbol
Parameter
Condition
CTH Source
Impedance
CTH Leakage Current
FREFOSC = 13.52127MHz
Demodulator Filter
Bandwidth @ 434MHz
Min
TA = 25ºC
TA = +105ºC
Programmable, see application section
Typ
Max
Units
120
kΩ
±2
± 800
nA
nA
Hz
1625
13000
Digital / Control Functions
DO pin output current
260
600
2
µsec
0.4 to 2
V
25
mV/dB
RSSI Output Current
400
µA
RSSI Output
Impedance
RSSI Response Time
200
Ω
0.3
sec
Output rise and fall
times
As output
source @ 0.8 Vdd
sink @ 0.2 Vdd
CI = 15pF, pin DO, 10-90%
µA
RSSI
RSSI DC Output
Voltage Range
RSSI response slope
Note 1.
-110dBm to -40dBm
50% data duty cycle, input power to
Antenna = -20dBm
Exceeding the absolute maximum rating may damage the device.
Note 2.
The device is not guaranteed to function outside of its operating rating.
Note 3.
Device is ESD sensitive. Use appropriate ESD precautions. Exceeding the absolute maximum rating may damage the device.
Note 4.
Sensitivity is defined as the average signal level measured at the input necessary to achieve 10-2 BER (bit error rate). The input signal is
defined as a return-to-zero (RZ) waveform with 50% average duty cycle (Manchester encoded) at a data rate of 1kbps.
Note 5.
When data burst does not contain preamble, duty cycle is defined as total duty cycle, including any “quiet” time between data bursts. When
data bursts contain preamble sufficient to charge the slice level on capacitor CTH, then duty cycle is the effective duty cycle of the burst
alone. [For example, 100msec burst with 50% duty cycle, and 100msec “quiet” time between bursts. If burst includes preamble, duty
cycle is TON/(TON+tOFF)= 50%; without preamble, duty cycle is TON/(TON+ TOFF + TQUIET) = 50msec/(200msec)=25%. TON is the (Average
number of 1’s/burst) × bit time, and TOFF = TBURST – TON.)
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MICRF211
Typical Characteristics
Sensitivity Graphs
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Functional Diagram
Figure 1. Simplified Block Diagram.
is set to 32 times the crystal reference frequency via a
phase-locked loop synthesizer with a fully integrated
loop filter.
Functional Description
Figure 1. Simplified Block Diagram that illustrates the
basic structure of the MICRF211. It is made of three
sub-blocks; Image Rejection UHF Down-converter, the
OOK Demodulator, and Reference and Control Logics.
Outside the device, the MICRF211 requires only three
components to operate: two capacitors (CTH, and
CAGC) and the reference frequency device, usually a
quartz crystal. An additional five components may be
used to improve performance. These are: power supply
decoupling capacitor, two components for the matching
network, and two components for the pre-selector band
pass filter.
Image Reject Filter and Band-Pass Filter
The IF ports of the mixer produce quadrature down
converted IF signals. These IF signals are low-pass
filtered to remove higher frequency products prior to the
image reject filter where they are combined to reject the
image frequencies. The IF signal then passes through a
third order band pass filter. The IF center frequency is
1.2MHz. The IF BW is 330kHz @ 433.92MHz, and this
varies with RF operating frequency. The IF BW can be
calculated via direct scaling:
Receiver Operation
⎛ Operating Freq (MHz) ⎞
⎟
433.92
⎠
⎝
BWIF = [email protected] MHz × ⎜
LNA
The RF input signal is AC-coupled into the gate circuit of
the grounded source LNA input stage. The LNA is a
Cascoded NMOS.
These filters are fully integrated inside the MICRF211.
After filtering, four active gain controlled amplifier stages
enhance the IF signal to proper level for demodulation.
OOK Demodulator
The demodulator section is comprised of detector,
programmable low pass filter, slicer, and AGC
comparator.
Mixers and Synthesizer
The LO ports of the Mixers are driven by quadrature
local oscillator outputs from the synthesizer block. The
local oscillator signal from the synthesizer is placed on
the low side of the desired RF signal to allow
suppression of the image frequency at twice the IF
frequency below the wanted signal. The local oscillator
March 2007
Detector and Programmable Low-Pass Filter
The demodulation starts with the detector removing the
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MICRF211
When the output signal is less than 750mV thresh-hold,
1.5µA current is sourced into the external CAGC
capacitor. When the output signal is greater than
750mV, a 15µA current sink discharges the CAGC
capacitor.
The voltage developed on the CAGC
capacitor acts to adjust the gain of the mixer and the IF
amplifier to compensate for RF input signal level
variation.
carrier from the IF signal. Post detection, the signal
becomes base band information. The programmable
low-pass filter further enhances the base band
information. There are four programmable low-pass
filter BW settings: 1625Hz, 3250Hz, 6500Hz, 13000Hz
for 433.92MHz operation. Low pass filter BW will vary
with RF Operating Frequency. Filter BW values can be
easily calculated by direct scaling. See equation below
for filter BW calculation:
Reference Control
There are 2 components in Reference and Control subblock: 1) Reference Oscillator and 2) Control Logic
through parallel Inputs: SEL0, SEL1, SHDN
⎛ Operating Freq (MHz) ⎞
BWOperating Freq = [email protected]* ⎜
⎟
433.92
⎝
⎠
It is very important to choose the filter setting that best
fits the intended data rate to minimize data distortion.
Demod BW is set at 13000Hz @ 433.92MHz as default
(assuming both SEL0 and SEL1 pins are floating). The
low pass filter can be hardware set by external pins
SEL0 and SEL1.
SEL0
SEL1
0
0
1625Hz
1
0
3250Hz
0
1
6500Hz
1
1
13000Hz
Reference Oscillator
Demod BW (@ 434MHz)
- default
Table 1: Demodulation BW Selection
Slicer, Slicing Level and Squelch
The signal prior to slicer is still linear demodulated AM.
Data slicer converts this signal into digital “1”s and “0”s
by comparing with the threshold voltage built up on the
CTH capacitor.
This threshold is determined by
detecting the positive and negative peaks of the data
signal and storing the mean value. Slicing threshold
default is 50%. After the slicer the signal is now digital
OOK data.
During long periods of “0”s or no data period, threshold
voltage on the CTH capacitor may be very low. Large
random noise spikes during this time may cause
erroneous “1”s at DO pin. Squelch pin when pull down
low will suppress these errors.
Figure 2: Reference Oscillator Circuit
The reference oscillator in the MICRF211 (Figure 2)
uses a basic Colpitts crystal oscillator configuration with
MOS transconductor to provide negative resistance. All
capacitors shown in Figure 2 are integrated inside
MICRF211.
R01 and R02 are external pins of
MICRF211. User only needs to connect reference
oscillation crystal.
Reference oscillator crystal frequency can be calculated:
FREF OSC = FRF/(32 + 1.1/12)
For 433.92 MHz, FREF OSC = 13.52127 MHz.
To operate the MICRF211 with minimum offset, crystal
frequencies should be specified with 10pF loading
capacitance.
AGC Comparator
The AGC comparator monitors the signal amplitude
from the output of the programmable low-pass filter.
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MICRF211
Application Information
Figure 3 – QR211HE1 Application Example, 433.92 MHz
The MICRF211 can be fully tested by using one of
many evaluation boards designed at Micrel for this
device. As an entry level, the QR211HE1 (Figure 3)
offers a good start for most applications. It has a
helical PCB antenna with its matching network, a
band-pass-filter front-end as a pre-selector filter,
matching network and the minimum components
required to make the device work, which are a crystal,
Cagc, and Cth capacitors. By removing the matching
network of the helical PCB antenna (C9 and L3), a
whip antenna (ANT2) or a RF connector (J2) can be
used instead. Figure 3 shows the entire schematic of
it for 433.92MHz. Other frequencies can be used and
the values needed are in the tables below.
Capacitor C9 and inductor L3 are the passive
elements for the helical PCB matching network. A
tight tolerance is recommended for these devices, like
2% for the inductor and 0.1pF for the capacitor. PCB
variations may require different values and
optimization. Table 2 shows the matching elements
for the device frequency range. For additional
information look for Small PCB Antennas for Micrel RF
Products application note.
Freq (MHz)
C9 (pF)
L3(nH)
390.0
1.2
43
418.0
1.2
36
433.92
1.5
30
which reduces the receiver performance. It is
calculated by the parallel resonance equation
f = 1/(2×PI×(SQRT L1×C8)). Table 3 shows the most
used frequency values.
Freq (MHz)
L1(nH)
390.0
6.8
24
418.0
6.0
24
433.92
5.6
24
Table 3. Band-Pass-Filter Front-End Values
There is no need for the band-pass-filter front-end for
applications where it is proven that the outside band
noise does not cause a problem. The MICRF211 has
image reject mixers which improve significantly the
selectivity and rejection of outside band noise.
Capacitor C3 and inductor L2 form the L-shape
matching network. The capacitor provides additional
attenuation for low frequency outside band noise and
the inductor provides additional ESD protection for the
antenna pin. Two methods can be used to find these
values, which are matched close to 50Ω. One method
is done by calculating the values using the equations
below and another by using a Smith chart. The latter
is made easier by using software that plots the values
of the components C8 and L1, like WinSmith by Noble
Publishing.
To calculate the matching values, one needs to know
the input impedance of the device. Table 4 shows the
input impedance of the MICRF211 and suggested
matching values for the most used frequencies. These
suggested values may be different if the layout is not
exactly the same as the one made here.
Table 2. Matching Values for the Helical PCB Antenna
To use another antenna, like the whip kind, remove
C9 and place the whip antenna in the hole provided in
the PCB. Also, a RF signal can be injected there.
L1 and C8 form the pass-band-filter front-end. Its
purpose is to attenuate undesired outside band noise
March 2007
C8 (pF)
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MICRF211
C3 (pF)
L2(nH)
Z device (Ω)
Figure 4: device’s input impedance, Z = 18.6 – j174.2Ω
390.0
1.5
47
22.5 – j198.5
418.0
1.5
43
21.4 – j186.1
433.92
1.5
39
18.6 – j174.2
Second, we plot the shunt inductor (39nH) and the
series capacitor (1.5pF) for the desired input
impedance (Figure 5). We can see the matching
leading to the center of the Smith Chart or close to
50Ω.
Freq (MHz)
Table 4: matching values for the most used frequencies
For the frequency of 433.92MHz, the input impedance
is Z = 18.6 – j174.2Ω, then the matching components
are calculated by,
Equivalent parallel = B = 1/Z = 0.606 + j5.68 msiemens
Rp = 1 / Re (B);
Xp = 1 / Im (B)
Rp = 1.65kΩ; Xp = 176.2Ω
Q = SQRT (Rp/50 + 1)
Q = 5.831
Xm = Rp / Q
Xm = 282.98Ω
Resonance Method For L-shape Matching Network
Lc = Xp / (2×Pi×f);
Lp = Xm / (2×Pi×f)
L2 = (Lc×Lp) / (Lc + Lp);
C3 = 1 / (2×Pi×f×Xm)
L2 = 39.8nH
C3 = 1.3pF
Doing the same calculation example with the Smith
Chart, it would appear as follows,
First, we plot the input impedance of the device,
(Z = 18.6 – j174.2)Ω @ 433.92MHz.(Figure 4).
Figure 5. Plotting the Shunt Inductor and Series
Capacitor.
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MICRF211
injection (32 × 13.52127MHz = 432.68MHz), that is,
its frequency is below the RF carrier frequency and
the image frequency is below the LO frequency. See
Figure 6. The product of the incoming RF signal and
local oscillator signal will yield the IF frequency, which
will be demodulated by the detector of the device.
Crystal Y1 or Y1A (SMT or leaded respectively) is the
reference clock for all the device internal circuits.
Crystal characteristics of 10pF load capacitance,
30ppm, ESR < 50Ω, -40ºC to +105ºC temperature
range are desired. Table 5 shows the crystal
frequencies and one of Micrel’s approved crystal
manufacturers (www.hib.com.br).
The oscillator of the MICRF211 is a Colpitts type. It is
very sensitive to stray capacitance loads. Thus, very
good care must be taken when laying out the printed
circuit board. Avoid long traces and ground plane on
the top layer close to the REFOSC pins RO1 and
RO2. When care is not taken in the layout, and
crystals from other vendors are used, the oscillator
may take longer times to start as well as the time to
good data in the DO pin to show up. In some cases, if
the stray capacitance is too high (> 20pF), the
oscillator may not start at all.
The crystal frequency is calculated by REFOSC = RF
Carrier/(32+(1.1/12)). The local oscillator is low side
REFOSC (MHz)
Carrier (MHz)
HIB Part Number
12.15269
390.0
SA-12.152690-F-10-H-30-30-X
13.02519
418.0
SA-13.025190-F-10-H-30-30-X
13.52127
March 2007
Figure 6. Low Side Injection Local Oscillator.
433.92
SA-13.521270-F-10-H-30-30-X
Table 5. Crystal Frequency and Vendor Part Number.
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JP1 and JP2 are the bandwidth selection for the
demodulator bandwidth. To set it correctly, it is
necessary to know the shortest pulse width of the
encoded data sent in the transmitter. Like in the
example of the data profile in the figure 7 below, PW2
is shorter than PW1, so PW2 should be used for the
demodulator bandwidth calculation which is found by
0.65/shortest pulse width. After this value is found, the
setting should be done according to Table 6. For
example, if the pulse period is 100µsec, 50% duty
cycle, the pulse width will be 50µsec (PW = (100µsec
× 50%) / 100). So, a bandwidth of 13kHz would be
necessary (0.65 / 50µsec). However, if this data
stream had a pulse period with 20% duty cycle, the
bandwidth required would be 32.5kHz (0.65 / 20µsec),
which exceeds the maximum bandwidth of the
demodulator circuit. If one tries to exceed the
maximum bandwidth, the pulse would appear
stretched or wider.
SEL0
JP1
SEL1
JP2
Demod.
BW
(hertz)
Shortest
Pulse
(µsec)
Maximum
baud rate for
50% Duty
Cycle (hertz)
Short
Short
1625
400
1250
Open
Short
3250
200
2500
Short
Open
6500
100
5000
Open
Open
13000
50
10000
SEL0
JP1
SEL1
JP2
Demod.
BW
(hertz)
Shortest
Pulse
(µsec)
Maximum
baud rate for
50% Duty
Cycle (Hertz)
Short
Short
1460
445
1123
Open
Short
2921
223
2246
Short
Open
5842
111
4493
Open
Open
11684
56
8987
Table 8. JP1 and JP2 setting, 390.0 MHz.
Capacitors C6 and C4, CTH and CAGC respectively
provide time base reference for the data pattern
received. These capacitors are selected according to
data profile, pulse duty cycle, dead time between two
received data packets, and if the data pattern has or
does not have a preamble. See Figure 7, example of
a data profile.
Figure 7. Example of a Data Profile.
Table 6. JP1 and JP2 setting, 433.92 MHz.
For best results the capacitors should always be
optimized for the data pattern used. As the baud rate
increases, the capacitor values decrease. Table 9
shows suggested values for Manchester Encoded
data, 50% duty cycle.
Other frequencies will have different demodulator
bandwidth limits, which are derived from the reference
oscillator frequency. Table 7 and Table 8 below shows
the limits for the other two most used frequencies.
BW
(hertz)
Shortest
Pulse
(µsec)
Maximum
baud rate for
50% Duty
Cycle (hertz)
SEL0
JP1
SEL1
JP2
Demod.
BW
(hertz)
Cth
Cagc
Short
1565
416
1204
Short
Short
1625
100nF
4.7µF
Open
Short
3130
208
2408
Open
Short
3250
47nF
2.2µF
Short
Open
6261
104
4816
Short
Open
6500
22nF
1µF
9633
Open
Open
13000
10nF
0.47µF
SEL0
JP1
SEL1
JP2
Demod.
Short
Open
Open
12523
52
Table 9. Suggested CTH and CAGC Values.
Table 7. JP1 and JP2 setting, 418.0 MHz.
JP3 is a jumper used to configure the digital squelch
function. When it is high, there is no squelch applied
to the digital circuits and the DO (data out) pin has a
hash signal. When the pin is low, the DO pin activity is
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MICRF211
which form a voltage divider for the AGC pin. One can
force a voltage in this AGC pin to purposely decrease
the device sensitivity. Special care is needed when
doing this operation, as an external control of the AGC
voltage may vary from lot to lot and may not work the
same for several devices.
Three other pins are worthy of comment. They are the
DO, RSSI, and shut down pins. The DO pin has a
driving capability of 0.4mA. This is good enough for
most of the logic family ICs in the market today. The
RSSI pin provides a transfer function of the RF signal
intensity vs voltage. It is very useful to determine the
signal to noise ratio of the RF link, crude range
estimate from the transmitter source and AM
demodulation, which requires a low CAGC capacitor
value.
The shut down pin (SHDN) is useful to save energy.
When its level close to VDD (SHDN = 1), the device is
not in operation. Its DC current consumption is less
than 1µA (do not forget to remove R3). When toggling
from high to low, there will be a time required for the
device to come to steady state mode, and a time for
data to show up in the DO pin. This time will be
dependent upon many things such as temperature,
crystal used, and if the there is an external oscillator
with faster startup time. Normally, with the crystal
vendors suggested, the data will show up in the DO
pin around 1msec time, and 2msec over the
temperature range of the device. When using an
external oscillator or reference oscillator signal, the
time is reduced considerably and can be around
140µsec. See Figures Figure 10 and 11.
considerably reduced. It will have more or less than
shown in the figure below depending on the outside
band noise. The penalty for using squelch is a delay in
getting a good signal in the DO pin, that is, it takes
longer for the data to show up. The delay is
dependent upon many factors such as RF signal
intensity, data profile, data rate, CTH and CAGC
capacitor values, and outside band noise. See Figure
8 and Figure 9 below.
Figure 8. Data Out Pin with No Squelch (SQ = 1).
Figure 9. Data Out Pin with Squelch (SQ = 0).
Other components used are C5, which is a decoupling
capacitor for the Vdd line, R4 reserved for future use
and not needed for the evaluation board, R3 for the
shutdown pin (SHDN = 0, device is operation), which
can be removed if that pin is connected to a
microcontroller or an external switch, R1 and R2
March 2007
Figure 10: Time-to-Good Data After Shut Down Cycle,
Room Temperature.
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MICRF211
Figure 11. Time to Good Data, External Oscillator,
Room Temperature.
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MICRF211
PCB Considerations and Layout
Figure 12 to 17 below show some of the printed circuit
layers for the QR211HE1 board. Use the Gerber files
provided (downloadable from Micrel Website) which
have the remaining layers needed to fabricate this
board. When copying or making your own boards,
make traces as short as possible. Long traces alter
the matching network and the values suggested are
no longer valid. Suggested Matching Values may vary
due to PCB variations. A PCB trace 100 mills (2.5mm)
long has about 1.1nH inductance. Optimization should
always be done with exhaustive range tests. Make
individual ground connections to the ground plane
with a Via for each ground connection. Do not share
Vias with ground connections. Each ground
connection = 1 via or more vias. Ground plane must
be solid and possibly without interruptions. Avoid
ground plane on top next to the matching elements. It
normally adds additional stray capacitance which
changes the matching. Do not use phenolic material,
only FR4 or better materials. Phenolic material is
conductive above 200MHz. RF path should be as
straight as possible avoiding loops and unnecessary
turns. Separate ground and VDD lines from other
circuits (microcontroller, etc). Known sources of noise
should be laid out as far as possible from the RF
circuits. Avoid thick traces, the higher the frequency,
the thinner the trace should be in order to minimize
losses in the RF path.
Figure 12. QR211HE1 Top Layer.
Figure 13. QR211HE1 Bottom Layer, Mirror Image.
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MICRF211
Figure 14. QR211HE1 Top Silkscreen Layer.
Figure 15. QR211HE1 Bottom Silkscreen Layer, Mirror Image.
Figure 16: QR211HE1 Dimensions.
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MICRF211
QR211HE1 Bill of Materials, 433.92 MHz
Item
Part Number
Manufacturer
ANT1
Description
Qty.
Helical PCB Antenna Pattern
ANT2
(np)50-ohm Ant
168mm 20 AWG, rigid wire
1
1
C3,C9
MuRata
1.5pF , 0402/0603
2
C4
Murata / Vishay
0.1µF, 0402/0603
1
C6,C5
Murata / Vishay
0.1µF, 0402/0603
2
C8
Murata
5.6pF, 0402/0603
1
JP1,JP
2
Vishay
short, 0402, 0Ω resistor
2
open, 0402, not placed
1
J2
(np) not placed
1
J3
CON6
1
JP3
L1
Coilcraft / Murata /
ACT1
24nH 5%, 0402/0603
1
L2
Coilcraft / Murata /
ACT1
39nH 5%, 0402/0603
1
L3
Coilcraft / Murata /
ACT1
30nH 2%, 0402/0603
1
(np) 0402, not placed
3
R1,R2,
R4
R3
Vishay
100kΩ
, 0402
1
Y1
HCM49
www.hib.com.br
(np)13.52127MHz Crystal
1
Y1A
HC49
www.hib.com.br
13.52127MHz Crystal
1
U1
MICRF211AYQS
QSOP16
1
Micrel Semiconductor
Table 10. QR211HE1 Bill of Materials, 433.92 MHz.
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MICRF211
Package Information
QSOP16 Package Type (AQS16)
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 at Purchaser’s own risk
and Purchaser agrees to fully indemnify Micrel for any damages resulting from such use or sale.
© 2007 Micrel, Incorporated.
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MICRF211
Revision History
Date
March 2007
Edits by:
Revision Number
18
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