MICRF213AYQS [MICREL]
3.3V, QwikRadio㈢ 315MHz Receiver; 3.3V ， QwikRadio㈢ 315MHz的接收器
| 型号： | MICRF213AYQS |
| 厂家： | 
MICREL SEMICONDUCTOR |
| 描述： | 3.3V, QwikRadio㈢ 315MHz Receiver |
| 文件： | 总16页 (文件大小：1087K) |
| 中文： | 中文翻译 | 下载： | 下载PDF数据表文档文件 |
MICRF213
3.3V, QwikRadio® 315MHz Receiver
General Description
Features
The MICRF213 is a general purpose, 3.3V QwikRadio
Receiver that operates at 315MHz with typical sensitivity
of -110dBm.
• Up to –110dBm sensitivity, 1kbps and BER 10E-02
• Image Rejection Mixer
• Frequency from 300MHz to 350MHz
• Low current consumption: 3.9mA @ 315MHz,
continuous on data rates to 7.2kbps (Manchester
Encoded)
The MICRF213 functions as
a super-heterodyne
receiver for OOK and ASK modulation up to 7.2kbps.
The down-conversion mixer also provides image
rejection. All post-detection data filtering is provided on
the MICRF213. Any one of four filter bandwidths may be
selected externally by the user using binary steps (from
1.18kHz to 9.44kHz, Manchester Encoded). 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.
• Analog RSSI Output
• No IF filter required
• Excellent selectivity and noise rejection
• Low external part count
Ordering Information
Part Number
Temperature Range
Package
MICRF213AYQS
–40° to +105°C
16-Pin QSOP
Typical Application
ANT1
230 mm (9.1 inches)
U1 MICRFAYQS
1
16
RO1
RO2
NC
C3
1.8pF
Y1
2
3
4
5
6
7
8
15
14
13
12
11
10
9
GNDRF
ANT
9.81563MHz
RSSI
CAGC
CTH
SEL1
DO
GNDRF
VDD
+3.3V
L2
68nH
C8
6.8pF
L1
39nH
SQ
C5
0.1µF
C6
0.47µF
C4
4.7µF
SEL0
SHDN
DO
GND
315MHz, 1kHz Baud Rate Example
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
M9999-052307-A
(408) 944-0800
May 2007
Micrel, Inc.
MICRF213
Pin Configuration
RO1
GNDRF
ANT
1
2
3
4
5
6
7
8
16 RO2
15 NC
14 RSSI
13 CAGC
12 CTH
11 SEL1
10 DO
GNDRF
VDD
SQ
SEL0
SHDN
9
GND
MICRF213AYQS
Pin Description
16-Pin
QSOP
Pin
Name
Pin Function
1
RO1
Reference resonator input connection to Colpitts oscillator stage. May also be driven by external reference
signal of 1.5V p-p amplitude maximum.
2
3
GNDRF Negative supply connection associated with ANT RF input.
ANT
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.
4
5
6
7
GNDRF Negative supply connection associated with ANT RF input.
VDD
SQ
Positive supply connection for all chip functions.
Squelch control logic input with an active internal pull-up when not shut down.
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
9
SHDN
GND
DO
Shutdown logic control input. Active internal pull-up.
Negative supply connection for all chip functions except RF input.
Demodulated data output.
10
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 subsection)
12
13
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.
CAGC
AGC filter capacitor connection. CAGC capacitor, normally greater than 0.47uF, is connected from this pin to
GND
14
15
16
RSSI
NC
Received signal strength indication output. Output is from a buffer with 200 ohms typical output impedance.
Not Connected (Connect to Ground)
RO2
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.
M9999-052307-A
(408) 944-0800
May 2007
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Micrel, Inc.
MICRF213
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).....................-65°C to +150°C
Maximum Receiver Input Power ........................+10dBm
EDS Rating(3) .................................................. 3KV HBM
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 = 0.47µF, fRX = 315 MHz unless otherwise noted.
Bold values indicate –40°C - TA - 105°C. 900bps data rate (Manchester encoded), reference oscillator frequency = 9.81563 MHz.
Symbol
IDD
Parameter
Condition
Min
Typ
3.9
Max
Units
mA
Operating Supply Current Continuous Operation, fRX = 315MHz
Shut down Current
ISHUT
0.33
µA
RF/IF Section
Image Rejection
20
dB
1st IF Center Frequency
fRX = 315MHz
0.86
MHz
Receiver Sensitivity @
1kbps
fRX = 315MHz (matched to 50Ω) BER=10-2
fRX = 315MHz
-110
dBm
kHz
ꢀ
IF Bandwidth
235
Antenna Input
Impedance
32.5 –
j235
fRX = 315MHz
Receive Modulation Duty
Cycle
Note 5
20
80
%
AGC Attack / Decay
Ratio
tATTACK / tDECAY
0.1
TA = 25ºC
TA = +105ºC
±2
nA
nA
V
AGC pin leakage current
AGC Dynamic Range
±800
1.13
1.70
RFIN @ -50dBm
RFIN @ -110dBm
V
Reference Oscillator
fRX = 315MHz
Reference Oscillator
Frequency
9.81563
300
MHz
kꢀ
Crystal Load Cap = 10pF
Reference Oscillator
Input Impedance
Reference Oscillator
Input Range
0.2
1.5
Vp-p
µA
Reference Oscillator
Source Current
V(REFOSC) = 0V
3.5
M9999-052307-A
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May 2007
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Micrel, Inc.
MICRF213
Symbol
Parameter
Condition
Min
Typ
Max
Units
Demodulator
CTH Source Impedance
FREFOSC = 9.81563MHz
165
kꢀ
CTH Leakage Current
TA = 25ºC
TA = +105ºC
±2
±800
nA
nA
SEL0=0, SEL1=0
SEL0=1, SEL1=0
SEL0=0, SEL1=1
SEL0=1, SEL1=1
1180
2360
4720
9400
Demodulator Filter
Bandwidth @ 315MHz
Hz
(Programmable, see
application section)
Digital / Control Functions
DO pin output current
As output
source @ 0.8Vdd
sink @ 0.2Vdd
260
600
µA
Output rise and fall times
CI = 15pF, pin DO, 10-90%
2
µsec
RSSI
RSSI DC Output Voltage
Range
-110dBm to -50dBm
-110dBm to -50dBm
0.4 – 1.9
V
RSSI response slope
RSSI Output Current
RSSI Output Impedance
RSSI Response Time
25
mV/dB
µA
400
200
±15
ꢀ
50% data duty cycle, input power to Antenna = -
20 dBm
0.3
Sec
Notes:
1.
2.
3.
Exceeding the absolute maximum rating may damage the device.
The device is not guaranteed to function outside of its operating rating.
Device is ESD sensitive. Use appropriate ESD precautions. Exceeding the absolute maximum rating may damage the device.
-2
4.
Sensitivity is defined as the average signal level measured at the input necessary to achieve 10 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.
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) x bit time, and Toff = Tburst -Ton.)
M9999-052307-A
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May 2007
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Micrel, Inc.
MICRF213
Typical Characteristics
Sensitivity Graphs
RSSI Voltage
vs. Input Power
DC Current
vs. Frequency
Selectivity
vs. Frequency Response
2.5
4.5
4.0
3.5
3.0
0
-10
-20
-30
-40
-50
-60
-70
-80
-90
2.0
1.5
1.0
0.5
0
-120 -100 -80
-60
-40
-20
280
300
320
340
360
304 308 312 316 320 324
FREQUENCY (MHz)
INPUT POWER (dBm)
FREQUENCY (MHz)
Sesitivity
vs. BER
AGC Voltage
vs. Input Power
-106
-108
-110
-112
-114
-116
1.8
1.7
1.6
1.5
1.4
1.3
1.2
1.1
1
1.00E-04 1.00E-03 1.00E-02 1.00E-01
BER
-150
-100
-50
0
INPUT POWER (dBm)
M9999-052307-A
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Micrel, Inc.
MICRF213
Functional Diagram
CAGC
RSSI
AGC
RSSI
IMAGE
REJECT
FILTER
RF
ANT
IF
Detector
Amp
Amp
Mixer
Mixer
OOK
Demodulator
VDD
Programmable
Low Pass Filter
–f
f
Control Logic
fLO
IF
Amp
VSS
SEL
i
DO
DO
Synthesizer
SEL
SQUELCH
SHDN
Control
Logic
Slicing
Level
CTH
Control Logic
Reference and Control
Reference
Oscillator
RO1
RO2
Crystal
Figure 1. Simplified Block Diagram
frequency below the wanted signal. The local oscillator
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. It is the basic
structure of the MICRF213. It is made of three sub-
blocks; Image Rejection UHF Down-converter, the OOK
Demodulator, and Reference and Control Logics.
Outside the device, the MICRF213 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. This removes 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 0.86MHz. The IF BW is 235KHz @
315MHz, this will vary with RF operating frequency. The
IF BW can be calculated via direct scaling:
Receiver Operation
LNA
OperatingFreq(MHz)
315
⎛
⎜
⎞
⎟
BWIF = BWIF@315MHz
×
⎝
⎠
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 MICRF213.
After filtering, four active gain controlled amplifier stages
enhance the IF signal to proper level for demodulation.
Mixers and Synthesizer
OOK Demodulator
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. This allows
suppression of the image frequency at twice the IF
The demodulator section is comprised of detector,
programmable low pass filter, slicer, and AGC
comparator.
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May 2007
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Micrel, Inc.
MICRF213
Detector and Programmable Low-Pass Filter
1.5µA current is then 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.
The demodulation starts with the detector removing the
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: 1180Hz, 2360Hz, 4270Hz, 9400Hz for
315MHz operation. Low pass filter BW will vary with RF
Operating Frequency. Filter BW values can be easily
calculated by direct scaling. See the equation below for
the filter BW calculation:
Reference Control
There are two components in Reference and Control
sub-block: 1) Reference Oscillator and, 2) Control Logic
through parallel Inputs: SEL0, SEL1, SHDN.
OperatingFreq(MHz)
315
⎛
⎜
⎞
⎟
BWOperating Freq = BW@315MHz
×
Reference Oscillator
⎝
⎠
VBIAS
It is very important to choose filter setting that best fits
the intended data rate as this will minimize data
distortion.
R1
R2
Demod BW is set at 9700Hz @ 315MHz as default
(assuming both SEL0 and SEL1 pins are floating). The
low pass filter can be hardware set by external pins
SEL0 and SEL1.
M1
gm
RO1
1
IBIAS
CC1
C0
Startup
Circuit
SEL0
SEL1
Demod BW (@ 315MHz)
1180Hz
CC2
0
1
0
1
0
0
1
1
M2
M3
2360Hz
4270Hz
RO2
9400Hz
- default
C1
Table 1. Demodulation BW Selection
M4
Normally on
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 becomes
digital OOK data.
Figure 2. Reference Oscillator Circuit
The reference oscillator in the MICRF213 (reference
Figure 2) uses a basic Colpitts crystal oscillator
configuration with a MOS transconductor to provide
negative resistance. All capacitors shown in the figure
are integrated inside MICRF213. R01 and R02 are
external pins of MICRF213. The user only need connect
the reference oscillation crystal.
During long periods of “0”s or no data period at all,
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.
Reference oscillator crystal frequency can be calculated
thus as:
FREFOSC = FRF/(32 + 1.1/12)
For 315MHz, FREFOSC = 9.81563 MHz.
AGC Comparator
To operate the MICRF213 with minimum offset, crystal
frequencies should be specified with 10pF loading
capacitance.
The AGC comparator monitors the signal amplitude
from the output of the programmable low-pass filter.
When the output signal is less than 750mV threshold,
M9999-052307-A
(408) 944-0800
May 2007
7
Micrel, Inc.
MICRF213
Application Information
ANT1
Helical PCB Antenna Pattern
Y1
+3.3V
C9
9.81563MHz
L3
75nH 2%
ANT2
R1
(np)
U1 MICRFAYQS
1
2
3
4
5
6
7
8
16
15
14
13
12
11
10
9
RO1
RO2
NC
C3
1.8pF
GNDRF
ANT
J2
(np)SMA
RSSI
CAGC
CTH
SEL1
DO
RSSI
DO
GNDRF
VDD
+3.3V
L2
68nH 5%
L1
39nH 5%
C8
6.8pF
SQ
C5
0.1µF
SEL0
SHDN
GND
JP3
open
JP1
short
R3
JR2
short
C6
0.47µF
C4
4.7µF
R2
(np)
+3.3V
1
2
3
4
5
6
+3.3V
GND
D0
DO
NC
SH
SH
RSSI
RSSI
Figure 3. QR213HE1 Application Example, 315MHz
The MICRF213 can be fully tested by using one of the
many evaluation boards designed by Micrel and
intended for use with this device. As an entry level,
the QR213HE1 (reference 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. The minimum components 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 for
315MHz. Other frequencies can be used and the
values needed are listed in the tables below.
L1 and C8 form the pass-band-filter front-end. Its
purpose is to attenuate undesired outside band noise
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)
303.825
315
C8 (pF)
6.8
L1 (nH)
39
6.8
39
345
5.6
39
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 the outside band noise
does not cause a problem. The MICRF213 has image
reject mixers which improve significantly the selectivity
and rejection of outside band noise.
Capacitor C9 and inductor L3 are the passive
elements for the helical PCB matching network. It is
recommended that a tight tolerance be used for these
devices; such as 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, reference the: Small PCB
Antennas for Micrel RF Products application note.
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 ways can be used to find these
values, which are matched close to 50ꢀ. 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.
Freq (MHz)
303.825
315
C9 (pF)
1.2
L3 (nH)
82
1.2
75
345
1.2
62
To calculate the matching values, one needs to know
the input impedance of the device. Table 4 shows the
input impedance of the MICRF213 and the suggested
matching values used for the most frequencies.
Table 2. Matching Values for the Helical PCB Antenna
To use another antenna, such as 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.
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May 2007
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Micrel, Inc.
MICRF213
Please keep in mind that these suggested values may
be different if the layout is not exactly the same as the
one depicted here.
Second, we plot the shunt inductor (68nH) and the
series capacitor (1.8pF) for the desired input
impedance (Figure 5). We can see the matching
leading to the center of the Smith Chart or close to
50ꢀ.
Freq (MHz)
303.825
315
C3 (pF)
1.8
L2 (nH)
72
Z device (Ω)
34.6– j245.1
32.5 – j235
25.3 – j214
1.8
68
345
1.8
56
Table 4. Matching Values for the
Most Used Frequencies
For the frequency of 315MHz, the input impedance is
Z = 32.5 – j235ꢀ, then the matching components are
calculated by:
Equivalent parallel = B = 1/Z = 0.577 + j4.175
msiemens
Rp = 1 / Re (B);
Rp = 1.733 kꢀ;
Q = SQRT (Rp/50 + 1)
Q = 5.972
Xp = 1 / Im (B)
Xp = 239.5 ꢀ
Xm = Rp / Q
Xm = 290.21 ꢀ
Resonance Method For L-shape Matching Network
Lc = Xp / (2.Pi.f);
L2 = (Lc.Lp) / (Lc + Lp);
L2 = 66.3nH
Lp = Xm / (2.Pi.f)
C3 = 1 / (2.Pi.f.Xm)
C3 = 1.74pF
Doing the same calculation example with the Smith
Chart, it would appear as follows,
First, we plot the input impedance of the device,
(Z = 32.5 – j235)ꢀ @ 315MHz.(Figure 4).
Figure 5. Plotting the Shunt Inductor
and Series Capacitor
Crystal Y1 or Y1A (SMT or leaded respectively) is the
reference clock for all the device internal circuits.
Desired crystal characteristics are: 10pF load
capacitance, 30ppm, ESR < 50ꢀ and a -40ºC to
+105ºC temperature range. Table 5 shows the crystal
frequencies and one of Micrel’s approved crystal
manufactures (www.hib.com.br).
The oscillator of the MICRF213 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
Figure 4. Device’s Input Impedance, Z = 32.5 – j235 Ω
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Micrel, Inc.
MICRF213
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.
according to Table 6. For example, if the pulse period
is 140µsec, 50% duty cycle, then the pulse width will
be 70µsec (PW = (140 µsec * 50%) / 100). So, a
bandwidth of 9.286kHz would be necessary (0.65 /
70µsec). However, if this data stream had a pulse
period with a 20% duty cycle, then the bandwidth
required would be 23.2kHz (0.65 / 28µsec), which
exceeds the maximum bandwidth of the demodulator
circuit. If one tries to exceed the maximum bandwidth,
the pulse would appear stretched or wider.
The crystal frequency is calculated by REFOSC = RF
Carrier/(32+(1.1/12)). The local oscillator is low side
injection (32 × 9.81563MHz = 314.1MHz), that is, its
frequency is below the RF carrier frequency and the
image frequency is below the LO frequency. Refer to
Figure 6. The product of the incoming RF signal and
local oscillator signal will yield the IF frequency, which
will then be demodulated by the detector of the
device.
SEL0
JP1
SEL1
JP2
Demod.
BW
(hertz)
Shortest
Pulse
(usec)
Maximum
baud rate for
50% Duty
Cycle (hertz)
Short
Open
Short
Open
Short
Short
Open
Open
1180
2360
4720
9400
551
275
138
69
908
1815
3631
7230
Image
Frequency
Desired
Signal
Table 6. JP1 and JP2 Setting, 315MHz
Capacitors C6 and C4, Cth and Cagc capacitors
respectively, provide the 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 not a preamble. See Figure 7 for an
example of a data profile.
f (MHz)
f
LO
Figure 6. Low Side Injection Local Oscillator
Other frequencies will have different demodulator
bandwidth limits, which are derived from the reference
oscillator frequency. Table 7 and Table 8, below,
show the limits for the other two most used
frequencies.
REFOSC
(MHz)
Carrier
(MHz)
HIB Part Number
9.467411
9.81563
303.825
315
SA-9.467411-F-10-H-30-30-X
SA-9.815630-F-10-H-30-30-X
SA-10.750450-F-10-H-30-30-X
10.75045
345.0
SEL0
JP1
SEL1
JP2
Demod.
Shortest
Pulse
(usec)
Maximum
baud rate for
50% Duty
Table 5. Crystal Frequency and Vendor Part Number
BW
(hertz)
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. Reference the
example of the data profile, in the Figure 7, below:
Cycle (hertz)
Short
Open
Short
Open
Short
Short
Open
Open
1140
2280
4550
9100
570
285
143
71
8770
1754
3500
7000
Table 7. JP1 and JP2 Setting, 303.825MHz
SEL0
JP1
SEL1
JP2
Demod.
Shortest
Pulse
(usec)
Maximum
baud rate for
50% Duty
BW
(hertz)
Cycle (Hertz)
Short
Open
Short
Open
Short
Short
Open
Open
1290
2580
5170
10340
504
252
126
63
992
Figure 7. Example of a Data Profile
1985
3977
7954
PW2 is shorter than PW1, so PW2 should be used for
the demodulator bandwidth calculation. The
calculation is found by 0.65/shortest pulse width. After
this value is found, the setting should be done
Table 8. JP1 and JP2 Setting, 345.0MHz
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Micrel, Inc.
MICRF213
For best results, the values 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 at 50% duty cycle.
SEL0
JP1
SEL1
JP2
Demod.
BW
Cth
Cagc
(hertz)
Short
Open
Short
Open
Short
Short
Open
Open
1400
2800
5300
9700
100nF
47nF
22nF
10nF
4.7uF
2.2uF
1uF
DO Pin
0.47uF
Table 9. Suggested Cth and Cagc Values
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 yields a
hash signal. When the pin is low, the DO pin activity is
considerably reduced. It will have more or less than
shown in the figure below depending upon the outside
band noise. The penalty for using squelch is a delay in
obtaining 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 9.
Figure 9. Data Out Pin with Squelch (SQ = 0)
Other components used include: 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;
and R1 and R2 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 in several devices.
Three other pins need to be discussed as well. 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 families 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.
DO Pin
The shut down pin (SHDN) is useful to save energy.
Making its level close to Vdd (SHDN = 1), the device
is then 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. Crystal vendors suggest that
the data will show up in the DO pin around 1msec
time, and 2msec over the temperature range of the
device. See Figure 10.
Figure 8. Data Out Pin with No Squelch (SQ = 1)
M9999-052307-A
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May 2007
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Micrel, Inc.
MICRF213
Figure 10. Time-to-Good Data After Shut Down Cycle,
Room Temperature
M9999-052307-A
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May 2007
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Micrel, Inc.
MICRF213
PCB Considerations and Layout
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. The
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 11 through 16 show some of the printed circuit
layers for the QR211HE1 board. The MICRF213
shares the exact same board with different component
values. Use the Gerber files provided (downloadable
from Micrel Website: www.micrel.com) which have the
remaining layers needed to fabricate this board. When
copying or making one’s own boards, be sure and
make the 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 of inductance.
Optimization should always be done with exhaustive
range tests. Make individual ground connections to
the ground plane with a via for each ground
Figure 11. QR211/213HE1 Top Layer
Figure 12. QR211/213HE1 Bottom Layer, Mirror Image
M9999-052307-A
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May 2007
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Micrel, Inc.
MICRF213
Figure 13. QR211/213HE1 Top Silkscreen Layer
Figure 14. QR211/213HE1 Bottom Silkscreen Layer, Mirror Image
Figure 15. QR211/213HE1 Dimensions
M9999-052307-A
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Micrel, Inc.
MICRF213
QR213HE1 Bill of Materials, 315MHz
Item
ANT1
ANT2
C3
Part Number
Manufacturer
Description
Qty.
1
Helical PCB Antenna Pattern
(np)50ꢀ Ant
230mm 20 AWG, rigid wire
1
MuRata(1)
1.8pF, 0402/0603
4.7µF, 0603/0805
0.1µF, 0402/0603
0.47µF, 0402/0603
6.8pF, 0402/0603
1.2pF, 0402/0603
short, 0402, 0ꢀ resistor
1
C4
Murata(1) / Vishay(2)
Murata(1) / Vishay(2)
Murata(1) / Vishay(2)
Murata(1)
Murata(1)
Vishay(2)
1
C5
1
C6
1
C8
1
C9
1
JP1,JP
2
2
JP3
J2
open, 0402, not placed
(np) not placed
1
1
1
1
1
1
2
1
1
1
1
J3
CON6
L1
Coilcraft(3) / Murata(1) / ACT1(4)
Coilcraft(3) / Murata(1) / ACT1(4)
Coilcraft(3) / Murata(1) / ACT1(4)
39nH 5%, 0402/0603
68nH 5%, 0402/0603
75nH 2%, 0402/0603
(np) 0402, not placed
100kꢀ, 0402
L2
L3
R1,R2
R3
Vishay(2)
HIB(5)
HIB(5)
Y1
HCM49
HC49
(np)9.81563MHz Crystal
9.81563MHz Crystal
3.3V, QwikRadio® 315MHz Receiver
Y1A
U1
MICRF213AYQS Micrel Inc.(6)
Notes:
1. Murata: www.murata.com
2. Vishay: www.vishay.com
3. Coilcraft: www.coilcraft.com
4. ACT1: www.act1.com
5. HIB: www.hib.com.br
6. Micrel, Inc.: www.micrel.com
M9999-052307-A
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May 2007
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Micrel, Inc.
MICRF213
Package Information
16-Pin QSOP (QS)
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.
© 2007 Micrel, Incorporated.
M9999-052307-A
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