MICRF218
3.3V, 315/433MHz Wide-IF Bandwidth ASK
Receiver
General Description
The MICRF218 is a 3.0V to 3.6V, 300MHz to 450MHz
ASK/OOK super-heterodyne receiver with user
selectable Intermediate Frequency (IF) Bandwidths of
550kHz or 1500kHz at 433.92MHz, making it an
excellent solution for use with low-cost SAW-based
transmitters or transmitters which use low-cost, medium-
grade (~30ppm) crystals. The device requires a single,
low-cost crystal to select the proper RF frequency,
integrated Automatic Gain Control (AGC), data slicer,
and programmable baseband filter bandwidths of
1.6kHz to 13kHz allowing the device to support bit-rates
up to 20kbps at 433.92MHz.
The MICRF218 consumes 4.0mA of supply current at
315MHz and 5.5mA of supply current at 433.92MHz.
The device also features a low-power shutdown mode
where the device consumes 1µA of supply current. The
device achieves a sensitivity of -108dBm at 1kbps. For
transmitters using higher-quality (~10ppm) crystals, the
MICRF219A/MICRF220 offer an IF-bandwidth of
330kHz and a sensitivity of -110dBm at 1kbps, which
can provide better sensitivity and longer range
performance.
Datasheets and support documentation are available on
Micrel’s website at:
www.micrel.com.
Features
•
Fully integrated 300MHz to 450MHz ASK/OOK
receiver
•
No external IF filter required
•
Wide IF-bandwidth filter supports reception of SAW
based and medium-grade (~30ppm) transmitter
•
Sensitivity at 433.92MHz at 1kbps with 0.1% BER
o
-108dBm sensitivity with 550kHz IF bandwidth
o
-106dBm sensitivity with 1500kHz IF bandwidth
•
Low-supply current
o
4.0mA at 315MHz
o
5.5mA at 433.92MHz
o
1µA low-power shutdown mode
•
Data rates to 10kbps (Manchester Encoded) @
433.92MHz
•
Duty cycling capable > 100:1 (shut down mode)
•
60dB analog received signal strength indicator
•
16-pin QSOP (4.9mm x 6.0mm) package
Typical Application
Y1
9.8131MHz
ANT
PCB Pattern
1
C2
1.5pF 50V
2
3
4
+3V
L1
39nH
C1
6.8pF
L2
68nH
C3
0.1µF 16V
5
6
7
8
U1
MICRF218AYQS
RO1
RO2
GNDRF
NC
ANT
RSSI
GNDRF
CAGC
VDD
CTH
IF_BW
SEL1
SEL0
DO
SHDN
GND
16
15
14
13
12
11
10
9
RSSI
DO
C4
0.1µF
16V
C5
4.7µF
6.3V
IF_BW CONTROL
315MHz/315.802, 900Hz Baud Rate Example
QwikRadio is a registered trademark of Micrel, Inc.
MLF and
MicroLeadFrame
are trademarks of Amkor Technology, 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
August 12, 2015
Revision 3.0
(408) 944-0800
Micrel
MICRF218
Ordering Information
Part Number
MICRF218AYQS
Temperature Range
–40° to +85°C
Package
16-Pin QSOP
Pin Configuration
RO1
GNDRF
ANT
GNDRF
Vdd
IF_BW
SEL0
SHDN
1
2
3
4
5
6
7
8
16
15
14
13
12
11
10
9
RO2
NC
RSSI
CAGC
CTH
SEL1
DO
GND
MICRF218AYQS
Pin Description
16-Pin
QSOP
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
Pin Name
RO1
GNDRF
ANT
GNDRF
VDD
IF_BW
SEL0
SHDN
GND
DO
SEL1
CTH
CAGC
RSSI
NC
RO2
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.
IF bandwidth control logic input. Use VDD for Wide IF Bandwidth or VSS for Narrow IF Bandwidth. This
pin must not be left floating, must be tied to VDD or VSS.
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 subsection)
Shutdown logic control input. Active internal pull-up and must be pulled low for Normal Operation.
Negative supply connection for all chip functions except RF input.
Demodulated data output.
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)
Demodulation threshold voltage integration capacitor. Capacitor to GND sets the settling time for the
demodulation data slicing level. Values above 1nF are recommended and should be optimized for data
rate and data profile.
AGC filter capacitor. A capacitor, normally greater than 0.47uF, is connected from this pin to GND
Received signal strength indication output. Output is from a buffer with 200 ohms typical output
impedance.
Not Connected
Reference resonator connection. 7pF in parallel with low resistance MOS switch to GND during normal
operation. Driven by startup excitation circuit during the internal startup control sequence.
August 12, 2015
2
Revision 3.0
(408) 944-0800
Micrel
MICRF218
Absolute Maximum Ratings
(1)
Supply Voltage (V
DD
) .................................................+5V
Input Voltage ............................................................. +5V
Junction Temperature ......................................... +150°C
Lead Temperature (soldering, 10sec.) ................ +260°C
Storage Temperature (T
S
) ..................... -65ºC to +150°C
Maximum Receiver Input Power ........................+10dBm
ESD Rating(3) .......................................................... 3kV
Operating Ratings
(2)
Supply voltage (V
DD
) ............................ +3.0V to +3.6V
Ambient Temperature (T
A
).................. –40°C to +85°C
Input Voltage (V
IN
) ..................................... 3.6V (max.)
Maximum Input RF Power .............................. –20dBm
Operating Frequency .................... 300MHz to 450MHz
Electrical Characteristics
(4)
Specifications apply for VDD = 3.0V, VSS = 0V, CAGC = 4.7µF, CTH = 0.1µF, Bold values indicate –40°C - T
A
+85°C.
Symbol
Parameter
Condition
Continuous Operation, f
RX
= 315MHz
20:1 Duty Cycle, f
RX
= 315MHz
Continuous Operation, f
RX
= 433.92MHz
20:1 Duty Cycle, f
RX
= 433.92MHz
Min
Typ
4.0
0.2
5.5
0.3
1
20
Max
Units
mA
mA
mA
mA
µA
dB
MHz
MHz
MHz
MHz
dBm
dBm
dBm
dBm
kHz
kHz
kHz
kHz
Ω
Ω
I
DD
MICRF218 Operating
Supply Current
Ishut
Shut down Current
Image Rejection
1 IF Center
Frequency
1 IF Center
Frequency
Receiver Sensitivity @
1kbps
Receiver Sensitivity @
1kbps
st
st
RF/IF Section
f
RX
= 315MHz, Narrow IF
f
RX
= 433.92MHz, Narrow IF
f
RX
= 315MHz, Wide IF
f
RX
= 433.92MHz, Wide IF
f
RX
= 315MHz, Narrow IF (50Ω)
f
RX
= 433.92MHz, Narrow IF (50Ω)
f
RX
= 315MHz, Wide IF (50Ω)
f
RX
= 433.92MHz, Wide IF (50Ω)
f
RX
= 315MHz, Narrow IF
f
RX
= 433.92MHz, Narrow IF
f
RX
= 315MHz, Wide IF
f
RX
= 433.92MHz, Wide IF
f
RX
= 315MHz
f
RX
= 433.92MHz
Note 6
20
0.98
1.4
1.8
2.4
-108
-108
-106
-106
400
550
1000
1500
16-j211
9.54-j152
80
IF Bandwidth
Antenna Input
Impedance
Receive Modulation
Duty Cycle
%
August 12, 2015
3
Revision 3.0
(408) 944-0800
Micrel
MICRF218
Electrical Characteristics
(4)
(Continued)
Specifications apply for VDD = 3.0V, VSS = 0V, CAGC = 4.7µF, CTH = 0.1µF, Bold values indicate –40°C - T
A
+85°C.
Symbol
Parameter
AGC Attack / Decay
Ratio
AGC pin leakage
current
AGC Dynamic Range
@ fRX = 433.92MHz
Condition
t
ATTACK
/ t
DECAY
T
A
= 25ºC
T
A
= +85ºC
RFIN @ -50dBm
RFIN @ -110dBm
f
RX
= 315MHz, Narrow IF, IF_BW = VSS
Crystal Load Cap = 10pF
f
RX
= 315MHz, Wide IF, IF_BW = VDD
Crystal Load Cap = 10pF
f
RX
= 433.92MHz Narrow IF, IF_BW = VSS
Crystal Load Cap = 10pF
f
RX
= 433.92MHz Wide IF , IF_BW = VDD
Crystal Load Cap = 10pF
Min
Typ
0.1
±2
± 800
1.13
1.70
Max
Units
nA
nA
V
V
Reference Oscillator
9.8131
9.78823
13.5178
13.48352
300
0.2
V(REFOSC) = 0V
3.5
1.5
MHz
MHz
MHz
MHz
kΩ
Vp-p
µA
kΩ
nA
Hz
Hz
Hz
Hz
kΩ
nA
Hz
Hz
Hz
Hz
Frequency
Input Impedance
Input Range
Source Current
Demodulator
CTH Source
Impedance
CTH Leakage Current
Demodulator Filter
Bandwidth @ 315
MHz
CTH Source
Impedance
CTH Leakage Current
Demodulator Filter
Bandwidth @ 433.92
MHz
f
REFOSC
= 9.8131MHz, 315MHz, Note 8
TA = 25ºC
TA = +85ºC
SEL0=0, SEL1=0
SEL0=0, SEL1=1
SEL0=1, SEL1=0
SEL0=1, SEL1=1
f
REFOSC
= MHz, 433.92MHz, note 8
TA = 25ºC
TA = +85ºC
SEL0=0, SEL1=0
SEL0=0, SEL1=1
SEL0=1, SEL1=0
SEL0=1, SEL1=1
165
±2
± 800
1180
2360
4720
9420
120
±2
± 800
1625
3250
6500
13000
August 12, 2015
4
Revision 3.0
(408) 944-0800
Micrel
MICRF218
Electrical Characteristics
(4)
(Continued)
Specifications apply for VDD = 3.0V, VSS = 0V, CAGC = 4.7µF, CTH = 0.1µF, Bold values indicate –40°C - T
A
+85°C.
Symbol
Parameter
Input High Voltage
Input Low Voltage
DO pin output current
Output rise and fall
times
Condition
Pins DO (As input), SHDN
Pins DO (As input), SHDN
Source @ 0.8 Vdd
Sink @ 0.2 Vdd
CI = 15 pF, pin DO, 10-90%
Min
0.8V
DD
Typ
Max
Units
V
Digital / Control Functions
0.2V
DD
V
µA
µsec
260
600
2
0.22
to 2
RSSI
RSSI DC Output
Voltage Range
RSSI response slope
RSSI Output Current
RSSI Output
Impedance
RSSI Response Time
50% data duty cycle, input power to
Antenna = -20 dBm
-90dBm to -40dBm
V
mV/
dBm
mA
Ω
Sec
35
±1.5
200
0.3
Notes:
1. Exceeding the absolute maximum rating may damage the device.
2.
3.
4.
The device is not guaranteed to function outside its operating rating.
Device are ESD sensitive. Use appropriate ESD precaution. Exceeding the absolute maximum rating may damage the device.
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. Conductive
measurement is performed using 50 ohm test circuit .
Spurious reverse isolation represents the spurious component that appear on the RF input pin (ANT) measured into 50 Ohms with an
input RF matching network.
When data burst does not contain preamble, the duty cycle is then 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 T
ON
/(T
ON
+ t
OFF
) = 50%; without preamble, duty cycle is T
ON
/(T
ON
+ T
OFF
+ T
QUIET
) = 50msec/(200msec) =
25%. T
ON
is the (Average number of 1’s/burst) × bit time, and T
OFF
= T
BURST
– T
ON
.)
Parameter scales linearly with reference oscillator frequency f
T
. For any reference oscillator frequency other than one of the tabulated
frequencies (called F
TAB
), compute new parameter value as the ratio:
Parameter at f
REFOSC
MHz = ( f
REFOSC
MHz /F
TAB
) × ( parameter at F
TAB
MHz )
8.
Parameter scales inversely with reference oscillator frequency fT. For any reference oscillator frequency other than one of the
tabulated frequencies (called F
TAB
), compute new parameter value as the ratio:
Parameter at f
REFOSC
MHz = ( F
TAB
/ f
REFOSC
MHz ) × ( parameter at F
TAB
MHz )
5.
6.
7.
August 12, 2015
5
Revision 3.0
(408) 944-0800
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