MICRF220
300MHz to 450MHz, 3.3V ASK/OOK Receiver
with RSSI and Squelch
General Description
The MICRF220 is a 300MHz to 450MHz super-
heterodyne, image-reject, RF receiver with automatic
gain control, ASK/OOK demodulator, analog RSSI
output, and integrated squelch features. It only requires
a crystal and a minimum number of external components
to implement. The MICRF220 is ideal for low-cost, low-
power, RKE, TPMS, and remote actuation applications.
The MICRF220 achieves
−110dBm
sensitivity at a bit
rate of 1kbps with 0.1% BER. Four demodulator filter
bandwidths are selectable in binary steps from 1625Hz
to 13kHz at 433.92MHz, allowing the device to support
bit rates up to 20kbps. The device operates from a
supply voltage of 3.0V to 3.6V, and typically consumes
4.3mA of supply current at 315MHz and 6.0mA at
433.92MHz. A shutdown mode reduces supply current to
0.1μA typical. The squelch feature decreases the activity
on the data output pin until valid bits are detected while
maintaining overall receiver sensitivity.
Data sheets and support documentation can be found on
Micrel’s web site at:
www.micrel.com.
Features
•
•
•
•
•
•
•
•
•
•
•
•
•
–110dBm sensitivity at 1kbps with 0.1% BER
Supports bit rates up to 20kbps at 433.92MHz
25dB image-reject mixer
No IF filter required
60dB analog RSSI output range
3.0V to 3.6V supply voltage range
4.3mA supply current at 315MHz
6.0mA supply current at 434MHz
0.1µA supply current in shutdown mode
Data output squelch until valid bits detected
16-pin QSOP package (4.9mm x 6.0mm)
−40˚C
to +105˚C temperature range
3kV HBM ESD Rating
Ordering Information
Part Number
MICRF220AYQS
Temperature Range
–40°C to +105°C
Package
16-Pin QSOP
Typical Application
433.92MHz, 1kbps Operation
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 2010
M9999-082610-A
RadioTech@micrel.com
or (408) 944-0800
Micrel, Inc.
MICRF220
Pin Configuration
MICRF220AYQS
Pin Description
Pin
Number
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
Pin
Name
RO1
GNDRF
ANT
GNDRF
VDD
SQ
SEL0
SHDN
GND
DO
SEL1
CTH
CAGC
RSSI
NC
RO2
Pin Function
Reference resonator connection to the Pierce oscillator. May also be driven by external reference signal of
200mVp-p to 1.5V p-p amplitude maximum. Internal capacitance of 7pF to GND during normal operation.
Ground connection for ANT RF input. Connect to PCB ground plane.
Antenna Input: RF Signal Input from Antenna. Internally AC coupled. It is recommended to use a matching
network with an inductor-to-RF ground to improve ESD protection.
Ground connection for ANT RF input. Connect to PCB ground plane.
Positive supply connection for all chip functions. Bypass with 0.1μF capacitor located as close to the VDD pin
as possible.
Squelch Control Logic-Level Input. An internal pull-up (5μA typical) pulls the logic-input HIGH when the device
is enabled. A logic LOW on SQ squelches, or reduces, the random activity on DO pin when there is no RF
input signal.
Demodulator Filter Bandwidth Select Logic-Level Input. This pin has an internal pull-up (3μA typical) when the
chip is on. Use in conjunction with SEL1 to control demodulation bandwidth.
Shutdown Control Logic-Level Input. A logic-level LOW enables the device. A logic-level HIGH places the
device in low-power shutdown mode. An internal pull-up (5μA typical) pulls the logic input HIGH.
Ground connection for all chip functions except for RF input. Connect to PCB ground plane.
Data Output. Demodulated data output. A current limited CMOS output during normal operation, 25kΩ pull-
down is present when device is in shutdown.
Demodulator Filter Bandwidth Select Logic-Level Input. This pin has an internal pull-up (3μA typical) when the
chip is on. Use in conjunction with SEL0 to Demodulation bandwidth.
Demodulation Threshold Voltage Integration Capacitor. Connect a 0.1μF capacitor from CTH pin-to-GND to
provide a stable slicing threshold.
AGC Filter Capacitor. Connect a capacitor from this pin to GND. Refer to the
AGC Loop and CAGC
section for
information on the capacitor value.
Received Signal Strength Indicator. The voltage on this pin is an inversed amplified version of the voltage on
CAGC. Output is from a switched capacitor integrating op amp with 250Ω typical output impedance.
No Connect. Leave this pin floating.
Reference resonator connection to the Pierce oscillator. Internal capacitance of 7pF to GND during normal
operation.
August 2010
2
M9999-082610-A
Micrel, Inc.
MICRF220
Absolute Maximum Ratings
(1)
Supply Voltage (V
DD
).................................................. +5V
ANT, SQ, SEL0, SEL1,
SHDN DC Voltage. ....................
−0.3V
to V
DD
+ 0.3V
Junction Temperature ...........................................+150ºC
Lead Temperature (soldering, 10sec.)..................+300°C
Storage Temperature .............................−65ºC to +150°C
Maximum Receiver Input Power ......................... +10dBm
ESD Rating
(3)
.................................................... 3kV HBM
Operating Ratings
(2)
Supply Voltage (V
DD
) ............................. +3.0V to +3.6V
Ambient Temperature (T
A
).................. –40°C to +105°C
ANT, SQ, SEL0, SEL1,
SHDN DC Voltage ................ ....−0.3V to V
DD
+ 0.3V
Maximum Input RF Power.................................. 0 dBm
Receive Modulation Duty Cycle ....................... 20~80%
Frequency Range .......................... 300MHz to 450MHz
Electrical Characteristics
V
DD
= 3.3V, V
SHDN
= GND = 0V, SQ = open, C
CAGC
= 4.7µF, C
CTH
= 0.1µF, unless otherwise noted.
Bold
values indicate
–40°C
≤
T
A
≤
105°C. “Bit rate” refers to the encoded bit rate throughout this datasheet (see Note 4).
Parameter
Operating Supply Current
Shutdown Current
Receiver
433.92MHz, V
SEL1
= V
SEL0
= 0V, BER = 1%
433.92MHz, V
SEL1
= V
SEL0
= 0V,
BER = 0.1%
315MHz, V
SEL1
= 0V, V
SEL0
= 3.3V,
BER = 1%
315MHz, V
SEL1
= 0V, V
SEL0
= 3.3V,
BER = 0.1%
Image Rejection
IF Center Frequency (f
IF
)
−3dB
IF Bandwidth
CAGC Voltage Range
Reference Oscillator
Reference Oscillator
Frequency
Reference Buffer Input
Impedance
Reference Oscillator Bias
Voltage
Reference Oscillator Input
Range
Reference Oscillator Source
Current
f
RF
= 315 MHz
f
RF
= 433.92 MHz
RO1 when driven externally
RO2
External input, AC couple to RO1
V
RO1
= 0V
0.2
300
9.81713
13.52313
1.6
1.15
1.5
MHz
kΩ
V
V
P-P
µA
f
IMAGE
= f
RF
– 2f
IF
f
RF
= 315MHz
f
RF
= 433.92MHz
f
RF
= 315MHz
f
RF
= 433.92MHz
−40dBm
RF input level
−100dBm
RF input level
−112.5
−110
−112.5
−110
25
0.85
1.18
235
330
1.15
1.55
dB
MHz
kHz
V
dBm
Condition
Continuous Operation, f
RF
= 315MHz
Continuous Operation, f
RF
= 433.92MHz
V
SHDN
= V
DD
Min.
Typ.
4.3
6.0
0.1
Max.
Units
mA
µA
Conducted Receiver
Sensitivity@1kbps (Note 5)
August 2010
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M9999-082610-A
Micrel, Inc.
MICRF220
Electrical Characteristics (Continued)
Parameter
Demodulator
CTH Source Impedance,
Note 6
CTH Leakage Current In
CTH Hold Mode
Digital / Control Functions
DO Pin Output Current
Output Rise Time
Output Fall Time
Input High Voltage
Input Low Voltage
Output Voltage High
Output Voltage Low
RSSI
RSSI DC Output Voltage
Range
RSSI Output Current
RSSI Output Impedance
RSSI Response Time
Notes:
1.
2.
3.
4.
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.
Encoded bit rate is 1/(shortest pulse duration) that appears at MICRF220 DO pin.
Condition
f
REF
= 9.81713MHz
f
REF
= 13.52313MHz
T
A
= +25ºC
T
A
= +105ºC
As output source @ 0.8 V
DD
As output sink @ 0.2 V
DD
15pF load on DO pin, transition time
between 0.1xV
DD
and 0.9xV
DD
SHDN, SEL0, SEL1, SQ
SHDN, SEL0, SEL1, SQ
DO
DO
−110dBm
RF input level
−50dBm
RF input level
5kΩ load to GND,
−50dBm
RF input level
V
SEL0
= V
SEL1
= 0V, RF input power stepped
from no input to
−50dBm
Min.
Typ.
165
120
1
10
300
680
600
200
Max.
Units
kΩ
nA
µA
ns
V
0.2V
DD
V
V
0.2V
DD
V
0.8V
DD
0.8V
DD
0.5
2.0
400
250
10
V
µA
Ω
ms
5.
In an ON/OFF keyed (OOK) signal, the signal level goes between a “mark” level (when the RF signal is ON) and a “space” level (when the RF
signal is OFF). Sensitivity is defined as the input signal level when “ON” necessary to achieve a specified BER (bit error rate). BER measured with
the built-in BERT function in Agilent E4432B using the PN9 sequence. Sensitivity measurement values are obtained using an input matching
network corresponding to 315MHz or 433.92MHz.
CTH source impedance is inversely proportional to the reference frequency. In production testing, the typical source impedance value is verified
with 12MHz reference frequency.
6.
August 2010
4
M9999-082610-A
Micrel, Inc.
MICRF220
Typical Characteristics
V
DD
= 3.3V, T
A
= +25ºC, BER measured with PN9 sequence, unless otherwise noted.
Current vs. Receiver
Frequency
6.5
6.0
Current vs. Supply Voltage
f
RF
= 433.92MHz
7.5
7.0
Current (mA)
6.5
6.0
5.5
5.0
4.5
-40ºC
+25ºC
+105ºC
Current vs. Supply Voltage
f
RF
= 315MHz
5.0
+105ºC
Current (mA)
Current (mA)
5.5
5.0
4.5
4.0
3.5
300 325 350 375 400 425 450
Receiver Frequency (MHz)
4.5
+25ºC
4.0
-40ºC
3.5
3.0
3.2
3.4
3.6
3.0
3.2
3.4
3.6
Supply Voltage (V)
Supply Voltage (V)
CAGC Voltage vs. Input
Power
2.0
1.8
CAGC Voltage (V)
+105ºC
RSSI vs. Input Power
2.5
2.0
RSSI Voltage (V)
-40ºC
10
BER vs. Input Power
V
SEL1
= V
SEL0
= 0V
433.92MHz
1.6
1.4
1.2
1.0
-125
-40ºC
+25ºC
BER (%)
1.5
1.0
0.5
+25ºC
+105ºC
315MHz
1
`
PN9 sequence
at 1kbps
-100
-75
-50
-25
0
0.0
-125
-100
-75
-50
-25
0
0.1
-116 -115 -114 -113 -112 -111 -110
Input Power (dBm)
Input Power (dBm)
Input Power (dBm)
Sensitivity at 1% BER
V
SEL1
= V
SEL0
= 0V
-98
-100
-102
-104
-106
-108
-110
-112
-114
-116
0
2
4
6
8
10
12
Bit Rate (kbps)
433.92MHz
315MHz
Sensitivity at 1% BER
V
SEL1
= 0V, V
SEL0
= 3.3V
-100
-102
Sensitivity (dBm)
Sensitivity (dBm)
Sensitivity at 1% BER
V
SEL1
= 3.3V, V
SEL0
= 0V
-98
-100
-102
-104
-106
-108
-110
-112
433.92MHz
315MHz
Sensitivity (dBm)
-104
-106
-108
433.92MHz
315MHz
-110
-112
-114
0
3
6
9
12
15 18
21
Bit Rate (kbps)
0
10
20
30
40
Bit Rate (kbps)
August 2010
5
M9999-082610-A
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