MICRF219A
300MHz to 450MHz ASK/OOK Receiver with
Auto-Poll, RSSI, and Squelch
General Description
The MICRF219A 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 MICRF219A is ideal for low-cost, low-power, RKE,
TPMS, and remote actuation applications.
The MICRF219A 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
Auto-polling mode with bit checking
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
13μA supply current in sleep mode
0.1μA supply current in shutdown mode
16-pin QSOP package (4.9mm x 6.0mm)
−40°C
to +105°C temperature range
3kV HBM ESD Rating
Ordering Information
Part Number
MICRF219AAYQS
Temperature Range
–40°C to +105°C
Package
16-Pin QSOP
_________________________________________________________________________________________________________________________
Typical Application
MICRF219A Typical Application Circuit (433.92MHz, 1kbps)
Micrel Inc. • 2180 Fortune Drive • San Jose, CA 95131 • USA • tel +1 (408) 944-0800 • fax + 1 (408) 474-1000 •
http://www.micrel.com
March 2011
M9999-032511-A
RadioTech@micrel.com
or (408) 944-0800
Micrel, Inc.
MICRF219A
Pin Configuration
MICRF219AAYQS
Pin Description
Pin
Number
1
2
3
4
5
6
7
Pin
Name
RO1
GNDRF
ANT
GNDRF
VDD
SQ
SEL0
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.
Tie this pin to VDD to ensure robust register programming. Use register bits D[4:3] to set 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. To ensure
that the part starts up correctly, connect a 1μF capacitor from VDD to SHDN, and a 50kΩ resistor from
SHDN pin to GND. After the supply voltage settles, apply a HIGH logic level voltage to SHDN to turn the
part off, then a LOW logic level voltage to turn the part on before programming or operating the device.
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.
Tie this pin to VDD to ensure robust register programming. Use register bits D[4:3] to set demodulation
bandwidth.
8
SHDN
9
10
11
GND
DO
SEL1
March 2011
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or (408) 944-0800
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MICRF219A
Pin Description (Continued)
Pin
Number
12
13
14
15
16
Pin
Name
CTH
CAGC
RSSI
SCLK
RO2
Pin Function
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.
Programming clock input.
Reference resonator connection to the Pierce oscillator. Internal capacitance of 7pF to GND during normal
operation.
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or (408) 944-0800
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MICRF219A
Absolute Maximum Ratings
(1)
Supply Voltage (V
DD
)......................................................+5V
ANT, SQ, SEL0, SEL1, SCLK,
SHDN DC Voltage. ........................
−0.3V
to V
DD
+ 0.3V
Junction Temperature .............................................. +150°C
Lead Temperature (soldering, 10sec.)..................... +300°C
Storage Temperature (T
S
).........................−65°C 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
Maximum Input RF Power...........................................0dBm
Receive Modulation Duty Cycle ........................20% to 80%
Frequency Range................................. 300MHz to 450MHz
Electrical Characteristics
(4)
V
DD
= 3.3V, V
SHDN
= 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
Sleep Current
Shutdown Current
Receiver
433.92MHz, D[4:3] = 00, BER = 1%
Conducted Receiver Sensitivity @
1kbps (Note 5)
433.92MHz, D[4:3] = 00, BER = 0.1%
315MHz, D[4:3] = 01, BER = 1%
315MHz, D[4:3] = 01, 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
= 315MHz
f
RF
= 433.92MHz
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
Only sleep clock is on
V
SHDN
= V
DD
Min.
Typ.
4.3
6.0
13
0.1
Max.
Units
mA
µA
µA
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MICRF219A
Electrical Characteristics
(4)
(Continued)
V
DD
= 3.3V, V
SHDN
= 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
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 MICRF219A DO pin:
Condition
f
REF
= 9.81713MHz
f
REF
= 13.52313MHz
T
A
= +25ºC
T
A
= +105ºC
As output source @ 0.8V
DD
As output sink @ 0.2V
DD
15pF load on DO pin, transition time between
0.1V
DD
and 0.9V
DD
SHDN, SQ
SHDN, SQ
DO
DO
−110dBm
RF input level
−50dBm
RF input level
5kΩ load to GND,
−50dBm
RF input level
D[4:3] = 00, 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 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 test, the typical source impedance value is verified with
12MHz reference frequency.
6.
March 2011
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