MICRF112
300MHz to 450MHz, +10dBm, 1.8V to 3.6V,
ASK/FSK Transmitter with Shutdown
General Description
The MICRF112 is a high-performance, easy to use, true
“Data-In, RF-Out,” ASK/FSK, phase-locked loop (PLL)
based, transmitter IC for applications in the 300MHz to
450MHz frequency range. These applications include
remote keyless entry (RKE) and tire pressure monitoring
(TPMS). The device needs only a low-cost crystal to
precisely set the desired RF frequency, and a few external
components for matching the power amplifier output to the
antenna.
The MICRF112 operates over the 1.8V to 3.6V operating
range and delivers +10dBm (CW) output power into a 50Ω
load, while consuming 11.5mA of supply current from a
3.0V power supply. In ASK mode, the device consumes
6.9mA of supply current at a data rate of 1kbps
(Manchester 50%). It features a low-power shutdown
mode in which the device typically consumes 50nA of
supply current. This makes it an ideal solution for battery
powered applications.
The MICRF112 is rated for the
−40°C
to +125°C
temperature range, and is available in 10-pin MSOP and
10-pin Ultra-Thin DFN packages. For automotive
applications, where AEC-Q100 qualification is required,
consider the MAQRF112. For ASK-only applications that
do not require shutdown, consider the MICRF113 in
SOT23-6.
Datasheets and support documentation can be found on
Micrel’s website at:
www.micrel.com.
Features
•
•
•
•
•
•
•
•
•
•
1.8V to 3.6V supply voltage range
Up to +10dBm output power (CW)
6.9mA supply current at 1kbps ASK (50% Manchester)
11.5mA supply current at +10dBm (FSK/CW)
1µA shutdown supply current
Data rates up to 50kbps ASK, 10kbps FSK
Crystal or ceramic resonators sets RF frequency
−40°C
to +125°C temperature range
10-pin MSOP (3.0mm x 4.9mm)
10-pin Ultra-Thin DFN (2mm x 2mm x 0.4mm)
Applications
•
•
•
•
•
•
•
•
•
Remote keyless entry systems (RKE)
Remote control (STB, HVAC, and appliances)
Garage door openers (GDO)
Tire pressure monitor systems (TPMS)
Outdoor weather stations
Security/Alarm systems
Lighting and fan remote controls
Doorbells
Irrigation control
Typical Application
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
February 2013
M9999-020713
Micrel, Inc.
MICRF112
Absolute Maximum Ratings
(1)
Supply Voltage (VDD) ................................................. +4.3V
Voltage on PAOUT ...................................................... +7.2V
Voltage on I/O Pins ........................ VSS – 0.3 to VDD + 0.3
Lead Temperature (soldering, 10s) .......................... +300°C
Storage Temperature (T
S
) .........................
−65°C
to +150°C
ESD Rating.................................................................Note 3
Operating Ratings
(2)
Supply Voltage (VDD) ...................................... 1.8V to 3.6V
Ambient Operating Temperature (T
A
) ........ -40°C to +125°C
Transmitter Frequency Range ............. 300MHz to 450MHz
Electrical Characteristics
(4)
Specifications apply for VDD = 3.0V, T
A
= 25°C, Freq
REFOSC
= 13.560MHz, EN = VDD. 1Kbps data rate, 50% duty cycle. R
L
50Ω load
(matched)
Parameter
Power Supply
Standby Supply Current, Iq
Mark Supply Current I
ON
EN = V
SS
@ 315MHz, P
OUT
= +10dBm
@ 433.92MHz, P
OUT
= +10dBm
SPACE Supply Current, I
OFF
@ 315MHz
@ 433.92MHz
RF Output Section and Modulation Limits:
Output Power Level, P
OUT
FSK or ASK "Mark"
Harmonics output for
315MHz
Harmonics Output for
433.92MHz
Extinction Ratio for ASK
FSK Modulation
Frequency Deviation
Data Rate
ASK Modulation
Data Rate
Occupied Bandwidth
VCO Section
315MHz Single Side Band
Phase Noise
433.92MHz Single Side Band
Phase Noise
Reference Oscillator Section
XTLIN, XTLOUT, XTLMOD
External Capacitance
Oscillator Start-Up Time
(6)
(4)
(4)
Condition
Min.
Typ.
Max.
Units
0.05
11.5
11.6
2.4
2.7
1
µA
mA
mA
mA
mA
@ 315MHz
10
10
−53
−53
−51
−65
80
dBm
dBm
dBc
dBc
dBc
dBc
dBc
@ 433.92MHz
@ 630MHz
@ 945MHz
(4)
(4)
2nd harm.
3rd harm.
(4)
@ 867.84MHz
2nd harm.
3rd harm.
@ 1301.76MHz
(4)
Load capacitor = 10pF, crystal type = HC49/U
22
10
kHz
Kbps
50
@ 315MHz
(5)
(5)
Kbps
kHz
kHz
<700
<1000
−76
−79
−72
−81
@ 433.92MHz
@ 100kHz from Carrier
@ 1000kHz from Carrier
@ 100kHz from Carrier
@ 1000kHz from Carrier
dBc/Hz
dBc/Hz
dBc/Hz
dBc/Hz
Pin capacitance
See Schematic C17 & C18
Crystal: HC49S
2
18
400
pF
pF
µs
February 2013
3
M9999-020713
Micrel, Inc.
Parameter
Digital/Control Section
Output Blanking
Digital Input (EN, ASK, and
FSK)
Digital Input Leakage Current
(EN, ASK, and FSK Pins)
Undervoltage Lock Out
(UVLO)
Notes:
1. Exceeding the absolute maximum rating may damage the device.
2. The device is not guaranteed to function outside its operating ratings.
3. Devices are ESD sensitive. Handling precautions recommended. Human body model, 1.5k in series with 100pF.
4. Measured using the circuit shown in the “Test Circuit” section.
5. RBW = 100kHz, OBW measured at
−20dBc.
6. Dependent on crystal.
MICRF112
Condition
Min.
Typ.
Max.
Units
STDBY transition from low to high
High (V
IH
)
Low (V
IL
)
High (V
IH
)
Low (V
IL
)
0.8 × V
DD
500
µs
V
0.2 × V
DD
V
µA
µA
V
0.05
0.05
1.6
February 2013
4
M9999-020713
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