MICRF103
Micrel
MICRF103
QwikRadio™ UHF ASK Transmitter
Final
General Description
The MICRF103 is a single chip Transmitter IC for remote
wireless applications. The device employs Micrel’s latest
QwikRadio™ technology. This device is a true ”data-in,
antenna-out” monolithic device. All antenna tuning is accom-
plished automatically within the IC which eliminates manual
tuning, and reduces production costs. The result is a highly
reliable yet extremely low cost solution for high volume
wireless applications. Because the MICRF103 is a true
single-chip radio transmitter, it is easy to apply, minimizing
design and production costs, and improving time to market.
The MICRF103 uses a novel architecture where the external
antenna is tuned by the internal UHF synthesizer. This
transmitter is designed to comply worldwide UHF unlicensed
band international radio regulations. The IC is compatible
with virtually all ASK/OOK (Amplitude Shift Keying/On-Off
Keyed) UHF receiver types from wide-band super-regenera-
tive radios to narrow-band, high performance super-hetero-
dyne receivers. The transmitter is designed to work with
transmitter data rates up to 115k bits per second.
The automatic tuning in conjunction with an external resistor,
insures that the transmitter output power stays constant at
maximum regulatory transmit power limits for the life of the
battery.
When coupled with Micrel’s family of QwikRadio™ receivers,
the MICRF103 provides the lowest cost and most reliable
remote actuator and RF link system available.
Features
•
•
•
•
•
•
•
•
•
•
Complete UHF transmitter on a monolithic chip
Frequency range 800MHz to 1GHz
Data rates to 115kbps
Automatic antenna alignment, no manual adjustment
Low external part count
Low standby current <1µA
Remote keyless entry systems (RKE)
Remote fan/light control
Garage door opener transmitters
Remote sensor data links
Applications
Ordering Information
Part Number
MICRF103BM
Temperature Range
–40°C to +85°C
Package
8-Pin SOIC
Typical Application
+5V
ASK DATA INPUT
4.7µF
RP1
100k
0.1µF
RP2
6.8k
MICRF103
PC
VDD
VSS
REFOSC
ASK
ANTP
1.0pF
8.2pF
27nH
10nH
ANTM
STBY
SAW Filter
1.0pF
100pF
50Ω
Monopole
PCB Antenna
Y1
27nH
100k
+5V
Note:
Example for 868MHz
Figure 1
QwikRadio is a trademark of Micrel, Inc. The QwikRadio ICs were developed under a partnership agreement with AIT of Orlando, Florida.
Micrel, Inc. • 1849 Fortune Drive • San Jose, CA 95131 • USA • tel + 1 (408) 944-0800 • fax + 1 (408) 944-0970 • http://www.micrel.com
June 2002
1
MICRF103
MICRF103
Micrel
Pin Configuration
PC 1
VDD 2
VSS 3
REFOSC 4
8 ASK
7 ANTP
6 ANTM
5 STBY
MICRF103BM
Pin Description
Pin Number
1
2
3
4
Pin Name
PC
VDD
VSS
REFOSC
Pin Function
Power Control Input. The voltage at this pin should be set between 0.1V to
0.4V for normal operation.
Positive power supply input for the IC.
This pin is the ground return for the IC. A power supply bypass capacitor
connected from VDD to VSS should have the shortest possible path.
This is the timing reference frequency which is the transmit frequency
divided by 64. Connect a crystal (mode dependent) between this pin and
VSS, or drive the input with an AC coupled 0.5Vpp input clock. See
Refer-
ence Oscillator
section in this data sheet under
Electrical Characteristics.
Input for transmitter stand-by control pin is pulled to VDD for transmit
operation and VSS for stand-by mode.
Negative RF power output to drive one side of the transmit antenna.
Positive RF power output to drive the other side of the transmit antenna.
Amplitude Shift Key modulation data input pin. For CW operation, connect
this pin to VDD.
5
6
7
8
STBY
ANTM
ANTP
ASK
MICRF103
2
June 2002
MICRF103
Micrel
Absolute Maximum Ratings
(Note 1)
Supply Voltage(V
DD
) ..................................................... +6V
Voltage on I/O Pins ............................. V
SS
–0.3 to V
DD
+0.3
Storage Temperature Range ................... -65°C to + 150°C
Lead Temperature (soldering, 10 seconds) ........... + 300°C
ESD Rating,
Note 3
Operating Ratings
(Note 2)
Supply Voltage (V
DD
) .................................... 4.75V to 5.5V
Maximum Supply Ripple Voltage ............................... 10mV
PC Input Range ...................................... 0.1V < V
PC
< 0.4V
Ambient Operating Temperature (T
A
) ........ –40°C to +85°C
Programmable Transmitter Frequency Range:
........................................................ 800MHz to 1GHz
Electrical Characteristics
Specifications apply for 4.75V < V
DD
< 5.5V, V
PC
= 0.35V, T
A
= 25°C, freq
REFOSC
= 13.5625MHz, STBY = V
DD
.
Bold
values indicate
–40°C
≤
T
A
≤
85°C unless otherwise noted.
Parameter
Power Supply
Standby Supply Current, I
Q
MARK Supply Current, I
ON
SPACE Supply Current, I
OFF
MARK/SPACE Ratio
V
STBY
< 0.5V
@868MHz
@915MHz
@868MHz
@915MHz
33%@868MHz
33%@915MHz
RF Output Section and Modulation Limits:
Maximum Power Level, P
OUT
Output Power Variation
Extinction ratio for ASK
Varactor tuning range
Reference Oscillator Section
Reference Oscillator Input
Impedance
Reference Oscillator Source
Current
Reference Oscillator Input
Voltage (peak-to-peak)
Digital / Control Section
Calibration Time
Power Amplifier Output Hold-off
Time from STBY
Transmitter Stabilization Time
From STBY
Maximum Data rate
- ASK modulation
STBY HIGH
STBY LOW
ASK Pin
V
IH
V
IL
V
IH
, input high voltage
V
IL
, input low voltage
ASK Input Current
ASK = 0V, 5.0V input current
–10
0.1
0.8V
DD
0.1V
DD
10
note 7, ASK=HIGH
note 4, STDBY transition from LOW to HIGH
crystal, ESR < 20Ω
from external reference (500mVpp)
crystal, ESR < 20Ω
duty cycle of the modulating signal = 50%
enable voltage
115
0.8V
DD
0.1V
DD
V
V
µA
20
5
9
12
ms
ms
ms
ms
kbits/s
V
0.2
300
5.0
1.0
kΩ
µA
V
PP
Note 5
@868MHz (EIRP)
@915MHz (EIRP)
over supply and temperature
38
2.6
-3
-3
±2
45
3.0
3.3
dBm
dBm
dBm
dBc
pF
0.10
19
20
14
15
16
17
26.5
27.5
18
21
µA
mA
mA
mA
mA
mA
mA
Condition
Min
Typ
Max
Units
June 2002
3
MICRF103
MICRF103
Note 1.
Note 2.
Note 3.
Note 4.
Exceeding the absolute maximum rating may damage the device.
The device is not guaranteed to function outside its operating rating.
Devices are ESD sensitive. Handling precautions recommended. Human body model, 1.5k in series with 100pF.
Micrel
After the release of the STDBY, the device requires an initialization time to settle the REFOSC and the internal PLL. The first MARK state
(ASK HIGH) after exit from STDBY needs to be longer than the initialization time. The subsequent low to high transitions will be treated as
data modulation whereby the envelope transition time will apply.
The varactor capacitance tuning range indicates the allowable external antenna component variation to maintain tune over normal production
tolerances of external components. Guaranteed by design not tested in production.
For the ASK modulation scheme, the part will accept ASK (digital ON/OFF) input and will transmit the data with a finite extinction ratio and the
pin will set the MARK power level.
When the device is first powered up or it loses power momentarily, it goes into the calibration mode to tune up the transmit antenna.
Note 5.
Note 6.
Note 7.
Test Circuit
MICRF103
PC
VDD
VSS
REFOSC
STBY
ANTP
7.1nH
200Ω
680pF
100Ω
50Ω
680pF
100Ω
4:1
ANTM
ASK
MICRF103
4
June 2002
MICRF103
Micrel
Typical Characteristics
Mark Current
vs. PC Voltage
35
30
MARK I
ON
(mA)
25
20
15
10
5
0
0
0.1 0.2 0.3 0.4 0.5 0.6 0.7
V
PC
(V)
MARK P
OUT
(dBm)
30
20
10
0
-10
-20
-30
-40
-50
0
0.1 0.2 0.3 0.4 0.5 0.6 0.7
V
PC
(V)
Output Power
vs. PC Pin Voltage
June 2002
5
MICRF103
NXP MCU
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