MICRF104
Micrel
MICRF104
1.8V, QwikRadio™ UHF ASK Transmitter
Final Information
General Description
The MICRF104 is a low voltage Transmitter IC for remote
wireless applications. The device employs Micrel’s latest
QwikRadio™ technology. This device is a true “data-in,
antenna-out” device. All antenna tuning is accomplished
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. The MICRF104 incorporates a DC/DC con-
verter to boost the input voltage up to 5V for the RF portion of
the IC. This feature enables the MICRF104 to operate off
supply voltages as low as 1.8V and transmit at power in
excess of –2dBm.
The MICRF104 uses a novel architecture where the external
loop antenna is tuned to the internal UHF synthesizer. This
transmitter is designed to comply worldwide UHF unlicensed
band intentional radiator 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 from 100 to 20k bits per second.
The automatic tuning in conjunction with the external resistor,
insures that the transmitter output power stays constant for
the life of the battery.
When coupled with Micrel’s family of QwikRadio™ receivers,
the MICRF104 provides the lowest cost and most reliable
remote actuator and RF link system available.
Features
•
•
•
•
•
Complete UHF transmitter on a chip
Frequency range 300MHz to 470MHz
Data rates to 20kbps
Automatic antenna alignment, no manual adjustment
Low external part count
Applications
•
•
•
•
Remote Keyless Entry Systems (RKE)
Remote Fan/Light Control
Garage Door Opener Transmitters
Remote Sensor Data Links
Ordering Information
Part Number
MICRF104BM
Temperature Range
0°C to +85°C
Package
14-Pin SOIC
Typical Application
L1
22µH
MICRF104
1.8V to 4V
Supply
1
10µF
2
3
4
5
VDDPWR
VSS
5V
VSS
REFOSC
EN
VSS
SW
PC
14
13
12
0.1µF
11
100pF 10µF
Power
Control
VDDRF
RF Standby
6
7
10
9
RFSTBY
ANTM
ASK
ANTP
8
DATA IN
LOOP
ANTENNA
(PCB TRACE)
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
November 8, 2001
1
MICRF104
MICRF104
Micrel
Pin Configuration
VDDPWR 1
VSS 2
5V 3
VSS 4
REFOSC 5
RFSTBY 6
ANTM 7
14 EN
13 VSS
12 SW
11 PC
10 VDDRF
9 ASK
8 ANTP
MICRF104BM
Pin Description
Pin Number
1
2, 4, 13
3
5
Pin Name
VDDPWR
VSS
5V
REFOSC
Pin Function
Positive power supply input for the DC/DC converter.
Ground return
5V Output from the DC / DC converter
This is the timing reference frequency which is the transmit frequency
divided by 32. 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
Input for transmitter standby control pin is pulled to VDDRF for transmit
operation and VSS for stand-by mode.
Negative RF power output to drive the low side of the transmit loop antenna
Positive RF power output to drive the high side of the transmit loop antenna
Amplitude Shift Key modulation data input pin.
Positive power supply input for the RF circuit. A power supply bypass
capacitor connected from VDDRF to VSS should have the shortest possible
path.
Power Control Input. The voltage at this pin should be set between 0.3V to
0.4V for normal operation.
DC/DC converter Switch. NPN output switch transistor collector.
Chip Enable input. Active high
6
7
8
9
10
RFSTBY
ANTM
ANTP
ASK
VDDRF
11
12
14
PC
SW
EN
MICRF104
2
November 8, 2001
MICRF104
Micrel
Absolute Maximum Ratings
(Note 1)
Supply Voltage(V
DDPWR
, V
DDRF
) .................................. +6V
Voltage on I/O Pin EN .................................................. [tbd]
Voltage on I/O Pins, RFSTBY, ASK, PC, ANTP, ANTM
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
DDPWR
) .................................. 1.8V to 4V
PC Input Range .................................. 0.15V < V
PC
< 0.35V
Ambient Operating Temperature (T
A
) ............ 0°C to +85°C
Programmable Transmitter Frequency Range: 300MHz to
470MHz
Electrical Characteristics
Specifications apply for V
DDPWR
= 1.8V, V
PC
= 0.35V, freq
REFOSC
= 12.1875MHz, RFSTBY = V
DDRF
, EN = V
DDPWR
.
T
A
= 25°C,
bold
values indicate 0°C
≤
T
A
≤
85°C unless otherwise noted.
Parameter
Power Supply
Shutdown current, I
VDDPWR
RF Standby supply, I
VDDPWR
RF Standby supply, I
VDDPWR
MARK supply current, I
ON
SPACE supply current, I
OFF
V
DDPWR
= 4V
Mean operating current
33% mark/space ratio, Note 4
33% mark/space ratio, V
DDRWR
= 4V, Note 4
5V Max. output current
Note 9, V
DDPWR
= 4V
5V Output Voltage range
Note 9
RF Output Section and Modulation Limits:
Output power level, P
OUT
Transmitted Power
@315MHz; Note 4, Note 5
@433MHz; Note 4, Note 5
@315MHz
@433MHz
Harmonics output
@ 315MHz
@433 MHz
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)
0.2
300
6
0.5
kΩ
µA
V
PP
Note 7
2nd harm.
3rd harm.
2nd harm.
3rd harm.
40
5
–2
–2.5
tbd
tbd
–46
–45
–50
–41
52
6.5
8
dBm
dBm
µV/m
µV/m
dBc
dBc
dBc
pF
15
35
4.75
5.25
EN = RFSTBY = V
SS
RFSTBY = V
SS
, EN = V
DDPWR
RFSTBY = V
SS
, EN = V
DDPWR
= 4V
Note 4,
Note 4, V
DDPWR
= 4V
50
1.5
0.6
31
12
22
9
25
10
41
17
30
12
34
14
µA
mA
mA
mA
mA
mA
mA
mA
mA
mA
mA
V
Condition
Min
Typ
Max
Units
November 8, 2001
3
MICRF104
MICRF104
Parameter
Digital / Control Section
Calibration time
Power amplifier output hold off
time from STBY
Transmitter Stabilization Time
From STBY
Maximum Data rate
- ASK modulation
V
RFSTBY
Enable Voltage
STBY Sink Current
V
EN
Enable Voltage
EN pin current
ASK pin
V
IH
, input high voltage
V
IL
, input low voltage
ASK input current
Note 1.
Note 2.
Note 3.
Note 4.
Micrel
Condition
Min
Typ
Max
Units
Note 8, ASK=HIGH
Note 9, STDBY transition from LOW to HIGH
Crystal, ESR < 20Ω
From External Reference (500mVpp)
Crystal, ESR < 20Ω
Duty cycle of the modulating signal = 50%
20
25
6
10
19
ms
ms
ms
ms
kbits/s
V
6.5
µA
V
0.3
V
µA
V
0.2V
DDRF
V
µA
0.75V
DDRF
0.6V
DDRF
5
High
Low
–10
0.8V
DDRF
–10
0.1
0.95V
DDPWR
10
ASK = 0V, 5.0V input current
10
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.
Supply current and output power are a function of the voltage input on the PC (power control) pin. All specifications in the Electrical Charac-
teristics table applies for condition V
PC
= 350mV. Increasing the voltage on the PC pin will increase transmit power and also increase MARK
supply current. Refer to the graphs "Output Power Versus PC Pin Voltage" and "Mark Current Versus PC Pin Voltage."
Output power specified into a 50Ω equivalent load using the test circuit in Figure 5.
Transmitted power measured 3 meters from the antenna using transmitter board TX102-2A in Figure 6.
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.
When the device is first powered up or it loses power momentarily, it goes into the calibration mode to tune up the transmit antenna.
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.
Note 5.
Note 6.
Note 7.
Note 8.
Note 9.
Note 10.
The MICRF102 was tested to be Compliant to Part 15.231 for maximum allowable TX power, when operated in accordance with a loop
antenna described in Figure 6.
MICRF104
4
November 8, 2001
MICRF104
Micrel
Typical Characteristics
Output Power vs
PC Pin Voltage
5
OUTPUT POWER (dBm)
0
CURRENT (mA)
Mark Current vs
PC Pin Voltage
25
20
15
10
5
0
0
-5
-10
-15
-20
-25
-30
-35
0
100 200 300 400 500 600
V
PC
(mV)
100 200 300 400 500 600
V
PC
(mV)
November 8, 2001
5
MICRF104
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