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PDF TH72001 Data sheet ( Hoja de datos )
| Número de pieza | TH72001 | |
| Descripción | 315MHz FSK Transmitter | |
| Fabricantes | Melexis | |
| Logotipo |  |
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Hay una vista previa y un enlace de descarga de TH72001 (archivo pdf) en la parte inferior de esta página. Total 20 Páginas | ||
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Features
Fully integrated PLL-stabilized LC VCO
Frequency range of 290MHz to 350MHz
Single-ended RF output
FSK through crystal pulling allows modulation
from DC to 40 kbit/s
High FSK deviation possible for wideband data
transmission
Wide power supply range from 2.1 V to 5.5 V
Very low standby current
On-chip low voltage detector
TH72001
315MHz
FSK Transmitter
High over-all frequency accuracy
FSK deviation and center frequency
independently adjustable
Adjustable output power range from
-12 dBm to +11 dBm
Adjustable current consumption from
3.2 mA to 10.3 mA
Conforms to EN 300 220 and similar standards
8-pin Small Outline Integrated Circuit (SOIC)
Ordering Code
Product Code Temperature Code
TH72001
K
TH72001
K
Package Code
DC
DC
Option Code
BAA-000
BAA-000
Packing Form Code
RE
TU
Legend:
Temperature Code:
Package Code:
Packing Form:
K for Temperature Range -40°C to 125°C
DC for SOIC
RE for Reel, TU for Tube
Ordering example:
TH72001KDC-BAA-000-RE
Application Examples
General digital data transmission
Tire Pressure Monitoring System (TPMS)
Remote Keyless Entry (RKE)
Low-power telemetry
Alarm and security systems
Garage door openers
Home automation
Pin Description
FSKDTA 1
FSKSW 2
ROI 3
ENTX 4
TH72001
8 VEE
7 OUT
6 VCC
5 PSEL
General Description
The TH72001 FSK transmitter IC is designed for applications in the 315 MHz industrial-scientific-medical
(ISM) band. It can also be used for any other system with carrier frequencies at
290 to 350MHz.
The transmitter's carrier frequency fc is determined by the frequency of the reference crystal fref. The
integrated PLL synthesizer ensures that the radio frequency (RF) can be achieved by using a crystal with a
reference frequency according to: fref = fc/N, where N = 32 is the PLL feedback divider ratio.
3901072001
Rev. 010
Page 1 of 20
Data Sheet
Jun/12
1 page  
TH72001
315MHz
FSK Transmitter
2.4 Output Power Selection
The transmitter is provided with an output power selection feature. There are four predefined output power
steps and one off-step accessible via the power selection pin PSEL. A digital power step adjustment was
chosen because of its high accuracy and stability. The number of steps and the step sizes as well as the
corresponding power levels are selected to cover a wide spectrum of different applications.
The implementation of the output power control
logic is shown in figure 4. There are two
matched current sources with an amount of
about 8 µA. One current source is directly
applied to the PSEL pin. The other current
source is used for the generation of reference
voltages with a resistor ladder. These reference
voltages are defining the thresholds between
the power steps. The four comparators deliver
thermometer-coded control signals depending
on the voltage level at the pin PSEL. In order to
have a certain amount of ripple tolerance in a
noisy environment the comparators are
provided with a little hysteresis of about 20 mV.
With these control signals, weighted current
sources of the power amplifier are switched on
or off to set the desired output power level
(Digitally Controlled Current Source). The
LOCK signal and the output of the low voltage
detector are gating this current source.
RPS
PSEL
&
&
&&&
OUT
Fig. 4: Block diagram of output power control circuitry
There are two ways to select the desired output power step. First by applying a DC voltage at the pin PSEL,
then this voltage directly selects the desired output power step. This kind of power selection can be used if
the transmission power must be changed during operation. For a fixed-power application a resistor can be
used which is connected from the PSEL pin to ground. The voltage drop across this resistor selects the
desired output power level. For fixed-power applications at the highest power step this resistor can be
omitted. The pin PSEL is in a high impedance state during the “TX standby” mode.
2.5 Lock Detection
The lock detection circuitry turns on the power amplifier only after PLL lock. This prevents from unwanted
emission of the transmitter if the PLL is unlocked.
2.6 Low Voltage Detection
The supply voltage is sensed by a low voltage detect circuitry. The power amplifier is turned off if the supply
voltage drops below a value of about 1.85 V. This is done in order to prevent unwanted emission of the
transmitter if the supply voltage is too low.
3901072001
Rev. 010
Page 5 of 20
Data Sheet
Jun/12
5 Page 
5 Typical Operating Characteristics
5.1 DC Characteristics
I SBY
5µA
4µA
3µA
2µA
1µA
200nA
Standby current
150nA
100nA
50nA
0
2.0 2.5 3.0 3.5 4.0 4.5
Vcc [V]
Fig. 6: Standby current limits
TH72001
315MHz
FSK Transmitter
125°C
85°C
25°C
5.0 5.5
6.0
power step 0
3.0
125°C
2.8 105°C
85°C
2.6
2.4 25°C
0°C
2.2
-20°C
2.0
-40°C
1.8
1.8 2.2 2.6 3.0 3.4 3.8 4.2 4.6 5.0 5.4 5.8
Vcc [V]
Fig. 7: Supply current in power step 0
3901072001
Rev. 010
Page 11 of 20
Data Sheet
Jun/12
11 Page | ||
| Páginas | Total 20 Páginas | |
| PDF Descargar | [ Datasheet TH72001.PDF ] | |
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