冰箱调温度Absolute Maximum Ratings
·Designed for Short-Range Wireless Data Communications ·Supports RF Data Transmission Rates Up to 115.2kbps ·3V,Low Current Operation plus Sleep Mode ·Stable,Easy to U,Low External Parts Count
TX5001
315.00MHz Hybrid Transmitter
The TX5001hybrid transmitter is ideal for short-range wireless data applications
where robust operation,small size,low power consumption and low cost are required.All critical RF functions are contained in the hybrid,simplifying and speeding design-in.The TX5001includes provisions for both on-off keyed (OOK)and amplitude-shift keyed (ASK)modulation.The TX5001employs SAW filtering to suppress output har-monics,facilitating compliance with FCC Part 15and similar regulations.
Transmitter Set-Up,3.0Vdc,-40to +850C最大的沙漠
Notes:
1.Do not allow the voltage applied to a control input pin to exceed Vcc +200mV.
2.The companion receiver to the TX6000is the RX6000.Plea e RFM’s web site at for details.
份内之事CAUTION:Electrostatic Sensitive Device.Obrve precautions when handling.
Transmitter Theory of Operation
Introduction
贝克特RFM’s TX-ries hybrid transmitters are specifically designed for short-range wireless data communication applications.The trans-mitters provide robust operation,very small size,low power con-sumption and low implementation cost.All critical RF functions are contained in the hybrid,simplifying and speeding design-in.The transmitters can be readily configured to support a wide range of data rates and protocol requirements.TX-ries transmitters feature excellent suppres
sion of output harmonics and virtually no other RF emissions,making them easy to certify to short-range(unlicend) radio regulations.
Transmitter Block Diagram
Figure1is the general block diagram of the transmitter.Plea refer to Figure1for the following discussions.
Antenna Port
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The only external RF components needed for the transmitter are the antenna and its matching components.Antennas prenting an im-pedance in the range of35to72ohms resistive can be satisfactorily matched to the RFIO pin with a ries matching coil and a shunt matching/ESD protection coil.Other antenna impedances can be matched using two or three components.For some impedances, two inductors and a capacitor will be required.A DC path from RFIO to ground is required for ESD protection.Transmitter Chain
The transmitter chain consists of a SAW coupled-resonator oscilla-tor followed by a modulated buffer amplifier.The SAW coupled res-onator output filter suppress transmitter harmonics to the antenna.
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Transmitter operation supports two modulation formats,on-off keyed(OOK)modulation,and amplitude-shift keyed(ASK)modula-tion.When OOK modulation is chon,the transmitter output turns completely off between“1”data puls.When ASK modulation is chon,a“1”pul is reprented by a higher transmitted power level,and a“0”is reprented by a lower transmitted power level. OOK modulation provides compatibility with first-generation ASH technology,and provides for power conrvation.ASK modulation must be ud for high data rates(data puls less than200µs). ASK modulation also reduces the effects of some types of interfer-ence and allows the transmitted puls to be shaped to control mod-ulation bandwidth.
The modulation format is chon by the state of the CNTRL0and the CNTRL1mode control pins,as discusd below.In the OOK mode,the oscillator amplifier TXA1and buffer amplifier TXA2are turned off when the voltage to the TXMOD input falls below220mV. In the OOK mode,the data rate is limited by the20/15µs turn-on and turn-off time of the oscillator.In the ASK mode TXA1is biad ON continuously,and the output of TXA2is modulated by the TXMOD input current.Minimum output power occurs in the ASK mode when the modulation driver sinks about10µA of current from the TXMOD pin.
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Figure1
The transmitter RF output power is proportional to the input current to the TXMOD pin.A ries resistor is ud to adjust the peak trans-mitter output power.0dBm of output power requires about250µA of input current.
Transmitter Mode Control
The three transmitter operating modes–transmit ASK,transmit OOK,and power-down(sleep),are controlled by the Modulation& Bias Control function,and are lected with the CNTRL1and CNTRL0control pins.Setting CNTRL1high and CNTRL0low place the unit in the ASK transmit mode.Setting CNTRL1low and CNTRL0high place the unit in the OOK transmit mode.Setting CNTRL1and CNTRL0both low place the unit in the power-down mode.(Note that the resistor driving TXMOD must also be low in the power-down mode to minimize power-down current.)CNTRL1and CNTRL0are CMOS compatible inputs.The inputs must be held at a logic level;they cannot be left unconnected.Turn-On Timing孙悟空的样子
The maximum time required for either the OOK or ASK transmitter mode to become operational is5ms after the supply voltage reaches2.2Vdc.The total turn-on time to stable transmitter opera-tion for a10ms power supply ri time is15ms.
Sleep and Wake-Up Timing
The maximum transition time from either transmit mode to the sleep mode(t TOS and t TAS)is15µs after CNTRL1and CNTRL0are both low(1µs fall time).
The maximum time required to switch from the sleep mode to either transmit mode(t STO and t STA)is21µs.Most of this time is due to the start-up of the transmitter oscillator.
