Datasheet TX5000 Datasheet (RFM)

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Page 1

· Designed for Short-Range Wireless Data Communications

· Supports RF Data Transmission Rates Up to 115.2 kbps

· 3 V, Low Current Operation plus Sleep Mode

· Stable, Easy to Use, Low External Parts Count

TX5000

433.92 MHz Hybrid

The TX5000 hybrid transmitter is ideal for short-range wireless data applications

Transmitter

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 designin. The TX5000 includes provisions for both on-off keyed (OOK) and amplitude-shift keyed (ASK) modulation. The TX5000 employs SAW filtering to suppress output har

monics, facilitating compliance with ETSI I-ETS 300 220 and similar regulations.

Absolute Maximum Ratings

Rating Value Units

Power Supply and All Input/Output Pins -0.3 to +4.0 V

Non-Operating Case Temperature -50 to +100

Soldering Temperature (10 seconds) 250

Electrical Characteristics

Characteristic Sym Notes Minimum Typical Maximum Units

Operating Frequency f

Modulation Types OOK & ASK

OOK Data Rate 10 kbps

ASK Data Rate 115.2 kbps

Transmitter Performance

Peak RF Output Power, 250 µA TXMOD Current P

Peak Current, 250 µA TXMOD Current I

OOK Turn On/Turn Off Times t

ASK Output Rise/Fall Times t

nd-4th

Harmonic Outputs -50 dBm

-10thHarmonic Outputs -55 dBm

Non-harmonic Spurious Outputs -50 dBm

Sleep Mode Current I

Sleep to Transmit Switch Time t

Transmit to Sleep Switch Time t

Control Input Logic Low Level 200 mV

Control Input Logic High Level 1 Vcc - 300 mV

Power Supply Voltage Range V

Operating Ambient Temperature T

ON/tOFF

TR/tTF

TOR

RTO

433.72 434.12 MHz

0 dBm

7.5 mA

20/15 µs

1.1/1.1 µs

0.7 µA

21 µs

15 µs

2.2 3.7 Vdc

-40 +85

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Transm itter O O K Configuration

Transm itter ASK Configuration

+ 3

VDC

T/S

GND3CNT

ESD

CNT

RL0

RL1PWIDTHPRATE

RFIO

GND1

AGC

VCC

DET

CAP

23456789

RFB

RFB1

+ 3

VDC

RFB2

TOP VIEW

VCC

DCB

CMP

DATA

INBBOUT

TXM

Transmitter Set-Up, 3.0 Vdc, -40 to +850C

Item Symbol OOK ASK ASK Units Notes

Nominal NRZ Data Rate

Minimum Signal Pulse SP

Maximum Signal Pulse SP

TXMOD Resistor R

DC Bypass Capacitor C

RF Bypass Capacitor 1 C

RF Bypass Capacitor 2 C

RF Bypass Bead L

Series Tuning Inductor L

Shunt Tuning/ESD Inductor L

NOM

MIN

MAX

TXM

DCB

RFB1

RFB2

RFB

ESD

+ 3

VDC

THLD1THLD

RREF

GND2

LPF

MOD

ADJ

1213141516171819

M odulation Input

GND3CNT

ESD

CNT

RL0

RL1PWIDTHPRATE

RFIO

GND1

AGC

VCC

DET

CAP

23456789

RFB

RFB1

+ 3

VDC

RFB2

T/S

TOP VIEW

VCC

DCB

1213141516171819

THLD1THLD

CMP

DATA

INBBOUT

RREF

GND2

LPF

MOD

ADJ

TXM

2.4 19.2 115.2 kbps see page 1

416.67 52.08 8.68 µs single bit

1666.68 208.32 34.72 µs 4 bits of same value

8.2 8.2 8.2 K ±5%, for 0 dBm output

4.7 4.7 4.7 µF tantalum

27 27 27 pF ±5% NPO

100 100 100 pF ±5% NPO

Fair-Rite Fair-Rite Fair-Rite vendor 2506033017YO or equivalent

56 56 56 nH 50 ohm antenna

220 220 220 nH 50 ohm antenna

M odulation Input

CAUTION: Electrostatic Sensitive Device. Observe precautions when handling.

Notes:

1. Do not allow the voltage applied to a control input pin to exceed Vcc + 200 mV.

2. The companion receiver to the TX6000 is the RX6000. Please see RFM’s web site at www.rfm.com for details.

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Transmitter Theory of Operation

Introduction

RFM’s TX-series hybrid transmitters are specifically designed for short-range wireless data communication applications. These 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-series transmitters feature excellent suppression of output harmonics and virtually no other RF emissions, making them easy to certify to short- range (unlicensed) radio regulations.

Transmitter Block Diagram

Figure 1 is the general block diagram of the transmitter. Please refer to Figure 1 for the following discussions.

Antenna Port

The only external RF components needed for the transmitter are the antenna and its matching components. Antennas presenting an im pedance in the range of 35 to 72 ohms resistive can be satisfactorily matched to the RFIO pin with a series 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 suppresses transmitter harmonics to the antenna.

Transmitter operation supports two modulation formats, on-off

keyed (OOK) modulation, and amplitude-shift keyed (ASK) modula tion. When OOK modulation is chosen, the transmitter output turns completely off between “1” data pulses. When ASK modulation is chosen, a “1” pulse is represented by a higher transmitted power level, and a “0” is represented by a lower transmitted power level. OOK modulation provides compatibility with first-generation ASH technology, and provides for power conservation. ASK modulation must be used for high data rates (data pulses less than 200 µs). ASK modulation also reduces the effects of some types of interfer ence and allows the transmitted pulses to be shaped to control mod ulation bandwidth.

The modulation format is chosen by the state of the CNTRL0 and the CNTRL1 mode control pins, as discussed below. In the OOK mode, the oscillator amplifier TXA1 and buffer amplifier TXA2 are

turned off when the voltage to the TXMOD input falls below 220 mV. In the OOK mode, the data rate is limited by the 20/15 µs turn-on and turn-off time of the oscillator. In the ASK mode TXA1 is biased ON continuously, and the output of TXA2 is modulated by the TXMOD input current. Minimum output power occurs in the ASK mode when the modulation driver sinks about 10 µA of current from the TXMOD pin.

Transm itter B lock D iagram

SAW

Coupled

R esonator

TXA1 TXA2

M odulation

& Bias Control

TXM

TRL1CNTRL0

Figure 1

SAW

F ilte r

Antenna

Ant

Tune

Tune/E S D

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The transmitter RF output power is proportional to the input current to the TXMOD pin. A series resistor is used to adjust the peak trans mitter output power. 0 dBm of output power requires about 250 µA 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 selected with the CNTRL1 and CNTRL0 control pins. Setting CNTRL1 high and CNTRL0 low place the unit in the ASK transmit mode. Setting CNTRL1 low and CNTRL0 high place the unit in the OOK transmit mode. Setting CNTRL1 and CNTRL0 both 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.) CNTRL1 and CNTRL0 are CMOS compatible inputs. These inputs must be held at a logic level; they cannot be left unconnected.

Turn-On Timing

The maximum time required for either the OOK or ASK transmitter

mode to become operational is 5 ms after the supply voltage reaches 2.2 Vdc. The total turn-on time to stable transmitter opera tion for a 10 ms power supply rise time is 15 ms.

Sleep and Wake-Up Timing

The maximum transition time from either transmit mode to the sleep

and t

mode (t

TOS

) is 15 µs after CNTRL1 and CNTRL0 are both

TAS

low (1 µs fall time).

The maximum time required to switch from the sleep mode to either

and t

transmit mode (t

STO

) is 21 µs. Most of this time is due to the

STA

start-up of the transmitter oscillator.

0.43" (10.9)

SM -20L P ackage D raw in g

0.38"

(9.65)

0.08" (2.03)

0.13" (3.30)

0.125" (3 .20 )

0.02" (0 .51 )

0.04" (1 .02 )

0.075" (1 .90 )

.4 6 0 0

Transm itter P in O ut

RFIO

GND3

CNTRL0

CNTRL1

VCC2

GND1

201

VCC1

TXM O D NC

GND2

.1 9 7 5

.2 1 2 5

.2 3 7 5

.1 7 2 5

.3 8 2 5

.3 5 7 5

.3 1 7 5

.2 7 7 5

.2 3 7 5

.1 9 7 5

.1 5 7 5

.1 1 7 5 .1 0 2 5

.0 7 7 5

0.000

.1 4 0

0.000

D im ensions in inches

S M -2 0 L P C B P a d L a y o u t

.2 7 0

.4 1 0

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Pin Descriptions

Pin Name Description

1 GND1 GND1 is the RF ground pin. GND2 and GND3 should be connected to GND1 by short, low-inductance traces.

2 VCC1

VCC1 is usually connected to the positive supply through a ferrite RF decoupling bead which is bypassed by an RF capacitor on the supply side. See the description of VCC2 (Pin 16) for additional information.

3 NC No connection. Printed circuit board pad may be grounded or floating.

4 NC No connection. Printed circuit board pad may be grounded or floating.

5 NC No connection. Printed circuit board pad may be grounded or floating.

6 NC No connection. Printed circuit board pad may be grounded or floating.

7 NC No connection. Printed circuit board pad may be grounded or floating.

The transmitter RF output voltage is proportional to the input current to this pin. A series resistor is used to adjust the peak transmitter output voltage. 0 dBm of output power requires 250 µA of input current. In the ASK mode, minimum output power occurs when the modulation driver sinks about 10 µA of current from this pin. In the OOK mode, input signals less than 220 mV completely turn the transmitter oscillator off. Internally, this pin appears to

VCC1 is the positive supply voltage pin for the transmitter output amplifier and the transmitter base-band circuitry.

for a 3 Vdc supply voltage is approxi

is in mA

TXM

8 TXMOD

be a diode in series with a small resistor. Peak transmitter output power P mately:

= 16*(I

)2, where POis in mW, and the peak modulation current I

TXM

A ±5% resistor value is recommended. In the OOK mode, this pin is usually driven with a logic-level data input (unshaped data pulses). OOK modulation is practical for data pulses of 200 µs or longer. In the ASK mode, this pin accepts analog modulation (shaped or unshaped data pulses). ASK modulation is practical for data pulses

8.7 µs or longer. This pin must be low in the power-down (sleep) mode. Please refer to the ASH Transceiver De signer’s Guide for additional information on modulation techniques.

9 NC No connection. Printed circuit board pad may be grounded or floating.

10 GND2 GND2 is an IC ground pin. It should be connected to GND1 by a short, low inductance trace.

11 NC No connection. Printed circuit board pad may be grounded or floating.

12 NC No connection. Printed circuit board pad may be grounded or floating.

13 NC No connection. Printed circuit board pad may be grounded or floating.

14 NC No connection. Printed circuit board pad may be grounded or floating.

15 NC No connection. Printed circuit board pad may be grounded or floating.

VCC2 is the positive supply voltage pin for the transmitter oscillator. Pin 16 must be bypassed with an RF capaci

16 VCC2

tor, and must also be bypassed witha1to10µFtantalum or electrolytic capacitor. Power supply voltage ripple should be limited to 10 mV peak-to-peak. See the ASH Transceiver Designer’s Guide for additional information.

CNTRL1 and CNTRL0 select the transmit modes. CNTRL1 high and CNTRL0 low place the unit in the ASK trans mit mode. CNTRL1 low and CNTRL0 high place the unit in the OOK transmit mode. CNTRL1 and CNTRL0 both low place the unit in the power-down (sleep) mode. CNTRL1 is a high-impedance input (CMOS compatible). An

17 CNTRL1

input voltage of 0 to 300 mV is interpreted as a logic low. An input voltage of Vcc - 300 mV or greater is inter preted as a logic high. An input voltage greater than Vcc + 200 mV should not be applied to this pin. A logic high requires a maximum source current of 40 µA. A logic low requires a maximum sink current of 25 µA (1 µA in sleep mode). This pin must be held at a logic level; it cannot be left unconnected.

18 CNTRL0

CNTRL0 is used with CNTRL1 to control the operating modes of the transmitter. See the description of CNTRL1 for more information.

19 GND3 GND3 is an IC ground pin. It should be connected to GND1 by a short, low inductance trace.

RFIO is the transmitter RF output pin. This pin is connected directly to the SAW filter transducer. Antennas pre senting an impedance in the range of 35 to 72 ohms resistive can be satisfactorily matched to this pin with a se

20 RFIO

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.

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RF O utput Pow er vs I

1.60

1.40

1.20

1.00

0.80

0.60

O u t p u t P o w e r in m W

0.40

0.20

25 50 75 100 125 150 175 200 275250225

in µ A

TXM

3 V

v s I

TXM

1.20

1.15

1.10

1.05

in V

1.00

TXM

0.95

0.90

0.85

25 50 75 100 125 150 175 200 275250225

TXM

in µ A

Note: Specifications subject to change without notice.

File: tx5000k.vp, 2003.07.20 rev