RF Monolithics, Inc.

Phone: (972) 233-2903

Fax: (972) 387-8148

E-mail: info@rfm.com

Page 1 of 6

RFM Europe

Phone: 44 1963 251383

Fax: 44 1963 251510

http://www.rfm.com

TX5002-070705

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

Complies with Directive 2002/95/EC (RoHS)

The TX5002 hybrid 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 TX5002 includes provisions for both on-off keyed (OOK) and
amplitude-shift keyed (ASK) modulation. The TX5002 employs SAW filtering to suppress output harmonics,
facilitating compliance with FCC Part 15 and similar regulations.

Rating

Value

Units

Power Supply and All Input/Output Pins

-0.3 to +4.0

Non-Operating Case Temperature

-50 to +100

°C

Soldering Temperature (10 seconds / 5 cycles max.)

260

°C

418.00 MHz

Hybrid

Transmitter

TX5002

SM-20L Case

Electrical Characteristics

Characteristic

Sym

Notes

Minimum

Typical

Maximum

Units

Operating Frequency

417.80

418.20

MHz

Modulation Types

OOK & ASK

OOK Data Rate

kbps

ASK Data Rate

115.2

kbps

Transmitter Performance

Peak RF Output Power, 250 µA TXMOD Current

dBm

Peak Current, 250 µA TXMOD Current

7.5

OOK Turn On/Turn Off Times

OFF

20/15

µs

ASK Output Rise/Fall Times

1.1/1.1

µs

2nd - 4th Harmonic Outputs

-50

dBm

5th - 10th Harmonic Outputs

-55

dBm

Non-harmonic Spurious Outputs

-50

dBm

Sleep Mode Current

0.7

µA

Sleep to Transmit Switch Time

TOR

µs

Transmit to Sleep Switch Time

RTO

µs

Control Input Logic Low Level

200

Control Input Logic High Level

Vcc - 300

Power Supply Voltage Range

2.2

3.7

Vdc

Operating Ambient Temperature

-40

+85

°C

RF Monolithics, Inc.

Phone: (972) 233-2903

Fax: (972) 387-8148

E-mail: info@rfm.com Page 2 of 6

RFM Europe

Phone: 44 1963 251383

Fax: 44 1963 251510

http://www.rfm.com

TX5002-070705

Notes:

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

2. The companion receiver to the TX5002 is the RX5002. Please see RFM's web site at www.rfm.com for details.

CAUTION: Electrostatic Device. Observe precautions when handling.

Item

Symbol

OOK

ASK

Units

Notes

Nominal NRZ Data Rate

NOM

2.4

19.2

115.2

kbps

see page 1

Minimum Signal Pulse

MIN

416.67

52.08

8.68

µs

single bit

Maximum Signal Pulse

MAX

1666.68

208.32

34.72

µs

4 bits of same value

TXMOD Resistor

TXM

8.2

±5%, for 0 dBm output

DC Bypass Capacitor

DCB

4.7

µF

tantalum

RF Bypass Capacitor 1

RFB1

±5% NPO

RF Bypass Capacitor 2

RFB2

100

±5% NPO

RF Bypass Bead

RFB

Fair-Rite

vendor

2506033017YO or equivalent

Series Tuning Inductor

50 ohm antenna

Shunt Tuning/ESD Inductor

ESD

220

50 ohm antenna

Transmitter Set-Up, 3.0 Vdc, -40 to +85 °C

Modulation Input

TOP VIEW

GND

CNT

RL0

CNT

RL1

WIDTH

RATE

THLD

RREF

GND2

MOD

DATA

LPF
ADJ

CMP

OUT

DET

AGC
CAP

VCC

RFIO

GND1

+ 3

VDC

Transmitter OOK Configuration

+ 3

VDC

TXM

RFB2

DCB

ESD

RFB1

RFB

T/S

Modulation Input

TOP VIEW

GND

CNT

RL0

CNT

RL1

WIDTH

RATE

THLD

RREF

GND2

MOD

DATA

LPF
ADJ

CMP

OUT

DET

AGC

CAP

VCC

RFIO

GND1

+ 3

VDC

Transmitter ASK Configuration

+ 3

VDC

TXM

RFB2

DCB

ESD

RFB1

RFB

T/S

RF Monolithics, Inc.

Phone: (972) 233-2903

Fax: (972) 387-8148

E-mail: info@rfm.com Page 3 of 6

RFM Europe

Phone: 44 1963 251383

Fax: 44 1963 251510

http://www.rfm.com

TX5002-070705

Figure 1

Transmitter Theory of Operation

Introduction

RFM's TX-series hybrid transmitters are specifically designed for short-
range wireless data communication applications. These transmitters pro-
vide robust operation, very small size, low power consumption and low im-
plementation cost. All critical RF functions are contained in the hybrid,
simplifying and speeding design-in. The transmitters can be readily con-
figured 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 Fig-
ure 1 for the following discussions.

Antenna Port

The only external RF components needed for the transmitter are the anten-
na and its matching components. Antennas presenting an impedance 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 com-
ponents. For some impedances, two inductors and a capacitor will be re-
quired. A DC path from RFIO to ground is required for ESD protection.

Transmitter Chain

The transmitter chain consists of a SAW coupled-resonator oscillator fol-
lowed by a modulated buffer amplifier. The SAW coupled resonator output
filter suppresses transmitter harmonics to the antenna.

Transmitter operation supports two modulation formats, on-off keyed
(OOK) modulation, and amplitude-shift keyed (ASK) modulation. When
OOK modulation is chosen, the transmitter output turns completely off be-
tween "1" data pulses. When ASK modulation is chosen, a "1" pulse is rep-
resented 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 inter-
ference and allows the transmitted pulses to be shaped to control modula-
tion 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 os-
cillator 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.

Transmitter Block Diagram

TXA1

TXA2

Antenna

SAW

Coupled

Resonator

SAW

Filter

Modulation

& Bias Control

TRL1

TRL0

Tune/ESD

Ant

Tune

TXM

RF Monolithics, Inc.

Phone: (972) 233-2903

Fax: (972) 387-8148

E-mail: info@rfm.com Page 4 of 6

RFM Europe

Phone: 44 1963 251383

Fax: 44 1963 251510

http://www.rfm.com

TX5002-070705

The transmitter RF output power is proportional to the input current to the
TXMOD pin. A series resistor is used to adjust the peak transmitter 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 func-
tion, 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 log-
ic 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 operation 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 mode
(t

TOS

and t

TAS

) is 15 µs after CNTRL1 and CNTRL0 are both low (1 µs fall

time).

The maximum time required to switch from the sleep mode to either trans-
mit mode (t

STO

and t

STA

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

the transmitter oscillator.

0.000

.140

.270

.410

.0775

.1025

.1175

.1575

.1975

.2375

.2775

.3175

.3575

.3825

.4600

.1975

.1725

.2125

.2375

Dimensions in inches

SM-20L PCB Pad Layout

Dimension

Inches

Min

Nom

Max

Min

Nom

Max

10.795

10.922

11.049

.425

.430

.435

9.525

9.652

9.779

.375

.380

.385

1.778

1.905

2.032

.070

.075

.080

3.048

3.175

3.302

.120

.125

.130

0.381

0.508

0.635

.015

.020

.025

0.889

1.016

1.143

.035

.040

.045

3.175

3.302

3.429

.125

.130

.135

1.778

1.905

2.032

.070

.075

0.80

SM-20L Package Drawing

Transmitter Pin Out

RFIO

TXMOD

GND1

VCC1

GND2

VCC2

GND3

CNTRL0

CNTRL1

RF Monolithics, Inc.

Phone: (972) 233-2903

Fax: (972) 387-8148

E-mail: info@rfm.com Page 5 of 6

RFM Europe

Phone: 44 1963 251383

Fax: 44 1963 251510

http://www.rfm.com

TX5002-070705

Pin Descriptions

Pin

Name

Description

GND1

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

VCC1

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

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

TXMOD

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

for a 3 Vdc supply voltage is approximately:

= 16*(I

TXM

)

, where P

is in mW, and the peak modulation current I

TXM

is in mA

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 Designer's Guide for additional information

on modulation techniques.

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

GND2

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

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

VCC2

VCC2 is the positive supply voltage pin for the transmitter oscillator. Pin 16 must be bypassed with an RF capacitor, and
must also be bypassed with a 1 to 10 µF tantalum 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

CNTRL1 and CNTRL0 select the transmit modes. CNTRL1 high and CNTRL0 low place the unit in the ASK transmit 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 input voltage of 0 to 300 mV is
interpreted as a logic low. An input voltage of Vcc - 300 mV or greater is interpreted 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.

CNTRL0

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

GND3

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

RFIO

RFIO is the transmitter RF output pin. This pin is connected directly to the SAW filter transducer. Antennas presenting an
impedance in the range of 35 to 72 ohms resistive can be satisfactorily matched to this 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 pro-
tection.

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ÐÐ»ÐµÐºÑ‚Ñ€Ð¾Ð½Ð½Ñ‹Ð¹ ÐºÐ¾Ð¼Ð¿Ð¾Ð½ÐµÐ½Ñ‚: TX5002