TRF4900
SINGLE-CHIP RF TRANSMITTER
SLWS092F – JULY 2000 – REVISED JANUARY 2002
Single-Chip RF Transmitter for 868-MHz
and 915-MHz ISM Bands
Typical Output Frequency Resolution of
230 Hz
850-MHz to 950-MHz Operation
FM/FSK Operation for Transmit
Ultrafast Lock Times From DDS
Implementation
Two Fully-Programmable Operational
Modes
24-Bit Direct Digital Synthesizer (DDS) With
11-Bit DAC
2.2-V to 3.6-V Operation
On-Chip Voltage-Controlled Oscillator
(VCO) and Phase-Locked Loop (PLL)
Flexible Serial Interface to TI MSP430
Microcontroller
On-Chip Reference Oscillator
Minimal External Components Required
Low Power Consumption
24-Pin Plastic Thin-Shrink Small-Outline
Package (TSSOP)
Typical Output Power of 7 dBm
PW PACKAGE
(TOP VIEW)
1
24
23
22
21
20
19
18
17
16
15
14
13
PD_OUT1
PLL_VCC
PD_SET
PD_OUT2
LOCKDET
PA_OUT
PA_GND
PA_VCC
GND
DIG_VCC
XOSC2
XOSC1
2
3
4
VCO_TANK1
VCO_TANK2
PLL_GND
DIG_GND
CLOCK
5
6
7
8
9
DATA
STROBE
MODE
10
11
12
DIG_GND
TX_DATA
NC
STDBY
description
The TRF4900 single-chip solution is an integrated circuit intended for use as a low cost FSK transmitter to
establish a frequency-agile RF link. The device is available in a 24-lead TSSOP package and is designed to
provideafully-functionalmultichanneltransmitter. Thechipisintendedforlinear(FM)ordigital(FSK)modulated
applications in the new 868-MHz European band and the North American 915-MHz ISM band. The single chip
transmitter operates down to 2.2 V and is expressly designed for low power consumption. The synthesizer has
a typical channel spacing of approximately 230 Hz to allow narrow-band as well as wide-band applications. Due
to the narrow channel spacing of the direct digital synthesizer (DDS), the DDS can be used to adjust the TX
frequency and allows the use of inexpensive reference crystals.
Two fully-programmable operation modes, Mode0 and Mode1, allow extremely fast switching between two
preprogrammed settings (e.g., TX_frequency_0/TX_frequency_1) without reprogramming the device. Each
functional block of the transmitter can be specifically enabled or disabled via the serial interface.
These devices have limited built-in ESD protection. The leads should be shorted together or the device placed in conductive foam
during storage or handling to prevent electrostatic damage to the MOS gates.
Please be aware that an important notice concerning availability, standard warranty, and use in critical applications of
Texas Instruments semiconductor products and disclaimers thereto appears at the end of this data sheet.
Copyright 2002, Texas Instruments Incorporated
PRODUCTION DATA information is current as of publication date.
Products conform to specifications per the terms of Texas Instruments
standard warranty. Production processing does not necessarily include
testing of all parameters.
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POST OFFICE BOX 655303 • DALLAS, TEXAS 75265