DATA SHEET
LND TRM34
LOW POWER 300 TO 500 MHz FSK TRANSMITTER
General Description
The LND TRM34 is a low power
Frequency Shift Keying (FSK)
transmitter designed to operate
at transmit frequencies between
300 and 500MHz. It is comprised
of a frequency synthesizer and
modulator, which accepts a
simple CMOS digital data input
and generates an FSK
modulated output. Output power
can be adjusted to a maximum
of 2dBm. The LND TRM34 has
been optimized for use in battery-
powered applications with low
current consumption in both
transmit and standby modes.
How Does it Work
Simply connect the supply (as
low as 2.6V), an external
oscillator to RO1 and RO2, and
all ground connections. The chip
converts logic level inputs to
balanced, complimentary,
frequency modulated outputs,
Out1 and Out 2. Output power
can be adjusted using resistor
values in Table 5, and can be
easily switched with logic input
to Standby Mode (extremely low
power) when not transmitting.
Component selections, network,
and antenna options are included
in this document.
VCC
VEE1 VEE2
VSUB
SBY
BYPS
RO1
RO2
crystal
oscillator
divide-
by-
64
VCO
phase
detector
charge
pump
Figure 1: Block Diagram
LF
VEE
Applications
• Wireless office and home
security systems
• Automotive remote locking/starting
• Consumer remote control units
• Radio data transmission
• Low power telemetry
Features
• Low current consumption in
transmit mode
• Low standby current
(typically a few nA)
• Conforms to requirements of
ETSI-300-220, PT1340 and
FCC Part 15
• Easy to use with low external
component count and cost
• No discrete external inductors
required
• Adjustable output power level
PS
OUT2
P.A.
OUT1
buffer
DATA