DATA SHEET
LND TRM33
LOW POWER 300 TO 500 MHz ASK TRANSMITTER
General Description
The LND TRM33 is a low power
Amplitude Shift Keying (ASK)
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 ASK
modulated output. Output power
can be adjusted to a maximum
of 2dBm. The LND TRM33 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,
amplitude 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.
SBY
BYPS
RO1
RO2
VCC
VEE1 VEE2
VSUB
ASK
modulator
crystal
oscillator
divide-
by-
64
VCO
charge
pump
phase
detector
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
Figure 1: Block Diagram
LF
VEE