U2740B
UHF AM/FM Transmitter
Description
The U2740B-B is an one-chip multi-purpose UHF
ASK/FSK transmitter IC designed for various applica-
tions within a wide frequency range. When a
Chip-Select
(CS) signal is supplied, the IC starts operation (Power-up,
XTO, VCO, PD) and the VCO is then locked to
128 f(XTO). The locked status is indicated at the
Lock-Detect
(LD) output.
The digital data is supplied to either an AM- or FM-input
pin, the output power being set via the AM-input pin. A
differential output enables simple applications with loop
antennas. An output driver (XTO_out) can be used for
clocking the microcontrolller.
Features
D
One-chip solution with few external components
D
Wide frequency range (200 to 500 MHz)
D
Single voltage supply (2.2 to 5.5 V) with power-down
D
D
D
D
D
D
feature
Adjustable output power with differential output for
loop antenna
PLL lock-detect signal
XTO output for
µC
clock
ESD protection according to MIL–STD. 883
(except Pins 1, 2, 13 and 14)
Low standby current <0.25
m
A for V
S
= 3 V
Single lithium-cell operation
Applications
D
D
D
D
Keyless entry (automotive, domestic,...)
Alarm systems
Remote control
Communication systems
Ordering Information
Extended Type Number
U2740B-BFP
Package
SO16
Remarks
System Block Diagram
1 Li cell
VCO
U2740B
Antenna
Encoder
Keys
M44Cx9x
PLL
Power
ampl.
XTO
RF–Transmitter
13350
Figure 1. System block diagram
TELEFUNKEN Semiconductors
Rev. A3, 24-Feb-97
1 (10)
Preliminary Information
TEMIC [ TEMIC SEMICONDUCTORS ]
