U3741BM
UHF ASK/FSK Receiver
Description
The U3741BM is a multi-chip PLL receiver device
supplied in an SO20 package. It has been specially
developed for the demands of RF low-cost data
transmission systems with low data rates from 1 kBaud to
10 kBaud (1 kBaud to 3.2 kBaud for FSK) in Manchester
or Bi-phase code. The receiver is well suited to operate
with the TEMIC PLL RF transmitter U2741B. Its main
applications are in the areas of telemetering, security
technology and keyless-entry systems. It can be used in
the frequency receiving range of f
0
= 300 MHz to
450 MHz for ASK or FSK data transmission. All the
statements made below refer to 433.92-MHz and
315-MHz applications.
Features
D
Minimal external circuitry requirements, no RF
components on the PC board except adaptation to the
receiver antenna
D
ESD protection according to MIL-STD. 883
(4KV HBM) except Pin POUT (2KV HBM)
D
D
D
D
High sensitivity, especially at low data rates
Sensitivity reduction possible even while receiving
Fully integrated VCO
Low power consumption due to configurable self
polling with a programmable timeframe check
operating temperature range –40°C to 105°C
D
High image frequency suppression due to 1 MHz IF
in conjunction with a SAW front-end filter. Up to
40 dB is thereby achievable with newer SAWs.
D
Programmable output port for sensitivity selection or
for controlling external periphery
D
Communication to
m
C possible via a single,
bi-directional data line
D
Supply voltage 4.5 V to 5.5 V,
D
Single-ended RF input for easy adaptation to
l
/4 antenna or printed antenna on PCB
D
Power management (polling) is also possible by
means of a separate pin via the
m
C
(300 kHz and 600 kHz)
D
Low-cost solution due to high integration level
D
2 different IF bandwidth versions are available
System Block Diagram
UHF ASK/FSK
Remote control transmitter
UHF ASK/FSK
Remote control receiver
1 Li cell
U2741B
PLL
U3741BM
Demod.
Control
1...3
m
C
Encoder
Keys M44Cx9x
XTO
IF Amp
Antenna Antenna
VCO
PLL
XTO
Power
amp.
LNA
VCO
14917
Figure 1. System block diagram
Rev. A1, 15-Oct-98
1 (25)
Preliminary Information
TEMIC [ TEMIC SEMICONDUCTORS ]
