FM T
RANSMITTER
& R
ECEIVER
M
ODULES
. (2
ND
G
ENERATION
)
FM-TX2-XXX
FM-RX2-XXX
Functional description:
The TX2 transmitter module is a two stage, SAW controlled FM transmitter operating between
2V and 6V and is available in 433.92MHz and 418.00 MHz versions. The 433.92 MHz unit is
type-approved to ETS 300-220 for European use and delivers nominally +9dBm from a 5V
supply at 12mA, while the 418.00 MHz unit has MPT 1340 type-approval for U.K. use and
delivers -3dBm from a 5V supply at 5mA. Both modules measure 12 x 32 x 3.8 mm.
The RX2 module is a double conversion FM superhet receiver capable of handling date rates of
upto 40kbit/s. The SIL style RX2 receiver measures 17.5 x 48 x 4.5 mm. It will operate from a
supply of 3-6V and draws 14mA when receiving. A fast-acting carrier detect and a power-up
enable time of less than 1ms This allows effective duty cycle power saving and a -107 dBm
sensitivity. This, combined with a SAW front-end filter results in an excellent RF performance
and EMC conformance.
TX2 transmitter:
fig. 1: TX2 block diagram
Pin description:
RF GND
(
pin 1)
RF ground pin, internally connected to
the module screen and pin 4 (0V). This
pin should be connected to the RF
return path (e.g. coax braid, main PCB
ground plane etc.)
RF out
(pin 2)
50
Ω
RF output to the antenna, it is DC
isolated internally. (see antenna section
of TX2 applications note for suggested
antenna/feeds).
Vcc
(pin 3)
+ve supply pin. The module will generate RF when the Vcc supply is present. Max ripple
content 0.1V
P-P
. A 100nF de-coupling ceramic capacitor is suggested.
0V
(
pin 4)
Supply ground connection, connected to pin 1 and screen.
TXD
(
pin 5)
This DC coupled modulation input will accept either serial digital data ( 0V to Vcc levels) or
high level linear signals. see TX2 applications note for suggested drive methods. Input
impedance is 100k
Ω
.
DS000022
Rev D
July ‘99
©1999
REG No 277 4001, ENGLAND.
Page 2
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