afs2-458 Radiometrix Ltd, afs2-458 Datasheet - Page 2

• Manufacturer Part Number: afs2-458
• Description: 500mw Uhf Rf Power Amplifier
• Manufacturer: Radiometrix Ltd

User interface
Pin description
Pin
RF
1
2
3
User
1
2
3
RF Module
1
2
3
NOTES:
[e-mail]
1.
2.
3.
4.
5.
6.
7.
This amplifier expects a 100mW power level to be output from the radio on transmit.
The TXE line should be tied to the TR2M TXE input. When this line is asserted (low) the amplifier is turned
on (drawing 280-300mA) and the RF switching connects it between the module and the aerial. When it is
inactive (high or floating) a low loss path is provided for the rx signals, from aerial to the module.
If a low power transmit mode is needed, the receive path is bidirectional, and capable of carrying up to
100mW of power. In this case the radio must be set to transmit, but the AFS2 pin TXE must be left in the
inactive (high) state.
Following the return of TXE to inactive (high), the AFS2 remains in transmit mode for another 15mS, to allow
the output of the radio to ramp down, before changing over to receive mode.
This unit requires a regulated +5v rail, during transmit, and during receive.
This version cannot be used with in i1200 modem mode, unless a separate means of driving the TXE pin is
provided. (see relevant application notes)
This is a 500mW output product. Good grounding (mount onto a groundplane and tack solder all can walls to
this), good quality aerials, properly mounted, and a low impedence power supply are required if full
performance is to be reliably obtained. If feasible, we recommend mounting the module, and the board it is on,
inside a metal enclosure, with the RF cable taken to a bulkhead connector. All signal and power feeds should
be filtered and/or decoupled.
Failure to observe these measures can cause modulation distortion ('recirculation' effects) or instability. Also
be aware of the effect that the strong RF fields generated by this device (and it's aerial) can have upon other
adjacent circuitry if this is not properly screened, filtered or otherwise protected. Regulators, sensitive
analogue circuitry, and microprocessors seem especially interference prone.
Name
RF GND
Aerial
RF GND
Vcc
0V
TXE
RF GND
RF in/out
RF GND
Function
RF Ground
RF connection to aerial (50 )
RF Ground
Regulated +5v supply, at <250mA
Supply Ground
Transmit mode enable (active low, 100K pullup to +5v)
RF Ground
RF connection to radio module
RF Ground
Figure 3: AFS2 pin-out and dimension
AFS2 - Short Technical Overview
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