Radiometrix Ltd.,

AFS2 data sheet

Page 2

User interface

Figure 3: AFS2 pin-out and dimension

Pin description

NOTES:

1.

This amplifier expects a 100mW power level to be output from the radio on transmit.

2.

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.

3.

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.

4.

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.

5.

This unit requires a regulated +5v rail, during transmit, and during receive.

6.

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)

7.

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.

Pin

Name

Function

RF

1

RF GND

RF Ground

2

Aerial

RF connection to aerial (50 Ω)

3

RF GND

RF Ground

User

1

Vcc

Regulated +5v supply, at <250mA

2

0V

Supply Ground

3

TXE

Transmit mode enable (active low, 100K pullup to +5v)

RF Module

1

RF GND

RF Ground

2

RF in/out

RF connection to radio module

3

RF GND

RF Ground