14

DATA SHEET - Rev 2.1

11/2012

ARA2017

ApplicATion infoRMATion

Transmit Enable / Disable

13). A logic high will turn the amplifier on. The gain

and current settings are retained during Tx disable

and do not need to be reloaded.

Gain/Attenuator Setting

The gain of the ARA2017 can be controlled via the

3-wire bus. Data bits D2 through D6 set the gain/

attenuator level, with 00000 being the min gain setting,

and 11111 being the max gain setting. A new gain/

attenuator setting can be loaded while the PGA is on

been cycled off /on.

output Stage current Setting

The ARA2017 consists of 2 gain stages. The input

is enabled. The current in the output stage can be

controlled via the 3-wire bus. Data bits D7 – D9 set

the current. 111 will set the output stage to maximum

current for maximum linearity. The current can be

lowered for improved efficiency at lower output

power levels, or lower linearity requirements. 000 will

Enable), but will not take effect until TX_EN has been

cycled off /on.

output Transformer

Matching the balanced output of the ARA2017 to a

single-ended 75  load is accomplished using a 1:1

turns ratio transformer. In addition to the balanced to

single-ended conversion, this transformer provides the

bias to the output amplifier stage via the center tap.

The transformer also cancels even mode distortion

products and common mode signals, such as the

voltage transients that occur while enabling and

disabling the amplifiers. As a result, care must be

taken when selecting the transformer to be used at

the output. It must be capable of handling the RF and

DC power requirements without saturating the core,

and it must have adequate isolation and good phase

and amplitude balance. It also must operate over

the desired frequency and temperature range for the

intended application.