AT1511

Preliminary product Information

FET BIAS CONTROLLER AND TONE DETECTION

2F, No.10, Prosperity RD. II, Science-Based Industrial Park, Hsinchu 300,Taiwan, R.O.C.

Tel: 886-3-563-0878

http://www.aimtron.com.tw

Fax: 886-3-563-0879

1

Features

•

Provides bias for GaAs and HEMT FETs

•

Drives up to three FETs

•

Dynamic FET protection

•

Drain current set by external resistor

•

Regulated negative rail generator requires

only 2 external capacitors

•

Choice in drain voltage

•

Wide supply voltage range

•

Polarisation switch for LNBs - supporting

zero volt gate switching

topology.

•

22kHz tone detection for band switching

•

Compliant with ASTRA control specifications

•

SSOP surface mount package

Applications

˙

Satellite receiver LNBs

˙

Private mobile radio (PMR)

˙

Cellular telephones

Description

The AT1511 includes bias circuits to drive up to

three external FETs. A control input to the

device selects either one of two FETs as

operational

using

0V

gate

switching

methodology, the third FET is permanently

active. This feature is particularly used as an

LNB polarisation switch. Also specific to LNB

applications is the enhanced 22kHz tone

detection and logic output feature which is used

to enable high and low band frequency switching.

The detector has been specifically designed to

reject inerference such as low frequency signals

additional external components.

Drain current setting of the AT1511 is user

selectable over the range 0 to 15mA, this is

achieved with the addition of a single resistor.

The series also offers the choice of FET drain

voltage, the AT1511 gives 2 volts.

These devices are unconditionally stable over

the full working temperature with the FETs in

place,

subject

to

the

inclusion

of

the

recommended gate and drain capacitors. These

ensure RF stability and minimal injected noise.

It is possible to use less than the devices full

complement of FET bias controls, unused drain

and gate connections can be left open circuit

without affecting operation of the remaining bias

circuits.

In order to protect the external FETs the circuits

have been designed to ensure that, under any

conditions including power up/down transients,

the gate drive from the bias circuits cannot

exceed the range -3.5V to 1V. Furthermore if the

negative rail experiences a fault condition, such

as overload or short circuit, the drain supply to

the FETs will shut down avoiding excessive

current flow.

The AT1511 are available in SSOP20 for the

minimum in device size. Device operating

temperature is -40 to 70°C to suit a wide range

of environmental conditions.

Aimtron reserves the right without notice to change this circuitry and specifications.