AT1511
Preliminary product Information
FET BIAS CONTROLLER AND TONE DETECTION
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
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
and DiSEqC
TM
tone bursts - without the use of
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.
Applications
˙Satellite
receiver LNBs
˙Private
mobile radio (PMR)
˙Cellular
telephones
Aimtron reserves the right without notice to change this circuitry and specifications.
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
Email:
service@aimtron.com.tw
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AIMTRON [ AIMTRON TECHNOLOGY ]
