6 STAGE FET LNA BIAS CONTROLLER

DESCRIPTION

The UTC L8603 is an advanced GaAs and HEMT FETs bias

controller. It is designed to operate from minimal supply rails and

intended primarily for satellite Low Noise Blocks (LNBs).

The UTC L8603 provides drain voltage and current control for

up to 6 external grounded source FETs with the addition of one

capacitor and a resistor.

The UTC L8603 is generating the regulated negative rail

required for FET gate biasing whilst operating from a single

supply of 2.1V to 5V. The -2V negative bias can also be used to

supply other external circuits.

Setting drain currents on the UTC L8603 only requires one

resistor which controls the drain current of the first stage FETS

(D1 and D4). The drain current is set internally to 10mA for the

remaining 4 FETs for the second and third stages. This allows the

operating current of input FETs to be adjusted to minimize noise,

whilst the following FET stages are fixed to minimize the number

of external components used.

FEATURES

* Provides Bias for up to 6 GaAs and HEMT FETs

2 x Amplifier FET Drain Current Programmable (4mA to15mA)

4 x Amplifier FET Drain Current Internally Fixed to 10mA

* Operating Range of 2.1V to 5V

* Ultra-low Operating Current of 1.1mA

* Dynamic FET Protection

* Amplifier FET Drain Voltages set at 2.0V,

* Regulated Negative Rail Generator Requires only 1 External Capacitor

* Low external Component Count

* Expended Temperature Range of -40°C to +105°C