ZNBG3000 Просмотр технического описания (PDF) - Zetex => Diodes

Номер в каталоге

Компоненты Описание

Список матч

ZNBG3000

FET BIAS CONTROLLER

Zetex => Diodes 

FET BIAS CONTROLLER

ISSUE 1- AUGUST 1998

DEVICE DESCRIPTION

The ZNBG series of devices are designed to

meet the bias requirements of GaAs and

HEMT FETs commonly used in satellite

receiver LNBs, PMR, cellular telephones etc.

with a minimum of external components.

With the addition of two capacitors and a

resistor the devices provide drain voltage

and current control for 3 external grounded

source FETs, generating the regulated

negative rail required for FET gate biasing

whilst operating from a single supply. This

negative bias, at -3 volts, can also be used to

supply other external circuits.

The ZNBG3000/1 contains three bias stages.

A single resistor allows FET drain current to

be set to the desired level. The series also

offers the choice of drain voltage to be set

for the FETs, the ZNBG3000 gives 2.2 volts

drain whilst the ZNBG3001 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.

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

• QSOP surface mount package

ZNBG3000

ZNBG3001

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 0.7V. 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 ZNBG3000/1 are available in QSOP16

packages for the minimum in devices 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

• Single in single out C Band LNB

4-137

Share Link: