znbg3000 Zetex Semiconductors plc., znbg3000 Datasheet - Page 7

• Manufacturer Part Number: znbg3000
• Description: Fet Bias Controller
• Manufacturer: Zetex Semiconductors plc.

APPLICATIONS INFORMATION (Continued)
The ZNBG devices have been designed to protect the external FETs from adverse operating
conditions. With a JFET connected to any bias circuit, the gate output voltage of the bias circuit
can not exceed the range -3.5V to 0.7V, under any conditions including powerup and powerdown
transients. Should the negative bias generator be shorted or overloaded so that the drain current
of the external FETs can no longer be controlled, the drain supply to FETs is shut down to avoid
damage to the FETs by excessive drain current.
The following diagram show the ZNBG3000/1 in typical LNB applications.
Single in/Single out C band LNB block diagram
4-143
ZNBG3000
ZNBG3001