GHz TECHNOLOGY INC. RESERVES THE RIGHT TO MAKE CHANGES WITHOUT FURTHER NOTICE. GHz RECOMMENDS THAT BEFORE
THE PRODUCT(S) DESCRIBED HEREIN ARE WRITTEN INTO SPECIFICATIONS, OR USED IN CRITICAL APPLICATIONS, THAT THE
PERFORMANCE CHARACTERISTICS BE VERIFIED BY CONTACTING THE FACTORY.
GHz Technology Inc. 3000 Oakmead Village Drive, Santa Clara, CA 95051-0808 Tel. 408 / 986-8031 Fax 408 / 986-8120
ZO-28/F
BIAS DEVICE
Thermal Tracking
GENERAL DESCRIPTION
The ZO-28/F is a bias device designed to work with very high power BiPolar
transistors, operating Class A and AB. It has extremely low source impedance
and high current handling capability. The package may be physically mounted
to the same heat sink as the RF transistor, providing very accurate thermal
tracking.
CASE OUTLINE
55GU
ABSOLUTE MAXIMUM RATINGS
Maximum Power Dissipation @ 25 C 40 Watts
o
Maximum Voltage and Current
BVis Injector to Supplier Voltage 35 Volts
Is Supplier Current 3.5 Amps
Ic Controller Current 0.3 Amps
Hfe Transistor Current Gain - Min 30
Maximum Temperatures
Storage Temperature - 65 to +150 C
o
Operating Junction Temperature +200 C
o
See Case Outline for Connections
ELECTRICAL CHARACTERISTICS @ 25 C
O
SYMBOL
CHARACTERISTICS
TEST
MIN
TYP
MAX
UNITS
CONDITIONS
BVsco
BViso
50
BViss
Hfe
Vcr
jc
Supplier - Controller Breakdown
Ii = 0. Is = 5 mA
4
Volts
Injector Open
INjector - Supplier Breakdown
Ii = 10 mA
Volts
Controller Opne
Injector - Supplier Breakdown
Ii = 50 mA
Volts
Controller Shorted
DC Current Gain
Ii = 1 A, Vis = 5 Volts
Voltage Drop across Diodes
Ii = 0A, Ic = 50 mA
Volts
Thermal Resistance
4.37
C/W
90
30
1.34
1.4
1.48
o
Initial Issue June, 1997
Ghz Technology Inc. 3000 Oakmead Village Drive, Santa Clara, CA 95051-0808 Tel. 408 / 986-8031 Fax 408 / 986-8120
Z0-28/F
Design of the Z0-28
The Z0-28 consists of three semiconductor elements, a transistor and two diodes. The only additional component
necessary is resistor Rc ( see figure) and the RF filtering necessary with any bias system. The Z0-28 operates as an emitter
follower, which accounts for its very low source impedance. The transistor can be operated from any voltage up to 28
Volts. The Z0-28 is capable of 40 Watts power dissipation, enough for most current and Voltage requirements. The power
transistor's quiescent base Voltage is determined by the value of Rc and the supply Voltage.
The two diodes provide the thermal tracking needed for thermally stable operation. One diode compensates for the RF
transistor's base-emitter junction in the Z0-28. By mounting the Z0-28 in thermal contact with the power transistor, the
other diode can compensate for the power devices base-emitter junction. The diodes are fabricated with the same
technology as the RF power transistor for improved thermal stability.
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