ZO-28/F BIAS DEVICE Thermal Tracking CASE OUTLINE GENERAL DESCRIPTION 55GU 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. ABSOLUTE MAXIMUM RATINGS Maximum Power Dissipation @ 25oC 40 Watts Maximum Voltage and Current BVis Injector to Supplier Voltage Is Supplier Current Ic Controller Current Hfe Transistor Current Gain - Min Maximum Temperatures Storage Temperature Operating Junction Temperature 35 Volts 3.5 Amps 0.3 Amps 30 - 65 to +150 oC +200 oC See Case Outline for Connections ELECTRICAL CHARACTERISTICS @ 25 OC SYMBOL CHARACTERISTICS BVsco Hfe Supplier - Controller Breakdown Injector Open INjector - Supplier Breakdown Controller Opne Injector - Supplier Breakdown Controller Shorted DC Current Gain Vcr Voltage Drop across Diodes θjc Thermal Resistance BViso BViss TEST CONDITIONS MIN TYP MAX UNITS Ii = 0. Is = 5 mA 4 Volts Ii = 10 mA 50 Volts Ii = 50 mA 90 Volts Ii = 1 A, Vis = 5 Volts 30 Ii = 0A, Ic = 50 mA 1.34 1.4 1.48 4.37 Volts o C/W Initial Issue June, 1997 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 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. Ghz Technology Inc. 3000 Oakmead Village Drive, Santa Clara, CA 95051-0808 Tel. 408 / 986-8031 Fax 408 / 986-8120