PURPOSE: To adapt a driver circuit to act also as a termination, clamp circuit, by switching operatively an I/O terminal of the driver circuit with an output impedance matching with transmission lines.
CONSTITUTION: In a driver circuit connected, to a device (DUT) by transmission lines, three kinds of analog signals are shifted positively (negatively) by level shifters 310, 315, 325 (320, 330, 335) by the use of a voltage VBEP (VBEN), and an analog multiplexer 350 (380) selects one signal by being controlled 390 by a digital signal and supplies it to an NPN (PNP) transistor 360 (365). And the DUT is driven by switching an I/O terminal between predetermined voltage levels VH, VL with an output impedance Z0 matching with transmission lines. If output of this DUT is specified as to be able to drive a terminal load, the transmission lines are terminated by level-switching the I/O terminal to a predetermined voltage level of the impedance Z0. If not specified, the driver circuit functions like a Z-clamp circuit.
SAAJIO EI SANIEREBICHI
BAANERU JII UESUTO
DEIBITSUDO KEI CHIAN
