The 33660 is a serial link bus interface device designed to provide bi-directional half-duplex communication interfacing in automotive diagnostic applications. It is designed to interface between the vehicle’s on-board microcontroller， and systems off-board the vehicle via the special ISO K line. The 33660 is designed to meet the Diagnostic Systems ISO9141 specification. The device’s K line bus driver’s output is fully protected against bus shorts and over-temperature conditions. The 33660 derives its robustness to temperature and voltage extremes by being built on a SMARTMOS process， incorporating CMOS logic， bipolar/MOS analog circuitry， and DMOS power FETs. Although the 33660 was principally designed for automotive applications， it is suited for other serial communication applications. It is parametrically specified over an ambient temperature range of -40 oC ≤ TA ≤ 125 oC and 8.0 V ≤ VBB ≤ 18 V supply. The economical SO-8 surface-mount plastic package makes the 33660 very cost effective.