This board forms the heart of an equipment upgrade for a new test mode now incorporated into production line test equipment for discrete semiconductors. This design was done for one of our customers, a holder of a Queen's Award for Enterprise.

With the requirement for very low voltage, high current power supplies for the latest processors in computers, power FETs are paralleled to make high efficiency, and thus cool, switchmode voltage regulators. The FETs have to be matched for on-resistance and switching speed. The switching speed of these power FETs is determined by their capacitance and intrinsic gate series resistance, which is typically 10 ohms or less. The normal technique of measuring these parameters is with a precision LCR bridge. Tests with these instruments take between 200msec and one second. This is far too slow for production line testing of these devices as the full datasheet set of tests needs to be done in less than 200ms. The bridge instruments are also very expensive as only a small part of their capability is used for this particular test.

Oneof our customers has been honoured by a Queen's Award for Enterprise for a second time. They make high throughput, end of production line test equipment for discrete semiconductors. In order to cope with a range of devices in three to six pin SOT-23 packages, we designed a smart scanner for them. This allows the generators in the main chassis to be multiplexed to any of the pins on the device. The control board pictured above includes additional force and measure functions for new high speed thermal tests and to excite additional device pins. The board includes the address decoding and drivers for the matrix relays.