Keywords: PMU, DCL, ATE, automated test equipment, parametric measurement unit, driver-comparator-load, instrumentation, mechanical relay, DUT, force and sense
This application note describes the unique built-in features of the Maxim DCLs (MAX9961/62, MAX9967/68) and the PMUs (MAX9949/50, MAX9951/52) that allow the user to eliminate the cost and board space associated with mechanical relays. A secondary benefit is the ability to enhance the conventional current drive capability of low current PMU's by taking advantage of the driver component of the DCL.
The MAX9949/50 are dual PMUs intended for ATE and other instrumentation. The small size, wide force and measurement range and high accuracy make the MAX9949-50 ideal for testers that require a PMU per pin or per site. The MAX9949/50 have a built in external buffer drive feature that can be used to expand the voltage and current range of the PMU depending on the user's application.
PMU Application Requiring 2mA < Iout < 50mA
In this mode the PMU is set to force and measure using its external range select feature. The Driver reference input is connected to the Rcom output of the PMU. The PMU's current sense amp measures the voltage across the DCL Force / Sense pins. This voltage represents the DUT current across the 45 ohm driver output resistance. (Figure 2)