ATE Contact Test thru’ Analog Switch

Conventional ATE Contact Test CASE#1 CASE#2 DUT pin is only connected to the ATE on the loadboard Force current -200ua on the DUT pin Measure voltage on the DUT pin DUT pin needs to be connected to the ATE and Support IC as well for other functional testing Use a mechanical relay to switch between ATE and Support IC Force current -200ua on the DUT pin Measure voltage on the DUT pin ATE_CH-xxx Rly Support IC ATE_CH-xxx DUT DUT

Relays Advantages Issues Low contact resistance – ~<0.5 ohms ATEs can easily control them Higher bandwidth Issues Bulky Expensive Mounting it and reworking it on the board when surface mounted Takes real estate on the board

Analog Switches Alternate solution to relays are analog switches Pros Small footprint, one IC can switch many DUT pin Easy manufacturability and rework Low cost High Bandwidth Issues Higher ‘ON’ resistance Pose problem in doing ATE contact test due to their own clamp diodes Need extra ATE supplies to power them

Analog Switches – No Issues Higher ‘ON’ resistance With good selection of a switch, this can be tolerated Need extra ATE supplies to power them Modern ATEs have many power supplies to power the analog switch Pose problem in doing ATE contact test due to their own clamp diodes This can be alleviated by skewing the power supplies of the switch

Regular Functional Test Supporting IC Regular VDD/VSS 3.3v Aout-B DUT Aout-A Ain ATE_CH-xxx With the analog switch supplies at 3.3v/0.0v, the switch’s Ain pins will connect to either Aout-A or Aout-B and both the clamp diodes on the switch’s pins will act as clamps during functional testing of the DUT thru the ATE or Receiver IC SEL 0v Regular IO control voltage for Mux control Vil = 0v Vih=3.3v

Contact Test Supporting IC Skewed VDD/VSS DUT Aout-B DUT Aout-A Ain ATE_CH-xxx SEL With the analog switch supplies at 1.3v/-2.0v, the switch’s Ain pin will be connected to Aout-A and both the clamp diodes of the switch’s pins will be reverse biased during contact test of the DUT pins thru the ATE -2v Skewed IO control voltage for Mux control Vil = -2v Vih=1.3v