Note

Application Note 11
3 Powered Testing With Digital
Vectors (ICT)
3.1 Using Voltage Identifier (VID) Signals
VCCP and VTT are used to power the test chip. The test chip does not provide control on the VID
signals to establish a VCCP voltage when plugged into a socket. A VID signal combination
should be connected to ground and controlled by the test equipment in such a way that an on-
board VCCP is generated that equals the on-board VTT voltage.
To determine which VID lines to use in order to keep VCCP equal to VTT, refer to the Voltage
Regulator Down (VRD) Design Guide for the processor being used (Section 1.2 of this document).
3.2 Using Control Signals
To ensure that the switches default to OFF when power is applied or while other devices are being
tested, the control signals are pulled to ground with 1 k resistors. Each control signal can turn a
grouping of approximately 128 switches ON and OFF.
Each ON/OFF switch pair tests three socket solder balls and socket contacts, not including the
control signals. A logic level high on the control signal will turn its associated switch to the ON
state.
Two pairs of Hcontrol and Lcontrol inputs are used to multiplex the signals that are received by the
test equipment across more than one switch pair in order to test the majority of power and ground
electrical socket connections.
Caution:
X - At no time should the control signal for the High Side and Low Side switches be driven high at
the same time, as occurs with some automated fault injection tools. A direct short from power to
ground would result and possibly damage the Intel
®
Socket Test Technology test chip and the
Table 3-1. Voltage Identifier Signals
Signal Name VID Ball
VID_0
AM2
VID_1
AL5
VID_2
AM3
VID_3
AL6
VID_4
AK4
VID_5
AL4