2 Note

Using Voltage Identifier (VID) Signals

307507-002 15

damage, drive only one control signal high at any time during the test while all others

are low.

The High Side switch of each switch pair is used to test a VCCP solder ball and contact

along with the shared signal solder ball and contact of the High and Low Side switch

pair. The control line for the High Side switch is driven to a logic high, thus turning

the switch ON and enabling an electrical connection between VCCP and the shared

signal. When this happens, a logic high should be received on the shared signal. At

the same time, the Low Side switch control signal will be at a logic low.

The Low Side switch of each switch pair is used to test a GND solder ball and contact

along with the shared signal solder ball and contact of the High and Low Side switch

pair. The control line for the Low Side switch is driven to a logic high, thus turning the

switch ON and enabling an electrical connection between GND and the shared signal.

A logic low should be received on the shared signal. At the same time, the High Side

switch control signal will be at a logic low.

One shared signal is used to test one VCCP and one GND connection. The lack of the

high/low signal transition would indicate an open on either the shared signal or the

power/ground connection used by that switch pair.

Figure 2 shows that Signal1, Vccp1, and Gnd1 as well as Signal2, Vccp2, and

Gnd2 can be verified through Hcontrol_0 and Lcontrol_0.

Table 5 - Control Signals

As with all powered digital

in-circuit testing, all other active components on the board that are connected to the

socket should be placed in a tri-state mode before testing with this technique.

Signal Name Signal Ball

Hcontrol_0

Lcontrol_0

J16

Hcontrol_1

Lcontrol_1

H15

Hcontrol_2

D14

Lcontrol_2

H16

Hcontrol_3

Lcontrol_3

J17