Keithley 6430 User Manual

11-20 Limit Testing
Limit test programming example
Diode breakdown voltage test is an example that readily lends itself to pass/fail analysis.
This test verifies the reverse and often the forward voltage at which the device begins to show a
large deviation in current for a small deviation in voltage. The test is performed by sourcing a
specified current level and then measuring the resulting voltage drop. The voltage drop is then
compared with one set of limits to determine if the diode passes, or fails and should be dis-
carded. Voltage measurements for failing diodes are also compared against a more restricted
range of limits to determine if they should be routed to QA (Quality Assurance) for further
analysis.
Test parameters for this test include:
• Source Function: current
• Sense Function: voltage
• Source Current: 100mA
• Source Delay: 100ms
• Limit 2 Upper Value: 0.85V
• Limit 2 Lower Value: 0.75V
• Limit 3 Upper Value: 0.82V
• Limit 3 Lower Value: 0.78V
Figure 11-11 demonstrates graphically how parts are sorted. Diodes with a voltage between
0.78V and 0.82V are considered good and will pass the limits test. Diodes that test with a
slightly wider voltage range are routed to QA for analysis, while those with the largest voltage
tolerance will be discarded.
Command* Description*
:SOURce2:BSIZe <n> Set Digital I/O port bit size (n = 3 or 4).
:SOURce2:TTL <NRf> | <NDN> Set I/O port bit pattern (NRf | NDN = pattern).
:SOURce2:TTL:ACTual? Query bit pattern on digital output port.
:SOURce2:TTL4:MODE <name> Set Digital I/O line 4 mode (name = EOTest or
BUSY).
:SOURce2:TTL4:BSTate <state> Set BUSY and EOT polarity (HI or LO).
:SOURce2:CLEar Clear digital output lines.
:SOURce2:CLEar:AUTO <state> Enable/disable I/O port auto clear (state = ON or
OFF).
:SOURce2:CLEar:AUTO:DELay <n> Set auto-clear delay (n = delay).
*LIMitX = LIMit2, LIMit3, LIMit5 through LIMit12.
Table 11-1 (cont.)
Limit commands
Bad Diode,
Discard
Bad Diode,
to QA
Good
Diode
Bad Diode,
to QA
Bad Diode,
Discard
Low Limit 2
(0.75V)
Low Limit 3
(0.78V)
Upper Limit 3
(0.82V)
Upper Limit 2
(0.85V)
Figure 11-11
Diode pass/fail limits

Keithley 6430 Specifications

General

Brand	Keithley
Model	6430
Category	Measuring Instruments
Language	English