
Reliability and Quality Assurance
9–20
Motorola Small–Signal Transistors, FETs and Diodes Device Data
UCL
LCL
UCL
LCL
CENTERLINE
A
B
C
B
A
B
C
B
A
B
C
B
A
B
C
B
A
ZONE A (+ 3 SIGMA)
ZONE B (+ 2 SIGMA)
ZONE C (+ 1 SIGMA)
ZONE C (– 1 SIGMA)
ZONE B (– 2 SIGMA)
ZONE A (– 3 SIGMA)
Figure 5. Control Chart Zones
Figure 6. One Point Outside Control Limit
Indicating Excessive Variability
Figure 7. Two Out of Three Points in Zone A or
Beyond Indicating Excessive Variability
Figure 8. Four Out of Five Points in Zone B or
Beyond Indicating Excessive Variability
Figure 9. Seven Out of Eight Points in Zone C or
Beyond Indicating Excessive Variability
SUMMARY
Motorola is committed to the use of STATISTICAL
PROCESS CONTROLS. These principles, used throughout
manufacturing have already resulted in many significant
improvements to the processes. Continued dedication to the
SPC culture will allow Motorola to reach the Six Sigma and
zero defect capability goals. SPC will further enhance the
commitment to TOTAL CUSTOMER SATISFACTION.