SLVK117 October   2022 TPS7H2221-SEP

 

  1.   Single-Event Effects Test Report of the TPS7H2221-SEP Load Switch
  2.   Trademarks
  3. 1 Introduction
  4. 2 Single-Event Effects (SEE)
  5. 3 Device and Test Board Information
  6. 4 Irradiation Facility and Setup
  7. 5 Depth, Range and LETEFF Calculation
  8. 6 Test Setup and Procedures
  9. 7 Destructive Single-Event Effects (DSEE)
    1. 7.1 Single-Event Latch-up (SEL) Results
    2. 7.2 Single-Event Burnout (SEB) and Single-Event Gate Rupture (SEGR) Results
  10. 8 Single-Event Transients (SET) and Single Event Functional Interrupt (SEFI)
    1. 8.1 Single Event Transient (SET)
    2. 8.2 Single Event Functional Interrupt (SEFI)
  11. 9 Event Rate Calculations
  12. 10Summary
  13.   A Appendix: Total Ionizing Dose from SEE Experiments
  14.   B Appendix: References

8.2 Single Event Functional Interrupt (SEFI)

SEFIs are defined as cases where a device stops functioning normally for an extended period of time (longer than a transient) and in some cases requires a power reset in order to allow the device to recover. During testing there was a concern of potential SEFIs when the device was operating with low voltage (<3.1-V) and high load (~1.25-A). In order to test this, six different devices were tested across a range of input conditions. Testing included keeping the load at 1.25-A while sweeping the input voltage down from 3.1-V until a SEFI occured. The LET for all tests was kept at either 42.7 or 46.8 MeV·cm2/mg using 129Xe or 109Ag at incident angle with a flux of ≈104 or 105 to a flunce range of 106 to 107. Test results and an example of the SEFI are reported and discussed below.

For testing done with the 109Ag Silver ion the QOD pin was tested under two different conditions. The first was tying it high to VOUT and the second was tying it high to PGOOD with a 2 kΩ resistor. In the case where QOD was tied to VOUT only VOUT was monitored, under this test condition there were no observed differences in transient behavior. In the case where QOD was tied to PGOOD the QOD pin was monitored seperately from VOUT, under this test condition the transient behavior on QOD aligned with the transient behavior on VOUT with no observable differences.

Table 8-3 Summary of TPS7H2221-SEP SEFI Test Condition and Results

For devices 3 and 4 fluence was only run to 1 x 106 as earlier results showed that the SEFI signature would occur well before 1 x 106.

Run #

Unit #

Ion

 LETEFF (MeV·cm2/mg) FLUX (ions·cm2/mg) FLUENCE
(# ions)

VIN (V)

LOAD (A)

SEFI OCCURED?

32

1

129Xe

42.7

1.19 x 104

3 x 106

3.1

1.25

No

33

1

 129Xe 42.7 1.12 x 104 3 x 106

2.9

 1.25

No

34

1

 129Xe 42.7 1.16 x 104 3 x 106

2.7

 1.25

No

35

1

 129Xe 42.7 1.13 x 104

7.33 x 105

1.8

 1.25

Yes

36

2

 129Xe 42.7 1.16 x 104 3 x 106

2.7

 1.25

No

37

2

 129Xe 42.7 1.07 x 104 3 x 106

2.6

 1.25

No

38

2

 129Xe 42.7 1.08 x 104 3 x 106

2.5

 1.25

No

39

2

 129Xe 42.7 1.10 x 104 3 x 106

2.4

 1.25

No

40

2

 129Xe 42.7 1.20 x 104

6.61 x 105

1.8

 1.25

Yes

41

3

 129Xe 42.7 1.19 x 104 1 x 106

1.8

 1.25

No

42

3

 129Xe 42.7 1.36 x 104 1 x 106

1.6

 1.25

No

43

4

 129Xe 42.7 1.06 x 104 1 x 106

1.6

 1.25

No

44

4

 129Xe 42.7 1.03 x 104 1 x 106

1.6

1.25

No

45

5

109Ag

46.8

1.06 x 105

1 x 107

2.4

1.25

No

46

6

 109Ag

46.8

9.44 x 104

9.98 x 106

2.4

1.25

No
Figure 8-5 Typical TPS7H2221-SEP SEFI.

During SEFI occurance all behavior was non-destructive and was fixed by toggling the "ON" pin to reset the device.

The results show that there is part to part variation as to whether the SEFI occurs at VIN = 1.8-V, however the device appears to be SEFI free at VIN ≥ 2.4-V with the full 1.25-A load. This SEFI testing provides high likeliness that the device will be fully operational at max load with VIN ≥ 2.4-V. Along with the six production samples that were tested, lookahead testing was conducted with four non-production samples that validate device functionality at this range. Although the device can be fully operational at VIN = 1.6-V or 1.8-V some devices showed the SEFI behavior at this voltage level. Because of this it is unlikely that the device can operate at max load with these voltage levels while under the effects of radiation.