Application Note 1666 Authors: Theju Bernard, Eric Thomson, Kevin Knudsen, Nick Vanvonno Single Event Effects Testing of the ISL75051SRH LDO SEE Testing: Summary and Conclusions Part Details Single Event Burnout/Latch-up • Function: 3A, radiation hardened, positive, ultra low dropout regulator • Name: ISL75051SRH No Single Event Burnout (SEB) was observed for the device up to an LET value of 86 MeV.cm2 /mg (+125°C). No Single Event Latch-up (SEL) were observed for the device up to an LET value of 86 MeV.cm2/mg (+125°C). • Operating supply voltage: Minimum = 2.2V, Maximum = 6.0V • Supply voltage absolute maximum: 6.7V Single Event Transient • Package hermetic 18 Ld dual in-line flatpack No SET on VOUT in excess of ±5% was observed at an effective LET of 86 MeV.cm2/mg. SET of up to ±4% were observed for an LET of 43 MeV.cm2/mg. The ISL75051SRH is a radiation hardened, low voltage, high current, single output LDO specified for up to 3.0A of continuous output current. These devices operate over an input voltage range of 2.2V to 6.0V and are capable of providing output voltages of 0.8V to 5V adjustable based on resistor divider setting. Dropout voltages as low as 65mV can be realized using the device. The OCP pin allows the short circuit output current limit threshold to be programmed by means of a resistor from the OCP pin to GND. The OCP setting range is from 0.5A minimum to 8.5A maximum. The resistor sets the constant current threshold for the output under fault conditions. The thermal shutdown feature disables the output if the device temperature exceeds the specified value, and it subsequently enters an ON/OFF cycle until the fault is removed. The ENABLE feature allows the part to be placed into a low current shutdown mode drawing about 1µA typical. When enabled, the device operates with a low ground current of 11mA typical, which provides for operation with low quiescent power consumption. Table 1 provides an overall summary of SEE tests results. Introduction This application note describes the Single Event Effects (SEE) tests performed on the ISL75051SRH to characterize its Single Event Burnout (SEB), Single Event Latch-up (SEL) and Single Event Transient (SET) sensitivity. The test facility was the Cyclotron at Texas A&M Radiation Effects Test laboratory. Reference Documents • ISL75051SRH Datasheet • AN1667 “ISL75051SRH High Performance 3A LDO Evaluation Board User Guide” showing ISL75051SRH evaluation board schematic and layout TABLE 1. OVERALL SEE TEST RESULTS (Note 1) TEST ±1% < SET < ±4% SET > ±5% TEMP (ºC) LET (Note 5) -- -- +125 86 MeV.cm2/mg No Single Event Burnouts or Latch-up seen up to VDD = 7.1V at a fluence of 8E + 6 particles/cm2. +25 86 MeV.cm2/mg VIN = 2.2V/4.0V/6.0V (Note 6) VOUT = 1.8V/5.6V SEB/L (Notes 2, 3) SET (Note 4) See report None UNITS REMARKS NOTES: 1. SEE tests performed in a closed loop configuration. The acronym "LET" in this report is used to refer to Linear Energy Transfer. 2. SEB is said to have occurred if a 5% increase in IDD is measured after exposure to the beam. A 0.2µF capacitor was connected from the BYP pin to GND for the purpose of bypass. The 7.1V defines the absolute maximum VIN that can be applied to the device under beam. The acronym "SEB/L" in this report is used to refer to Single Effect Burnout and Latch-up. 3. SEL results: No latch-up condition observed. The acronym "SEB/L" in this report is used to refer to Single Effect Burnout and Latch-up. 4. The acronym "SET" in this report is used to refer to Single Event Transient. 5. LET of 86 was achieved by using a LET of 43 beam and rotating the test sample by 60°. The acronym "LET" in this application note is used to refer to linear energy transfer. 6. The recommended operating VIN for the device is 6.0V, which equates to a 15% derating from the Single Event Breakdown survival voltage of 7.1V. October 14, 2011 AN1666.0 1 CAUTION: These devices are sensitive to electrostatic discharge; follow proper IC Handling Procedures. Copyright Intersil Americas Inc. 2011. All Rights Reserved. 1-888-INTERSIL or 1-888-468-3774 | Intersil (and design) is a trademark owned by Intersil Corporation or one of its subsidiaries. All other trademarks mentioned are the property of their respective owners. Application Note 1666 >±15mV to ±75mV under beam at a fluence of 1x106 particles/cm². For details on SEE events and types detected during testing, see the tables and plots in this application note. Note that ±75mV is ±5% of the output when VOUT = 1.5V and is used as a worst case condition, so for an output voltage greater than 1.5V, the SET amplitude as a percentage is smaller. Irradiation Test Facility • Name: TAMU • Location: College Station, TX • Date: June 25, 2011 • Test Characteristics (15MeV Beam): Cross-section Calculation - LET of 43: 109 Ag - LET of 86: 109 Ag at angle 60 For details on test conditions, fluence, and cross sections, see tables and plots in this application note. Cross sections are calculated as shown by Equation 1: (EQ. 1) CS (LET) = N/F where: Test Description The objective of the test was to characterize the SEE performance of the LDO at the LET levels shown in “Irradiation Test Facility” on page 2. Single Event Latch-up or Burnout event occurrence (SEB/SEL) was measured under beam at a fluence of 1x106 particles/cm². A permanent change in the device supply current after application of the beam is indicative of a burnout condition. If the increased current is reset by cycling power, it is termed a latch-up. Single Event Transient (SET) events were measured on the output of the LDO and were in the range of • CS is the SET cross section (cm²), expressed as a function of the heavy ion LET • LET is the Linear Energy Transfer in MeV.cm²/mg • N is the total number of SET events • F is Fluence in particles/cm², corrected according to the incident angle, if any. A value of 1/F is the assumed cross section when no event is observed. Test Set-up Diagrams Device Block Diagram COMP VIN 5V LDO VCC5 REFIN REFOUT 600 mV 600 mV POWER PMOS REFERENCE BIAS CURRENT LIMIT VOUT SENSE THERMAL SHUTDOWN LEVEL SHIFT ADJ PGOOD DELAY 540 mV GND Device Pin Connections 2 GND 1 18 PG VOUT 2 17 VIN VOUT 3 16 VIN VOUT 4 15 VIN VOUT 5 14 VIN VOUT 6 13 VIN VOUT 7 12 VIN VADJ 8 11 OCP BYP 9 10 EN GND AN1666.0 October 14, 2011 Application Note 1666 SEE Evaluation PWB Layout FIGURE 1. SILK SCREEN TOP FIGURE 2. SILK SCREEN BOTTOM Schematic of SEE Evaluation Board 3 AN1666.0 October 14, 2011 Application Note 1666 Test Set-up Description The SEE evaluation board was wired in the configuration shown in “Schematic of SEE Evaluation Board” on page 3. The silkscreen top and bottom for the evaluation board used are shown at figure 3 and 4. The overall test set-up includes the test jig containing two evaluation boards mounted and wired through a 20-ft cable to the data room. The end of the 20-ft cable in the data room was connected to a switch board. The switch board was wired to the power supplies and monitoring equipment and scopes. Biasing used for SEE test runs was VIN = 2.2V/4.0V/6.0V for VOUT = 1.8V/1.8V/5.6V, respectively. Signals from the switch board were connected to four LECROY oscilloscopes: three set to capture transients due to VOUT, and a fourth set to monitor PGOOD events in real time. Test Method SET events are recorded when movement on VOUT due to an ion strike causes it to exceed the set window trigger of ±15mV. a. Oscilloscope 1 is set to trigger to a VOUT window of ±15mV and a trigger position at 10%. Measurements on Oscilloscope 1 are CH1 = VOUT, CH2 = OCP, CH3 = BYP, CH4 = PGOOD. b. Oscilloscope 2 is set to trigger to a VOUT window of ±15mV and a trigger position at 90%. Measurements on Oscilloscope 1 are CH1 = VOUT, CH2 = OCP, CH3 = BYP, CH4 = PGOOD. c. Oscilloscope 3 is set to trigger to a VOUT window of ±75mV and a trigger position at 10%. Measurements on Oscilloscope 1 are CH1 = VOUT, CH2 = OCP, CH3 = BYP, CH4 = PGOOD. d. Oscilloscope 4 is set to trigger to a PGOOD falling of 200mV and a trigger position at 10%. Measurements on Oscilloscope 1 are CH1 = VOUT, CH2 = OCP, CH3 = BYP, CH4 = PGOOD. The switch board at the end of the 20-ft cabling was found to require terminations of 10nF to keep the noise on the waveforms to a minimum. It should be noted that no events of greater than ±75mV were present at LET 86, so Oscilloscope 3 had no captures. All captured waveforms are in the range of ±15mV to ±75mV, resulting in captures on Oscilloscopes 1 and 2; therefore, analysis in this application note summarizes these events. Test Overview Details of the SET tests are summarized in Tables 2 and 3. The waveforms captured for each run are plotted as a composite, along with ±75mV limit lines that have been added to show that all captures are within the set window. The resultant plots are shown in Figures 3 through 26. The histogram plots in Figures 27 through 32 provide amplitude distribution on the Oscilloscope 1 and 2 captures. Details of the SEB/L tests are summarized in Table 5. An overall summary of all SEE tests is shown in Table 1. TABLE 2. DETAILS OF SET TESTS PERFORMED AT LIGHT LOAD BASED ON VOUT CAPTURES TEST ID DEVICE# ION ANGLE (°) EFF LET (MeV.cm2/mg) FLUENCE PER RUN (PARTICLES/ cm2) TOTAL EVENTS EVENT CROSS SECTION (cm2) SET +25°C LET of 86 VIN = 2.2V, VOUT = 1.8V, IOUT = 0.1A, COUT = 220µF, ISL75051SRH 405 26 109Ag 60.00 86.60 2.0 x 10+6 227 1.14 x 10-4 429 11 109Ag 60.00 86.60 2.0 x 10+6 230 1.15 x 10-4 444 10 109Ag 60.00 86.60 2.0 x 10+6 263 1.32 x 10-4 15 109Ag 86.60 2.0 x 10+6 120 6.00 x 10-4 446 60.00 TOTAL FLUENCE IN PARTICLES/cm2 8.0 x 10+6 TOTAL EVENTS 840 1.05 x 10-4 SET +25°C LET of 86 VIN = 4.0V, VOUT = 1.8V, IOUT = 0.1A, COUT = 220µF, ISL75051SRH 26 109Ag 431 11 109Ag 442 10 441 15 407 86.60 2.0 x 10+6 153 7.65 x 10-5 60.00 86.60 2.0 x 10+6 268 1.34 x 10-4 109Ag 60.00 86.60 2.0 x 10+6 199 9.95 x 10-5 109Ag 60.00 86.60 2.0 x 10+6 97 4.85 x 10-5 60.00 TOTAL FLUENCE IN PARTICLES/cm2 8.0 x 10+6 TOTAL EVENTS 717 8.96 x 10-5 SET +25°C LET of 86 VIN = 6.0V, VOUT = 5.6V, IOUT = 0.1A, COUT = 220µF, ISL75051SRH 411 26 109Ag 60.00 86.60 2.0 x 10+6 508 2.54 x 10-4 437 11 109Ag 60.00 86.60 2.0 x 10+6 253 1.27 x 10-4 449 10 109Ag 60.00 86.60 2.0 x 10+6 440 2.20 x 10-4 451 15 109Ag 60.00 86.60 2.0 x 10+6 247 1.24 x 10-4 TOTAL FLUENCE IN PARTICLES/cm2 8.0 x 10+6 4 TOTAL EVENTS 1448 1.81 x 10-4 AN1666.0 October 14, 2011 Application Note 1666 TABLE 3. DETAILS OF SET TESTS PERFORMED AT MAX LOAD BASED ON VOUT CAPTURES TEST ID DEVICE# ION ANGLE (°) EFF LET (MeV.cm2/mg) FLUENCE PER RUN (PARTICLES/ (cm2) TOTAL EVENTS EVENT CROSS SECTION (cm2) SET +25°C LET of 86 VIN = 2.2V, VOUT = 1.8V, IOUT = 3.0A, COUT = 220µF, ISL75051SRH 406 26 109Ag 60.00 86.60 2.0 x 10+6 255 1.28 x 10-4 430 11 109Ag 60.00 86.60 2.0 x 10+6 246 1.23 x 10-4 445 10 109Ag 60.00 86.60 2.0 x 10+6 253 1.27 x 10-4 447 15 109Ag 60.00 86.60 2.0 x 10+6 618 3.09 x 10-4 TOTAL FLUENCE IN PARTICLES/cm2 8.0 x 10+6 TOTAL EVENTS 1372 1.72 x 10-4 SET +25°C LET of 86 VIN = 4.0V, VOUT = 1.8V, IOUT = 1.0A, COUT = 220µF, ISL75051SRH 408 26 109Ag 60.00 86.60 2.0 x 10+6 655 3.28 x 10-4 432 11 109Ag 60.00 86.60 2.0 x 10+6 252 1.26 x 10-4 443 10 109Ag 60.00 86.60 2.0 x 10+6 253 1.27 x 10-4 448 15 109Ag 60.00 86.60 2.0 x 10+6 251 1.26 x 10-4 TOTAL FLUENCE IN PARTICLES/cm2 8.0 x 10+6 TOTAL EVENTS 1411 1.76 x 10-4 SET +25°C LET of 86 VIN = 6.0V, VOUT = 5.6V, IOUT = 3.0A, COUT = 220µF, ISL75051SRH 412 26 109Ag 60.00 86.60 2.0 x 10+6 252 1.26 x 10-4 439 11 109Ag 60.00 86.60 2.0 x 10+6 252 1.26 x 10-4 450 10 109Ag 60.00 86.60 2.0 x 10+6 282 1.41 x 10-4 452 15 109Ag 60.00 86.60 2.0 x 10+6 251 1.26 x 10-4 TOTAL FLUENCE IN PARTICLES/cm2 8.0 x 10+6 TOTAL EVENTS 1037 1.30 x 10-4 TABLE 4. VOUT SET HISTOGRAM DATA VOUT BIN (mV) VIN = 2.2V. IOUT = 0.1A VIN = 4.0V IOUT = 0.1A VIN = 6.0V IOUT = 0.1A VIN = 2.2V IOUT = 3.0A VIN = 4.0V IOUT = 1.0A VIN = 6.0V IOUT = 3.0A -75 0 0 0 0 0 1 -70 0 0 0 0 0 1 -65 0 0 0 0 0 56 -60 0 0 0 2 0 174 -55 0 0 0 286 0 159 -50 0 0 0 188 0 133 -45 0 0 0 102 0 98 -40 0 0 0 292 0 47 -35 0 0 0 93 4 8 -30 0 0 12 55 270 4 -25 0 0 142 29 509 3 -20 0 0 412 17 126 45 -15 1 2 284 28 324 89 -10 39 40 164 61 54 41 5 AN1666.0 October 14, 2011 Application Note 1666 TABLE 4. VOUT SET HISTOGRAM DATA (Continued) VOUT BIN (mV) VIN = 2.2V. IOUT = 0.1A VIN = 4.0V IOUT = 0.1A VIN = 6.0V IOUT = 0.1A VIN = 2.2V IOUT = 3.0A VIN = 4.0V IOUT = 1.0A VIN = 6.0V IOUT = 3.0A -5 548 341 226 165 84 70 0 252 334 211 54 40 108 5 52 35 316 5 0 109 10 107 47 28 85 7 81 15 169 142 44 660 26 17 20 104 160 359 461 849 58 25 79 88 331 66 437 69 30 53 35 198 59 16 24 35 45 47 140 36 24 237 40 73 36 29 0 20 254 45 65 41 0 0 15 150 50 30 23 0 0 4 36 55 43 16 0 0 8 2 60 20 23 0 0 3 0 65 0 24 0 0 2 0 70 0 0 0 0 0 0 75 0 0 0 0 0 0 See “SET VOUT See Figure 27 Histogram Plots for ISL75051SRH (Note 11)” on page 13 See Figure 28 6 See Figure 29 See Figure 30 See Figure 31 See Figure 32 AN1666.0 October 14, 2011 Application Note 1666 Typical SET Captures at IOUT = 0.1A (Notes 7, 8) FIGURE 3. TYPICAL CAPTURE AT V IN = 2.2V, RUN 405 FIGURE 4. TYPICAL CAPTURE AT V IN = 2.2V, RUN 429 (Note 8) FIGURE 5. TYPICAL CAPTURE AT V IN = 2.2V, RUN 444 FIGURE 6. TYPICAL CAPTURE AT V IN = 2.2V, RUN 446 7 AN1666.0 October 14, 2011 Application Note 1666 Typical SET Captures at IOUT = 0.1A (Notes 7, 8) (Continued) FIGURE 7. TYPICAL CAPTURE AT V IN = 4.0V, RUN 407 FIGURE 8. TYPICAL CAPTURE AT V IN = 4.0V, RUN 431 (Note 8) FIGURE 9. TYPICAL CAPTURE AT V IN = 4.0V, RUN 442 FIGURE 10. TYPICAL CAPTURE AT V IN = 4.0V, RUN 441 8 AN1666.0 October 14, 2011 Application Note 1666 Typical SET Captures at IOUT = 0.1A (Notes 7, 8) (Continued) FIGURE 11. TYPICAL CAPTURE AT V IN = 6.0V, RUN 411 FIGURE 12. TYPICAL CAPTURE AT V IN = 6.0V, RUN 437 FIGURE 13. TYPICAL CAPTURE AT V IN = 6.0V, RUN 449 FIGURE 14. TYPICAL CAPTURE AT V IN = 6.0V, RUN 451 NOTES: 7. Composite of all captured transients per run shown. For a distribution on the transients on VOUT, see histogram data and histograms in “VOUT SET HISTOGRAM DATA” on page 5 and “SET VOUT Histogram Plots for ISL75051SRH (Note 11)” on page 13. 8. The horizontal axis time per division is 10µs except for Figures 4, 8, 12, 16, 20, and 24, which are at 20µs per division. 9 AN1666.0 October 14, 2011 Application Note 1666 Typical SET Captures at IOUT = 1A (Note 7,8,9 ) FIGURE 15. TYPICAL CAPTURE AT V IN = 4.0V, RUN 408 FIGURE 16. TYPICAL CAPTURE AT V IN = 4.0V, RUN 432 FIGURE 17. TYPICAL CAPTURE AT V IN = 4.0V, RUN 443 FIGURE 18. TYPICAL CAPTURE AT V IN = 4.0V, RUN 448 NOTE: 9. The waveforms signature observed in Figures 15 through 18 is caused by the handoff between main and redundant references during an SET event. This does not affect normal operation of the device. 10 AN1666.0 October 14, 2011 Application Note 1666 Typical SET Captures at IOUT = 3A (Note 7, 8, 10) FIGURE 19. TYPICAL CAPTURE AT V IN = 2.2V, RUN 406 FIGURE 20. TYPICAL CAPTURE AT V IN = 2.2V, RUN 430 (Note 8) FIGURE 21. TYPICAL CAPTURE AT V IN = 2.2V, RUN 445 FIGURE 22. TYPICAL CAPTURE AT V IN = 2.2V, RUN 447 11 AN1666.0 October 14, 2011 Application Note 1666 Typical SET Captures at IOUT = 3A (Note 7, 8, 10) (Continued) FIGURE 23. TYPICAL CAPTURES AT V IN = 6.0V, RUN 412 FIGURE 24. TYPICAL CAPTURES AT V IN = 6.0V, RUN 439 (Note 8) FIGURE 25. TYPICAL CAPTURE AT V IN = 6.0V, RUN 450 FIGURE 26. TYPICAL CAPTURE AT V IN = 6.0V, RUN 452 NOTE: 10. The waveforms signature observed in Figures 19 through 26 is caused by the handoff between main and redundant references during an SET event. This does not affect normal operation of the device. 12 AN1666.0 October 14, 2011 Application Note 1666 SET VOUT Histogram Plots for ISL75051SRH (Note 11) 600 500 300 SET LET of 86 VIN = 4.0V VOUT = 1.8V IOUT = 0.1A COUT = 220µF 350 300 EVENTS 400 EVENTS 400 SET LET of 86 VIN = 2.2V VOUT = 1.8V IOUT = 0.1A COUT = 220µF 200 250 200 150 100 100 50 0 -75 -65 -55 -45 -35 -25 -15 -5 5 0 -75 -65 -55 -45 -35 -25 -15 -5 15 25 35 45 55 65 75 5 15 25 35 45 55 65 75 POSITIVE AND NEGATIVE OVERSHOOT IN mV TOTAL EVENTS = 840, AREA OF CROSS SECTION = 1.05 x 10-4cm2 POSITIVE AND NEGATIVE OVERSHOOT IN mV TOTAL EVENTS = 717, AREA OF CROSS SECTION = 0.89625 x 10-4cm2 FIGURE 27. V IN = 2.2V at 0.1A FIGURE 28. V IN = 4.0V at 0.1A 700 450 SET LET of 86 VIN = 6.0V VOUT = 5.6V IOUT = 0.1A COUT = 220µF 400 350 500 EVENTS EVENTS 300 250 200 SET LET of 86 VIN = 2.2V VOUT = 1.8V IOUT = 3.0A COUT = 220µF 600 150 400 300 200 100 100 50 0 -75 -65 -55 -45 -35 -25 -15 -5 5 0 -75 -65 -55 -45 -35 -25 -15 -5 15 25 35 45 55 65 75 5 15 25 35 45 55 65 75 POSITIVE AND NEGATIVE OVERSHOOT IN mV TOTAL EVENTS = 1448, AREA OF CROSS SECTION = 1.81 x 10-4cm2 POSITIVE AND NEGATIVE OVERSHOOT IN mV TOTAL EVENTS = 1372, AREA OF CROSS SECTION = 1.715 x 10-4cm2 FIGURE 29. V IN = 6.0V at 0.1A FIGURE 30. V IN = 2.2V at 3.0A 900 700 250 200 EVENTS 600 EVENTS 300 SET LET of 86 VIN = 4.0V VOUT = 1.8V IOUT = 1.0A COUT = 220µF 800 500 400 300 SET LET of 86 VIN = 6.0V VOUT = 5.6V IOUT = 3.0A COUT = 220µF 150 100 200 50 100 0 -75 -65 -55 -45 -35 -25 -15 -5 5 15 25 35 45 55 65 75 0 -75 -65 -55 -45 -35 -25 -15 -5 5 15 25 35 45 55 65 75 POSITIVE AND NEGATIVE OVERSHOOT IN mV TOTAL EVENTS = 1411, AREA OF CROSS SECTION = 1.76375 x 10-4cm2 POSITIVE AND NEGATIVE OVERSHOOT IN mV TOTAL EVENTS = 1037, AREA OF CROSS SECTION = 1.29625x 10-4cm2 FIGURE 31. V IN = 4.0V at 1.0A FIGURE 32. V IN = 6.0V at 3.0A NOTE: 11. Oscilloscope set to trigger to VOUT window of ±15mV over the nominal VOUT value. The two peaks represent positive and negative transients. 13 AN1666.0 October 14, 2011 Application Note 1666 TABLE 5. DETAILS OF SEB/L TESTS TEMP (°C) 125 125 125 125 LET (MeV.cm2/mg) BYP CAP (µF) 86 0.2 86 0.2 86 0.2 86 0.2 VDD (V) 7.1 7.1 7.1 7.1 TOTAL EVENTS LATCH EVENTS CUMULATIVE FLUENCE (PARTICLES/cm2) CUMULATIVE CROSS SECTION (cm2) DEVICE SEB/L 0 2.0 x 10+6 5.0 x 10-7 1 PASS 0 2.0 x 10+6 5.0 x 10-7 2 PASS 0 2.0 x 10+6 5.0 x 10-7 3 PASS 0 2.0 x 10+6 5.0 x 10-7 4 PASS 0 OVERALL FLUENCE 8.0 x 10+6 OVERALL CROSS SECTION 1.25 x 10-7 TOTAL UNITS 4 Die Map and Mask Number FIGURE 33. ISL75051SRH DIE MAP FIGURE 34. ISL75051SRH MASK NUMBER Intersil Corporation reserves the right to make changes in circuit design, software and/or specifications at any time without notice. Accordingly, the reader is cautioned to verify that the Application Note or Technical Brief is current before proceeding. For information regarding Intersil Corporation and its products, see www.intersil.com 14 AN1666.0 October 14, 2011