Single Event Latchup (SEL)

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Single Event Latchup(SEL)
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Definitions
Single Event Latchup (SEL) is a potentially
destructive condition involving parasitic circuit
elements forming a silicon controlled rectifier
(SCR). In traditional SEL, the device current
may destroy the device if not current limited and
removed "in time." A "microlatch" is a subset of
SEL where the device current remains below the
maximum specified for the device. A removal of
power to the device is required in all
non-catastrophic SEL conditions in order to
recover device operations.
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Latchup Basics
From Harris
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Latchup BasicsEquivalent Circuit
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EPI Layer, Latchup, and Ion Range
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SEL - QL3025 0.35 ?m
BNL 02/98 S/N QL1 Run T2 VBIAS 5.0V,
3.3V Titanium _at_ 0 Deg LET 18.8 MeV-cm2/mg
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Chip Express Latchup Comparison
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SELTH Variability
S/N Lot No. D/C Threshold X-Sec Prolonged Latchup
Allowed? A1 U1P126 9646 52.9 1.5E-06 no A4 U1P0
61 9402 52.9 4.50E-06 no B1 U1P054 9851 52.9 3.4
E-07 no B2 U1P054 9851 43.2 2.0E-06 no B3 U1P0
54 9851 52.9 3.0E-06 yes B4 U1P054 9851 52.9 1.5
E-06 yes B5 U1P054 9851 gt 74.7 no
latchup - B6 U1P054 9851 gt 74.7 no
latchup - C1 U1P054 9844 52.9 3.0E-06 no C2 U1
P054 9844 43.2 no data _at_75 yes C3 U1P054 9844 74
.7 no data _at_75 no D1 U1P126 9704 43.2 6.7E-06 n
o D2 U1P126 9704 43.2 9.4E-06 no D3 U1P126 9704
43.2 no data _at_75 yes D4 U1P126 9704 lt 37.4 no
data _at_75 yes D5 U1P126 9704 lt 43.2 no data
_at_75 yes
SEL Summary for A1020B. A large set of parts
from multiple lots were tested, showing a wide
range of SEL LETTH and latchup currents. Some
latchups were destructive with either higher ICC
or functional failure.
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Distribution of Peak Latchup Currents for the
A1020B (MEC)
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Single Event LatchupIon Energy Dependence
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Latchup Summary
Device Type Pre-prod. RH1020 QL24X32B RT54SX16/3
2 A54SX32A QYH530 CX2041 CX3001 A54SX16 QL3025
XQR4062XL
Size/Voltage (nominal core) 1.0 ?m / 5.0 0.65 ?m
/ 5.0 0.8 ?m / 3.3 0.25 ?m / 2.5 0.8 ?m / 5.0 0.6
?m / 2.5 0.35 ?m / 3.3 0.35 ?m / 3.3 0.35 ?m /
3.3 0.35 ?m / 3.3
Comments Destructive One-Mask LPGA Destructi
ve
Threshold (MeV-cm2/mg) gt 74 lt 18 gt 120 High
52 gt 37 Low gt 74 lt 11 gt 100
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Single Event Latchup
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Ex. SEL Detection and Clearing
Note that FPGA have high I/O count with diodes to
VCC and GND in most cases.
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SEL Test Results
Shutter Opened