ISL70001SRH Neutron Test Report

Neutron testing of the ISL70001SRH POL converter
Nick van Vonno
Intersil Corporation
25 June 2012
Table of Contents
1. Introduction
2. Part Description
3. Test Description
3.1 Irradiation facility
3.2 Characterization equipment
3.3 Experimental Matrix
4 Results
4.1 Test results
4.2 Variables data
5 Discussion and conclusion
6 Appendices
7 Document revision history
1. Introduction
This report summarizes results of neutron testing of the ISL70001SRH point of load converter (POL).
The test was conducted in order to determine the sensitivity of the part to the displacement damage caused
by the neutron environment.
2: Part Description
The ISL70001SRH is a high efficiency monolithic synchronous buck regulator with integrated power
MOSFET devices, eliminating the need for external MOSFET devices. The part is designed for point of load
(POL) applications and provides a single chip power management solution for digital ICs such as processors
and field programmable gate arrays. The ISL70001SRH is designed and rated for the total dose and SEE
environments as encountered in space and is manufactured in compliance with MIL-PRF-38535. The part
operates over an input voltage range of 3V to 5.5V and provides a regulated output voltage that is externally
adjustable from 0.8V to ~85% of the input voltage. Output load current capacity is 6A for T J < +145°C. The
ISL70001SRH utilizes peak current-mode control with integrated compensation and switches at a fixed
frequency of 1MHz. The high level of integration provided by integrating the power MOSFET devices makes
the ISL70001SRH a good choice to power small form factor applications in space systems. A simplified block
diagram of the part is shown in Figure 1.
1
AVDD
AGND
DVDD
DGND
EN
POWER-ON
RESET (POR)
PORSEL
PVINx
EA
FB
CURRENT
SENSE
SLOPE
COMPENSATION
SOFT
START
SS
GM
PWM
CONTROL
LOGIC
GATE
DRIVE
LXx
COMPENSATION
PGNDx
UV
POWER-GOOD
PGOOD
REF
PWM
REFERENCE
0.6V
BIT
TRIM
TRIM
TDI
TDO
ZAP
SYNC
M/S
Fig. 1: ISL70001SRH block diagram.
The ISL70001SRH is implemented in a commercial submicron BiCMOS process optimized for power
management applications, with 0.6um minimum ground rules and three layers of interconnect. Active devices
include low voltage CMOS and high voltage DMOS devices as well as complementary bipolars. The process
is in volume production under MIL-PRF-38535 certification and is used for a wide range of commercial power
management devices. In order to retain the advantages of volume production, the ISL70001SRH was
designed for total dose and SEE hardness using well-known ‘hardened by design’ techniques, including
closed geometry N-channel devices, guard rings and latchup-prevention layout design.
3: Test Description
3.1 Irradiation Facilities
Neutron irradiation was performed at the Fast Burst Reactor facility at White Sands Missile Range
(White Sands, NM), which provides a controlled 1MeV equivalent neutron flux. Parts were tested in an
unbiased configuration with all leads open. As neutron irradiation activates many of the elements found in a
packaged integrated circuit, the parts exposed at the higher neutron levels required significant ‘cooldown time’
before being shipped back to Palm Bay for electrical testing.
3.2 Characterization equipment and procedures
Electrical testing was performed before and after irradiation using the production automated test
equipment (ATE). All electrical testing was performed at room temperature. Final data was taken 2
September 2011.
2
3.3 Experimental matrix
Testing proceeded in accordance with the guidelines of MIL-STD-883 Test Method 1017. The
experimental matrix consisted of five samples irradiated at 2 x 1012 n/cm2, five samples irradiated at 1 x 1013
n/cm2, five samples irradiated at 3 x 1013 n/cm2 and five samples irradiated at 1 x 1014 n/cm2. Three control
units were used.
5962R0922502VXC samples were drawn from lot number I2K14H01YGD (P6 BiMOS) and were
packaged in 48-lead flatpacks, code RKU. The date code was X1008ABB5, and the mask number for lot
I2K14H01YGD was 53695A01. The lot was processed at the IBM Burlington, Vermont facility. Table 1, below,
shows sample serial numbers for each experimental cell.
WSMR shot ID
Exposure level
Serial numbers
DTR-11094
DTR-11097
DTR-11100
DTR-11103
Control units
2 x 1012
1 x 1013
3 x 1013
1 x 1014
1207, 1208, 1210, 1234, 1235
1336, 1238, 1239, 1241, 1242
1244, 1247, 1250, 1263, 1264
1265, 1266, 1267, 1268, 1269
1270, 1272, 1274
Table 1: Neutron irradiation experimental matrix.
4: Results
4.1 Test results
Neutron testing of the ISL70001SRH is complete and the results are reported in the balance of this
report.
4.2 Variables data
The plots in Figs. 2 through 46 show data plots for key parameters before and after irradiation to each
level. The plots show the median as a function of neutron irradiation; we chose to use the median because of
the relatively small sample sizes involved.
3
0
0.3
-0.2
0.2
Master/Slave input HIGH current, uA
Enable LOW input current, uA
MS_IIH
-0.4
-0.6
-0.8
EN_IIL
-1
Spec limit
-1.2
Spec limit
0.1
Spec limit
0
-0.1
-0.2
Spec limit
-1.4
1.00E+11
Pre-irradiation
1.00E+12
1.00E+13
Neutron dose, n/cm2
-0.3
1.00E+11
Pre-irradiation
1.00E+14
0.3
MS_IIL
Master/Slave input LOW current, uA
-0.2
Enable HIGH input current, uA
1.00E+14
Fig. 4: ISL70001SRH master/slave control pin HIGH input
current as a function of neutron irradiation. Sample size
was 5 for each cell (2 x 1012 n/cm2, 1 x 1013 n/cm2, 3 x
1013 n/cm2 and 1 x 1014 n/cm2), with three control units.
The data sheet limits are -0.25uA to +0.25uA.
0
-0.4
-0.6
-0.8
EN_IIH
-1
Spec limit
-1.4
1.00E+11
Pre-irradiation
1.00E+13
Neutron dose, n/cm 2
Fig. 2: ISL70001SRH enable LOW input current as a
function of neutron irradiation. Sample size was 5 for
each cell (2 x 1012 n/cm2, 1 x 1013 n/cm2, 3 x 1013
n/cm2 and 1 x 1014 n/cm2), with three control units. The
data sheet limits are -1.2uA to -0.2uA.
-1.2
1.00E+12
Spec limit
1.00E+12
Neutron dose,
1.00E+13
0.2
Spec limit
0.1
0
-0.1
-0.2
-0.3
1.00E+11
Pre-irradiation
1.00E+14
n/cm 2
Spec limit
1.00E+12
1.00E+13
1.00E+14
Neutron dose, n/cm 2
Fig. 5: ISL70001SRH master/slave control pin LOW input
current as a function of neutron irradiation. Sample size
was 5 for each cell (2 x 1012 n/cm2, 1 x 1013 n/cm2, 3 x
1013 n/cm2 and 1 x 1014 n/cm2), with three control units.
The data sheet limits are -0.25uA to +0.25uA.
Fig. 3: ISL70001SRH enable HIGH input current as a
function of neutron irradiation. Sample size was 5 for
each cell (2 x 1012 n/cm2, 1 x 1013 n/cm2, 3 x 1013
n/cm2 and 1 x 1014 n/cm2), with three control units. The
data sheet limits are -1.2uA to -0.1uA.
4
0.3
0.2
0.2
SYNC_IIH
Spec limit
SYNC input HIGH current, uA
POR threshold select input HIGH current, uA
0.3
0.1
0
-0.1
PORSEL_IIH
Spec limit
0.1
Spec limit
0
-0.1
-0.2
-0.2
Spec limit
-0.3
1.00E+11
Pre-irradiation
1.00E+12
1.00E+13
-0.3
1.00E+11
Pre-irradiation
1.00E+14
1.00E+12
1.00E+14
Fig. 8: ISL70001SRH SYNC input pin HIGH input
current as a function of neutron irradiation. Sample size
was 5 for each cell (2 x 1012 n/cm2, 1 x 1013 n/cm2, 3 x
1013 n/cm2 and 1 x 1014 n/cm2), with three control units.
The data sheet limits are -0.25uA to +0.25uA.
Fig. 6: ISL70001SRH POR threshold select HIGH
input current as a function of neutron irradiation.
Sample size was 5 for each cell (2 x 1012 n/cm2, 1 x
1013 n/cm2, 3 x 1013 n/cm2 and 1 x 1014 n/cm2), with
three control units. The data sheet limits are -0.25uA to
+0.25uA.
0.3
0.4
0.2
0.2
0
SYNC input LOW current, uA
POR threshold select input LOW current, uA
1.00E+13
Neutron dose, n/cm 2
Neutron dose, n/cm2
0.1
0
-0.1
-0.2
-0.3
1.00E+11
Pre-irradiation
PORSEL_IIL
-0.2
-0.4
-0.6
-0.8
-1
SYNC_IIL
Spec limit
-1.2
Spec limit
Spec limit
-1.4
Spec limit
1.00E+12
Neutron dose,
1.00E+13
-1.6
1.00E+11
Pre-irradiation
1.00E+14
n/cm 2
1.00E+12
1.00E+13
1.00E+14
Neutron dose, n/cm 2
Fig. 7: ISL70001SRH POR threshold select LOW input
current as a function of neutron irradiation. Sample
size was 5 for each cell (2 x 1012 n/cm2, 1 x 1013 n/cm2,
3 x 1013 n/cm2 and 1 x 1014 n/cm2), with three control
units. The data sheet limits are -0.25uA to +0.25uA.
Fig. 9: ISL70001SRH SYNC input pin LOW input
current as a function of neutron irradiation. Sample size
was 5 for each cell (2 x 1012 n/cm2, 1 x 1013 n/cm2, 3 x
1013 n/cm2 and 1 x 1014 n/cm2), with three control units.
The data sheet limits are -0.25uA to +0.25uA.
5
0.3
0.5
FB_IBIAS
Spec limit
0.3
Spec limit
0.1
LX HIGH leakage, uA
Feedback input bias current, uA
0.2
0
-0.1
LX1
LX2
LX3
LX4
LX5
LX6
Spec limit
Spec limit
0.1
-0.1
-0.3
-0.2
-0.3
Pre-irradiation
1.00E+11
1.00E+12
1.00E+13
-0.5
1.00E+11
Pre-irradiation
1.00E+14
Neutron dose, n/cm 2
1.00E+12
1.00E+13
1.00E+14
Neutron dose, n/cm2
Fig. 12: ISL70001SRH LX HIGH leakage current, all six
LX outputs, as a function of neutron irradiation. Sample
size was 5 for each cell (2 x 1012 n/cm2, 1 x 1013 n/cm2, 3
x 1013 n/cm2 and 1 x 1014 n/cm2), with three control units.
The data sheet limits are -0.4uA to +0.5uA.
Fig. 10: ISL70001SRH feedback input bias current as
a function of neutron irradiation. Sample size was 5 for
each cell (2 x 1012 n/cm2, 1 x 1013 n/cm2, 3 x 1013
n/cm2 and 1 x 1014 n/cm2), with three control units.
The data sheet limits are -0.25uA to +0.25uA.
0.615
0.5
0.4
0.61
Trimmed reference voltage, V
0.3
LX LOW leakage, uA
0.2
0.1
0
-0.1
-0.2
LX1
LX2
LX3
LX4
LX5
LX6
Spec limit
Spec limit
-0.5
1.00E+11
Pre-irradiation
1.00E+12
0.6
VREF_post_trim
0.595
-0.3
-0.4
0.605
Spec limit
Spec limit
1.00E+13
0.59
1.00E+11
Pre-irradiation
1.00E+14
1.00E+12
1.00E+13
1.00E+14
Neutron dose, n/cm 2
Neutron dose, n/cm2
Fig. 11: ISL70001SRH LX LOW leakage current, all six
LX outputs, as a function of neutron irradiation. Sample
size was 5 for each cell (2 x 1012 n/cm2, 1 x 1013 n/cm2,
3 x 1013 n/cm2 and 1 x 1014 n/cm2), with three control
units. The data sheet limits are -0.4uA to +0.4uA.
Fig. 13: ISL70001SRH trimmed reference voltage as a
function of neutron irradiation. Sample size was 5 for each
cell (2 x 1012 n/cm2, 1 x 1013 n/cm2, 3 x 1013 n/cm2 and 1 x
1014 n/cm2), with three control units. The data sheet limits
are 0.594V to 0.606V.
6
0.615
Reference voltage, maximum input voltage, V
1.23
Trimmed bandgap voltage, V
1.22
1.21
1.2
1.19
1.18
VBG_post_trim
Spec limit
Spec limit
1.17
1.00E+11
Pre-irradiation
1.00E+12
1.00E+13
VREF_VMAX
0.61
Spec limit
Spec limit
0.605
0.6
0.595
0.59
1.00E+11
Pre-irradiation
1.00E+14
1.00E+12
Neutron dose, n/cm2
Fig. 14: ISL70001SRH trimmed bandgap voltage as a
function of neutron irradiation. Sample size was 5 for
each cell (2 x 1012 n/cm2, 1 x 1013 n/cm2, 3 x 1013
n/cm2 and 1 x 1014 n/cm2), with three control units. The
data sheet limits are 1.175V to 1.225V.
6
VRF_VMIN
ISD_3.6V
Shutdown supply current, 3.6V in, mA
Reference voltage, minimum input voltage, V
1.00E+14
Fig. 16: ISL70001SRH reference output voltage, 5.5V
in, as a function of neutron irradiation. Sample size was
5 for each cell (2 x 1012 n/cm2, 1 x 1013 n/cm2, 3 x 1013
n/cm2 and 1 x 1014 n/cm2), with three control units. The
data sheet limits are 0.594V to 0.606V.
0.612
Spec limit
0.607
Spec limit
0.602
0.597
0.592
1.00E+11
Pre-irradiation
1.00E+13
Neutron dose, n/cm2
1.00E+12
1.00E+13
5
Spec limit
4
Spec limit
3
2
1
0
1.00E+11
Pre-irradiation
1.00E+14
1.00E+12
1.00E+13
1.00E+14
Neutron dose, n/cm2
Neutron dose, n/cm 2
Fig. 15: ISL70001SRH reference output voltage, 3.6V
in, as a function of neutron irradiation. Sample size
was 5 for each cell (2 x 1012 n/cm2, 1 x 1013 n/cm2, 3 x
1013 n/cm2 and 1 x 1014 n/cm2), with three control units.
The data sheet limits are 0.594V to 0.606V.
Fig. 17: ISL70001SRH shutdown supply current, 3.6V in,
as a function of neutron irradiation. Sample size was 5 for
each cell (2 x 1012 n/cm2, 1 x 1013 n/cm2, 3 x 1013 n/cm2
and 1 x 1014 n/cm2), with three control units. The data
sheet limits are 1.0mA to 5.0mA.
7
10
1200
ISD_5.5V
1100
Oscillator frequency, post trim, KHz
Shutdown supply current, 5.5V in, mA
9
Spec limit
8
Spec limit
7
6
5
4
3
2
1.00E+11
Pre-irradiation
1.00E+12
Neutron dose,
1.00E+13
700
OSC_Ch A
OSC_Ch B
600
OSC_Ch C
Spec limit
500
Spec limit
1.00E+13
1.00E+14
Fig. 20: ISL70001SRH oscillator frequency, all three
channels, as a function of neutron irradiation. Sample
size was 5 for each cell (2 x 1012 n/cm2, 1 x 1013 n/cm2,
3 x 1013 n/cm2 and 1 x 1014 n/cm2), with three control
units. The data sheet limits are 875KHz to 1125KHz.
1200
IREF, Ch A
IREF, Ch B
IREF, Ch C
Spec limit
1100
Spec limit
1.04
1.02
1
0.98
1000
900
800
OSC_VMIN
OSC_VMAX
0.96
700
0.94
0.92
1.00E+11
Pre-irradiation
1.00E+12
Neutron dose, n/cm 2
Oscillator frequency, KHz
Reference current, post trim, mA
800
400
1.00E+11
Pre-irradiation
1.00E+14
1.1
1.06
900
n/cm 2
Fig. 18: ISL70001SRH shutdown supply current, 5.5V
in, as a function of neutron irradiation. Sample size
was 5 for each cell (2 x 1012 n/cm2, 1 x 1013 n/cm2, 3 x
1013 n/cm2 and 1 x 1014 n/cm2), with three control units.
The data sheet limits are 3.0mA to 9.5mA.
1.08
1000
Spec limit
Spec limit
1.00E+12
1.00E+13
600
1.00E+11
Pre-irradiation
1.00E+14
1.00E+12
1.00E+13
1.00E+14
Neutron dose, n/cm 2
Neutron dose, n/cm 2
Fig. 19: ISL70001SRH post trim reference current as a
function of neutron irradiation. Sample size was 5 for
each cell (2 x 1012 n/cm2, 1 x 1013 n/cm2, 3 x 1013
n/cm2 and 1 x 1014 n/cm2), with three control units. The
data sheet limits are 0.93mA to 1.09mA.
Fig. 21: ISL70001SRH oscillator frequency vs. input
voltage as a function of neutron irradiation. Sample size
was 5 for each cell (2 x 1012 n/cm2, 1 x 1013 n/cm2, 3 x
1013 n/cm2 and 1 x 1014 n/cm2), with three control units.
The data sheet limits are 875KHz to 1125KHz.
8
50
180
45
160
40
Supply current, 3.6V, mA
Minimum ON time, ns
200
140
120
100
80
MIN_TON_Ch a
60
40
MIN_TON_Ch B
MIN_TON_Ch C
35
30
25
20
IDD, 3.6V
15
10
Spec limit
5
Spec limit
Spec limit
20
0
1.00E+11
Pre-irradiation
Spec limit
1.00E+12
1.00E+13
0
1.00E+11
Pre-irradiation
1.00E+14
1.00E+12
1.00E+13
1.00E+14
Neutron dose, n/cm 2
Neutron dose, n/cm 2
Fig. 22: ISL70001SRH minimum ON time, all three
channels, as a function of neutron irradiation. Sample
size was 5 for each cell (2 x 1012 n/cm2, 1 x 1013 n/cm2,
3 x 1013 n/cm2 and 1 x 1014 n/cm2), with three control
units. The data sheet limit is 175ns maximum..
Fig. 24: ISL70001SRH supply current, 3.6V in, as a
function of neutron irradiation. Sample size was 5 for
each cell (2 x 1012 n/cm2, 1 x 1013 n/cm2, 3 x 1013 n/cm2
and 1 x 1014 n/cm2), with three control units. The data
sheet limits are 7.0mA to 45.0mA.
120
70
MIN_TOFF_Ch A
100
60
MIN_TOFF_Ch B
MIN_TOFF_Ch C
Supply current, 5.5V, mA
Minimum OFF time, ns
Spec limit
80
Spec limit
60
40
50
40
30
IDD, 5.5V
20
Spec limit
20
0
1.00E+11
Pre-irradiation
10
1.00E+12
1.00E+13
Spec limit
0
1E+11
Pre-irradiation
1.00E+14
Neutron dose, n/cm 2
1E+12
1E+13
1E+14
Neutron dose, n/cm 2
Fig. 23: ISL70001SRH minimum OFF time, all three
channels, as a function of neutron irradiation. Sample
size was 5 for each cell (2 x 1012 n/cm2, 1 x 1013 n/cm2,
3 x 1013 n/cm2 and 1 x 1014 n/cm2), with three control
units. The data sheet limit is 100ns maximum.
Fig. 25: ISL70001SRH supply current, 5.5V in, as a
function of neutron irradiation. Sample size was 5 for
each cell (2 x 1012 n/cm2, 1 x 1013 n/cm2, 3 x 1013 n/cm2
and 1 x 1014 n/cm2), with three control units. The data
sheet limits are 7.0mA to 65.0mA.
9
200
1
190
0.8
Lower FET ON resistance, mohm
Function test, external sync, 3.6V, V
0.9
0.7
0.6
0.5
0.4
FUNC_VMIN
0.3
0.2
Spec limit
0.1
Spec limit
0
1.00E+11
Pre-irradiation
180
LX1
LX2
LX3
LX4
LX5
LX6
Spec limit
Spec limit
170
160
150
140
130
1.00E+12
1.00E+13
120
1.00E+11
Pre-irradiation
1.00E+14
Neutron dose, n/cm 2
1.00E+12
1.00E+13
1.00E+14
Neutron dose, n/cm2
Fig. 26: ISL70001SRH external sync functional test,
3.6V in, as a function of neutron irradiation. Sample
size was 5 for each cell (2 x 1012 n/cm2, 1 x 1013 n/cm2,
3 x 1013 n/cm2 and 1 x 1014 n/cm2), with three control
units. The data sheet limits are 0.7V to 0.9V.
Fig. 28: ISL70001SRH lower FET ON resistance, all six
LX blocks, as a function of neutron irradiation. Sample
size was 5 for each cell (2 x 1012 n/cm2, 1 x 1013 n/cm2, 3
x 1013 n/cm2 and 1 x 1014 n/cm2), with three control units.
The data sheet limits are 130.0mohm to 182.0mohm.
15
3.4
10
3.2
Spec limit
3
Spec limit
Lower FET ON resistance match, %
Function test, external sync, 5.5V, V
FUNC_VMAX
2.8
2.6
2.4
0
-5
-10
2.2
2
1.00E+11
Pre-irradiation
5
1.00E+12
1.00E+13
LX1
LX2
LX3
LX4
LX5
LX6
Spec limit
Spec limit
-15
1.00E+11
Pre-irradiation
1.00E+14
Neutron dose, n/cm 2
1.00E+12
1.00E+13
1.00E+14
Neutron dose, n/cm 2
Fig. 27: ISL70001SRH external sync functional test,
5.5V in, as a function of neutron irradiation. Sample
size was 5 for each cell (2 x 1012 n/cm2, 1 x 1013 n/cm2,
3 x 1013 n/cm2 and 1 x 1014 n/cm2), with three control
units. The data sheet limits are 2.4V to 3.2V.
Fig. 29: ISL70001SRH lower FET ON resistance match,
all six LX blocks, as a function of neutron irradiation.
Sample size was 5 for each cell (2 x 1012 n/cm2, 1 x 1013
n/cm2, 3 x 1013 n/cm2 and 1 x 1014 n/cm2), with three
control units. The data sheet limits are -11.0% to +7.0%.
10
400
270
LX1
LX2
LX3
LX4
LX5
LX6
Spec limit
350
SYNC VOL and VOH at 3.6 and 5.5V, mV
Upper FET ON resistance, mohm
290
Spec limit
250
230
210
190
VOH, 3.6V
VOL, 3.6V
VOH, 5.5V
VOL, 5.5V
Spec limit
Spec limit
300
250
200
150
100
170
50
150
1.00E+11
Pre-irradiation
1.00E+12
1.00E+13
0
1.00E+11
Pre-irradiation
1.00E+14
15
0.7
10
0.65
5
0
-5
-10
LX2
LX3
LX4
LX5
LX6
Spec limit
Spec limit
1.00E+13
1.00E+14
Fig. 32: ISL70001SRH SYNC pin VOL and VOH, 3.6V
and 5.5V in, as a function of neutron irradiation. Sample
size was 5 for each cell (2 x 1012 n/cm2, 1 x 1013 n/cm2, 3
x 1013 n/cm2 and 1 x 1014 n/cm2), with three control units.
The data sheet limits are 25.0mV to 350.0mV.
Enable threshold, 3.6V and 5.5V, V
Upper FET ON resistance match, %
Fig. 30: ISL70001SRH upper FET ON resistance, all
six LX blocks, as a function of neutron irradiation.
Sample size was 5 for each cell (2 x 1012 n/cm2, 1 x
1013 n/cm2, 3 x 1013 n/cm2 and 1 x 1014 n/cm2), with
three control units. The data sheet limits are
190.0mohm to 260.0mohm.
LX1
1.00E+12
Neutron dose, n/cm 2
Neutron dose, n/cm2
0.6
0.55
0.5
EN_THR_3.6V
EN_THR_5.5V
0.45
Spec limit
Spec limit
-15
1.00E+11
Pre-irradiation
1.00E+12
1.00E+13
0.4
1.00E+11
Pre-irradiation
1.00E+14
Neutron dose, n/cm 2
1.00E+12
1.00E+13
1.00E+14
Neutron dose, n/cm 2
Fig. 33: ISL70001SRH ENABLE threshold, 3.6V and
5.5V in, as a function of neutron irradiation. Sample size
was 5 for each cell (2 x 1012 n/cm2, 1 x 1013 n/cm2, 3 x
1013 n/cm2 and 1 x 1014 n/cm2). The data sheet limits are
0.56V to 0.64V.
Fig. 31: ISL70001SRH upper FET ON resistance
match, all six LX blocks, as a function of neutron
irradiation. Sample size was 5 for each cell (2 x 1012
n/cm2, 1 x 1013 n/cm2, 3 x 1013 n/cm2 and 1 x 1014
n/cm2), with three control units. The data sheet limits
are -9.0% to +10.0%.
11
120
80
Undervoltage trip threshold, 3.6V, %
PGOOD Rising threshold, 3.6V, %
115
110
105
100
95
90
85
Channel A
Channel B
Channel C
Spec limit
Spec limit
80
1.00E+11
Pre-irradiation
79
Channel A
Channel B
78
Channel C
Spec limit
77
Spec limit
76
75
74
73
72
71
1.00E+12
1.00E+13
70
Pre-irradiation
1.00E+11
1.00E+14
1.00E+12
18
Error amplifier input offset voltage, 3.6V, mV
100
PGOOD falling threshold, 3.6V, %
95
90
85
80
Channel A
Channel B
70
Channel C
Spec limit
65
Spec limit
60
1.00E+11
Pre-irradiation
1.00E+14
Fig. 36: ISL70001SRH undervoltage trip threshold, all
three channels, 3.6V in, as a function of neutron
irradiation. Sample size was 5 for each cell (2 x 1012
n/cm2, 1 x 1013 n/cm2, 3 x 1013 n/cm2 and 1 x 1014 n/cm2).
The data sheet limits are 71.0% to 79.0%.
Fig. 34: ISL70001SRH POR Rising threshold, 3.6V
and 5.5V in, as a function of neutron irradiation.
Sample size was 5 for each cell (2 x 1012 n/cm2, 1 x
1013 n/cm2, 3 x 1013 n/cm2 and 1 x 1014 n/cm2). The
data sheet limits are 107.0% to 115.0%.
75
1.00E+13
Neutron dose, n/cm 2
Neutron dose, n/cm2
1.00E+12
1.00E+13
16
Channel A
Channel B
14
Channel C
Spec limit
12
Spec limit
10
8
6
4
2
0
-2
1.00E+11
Pre-irradiation
1.00E+14
Neutron dose, n/cm2
1.00E+12
1.00E+13
1.00E+14
Neutron dose, n/cm 2
Fig. 37: ISL70001SRH error amplifier input offset
voltage, all three channels, 3.6V input, as a function of
neutron irradiation. Sample size was 5 for each cell (2 x
1012 n/cm2, 1 x 1013 n/cm2, 3 x 1013 n/cm2 and 1 x 1014
n/cm2). The data sheet limits are -0.8mV to +0.8mV.
Fig. 35: ISL70001SRH POR Falling threshold, 3.6V
and 5.5V in, as a function of neutron irradiation.
Sample size was 5 for each cell (2 x 1012 n/cm2, 1 x
1013 n/cm2, 3 x 1013 n/cm2 and 1 x 1014 n/cm2). The
data sheet limits are 85.0% to 93.0%.
12
35
Error amplifier input offset voltage, 5.5V, mV
Feedback adjust range, negative, 3.6V, mV
0
-2
-4
-6
-8
Channel A
Channel B
Channel C
Spec limit
-10
Spec limit
-12
1.00E+11
Pre-irradiation
1.00E+12
1.00E+13
30
25
Channel A
Channel B
Channel C
Spec limit
Spec limit
20
15
10
5
0
-5
1.00E+11
Pre-irradiation
1.00E+14
1.00E+12
Neutron dose, n/cm 2
Fig. 38: ISL70001SRH negative feedback adjust
range, all three channels, 3.6V in, as a function of
neutron irradiation. Sample size was 5 for each cell (2
x 1012 n/cm2, 1 x 1013 n/cm2, 3 x 1013 n/cm2 and 1 x
1014 n/cm2). The data sheet limits are -11.0mV to 1.5mV.
0
Channel A
Channel B
Feedback adjust range, negative, 5.5V, mV
Feedback adjust range, positive, 3.6V, mV
1.00E+14
Fig. 40: ISL70001SRH error amplifier input offset
voltage, all three channels, 5.5V input, as a function of
neutron irradiation. Sample size was 5 for each cell (2 x
1012 n/cm2, 1 x 1013 n/cm2, 3 x 1013 n/cm2 and 1 x 1014
n/cm2). The data sheet limits are -2.0mV to +2.0mV.
12
10
Channel C
8
1.00E+13
Neutron dose, n/cm 2
Spec limit
Spec limit
6
4
2
0
1.00E+11
Pre-irradiation
1.00E+12
1.00E+13
Channel A
Channel B
Channel C
Spec limit
-2
-4
Spec limit
-6
-8
-10
-12
Pre-irradiation
1.00E+11
1.00E+14
Neutron dose, n/cm 2
1.00E+12
1.00E+13
1.00E+14
Neutron dose, n/cm 2
Fig. 41: ISL70001SRH negative feedback adjust range,
all three channels, 5.5V in, as a function of neutron
irradiation. Sample size was 5 for each cell (2 x 1012
n/cm2, 1 x 1013 n/cm2, 3 x 1013 n/cm2 and 1 x 1014
n/cm2). The data sheet limits are -11.0mV to -1.9mV.
Fig. 39: ISL70001SRH positive feedback adjust range,
all three channels, 3.6V in, as a function of neutron
irradiation. Sample size was 5 for each cell (2 x 1012
n/cm2, 1 x 1013 n/cm2, 3 x 1013 n/cm2 and 1 x 1014
n/cm2). The data sheet limits are +1.5mV to +11.0mV.
13
14
Channel A
Channel B
Channel C
Spec limit
13
Channel A
Channel B
Channel C
Spec limit
10
12
8
Overcurrent counter, cycles
Feedback adjust range, positive, 5.5V, mV
12
Spec limit
6
4
Spec limit
11
10
9
8
2
7
0
1.00E+11
Pre-irradiation
1.00E+12
1.00E+13
6
1.00E+11
Pre-irradiation
1.00E+14
1.00E+12
1.00E+14
Fig. 44: ISL70001SRH overcurrent counter delay as a
function of neutron irradiation. Sample size was 5 for
each cell (2 x 1012 n/cm2, 1 x 1013 n/cm2, 3 x 1013 n/cm2
and 1 x 1014 n/cm2). The data sheet limits are 8 to 13
cycles.
Fig. 42: ISL70001SRH positive feedback adjust range,
all three channels, 5.5V in, as a function of neutron
irradiation. Sample size was 5 for each cell (2 x 1012
n/cm2, 1 x 1013 n/cm2, 3 x 1013 n/cm2 and 1 x 1014
n/cm2). The data sheet limits are +1.5mV to +11.0mV.
2.5
12
VMIN
10
VMAX
2
Overcurrent trip level, 3.6V, A
Feedback adjust margin, 3.6V and 5.5V, mV
1.00E+13
Neutron dose, n/cm2
Neutron dose, n/cm 2
Spec limit
8
Spec limit
6
4
1
OC trip level
0.5
2
0
1.00E+11
Pre-irradiation
1.5
Spec limit
Spec limit
1.00E+12
1.00E+13
0
1E+11
Pre-irradiation
1.00E+14
Neutron dose, n/cm 2
1E+12
1E+13
1E+14
Neutron dose, n/cm2
Fig. 43: ISL70001SRH feedback adjust margin, 3.6V
and 5.5V input, as a function of neutron irradiation.
Sample size was 5 for each cell (2 x 1012 n/cm2, 1 x
1013 n/cm2, 3 x 1013 n/cm2 and 1 x 1014 n/cm2). The
data sheet limit is 11.0mV maximum.
Fig. 45: ISL70001SRH overcurrent trip level, 3.6V input,
as a function of neutron irradiation. Sample size was 5
for each cell (2 x 1012 n/cm2, 1 x 1013 n/cm2, 3 x 1013
n/cm2 and 1 x 1014 n/cm2). The data sheet limits are
1.4A to 2.2A.
14
3
Overcurrent trip level, 5.5V, A
2.5
2
Fig. 46: ISL70001SRH overcurrent trip level, 5.5V input,
as a function of neutron irradiation. Sample size was 5
for each cell (2 x 1012 n/cm2, 1 x 1013 n/cm2, 3 x 1013
n/cm2 and 1 x 1014 n/cm2). The data sheet limits are
1.5A to 2.4A.
1.5
1
0.5
OC trip level
Spec limit
Spec limit
0
1E+11
Pre-irradiation
1E+12
1E+13
1E+14
Neutron dose, n/cm 2
5: Discussion and conclusion
This document reports the results of neutron testing of the ISL70001SRH point of load converter. Parts
were irradiated to levels of 2 x 1012 n/cm2, 1 x 1013 n/cm2, 3 x 1013 n/cm2 and 1 x 1014 n/cm2. ATE
characterization testing was performed before and after the irradiations, and three control units were used to
insure repeatable data. Variables data for selected parameters is presented in Figs. 2 through 46. We will
discuss the results on a parameter by parameter basis. It should be realized when reviewing the data that
each neutron irradiation was made on a different 5-unit sample; this is not total dose testing, where the
damage is cumulative. The 2 x 1012 n/cm2 level is of some interest in the context of recent developments in
the JEDEC community, where the discrete component vendors have signed up for characterization testing
(but not for acceptance testing) at this level. This industry trend led to the present work, which determines the
response of the part to several neutron levels.
The ISL70001SRH is not formally designed for neutron hardness. The part is built in a BiCMOS process,
and the CMOS elements may be expected to perform well in this environment. The bipolar transistors are
minority carrier devices, however, and were expected to be sensitive at the higher levels. This expectation
turned out to be correct. We will discuss the results on a parameter by parameter basis and then draw some
conclusions.
The enable LOW and HIGH input currents (Figs. 2 and 3) and the master/slave control pin LOW and
HIGH input currents (Figs. 5 and 4) were stable, and within the specification limits after 1 x 1014 n/cm2. The
power on reset (POR) threshold select LOW and HIGH input currents (Figs. 6 and 7) were stable, and within
the specification limits after 1 x 1014 n/cm2. The sync input pin HIGH input current (Fig. 8) remained stable
and was within the specification limits after 1 x 1014 n/cm2, but the equivalent LOW current (Fig. 9) was out of
specification after 1 x 1014 n/cm2 and marginally out of specification at 1 x 1013 n/cm2.
The feedback input bias current (Fig. 10) remained within specification after 1 x 1014 n/cm2.
The LX LOW and LX HIGH leakage current (Figs. 11 and 12) remained very stable to 1 x 1014 n/cm2,
reflecting good performance by these large integrated MOSFET devices.
The trimmed reference voltage and reference output voltage (Figs. 13, 15 and 16) increased marginally
beyond the +1% mark at 3 x 1013 n/cm2, passing an increased limit of +1.5%, but were well out of
specification after 1 x 1014 n/cm2. The trimmed bandgap voltage (Fig. 14) remained within specification after 1
x 1014 n/cm2. The post trim reference current (Fig. 18) showed a minor increase but was still within
specifications after 1 x 1014 n/cm2.
15
The shutdown supply current (Figs. 17 and 18) at both 3.6V and 5.5V remained very stable through 1 x
1014 n/cm2. The supply current at both 3.6V in and 5.5V (Figs. 24 and 25) in remained flat to 3 x 1013 n/cm2
and was just out of specification after 1 x 1014 n/cm2.
The oscillator frequency and the input voltage rejection of this parameter (Figs. 20 and 21) remained
within specification at 3 x 1013 n/cm2 but were out of specification after 1 x 1014 n/cm2. The minimum ON time
and minimum OFF time (Figs. 22 and 23) were stable through 3 x 1013 n/cm2 and were still within
specifications after 1 x 1014 n/cm2.
A functional test at 3.6V (Fig. 26) input remained flat to 3 x 1013 n/cm2 and was nonfunctional after 1 x
n/cm2. The equivalent test at 5.5V (Fig. 27) in remained functional through 1 x 1014 n/cm2.
1014
The lower and upper FET ON resistance and ON resistance match remained very stable (Figs. 28
through 31) through 1 x 1014 n/cm2, also reflecting good performance by these large integrated MOSFET
devices.
The SYNC pin VOL and VOH for both the 3.6V and 5.5V in cases, the ENABLE threshold at 3.6V and
5.5V in and the POR Rising and falling threshold at 3.6V and 5.5V remained flat (Figs. 32 through 35) to 3 x
1013 n/cm2 and were nonfunctional after 1 x 1014 n/cm2.
The undervoltage trip threshold (Fig. 36) remained within specifications after 1 x 1014 n/cm2.
The error amplifier input offset voltage (Fig. 37) for the 3.6V in case (all three channels) remained within
specifications at 2 x 1012 n/cm2, met a 5mV spec at 1 x 1013 n/cm2 and exceeded 10mV after 3 x 1013 and 1 x
1014 n/cm2. At 5.5V in (Fig. 40), this parameter remained within specifications after 2 x 1012 n/cm2, met a 5mV
spec at 1 x 1013 n/cm2 and exceeded 15mV after 3 x 1013 and 1 x 1014 n/cm2. The error amplifier Vmin and
Vmax values (not shown) became increasingly positive with increased exposure. The negative and positive
feedback adjust range for 3.6V in and 5.5V (Figs. 38, 39, 41 and 42) also increased, tracking the error
amplifier shifts and resulting in the adjust margin being stable through 3 x 1013 and remaining within
specifications after 1 x 1014 n/cm2.
The overcurrent counter delay (Fig. 44) was stable to 1 x 1014 n/cm2. The overcurrent trip levels for both
3.6V input and 5.5V input (Figs. 45 and 46) remained flat to 3 x 1013 n/cm2 and were nonfunctional after 1 x
1014 n/cm2.
We conclude that the ISL70001SRH is capable of post 3 x 1013 n/cm2 operation with selected parametric
relaxations such as error amp and voltage reference parameters. The part is not capable of post 1 x 1014
n/cm2 performance as many parameters changed drastically and several units did not pass gross function
tests.
16
6: Appendices
6.1: Reported parameters.
Fig.
Parameter
Limit, low
Limit,
high
Units
2
3
Enable LOW input current
Enable HIGH input current
Master/slave control pin HIGH input
current
Master/slave control pin LOW input
current
POR threshold select HIGH input current
POR threshold select LOW input current
SYNC input pin HIGH input current
SYNC input pin LOW input current
Feedback input bias current
LX LOW leakage current
LX HIGH leakage current
Trimmed reference voltage
Trimmed bandgap voltage
Reference output voltage
Reference output voltage
Shutdown supply current
Shutdown supply current
Post trim reference current
Oscillator frequency
Oscillator frequency vs. input voltage
Minimum ON time
Minimum OFF time
Supply current
Supply current
Functional test
Functional test
Lower FET ON resistance
Lower FET ON resistance match
Upper FET ON resistance
Upper FET ON resistance match
SYNC pin VOL and VOH
ENABLE threshold
POR Rising threshold
POR Falling threshold
Undervoltage trip threshold
Error amplifier input offset voltage
Negative feedback adjust range
Positive feedback adjust range
Error amplifier input offset voltage
Negative feedback adjust range
-1.2
-1.2
+0.1
+0.1
µA
µA
-0.25
+0.25
µA
-0.25
-0.25
-0.25
-0.25
-0.25
-0.25
-0.4
-0.4
0.594
1.175
0.594
0.594
1.0
3.0
0.93
875
875
+0.25
+0.25
+0.25
+0.25
+0.25
+0.25
+0.4
+0.4
0.606
1.225
0.606
0.606
5.0
9.5
1.09
1125
1125
175
100
45.0
65.0
0.9
3.2
182.0
+7.2
260.0
+10.0
350.0
0.64
115.0
93.0
79.0
+0.8
-1.5
+11.0
+2.0
-1.9
µA
µA
µA
µA
µA
µA
µA
µA
V
V
V
V
mA
mA
mA
KHz
KHz
ns
ns
mA
mA
V
V
mohm
%
mohm
%
mV
V
%
%
%
mV
mV
mV
mV
mV
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
7.0
7.0
0.7
2.4
130.0
-11.0
190.0
-9.0
25.0
0.56
107.0
85.0
71.0
-0.8
-11.0
+1.5
-2.0
-11.0
17
Notes
3.6V in
5.5V in
3.6V in
5.5V in
3.6V in
5.5V in
3.6V in
5.5V in
3.6V and 5.5V
3.6V and 5.5V
3.6V and 5.5V
3.6V and 5.5V
3.6V in
3.6V in
3.6V in
3.6V in
5.5V in
5.5V in
42
43
44
45
46
Positive feedback adjust range
Feedback adjust margin
Overcurrent counter delay
Overcurrent trip level
Overcurrent trip level
+1.5
8
1.4
1.5
7: Document revision history
Revision
0
Date
June 2012
Pages
All
Comments
Original issue
18
+11.0
11.0
13
2.2
2.4
mV
mV
cycles
A
A
5.5V in
3.6V and 5.5V
3.6V in
5.5V in