This is information on a product in full production.
March 2012 Doc ID 17862 Rev 3 1/12
12
SM4TY
Automotive 400 W Transil™
Datasheet − production data
Features
■Peak pulse power:
– 400 W (10/1000 µs)
– 2.3 kW (8/20 µs)
■Stand-off voltage range: from 5 V to 70 V
■Unidirectional and bidirectional types
■Low leakage current:
– 0.2 µA at 25 °C
– 1 µA at 85 °C
■Operating Tj max: 150 °C
■High power capability at Tj max:
– 270 W (10/1000 µs)
■JEDEC registered package outline
■Resin meets UL 94, V0
■AEC-Q101 qualified
Complies with the following standards
■ISO 10605, C = 150 pF, R = 330 Ω:
– 30 kV (air discharge)
– 30 kV (contact discharge)
■ISO 10605, C = 330 pF, R = 330 Ω:
– 30 kV (air discharge)
– 30 kV (contact discharge)
■ISO 7637-2(a)
– pulse 1: VS = -100 V
– pulse 2a: VS = +50 V
– pulse 3a: VS = -150 V
– pulse 3b: VS = +100 V
Description
The SM4TY Transil series has been designed to
protect sensitive automotive circuits against
surges defined in ISO 7637-2 and against
electrostatic discharges according to ISO 10605.
The planar technology makes it compatible with
high-end circuits where low leakage current and
high junction temperature are required to provide
reliability and stability over time. SM4TY devices
are packaged in SMA (SMA footprint in
accordance with IPC 7531 standard).
TM: Transil is a trademark of STMicroelectronics
a. Not applicable to parts with stand-off voltage lower
than the average battery voltage (13.5 V)
K
A
Unidirectional Bidirectional
SMA
(JEDEC DO-214AC)
www.st.com
Characteristics SM4TY
2/12 Doc ID 17862 Rev 3
1 Characteristics
Figure 1. Electrical characteristics - definitions
Figure 2. Pulse definition for electrical characteristics
Table 1. Absolute maximum ratings (Tamb = 25 °C)
Symbol Parameter Value Unit
VPP Peak pulse voltage
ISO 10605 (C = 150 pF, R = 330 Ω)
Contact discharge
Air discharge
ISO 10605, C = 150 pF, R = 330 Ω:
Contact discharge
Air discharge
30
30
30
30
kV
PPP Peak pulse power dissipation(1) T
j initial = Tamb 400 W
Tstg Storage temperature range -65 to + 150 °C
TjOperating junction temperature range -55 to + 150 °C
TLMaximum lead temperature for soldering during 10 s. 260 °C
1. For a surge greater than the maximum values, the diode will fail in short-circuit.
V
CL
V
BR
V
RM
I
RM
I
R
I
PP
V
I
I
RM
I
R
I
PP
V
RM
V
BR
V
CL
V
CL
V
BR
V
RM
I
RM
I
R
I
PP
V
I
I
RM
I
R
I
PP
V
RM
V
BR
V
CL
V
CL
V
BR
V
RM
I
RM
I
R
I
PP
V
I
I
F
V
F
V
CL
V
BR
V
RM
I
RM
I
R
I
PP
V
I
I
F
V
F
Unidirectional
Bidirectional
Symbol Parameter
V Stand-off voltage
V Breakdown voltage
V Clamping voltage
I Leakage current @ V
I Peak pulse current
T Voltage temperature coefficient
V Forward voltage drop
R Dynamic resistance
RM
BR
CL
RM RM
PP
F
D
α
100
50
0
Pulse waveform
tr = rise time (µs)
tp = pulse duration time (µs)
t
%IPP
tp
tr
SM4TY Characteristics
Doc ID 17862 Rev 3 3/12
Table 2. Electrical characteristics, typical values if not otherwise stated (Tamb = 25 °C)
Order code
IRM max @ VRM VBR @ IR (1) VCL @ IPP
10/1000 µs
RD
10/1000
µs
VCL @ IPP
8/20 µs
RD
8/20
µs αT (2)
25 °C 85 °C min. typ. max. max. max. max
µA V V mA V(3) A(4) ΩV(3) A(4) Ω10-4/
°C
SM4T6V7AY/CAY 20 50 5 6.4 6.74 7.1 10 9.2 43.5 0.049 13.4 174 0.036 5.7
SM4T7V6AY/CAY 20 50 6.5 7.2 7.58 8.0 10 11.2 35.7 0.091 14.5 160 0.041 6.1
SM4T10AY/CAY 20 50 8.5 9.4 9.9 10.4 1 14.4 27.7 0.145 19.5 124 0.073 7.3
SM4T12AY/CAY 0.2 1 10 11.1 11.7 12.3 1 17.0 23.5 0.201 21.7 106 0.089 7.8
SM4T14AY/CAY 0.2 1 12 13.3 14.0 14.7 1 19.9 20.1 0.259 25.3 91 0.116 8.3
SM4T15AY/CAY 0.2 1 13 14.4 15.2 16.0 1 21.5 18.6 0.298 27.2 85 0.132 8.4
SM4T18AY/CAY 0.2 1 15 16.7 17.6 18.5 1 24.4 16.4 0.361 32.5 71 0.197 8.8
SM4T21AY/CAY 0.2 1 18 20.0 21.1 22.2 1 29.2 13.7 0.514 39.3 59 0.291 9.2
SM4T23AY/CAY 0.2 1 20 22.2 23.4 24.6 1 32.4 12.3 0.637 42.8 54 0.338 9.4
SM4T26AY/CAY 0.2 1 22 24.4 25.7 27.0 1 35.5 11.2 0.760 48.3 48 0.444 9.6
SM4T28AY/CAY 0.2 1 24 26.7 28.1 29.5 1 38.9 10.3 0.912 50 46 0.446 9.6
SM4T30AY/CAY 0.2 1 26 28.9 30.4 31.9 1 42.1 9.5 1.07 53.5 43 0.502 9.7
SM4T33AY/CAY 0.2 1 28 31.1 32.7 34.3 1 45.4 8.8 1.26 59 39 0.632 9.8
SM4T35AY/CAY 0.2 1 30 33.3 35.1 36.9 1 48.4 8.3 1.39 64.3 36 0.762 9.9
SM4T39AY/CAY 0.2 1 33 36.7 38.6 40.5 1 53.3 7.5 1.70 69.7 33 0.884 10
SM4T47AY/CAY 0.2 1 40 44.4 46.7 49.0 1 64.5 6.2 2.49 84 27 1.30 10.1
SM4T50AY/CAY 0.2 1 43 47.8 50.3 52.8 1 69.4 5.7 2.91 91 25 1.53 10.2
SM4T56AY/CAY 0.2 1 48 53.3 56.1 58.9 1 77.4 5.2 3.56 100 23 1.79 10.3
SM4T68AY/CAY 0.2 1 58 64.4 67.8 71.2 1 93.6 4.3 5.21 121 19 2.62 10.4
SM4T82AY/CAY 0.2 1 70 77.8 81.9 86.0 1 113 3.5 7.72 146 16 3.75 10.5
1. Pulse test: tp < 50 ms
2. To calculate maximum clamping voltage at other surge level, use the following formula: VCLmax = VCL - RD x (IPP - IPPappli)
where IPPappli is the surge current in the application
3. To calculate VBR or VCL versus junction temperature, use the following formulas:
VBR @ TJ = VBR @ 25 °C x (1 + αT x (TJ - 25))
VCL @ TJ = VCL @ 25 °C x (1 + αT x (TJ - 25))
4. Surge capability given for both directions for unidirectional and bidirectional types.
Characteristics SM4TY
4/12 Doc ID 17862 Rev 3
Figure 3. Peak pulse power dissipation
versus initial junction temperature
Figure 4. Peak pulse power versus
exponential pulse duration
(Tj initial = 25 °C)
0
100
200
300
400
500
0 25 50 75 100 125 150 175
P (W)
PP
T (°C)
j
Pulse = 10/1000 µs
0.1
1.0
10.0
1.0E-03 1.0E-02 1.0E-01 1.0E+00 1.0E+01
P (kW)
PP
tp(ms)
Figure 5. Clamping voltage versus peak
pulse current (exponential
waveform, maximum values)
Figure 6. Junction capacitance versus
reverse applied voltage for
unidirectional types (typical values)
I (A)
PP
0.1
1.0
10.0
100.0
1000.0
1 10 100 1000
10/1000 µs
8/20 µs
V (V)
CL
T initial = 25 °C
j
SM4T6V7AY/CAY
SM4T30AY/CAY
SM4T82AY/CAY
C(pF)
10
100
1000
10000
1 10 100 1000
SM4T6V7AY
SM4T30AY
SM4T82AY
V (V)
R
F = 1 Mhz
V = 30 mV
T = 25 °C
OSC RMS
j
Figure 7. Junction capacitance versus
reverse applied voltage for
bidirectional types (typical values)
Figure 8. Relative variation of thermal
impedance, junction to ambient,
versus pulse duration
C(pF)
10
100
1000
10000
1 10 100 1000
SM4T6V7CAY
SM4T30CAY
SM4T82CAY
V (V)
R
F = 1 Mhz
V = 30 mV
T = 25 °C
OSC RMS
j
0.01
0.10
1.00
1.0E-03 1.0E-02 1.0E-01 1.0E+00 1.0E+01 1.0E+02 1.0E+03
Recommended pad layout
Z/R
th(j-a) th(j-a)
tp(s)
Printed circuit board FR4,
copper thickness = 35 µm
SM4TY Characteristics
Doc ID 17862 Rev 3 5/12
Figure 11. Peak forward voltage drop versus peak forward current (typical values)
Figure 9. Thermal resistance junction to
ambient versus copper surface
under each lead
Figure 10. Leakage current versus junction
temperature (typical values)
0
10
20
30
40
50
60
70
80
90
100
110
120
130
0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0
R (°C/W)
th(j-a)
S (cm²)
Cu
Printed circuit board FR4,
copper thickness = 35 µm
1.E-01
1.E+00
1.E+01
1.E+02
1.E+03
25 50 75 100 125 150
I (nA)
R
T (°C)
j
V=V
V10V
RRM
RM ≥
V=V
V < 10 V
RRM
RM
1.0E-02
1.0E-01
1.0E+00
1.0E+01
1.0E+02
0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5
T = 125 °C
j
I (A)
FM
T = 25 °C
j
V (V)
FM
Characteristics SM4TY
6/12 Doc ID 17862 Rev 3
Figure 12. ISO7637-2 pulse 1 response (VS = -100 V)
Figure 13. ISO7637-2 pulse 2a response (VS = 50 V)
10
-10
0
-40
-30
-20
-50
-0.5 0.0 0.5 1.0 1.5 2.0 2.5
-0.5 0.0 0.5 1.0 1.5 2.0 2.5
Voltage (V)
Voltage
Current
Current (A)
Time (ms)
Time (ms)
SM4T39AY
SM4T39CAY
SM4T39AY
SM4T39CAY
-15
-10
0.0
0
5
50
10
20
30
40
0
-51 -1 49 99 149 199 249
-51 -1 49 99 149 199 249
0
4
-4
Voltage (V) Voltage
Current
Current (A)
Time (µs)
Time (µs)
SM4T39AY
SM4T39CAY
SM4T39AY
SM4T39CAY
SM4TY Characteristics
Doc ID 17862 Rev 3 7/12
Figure 14. ISO7637-2 pulse 3a response (VS = -150 V)
Figure 15. ISO7637-2 pulse 3b response (VS = 100 V)
Note: ISO7637-2 pulses responses are not applicable for product with a stand off voltage lower
than the average battery voltage (13.5 V).
-60
-50
-40
-30
-20
-10
0
10
20
30
-2
-1.5
-1
-0.5
0
0.5
-2.5
-0.2 0.8 1.8 0.0 0.0 0.0
-0.2 0.8 1.8 0.0 0.0 0.0
Voltage
(
V
)
Voltage
Current
Current (A)
Time (µs)
Time (µs)
SM4T39AY
SM4T39CAY
SM4T39AY
SM4T39CAY
0
20
30
40
50
10
-0.2 1.80.8
-0.4
1.2
0.8
0.4
0.0
-0.2 1.80.8
-0.2 1.8
0.8
SM4T39AY
SM4T39CAY
SM4T39AY
SM4T39CAY
Voltage (V)
Voltage
Current
Current (A)
Time (µs)
Time (µs)
Application and design guidelines SM4TY
8/12 Doc ID 17862 Rev 3
2 Application and design guidelines
More information is available in the Application note AN2689 “Protection of automotive
electronics from electrical hazards, guidelines for design and component selection”.
3 Ordering information scheme
Figure 16. Ordering information scheme
Surface mount
Surge rating
4= 400 W Transil in SMA
Breakdown voltage
Types
CA = Bidirectional
A = Unidirectional
Automotive grade
SM 4T XX CA Y
SM4TY Package information
Doc ID 17862 Rev 3 9/12
4 Package information
●Case: JEDEC DO-214AB molded plastic over planar junction
●Terminals: solder plated, solderable as per MIL-STD-750, Method 2026
●Polarity: for unidirectional types the band indicates cathode
●Flammability: epoxy is rated UL 94, V0
●RoHS package
In order to meet environmental requirements, ST offers these devices in different grades of
ECOPACK® packages, depending on their level of environmental compliance. ECOPACK®
specifications, grade definitions and product status are available at: www.st.com.
ECOPACK® is an ST trademark.
Table 3. SMA dimensions
Ref.
Dimensions
Millimeters Inches
Min. Max. Min. Max.
A1 1.90 2.45 0.075 0.094
A2 0.05 0.20 0.002 0.008
b 1.25 1.65 0.049 0.065
c 0.15 0.40 0.006 0.016
D 2.25 2.90 0.089 0.114
E 4.80 5.35 0.189 0.211
E1 3.95 4.60 0.156 0.181
L 0.75 1.50 0.030 0.059
Figure 17. SMA footprint dimensions in
mm (inches)
Figure 18. Marking layout(1)
1. Marking layout can vary according to assembly location.
E
CL
E1
D
A1
A2 b
2.63
(0.104)
5.43
(0.214)
1.4
1.64
(0.064)
1.4
(0.055) (0.055)
y w wz
x x x
ECOPACK compliance
Z: Manufacturing location
Y: Year
WW: week
Cathode bar (unidirectional devices only )
x
XXXX: Marking
Package information SM4TY
10/12 Doc ID 17862 Rev 3
Table 4. Marking
Order code Marking Order code Marking
SM4T6V7AY AEY SM4T6V7CAY AAY
SM4T7V6AY DUCY SM4T7V5CAY DBCY
SM4T10AY DUHY SM4T10CAY DBHY
SM4T12AY AXY SM4T12CAY ACY
SM4T14AY DUKY SM4T14CAY DBKY
SM4T15AY BGY SM4T15CAY BHY
SM4T18AY BMY SM4T18CAY AJY
SM4T21AY DUQY SM4T21CAY DBQY
SM4T23AY DURY SM4T23CAY DBRY
SM4T26AY DUSY SM4T26CAY DBSY
SM4T28AY DUTY SM4T28CAY DBTY
SM4T30AY DUUY SM4T30CAY DBUY
SM4T33AY CGY SM4T33CAY CHY
SM4T35AY CKY SM4T35CAY CLY
SM4T39AY CMY SM4T39CAY CNY
SM4T47AY DUZY SM4T47CAY DBZY
SM4T50AY EUAY SM4T50CAY EBAY
SM4T56AY CXY SM4T56CAY CYY
SM4T68AY EUFY SM4T68CAY EBFY
SM4T82AY EUIY SM4T82CAY EBIY
SM4TY Ordering information
Doc ID 17862 Rev 3 11/12
5 Ordering information
6 Revision history
Table 5. Ordering information
Order code Marking Package Weight Base qty Delivery mode
SM4TxxxAY/CAY(1)
1. Where xxx is nominal value of VBR and A or CA indicates unidirectional or bidirectional version. See
Table 2 for list of available devices and their order codes
See Table 4 on page 10 SMA 0.072 g 5000 Tape and reel
Table 6. Document revision history
Date Revision Changes
08-Sep-2010 1 Initial release.
09-Nov-2011 2 Added order codes in Table 2 and Table 4. Updated
Figure 5, 6 and 7.
27-Mar-2012 3 Added footnote on page 1.
SM4TY
12/12 Doc ID 17862 Rev 3
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