DocID17862 Rev 4 7/12
SM4TY Characteristics
12
Figure 14. ISO7637-2 pulse 3a response (V
S
= -150 V)
Figure 15. ISO7637-2 pulse 3b response (V
S
= 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 DocID17862 Rev 4
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
DocID17862 Rev 4 9/12
SM4TY Package information
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 package 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
C
L
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

SM4T50AY

Mfr. #:
Manufacturer:
STMicroelectronics
Description:
TVS Diodes / ESD Suppressors 400 W 2.3kW Transil 5V to 70V Uni
Lifecycle:
New from this manufacturer.
Delivery:
DHL FedEx Ups TNT EMS
Payment:
T/T Paypal Visa MoneyGram Western Union