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SMA (DO-214AC) · SS34
ActiveSchottky Rectifier (40V/3A)
SS34
Vishay · SMA (DO-214AC) · Schottky Rectifier (40V/3A)
Price on Request
Get a competitive quote within 24 hours. Volume discounts available. Shenzhen stock ships in 1-2 business days.
Overview
The SS34 is the 40 V, 3 A member of the SS32 to SS36 surface-mount Schottky barrier rectifier family: a planar metal-semiconductor junction with an integrated guard ring for overvoltage protection, specified for low-voltage high-frequency inverters, freewheeling, DC-DC conversion and polarity protection. Vishay marks the SS34 as S4, rates it MSL level 1 per J-STD-020 with a 260 °C lead-free reflow peak, and offers AEC-Q101 qualified ordering options for automotive builds.
Electrical limits are: 40 V repetitive peak reverse voltage and DC blocking voltage with 28 Vrms; 3.0 A maximum average forward rectified current, derated against lead temperature; 100 A peak forward surge for an 8.3 ms half sine superimposed on rated load; 0.5 V maximum instantaneous forward voltage at 3.0 A on a 300 µs pulse test; reverse leakage of 0.5 mA maximum at rated DC blocking voltage and 25 °C, rising to 20 mA at 100 °C; 20 mJ non-repetitive avalanche energy at IAS = 2 A with a 10 mH inductor; 10,000 V/µs dV/dt; 55 °C/W junction-to-ambient and 17 °C/W junction-to-lead thermal resistance on a 14 mm x 14 mm copper pad; and a -55 °C to +150 °C junction range. Being a majority-carrier device it has no reverse-recovery charge, so switching loss is essentially capacitive.
One sourcing detail trips up buyers regularly: case size. Vishay publishes the SS32 to SS36 family in the SMC (DO-214AB) outline, whose body measures roughly 6.6 mm to 7.1 mm by 5.6 mm to 6.2 mm, while the majority of SS34 second sources in the Asian market — MCC, MDD, Hottech, Rectron and PANJIT under the SK34 designation — ship the smaller SMA (DO-214AC) case at roughly 4.6 mm by 2.9 mm. The two are not footprint-compatible, so confirm the case code with your supplier before the layout is frozen, and never mix them on one reel.
Thermally, the part is honest: 3.0 A at 0.5 V is 1.5 W, and at 55 °C/W junction-to-ambient that requires a generous copper pour, airflow, or duty-cycle derating — on minimal copper, design for 1.5 A to 2 A continuous. Hot reverse leakage is the other derating factor: 20 mA at 40 V and 100 °C is 0.8 W of reverse dissipation, which is why a 60 V SS36 is the better choice for 24 V rails and hot enclosures. Counterfeiting is heavy in this category, with SS14 (1 A) and SS32 (20 V) parts remarked as SS34; qualify lots by measuring VF at 3 A, reverse leakage at 40 V cold and hot, package dimensions, marking (S4 for Vishay) and die size by X-ray. Reels are 850 pcs on 7 inch and 3,500 pcs on 13 inch tape; Shenzhen stock ships in 1 to 2 days.
Key Features
- 40 V VRRM / 28 Vrms with 3.0 A average forward rectified current
- 0.5 V maximum forward drop at 3.0 A — no reverse-recovery charge
- 100 A 8.3 ms surge capability plus a 20 mJ avalanche energy rating
- Guard-ring protected Schottky, 10,000 V/µs dV/dt, 150 °C junction, MSL 1
- AEC-Q101 qualified ordering options for automotive designs
Typical Applications
- Output rectification and freewheeling in 5 V to 24 V buck converters
- Reverse-polarity protection on 12 V and 24 V DC inputs
- Solar panel bypass and battery OR-ing or blocking duty
- LED driver outputs and constant-current lighting modules
- Motor, relay and solenoid freewheeling in industrial controllers
- Secondary rectification in switch-mode supplies below 3 A continuous
Specifications
- Repetitive Peak Reverse Voltage (VRRM)
- 40 V
- Average Forward Rectified Current (IF(AV))
- 3.0 A
- Peak Forward Surge Current (IFSM, 8.3 ms Half Sine)
- 100 A
- Maximum Instantaneous Forward Voltage (VF at 3.0 A)
- 0.5 V
- Maximum DC Reverse Current (IR at Rated VDC, 25 °C)
- 0.5 mA
- Maximum DC Reverse Current (IR at Rated VDC, 100 °C)
- 20 mA
- Reverse Recovery Time
- None (Schottky, Majority Carrier)
- Operating Junction Temperature
- -55 to +150 °C
- Pins
- 2
- RoHS
- Compliant
Procurement Tips
Write both the brand and the case code (SMA versus SMC) on the BOM line, and require a hot reverse-leakage test at 40 V — remarked SS14 and SS32 devices are the standard substitution and they only fail once the enclosure is warm.
Frequently Asked Questions
SS34 versus SS36 — is the higher-voltage part better?
Both are 3 A Schottkys in the same family. The SS36 trades a slightly higher forward drop (0.75 V versus 0.5 V maximum) for a 60 V rating and lower hot leakage (10 mA versus 20 mA at 100 °C). On a 24 V rail, in a hot enclosure, or anywhere transients are expected, the SS36 is the safer choice.
SS34 versus 1N5819?
Same 40 V Schottky class, different current and mounting: the 1N5819 is a 1 A axial DO-41 through-hole part at 0.6 V maximum, the SS34 is a 3 A surface-mount part at 0.5 V maximum. Neither is a footprint substitute for the other.
Is the SS34 in SMA or SMC?
It depends on the manufacturer. Vishay specifies the SS32 to SS36 family in SMC (DO-214AB), while Diodes Inc, MCC, MDD, Hottech and PANJIT (SK34) supply SS34 in SMA (DO-214AC). The body sizes differ substantially, so confirm the case code and use the vendor pad layout before freezing the PCB.
How much current can an SS34 really carry?
The 3.0 A rating assumes adequate lead temperature and copper. With 55 °C/W junction-to-ambient on a 14 mm x 14 mm pad, 3 A means about 1.5 W of dissipation, so on minimal copper derate to 1.5 A to 2 A or add airflow and a larger pour.
Can I use the SS34 for automotive 12 V load dump protection?
On its own, no. A 40 V rating is marginal against load-dump and jump-start transients on a 12 V system. Use the 60 V SS36, add a TVS clamp, or select an AEC-Q101 qualified Schottky with a higher voltage rating.
How do I detect a counterfeit SS34?
Measure VF at 3.0 A (genuine parts stay below 0.5 V), then reverse-bias at 40 V and measure leakage at 25 °C and at 100 °C (limits 0.5 mA and 20 mA). Check package dimensions and marking against the vendor datasheet, verify reel labels and quantities, and X-ray samples — remarked SS14 and SS32 parts have visibly smaller dies.
What are the MOQ and lead times?
MOQ is one reel: 850 pcs on 7 inch tape or 3,500 pcs on 13 inch tape for Vishay SS34-E3/57T and SS34-E3/9AT, or 100 pcs loose for prototyping. Shenzhen stock ships in 1 to 2 days; authorized Vishay channel replenishment takes 4 to 8 weeks.
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