The MEAN WELL SD-350B-12 is an enclosed single-output DC/DC converter delivering 12 V at up to 27.5 A (330 W). The B input version accepts 20–36 VDC. A built-in DC fan provides forced-air cooling. Select the load using the output limits and the input-voltage and temperature derating curves.
Product Datasheet
Download MEAN WELL SD-350 Datasheet (PDF)
The SD-350 section is on PDF pages 15, 16, 17. Refer to the complete mechanical drawings and notes when planning installation.
Model and Output Ratings
| Full model |
SD-350B-12 |
| Series |
SD-350 |
| Output code |
12: 12 VDC nominal output |
| DC output voltage |
12 V |
| Rated output current |
27.5 A |
| Rated output power |
330 W |
| Output current range |
0–27.5 A |
| Output voltage adjustment |
11–16 VDC |
| Maximum ripple and noise |
120 mVp-p |
| Voltage tolerance |
±1.0% |
| Line regulation |
±0.3% |
| Load regulation |
±1.0% |
The series number identifies the product family. Use the stated model-specific rated current and power when selecting the load.
Input and Electrical Performance
| DC input range |
20–36 VDC |
| Input code |
B: 24 VDC nominal input |
| Typical efficiency |
80% |
| Typical DC input current |
16 A at 24 VDC |
| Set-up / rise time |
300 / 50 ms at full load |
| Switching frequency |
100 kHz, as shown in the block diagram |
Unless otherwise specified, catalogue parameters are measured at 24 VDC input, rated load and 25°C ambient. Ripple and noise are measured with 20 MHz bandwidth using a 12-inch twisted pair terminated with parallel 0.1 µF and 47 µF capacitors. Voltage tolerance includes set-up tolerance, line regulation and load regulation.
Protection
| Short-circuit protection |
Included |
| Overload threshold |
105–135% of rated output power |
| Overload recovery |
Output shutdown; reapply input power to recover |
| Overvoltage threshold |
16.8–20 V |
| Overvoltage recovery |
Output shutdown; reapply input power to recover |
| Overtemperature recovery |
Output shutdown; automatic recovery after the temperature falls |
Cooling and Operating Limits
| Cooling |
Forced-air cooling by built-in DC fan |
| Working temperature |
−20 to +60°C, subject to derating |
| Temperature derating, horizontal installation |
80% load at −20°C, rising to 100% at 0°C; 100% through 50°C, then decreasing linearly to 60% at 60°C |
| Input-voltage derating |
90% load at 20 VDC, rising to 100% at 24 VDC; 100% through 36 VDC |
| Altitude temperature derating |
5°C per additional 1000 m above 2000 m |
| Working humidity |
20–90% RH, non-condensing |
| Storage temperature and humidity |
−40 to +85°C; 10–95% RH |
| Temperature coefficient |
±0.03%/°C from 0 to 50°C |
| Vibration |
10–500 Hz, 2 G; 10 minutes per cycle and 60 minutes on each X, Y and Z axis |
Apply the input-voltage and temperature restrictions together. Keep the fan inlet and airflow path clear.
Dimensions, Connections and Mounting
| Body dimensions, L × W × H |
215 × 115 × 50 mm |
| Case number |
912B |
| Mechanical-drawing tolerance |
±1 mm |
| Width across mounting tabs |
135 mm, as shown in the drawing |
| Terminal projection |
14.5 mm maximum beyond the body |
| Mounting-thread details |
4 × M4, L = 5 mm; 6 × M3, L = 3 mm; side 6 × M4, L = 6 mm |
| DC input terminal assignment |
Pin 1: V+; pin 2: V− |
| Protective earth terminal |
Pin 3: FG |
| DC output terminal assignment |
Pins 4, 5 and 6: V−; pins 7, 8 and 9: V+ |
| Local controls and indicator |
Output-voltage adjustment and LED |
Use the mounting-hole positions and thread lengths in the SD-350 mechanical drawing. The mounting-tab width and terminal projection are separate from the specified body dimensions. Connect FG to protective earth and observe the DC input and output polarities.
Select installation wiring and mounting hardware to suit the electrical ratings and the drawing.
Safety and EMC
| Catalogue-listed safety approvals |
EAC TP TC 004 |
| Safety design reference |
AS/NZS 62368.1 |
| Withstand voltage |
Input–output: 1.5 kVAC; input–FG: 2 kVAC; output–FG: 0.5 kVAC |
| Isolation resistance |
Input–output, input–FG and output–FG: 100 MΩ at 500 VDC, 25°C and 70% RH |
| EMC emission |
BS EN / EN 55032 (CISPR 32), Class B; EAC TP TC 020 |
| EMC immunity |
BS EN / EN 61000-4-2/-3/-4/-6/-8; BS EN / EN 55035, light-industry level; EAC TP TC 020 |
The AS/NZS entry is a design reference. The converter is a component for installation in final equipment. The catalogue EMC tests used a 360 × 360 mm metal plate, 1 mm thick; the finished equipment must be checked against its applicable EMC requirements.
Mass and Catalogue References
| Mass, catalogue PACKING reference per unit |
1100 g |
| Catalogue packing |
1.1 kg; 12 units / 14.4 kg / 0.9 CUFT |
| Minimum MTBF |
1705.6K hours, Telcordia SR-332 (Bellcore); 263.9K hours, MIL-HDBK-217F at 25°C |
| Catalogue burn-in test |
100% full load |
| Catalogue warranty |
2 years |
The unit mass is the single-unit reference in the catalogue PACKING field, rather than a measured shipping weight.
