The MEAN WELL DDR-480B-24 is a fanless DIN rail DC/DC converter rated at 24 V, 20 A and 480 W. Its B-code input supports 16.8–33.6 VDC continuously, with a separate 14.4–16.8 VDC band for 100 ms. The metal enclosure provides reinforced 4 kVDC input-to-output isolation, adjustable output, a DC OK relay, remote ON/OFF and active current sharing. A 720 W peak is available for up to 5 seconds under the specified temperature and loading conditions.
Product Datasheet
Download MEAN WELL DDR-480 Datasheet (PDF)
The DDR-480 section is on PDF pages 32, 33, 34, 35, 36, 37, 38, 39, 40. Refer to the complete mechanical drawings and notes when planning installation.
Model and Output Ratings
| Full model |
DDR-480B-24 |
| Series |
DDR-480 |
| Input code |
B |
| DC output voltage |
24 V |
| Rated output current |
20 A |
| Rated output power |
480 W |
| Output current range |
0–20 A |
| Output voltage adjustment range |
24–28 V |
| Peak output current |
30 A |
| Peak output power |
720 W |
| Peak duration |
5 seconds maximum |
| Maximum ripple and noise |
120 mVp-p |
| Voltage tolerance |
±1.0% |
| Line regulation |
±0.5% |
| Load regulation |
±1.0% |
Adjust the output with the front-panel Vo Adj. control and retain the current, power and thermal limits. The adjustment range is the specified voltage interval.
Suitable applications include railway and industrial control, security, factory automation and telecommunications. The converter can provide DC voltage conversion, additional input/output insulation and compensation for cable voltage drop within its adjustment range.
Input and Hold-up Performance
| Continuous DC input range |
16.8–33.6 VDC |
| 100 ms input range |
14.4–16.8 VDC |
| Reference DC input |
24 VDC |
| Typical efficiency |
91% |
| Typical DC input current |
23 A at 24 VDC |
| Typical inrush current |
30 A |
| Set-up / rise time |
500 / 60 ms |
| Minimum hold-up at 100% load |
10 ms at 24 VDC |
| Minimum hold-up at 70% load |
16 ms at 24 VDC |
| Supply interruption classification |
EN 50155:2021, S2; 10 ms at full load |
| Normal measurement conditions |
24 VDC input, rated load and 25°C ambient |
The 100 ms low-input band is a short-duration condition and does not extend the continuous input range. Apply the separate input-voltage derating curve before selecting the load.
Use the dedicated model hold-up-versus-load curve for other load levels. A larger hold-up duration at reduced load is not a full-load rating.
Ripple and noise are measured at 20 MHz bandwidth using a 12-inch twisted pair terminated by parallel 0.1 µF and 47 µF capacitors. Voltage tolerance includes set-up tolerance, line regulation and load regulation.
Peak Loading and Protection
| Peak loading capability |
150% of the model rated output power for the stated peak duration |
| Protection functions |
Short circuit, overload, overvoltage, overtemperature, input reverse polarity and input undervoltage |
| Sustained overload response |
Constant-current limiting at 105–135% of rated output power; automatic recovery after the overload is removed |
| Overvoltage threshold |
28.8–35 V |
| Overvoltage recovery |
Output shutdown; reapply input power to recover |
| Overtemperature recovery |
Output shutdown; reapply input power to recover |
| Input undervoltage turn-on specification |
≥16.8 VDC |
| Input undervoltage turn-off specification |
≤16.5 VDC |
| Input undervoltage recovery |
Automatic when the input rises above the operating threshold |
| Internal input fuse reference |
5 × Conquer MST, 10 A, 250 V; time-lag |
The catalogue loading example shows 480 W for 100 seconds followed by 720 W for 5 seconds. These are conditional pulse-load patterns; peak power is not a continuous rating. Apply the peak-temperature curve as well as the continuous-load limits.
After the initial peak interval, a sustained overload enters the specified constant-current protection region. Keep planned peaks within 5 seconds; the overload-protection response does not authorize a longer peak interval.
Two MOSFETs in series with the negative input prevent output when input polarity is reversed. Correct the polarity before restoring operation.
A start-up resistor limits inrush current and is then bypassed by MOSFETs. The fuse references identify internal protection components; they are not an external fuse-selection instruction.
Current Sharing
| Maximum parallel units |
4 |
| Output-voltage matching |
Difference strictly less than 0.2 V |
| Total output-current limit |
Rated current per unit × number of units × 0.9 |
| Minimum parallel load |
Strictly greater than 3% × rated current per unit × number of units |
| Four-unit current limit at the stated unit ratings |
72 A |
| Current-sharing connections |
Connect P+ to P+ and P− to P− across all participating units |
The series specification describes current sharing up to 1920 W (3+1 units). Size the usable load with the 0.9 current formula, the actual model rating and all applicable derating conditions. The headline aggregate rating is not an unconditional usable load or N+1 capacity guarantee.
Use matching output-voltage units, connect the outputs and sharing terminals as illustrated, and adjust their output-voltage differences to less than 0.2 V. Consult the manufacturer for arrangements beyond four units.
DC OK Relay and Remote ON/OFF
| DC OK contact closed |
Power supply on / DC OK |
| DC OK contact open |
Power supply off / DC fail |
| Maximum DC OK contact rating |
30 VDC, 1 A resistive load |
| Remote-control terminals |
TB1 pin 4 relative to TB1 pin 2 (−Vin) |
| Output ON |
Remote input open, or 5.5–10 VDC |
| Output OFF |
Remote input shorted, or 0–0.8 VDC |
| Front-panel indication |
DC OK indicator |
Observe the relay contact rating when connecting an external monitoring circuit. Remote ON/OFF controls the converter output; disconnect the DC input before installing or servicing wiring.
Terminal Assignment and Wiring
| TB1 pin 1 |
FG / protective earth |
| TB1 pin 2 |
DC input −Vin |
| TB1 pin 3 |
DC input +Vin |
| TB1 pin 4 |
Remote ON/OFF |
| TB2 pins 1, 2 |
DC output +Vo |
| TB2 pins 3, 4 |
DC output −Vo |
| TB2 pins 5, 6 |
DC OK relay contact |
| TB2 pin 7 |
P+ current sharing |
| TB2 pin 8 |
P− current sharing |
Observe the numbered terminals in the mechanical drawing. Connect FG to the installation protective-earth system and size the DC conductors and terminations for this model’s input and output currents.
Keep the DC OK contacts separate from the DC power and current-sharing connections. Allow access to the terminals, Vo Adj. control and rail latch after installation.
Cooling, Temperature and Input Derating
| Cooling |
Free-air convection; fanless |
| Required orientation for the published curves |
Vertical |
| Working ambient range |
−40 to +80°C, subject to derating |
| Continuous-load temperature curve |
100% through 55°C; reduce along the plotted line to 40% at 80°C |
| Full 150% peak temperature range |
−40 to +60°C, within the peak-duration limit |
| Load at minimum continuous input |
80% |
| Input for 100% load |
21.6 VDC and above within the continuous input range |
| Operating altitude |
Up to 5000 m; overvoltage category II |
| Altitude temperature derating |
Above 2000 m: reduce permitted ambient temperature by 3.5°C per additional 1000 m |
Input-voltage and temperature limits apply together. At low input, follow the rising input-derating line between the minimum continuous voltage and the full-load input point; short-duration input operation is not a full-load continuous extension.
Above 60°C, reduce the allowed 5-second peak along its separate upper curve to 40% load at 80°C. The model-specific continuous-load curve remains a separate constraint.
Provide unobstructed airflow around the installed converter. Do not treat the ambient range, peak capability or altitude statement as an unconditional full-load rating.
Environmental and Mechanical Data
| Working humidity |
5–95% RH, non-condensing |
| Storage temperature / humidity |
−40 to +85°C; 5–95% RH, non-condensing |
| Temperature coefficient |
±0.03%/°C over 0–55°C |
| Component vibration |
10–500 Hz, 5 G; 10 minutes per cycle; 60 minutes on each X, Y and Z axis |
| Vibration mounting requirement |
Compliance with IEC 61373 |
| Catalogue body dimensions, W × H × D |
85.5 × 125.2 × 129.2 mm |
| Case reference |
984F |
| Drawing tolerance |
±1 mm |
| DIN rail compatibility |
TS35/7.5 or TS35/15 |
| Rail supply status |
Reference rail shown; not included with the unit |
| Unit mass, catalogue PACKING reference |
1375 g |
| Catalogue packing |
1.375 kg; 8 units / 12 kg / 0.95 CUFT |
| Minimum MTBF |
750.3K hours, Telcordia SR-332 (Bellcore); 101.7K hours, MIL-HDBK-217F at 25°C |
| Nominal switching frequency |
65 kHz |
| Catalogue warranty |
3 years |
Use the illustrated DIN rail mounting and removal arrangement. The body dimensions do not include the installed rail, external wiring or cable-bend clearance. Select the rail and installation hardware for the enclosure.
The listed mass is the explicit per-unit catalogue packing reference; it is not a measured installation mass or the gross mass of an individual shipping box.
Safety, Isolation and EMC
| Catalogue-listed safety approvals |
IEC 62368-1; UL 62368-1; AS/NZS 62368-1; EAC TP TC 004 |
| Input-to-output isolation |
4 kVDC; reinforced isolation |
| Input-to-FG withstand voltage |
2.5 kVDC |
| Output-to-FG withstand voltage |
0.71 kVDC |
| Isolation resistance |
>100 MΩ between input–output, input–FG and output–FG at 500 VDC, 25°C and 70% RH |
| Conducted emissions |
BS EN / EN 55032, Class A |
| Radiated emissions |
BS EN / EN 55032, Class B |
| Immunity standards |
BS EN / EN 55035 |
| Railway standards |
BS EN / EN 50155; IEC 60571; IEC 61373 shock and vibration; BS EN / EN 50121-3-2 EMC; BS EN / EN 45545-2 fire protection |
The six listed immunity tests use criterion A: ESD level 3 at 8 kV air and 6 kV contact; radiated RF level 3 at 10 V/m; EFT/burst level 3 at 2 kV; surge level 3 at 1 kV line–line and 2 kV line–line–FG; conducted RF level 3 at 10 V; and magnetic field level 4 at 30 A/m.
The emissions table names BS EN / EN 61000-3-3 for voltage flicker without a numerical test level; it does not specify a harmonic-current limit. Confirm EMC compliance of the complete equipment after integration.
Railway Environmental and Fire Tests
The catalogue reports PASS for EN 50155 dry heat (section 13.4.5: 70°C for 6 hours and 85°C for 10 minutes); cyclic damp heat (13.4.8: 25–55°C, 90–100% RH, 48 hours); vibration (13.4.10: 19°C, 65% RH, 10 minutes); shock (13.4.10: 21 ±3°C, 65 ±5% RH, 30 ms ×18); low-temperature storage (13.4.6: −40°C, 16 hours); and salt mist (13.4.13: 35 ±2°C, 96 hours). These test conditions do not expand continuous operating limits.
EN 45545-2:2020 results are marked PASS at HL1, HL2 and HL3 for all listed items: PCB R22 oxygen index, smoke density and smoke toxicity; PCB R24 oxygen index; PCB R25 glow-wire; potting R24 oxygen index; and terminal-block R26 vertical flame. Test methods are EN ISO 4589-2:2017, EN ISO 5659-2:2017, EN 17084:2018, EN 60695-2-11:2014 and EN 60695-11-10:2013 as applicable. Component results do not certify the entire vehicle or equipment.
