VOFM-280B-54-UM2

AC-DC,54 ,SIN OUT,U-FRA,TER BLO CONN,MED

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Manufacturer: CUI
Product type: AC / DC Open Frame Power Supplies
SVHC: No SVHC (04-Feb-2026)
Delivery and price
Units per pack	40
Price	119.2 €
Current stock	10+
Lead time	30 days
Datasheet
**date** 11/18/2024 **page** 1 of 6 

|**SERIES:**VOFM-280B**│** **DESCRIPTION:**AC-DC POWER SUPPLY<br>**FEATURES**<br>• 200 W with natural convection, 280 W with forced air cooling<br>• certified to EN/UL 60601-1, 2xMOPP<br>• designed to meet EN 60601-1-2<br>• designed to meet EN 55011/EN 55032<br>• universal input range 90 ~ 264 Vac<br>• 5 V standby and 12 V fan outputs<br>• output short circuit, over current, over voltage,<br>and over temperature protection<br>• operating altitude 3,000 m<br>• operating temperature range -20 ~ 70 °C with derating<br>• remote ON/OFF control<br>.|**SERIES:**VOFM-280B**│** **DESCRIPTION:**AC-DC POWER SUPPLY<br>**FEATURES**<br>• 200 W with natural convection, 280 W with forced air cooling<br>• certified to EN/UL 60601-1, 2xMOPP<br>• designed to meet EN 60601-1-2<br>• designed to meet EN 55011/EN 55032<br>• universal input range 90 ~ 264 Vac<br>• 5 V standby and 12 V fan outputs<br>• output short circuit, over current, over voltage,<br>and over temperature protection<br>• operating altitude 3,000 m<br>• operating temperature range -20 ~ 70 °C with derating<br>• remote ON/OFF control<br>.|**SERIES:**VOFM-280B**│** **DESCRIPTION:**AC-DC POWER SUPPLY<br>**FEATURES**<br>• 200 W with natural convection, 280 W with forced air cooling<br>• certified to EN/UL 60601-1, 2xMOPP<br>• designed to meet EN 60601-1-2<br>• designed to meet EN 55011/EN 55032<br>• universal input range 90 ~ 264 Vac<br>• 5 V standby and 12 V fan outputs<br>• output short circuit, over current, over voltage,<br>and over temperature protection<br>• operating altitude 3,000 m<br>• operating temperature range -20 ~ 70 °C with derating<br>• remote ON/OFF control<br>.|**SERIES:**VOFM-280B**│** **DESCRIPTION:**AC-DC POWER SUPPLY<br>**FEATURES**<br>• 200 W with natural convection, 280 W with forced air cooling<br>• certified to EN/UL 60601-1, 2xMOPP<br>• designed to meet EN 60601-1-2<br>• designed to meet EN 55011/EN 55032<br>• universal input range 90 ~ 264 Vac<br>• 5 V standby and 12 V fan outputs<br>• output short circuit, over current, over voltage,<br>and over temperature protection<br>• operating altitude 3,000 m<br>• operating temperature range -20 ~ 70 °C with derating<br>• remote ON/OFF control<br>.|**SERIES:**VOFM-280B**│** **DESCRIPTION:**AC-DC POWER SUPPLY<br>**FEATURES**<br>• 200 W with natural convection, 280 W with forced air cooling<br>• certified to EN/UL 60601-1, 2xMOPP<br>• designed to meet EN 60601-1-2<br>• designed to meet EN 55011/EN 55032<br>• universal input range 90 ~ 264 Vac<br>• 5 V standby and 12 V fan outputs<br>• output short circuit, over current, over voltage,<br>and over temperature protection<br>• operating altitude 3,000 m<br>• operating temperature range -20 ~ 70 °C with derating<br>• remote ON/OFF control<br>.|**SERIES:**VOFM-280B**│** **DESCRIPTION:**AC-DC POWER SUPPLY<br>**FEATURES**<br>• 200 W with natural convection, 280 W with forced air cooling<br>• certified to EN/UL 60601-1, 2xMOPP<br>• designed to meet EN 60601-1-2<br>• designed to meet EN 55011/EN 55032<br>• universal input range 90 ~ 264 Vac<br>• 5 V standby and 12 V fan outputs<br>• output short circuit, over current, over voltage,<br>and over temperature protection<br>• operating altitude 3,000 m<br>• operating temperature range -20 ~ 70 °C with derating<br>• remote ON/OFF control<br>.|**SERIES:**VOFM-280B**│** **DESCRIPTION:**AC-DC POWER SUPPLY<br>**FEATURES**<br>• 200 W with natural convection, 280 W with forced air cooling<br>• certified to EN/UL 60601-1, 2xMOPP<br>• designed to meet EN 60601-1-2<br>• designed to meet EN 55011/EN 55032<br>• universal input range 90 ~ 264 Vac<br>• 5 V standby and 12 V fan outputs<br>• output short circuit, over current, over voltage,<br>and over temperature protection<br>• operating altitude 3,000 m<br>• operating temperature range -20 ~ 70 °C with derating<br>• remote ON/OFF control<br>.|**SERIES:**VOFM-280B**│** **DESCRIPTION:**AC-DC POWER SUPPLY<br>**FEATURES**<br>• 200 W with natural convection, 280 W with forced air cooling<br>• certified to EN/UL 60601-1, 2xMOPP<br>• designed to meet EN 60601-1-2<br>• designed to meet EN 55011/EN 55032<br>• universal input range 90 ~ 264 Vac<br>• 5 V standby and 12 V fan outputs<br>• output short circuit, over current, over voltage,<br>and over temperature protection<br>• operating altitude 3,000 m<br>• operating temperature range -20 ~ 70 °C with derating<br>• remote ON/OFF control<br>.|AC-DC POWER SUPPLY||**date**<br>**page**|11/18/2024<br>1 of 6<br>||
|---|---|---|---|---|---|---|---|---|---|---|---|
|**MODEL**||||||**output**<br>**voltage**|**output**<br>**current1**|**output**<br>**power1,2**|**ripple**<br>**and noise3**|**efficiency4**||
||||||||**max**|**max**|**max**||**typ**|
|||||||(Vdc)|(A)|(W)|(mVp-p)||**(%)**|
|VOFM-280B-12||||||12|23.33|280|150||91|
|VOFM-280B-24||||||24|11.66|280|240||91|
|VOFM-280B-28||||||28|10.0|280|280||91|
|VOFM-280B-36||||||36|7.77|280|300||91|
|VOFM-280B-48||||||48|5.83|280|300||91|
|VOFM-280B-54||||||54|5.18|280|400||91|



- Notes: 1. Maximum output power is 280 W with 18 CFM forced air cooling. For open frame models, the maximum output power is 210 W with natural convection, for U-frame models 200 W with natural convection. 

2. With forced air (18 CFM). 

3. Ripple is measured with 20 MHz bandwidth and 47 µF tantalum capacitor in parallel with a 0.1 µF capacitor at output connector. 

4. At 230 Vac, full load. 

5. All specifications are measured at Ta=25°C, nominal input voltage, and rated output load unless otherwise specified. 

## **PART NUMBER KEY** 

## **- - - VOFM 280B XX X XX** 

Base Number 

Output Voltage 

| ~~7~~ Chassis mount: “blank” = open frame U = U frame 

Output Connections: “blank” = C-connector M1 = molex connector M2 = terminal block connector 

**cui** .com 

**CUI Inc │ SERIES:** VOFM-280B **│ DESCRIPTION:** AC-DC POWER SUPPLY 

**date** 11/18/2024 **│ page** 2 of 6 

## **INPUT** 

|**INPUT**||||||
|---|---|---|---|---|---|
|**parameter**|**conditions/description**|**min**|**typ**|**max**|**units**|
|voltage||90|115~230|264|Vac|
|frequency||47|50~60|63|Hz|
|current|at 115 Vac, 50 Hz|||3.5|A|
|inrush current|at 230 Vac, cold start|||60|A|
|power factor|at full load||0.9|||
|touch  current|at 264 Vac|||94|µA|
|no load power consumption||||0.5|W|
|remote on/of6|logic high (3.5~5.15 Vdc)<br>logic low (<1 Vdc)|||||
|Notes:<br>6. Position in CN4 pin 3 & pin 4 (pin 3 is INHIBIT, pin 4 is GND).||||||



|**OUTPUT**||||||
|---|---|---|---|---|---|
|**parameter**|**conditions/description**|**min**|**typ**|**max**|**units**|
|load regulation|12 & 24 Vdc output model<br>all other outputs||±3<br>±2||%<br>%|
|hold-up time|||10||ms|
|transient response|10% to full load deviation recovery time|< 20mS 10% max||||
|temperature coefcient|||±0.01||%/°C|
|fan output|12 Vdc / 0.3 A|||||
|switching frequency||80||100|kHz|
|remote on/of6|logic high (3.5~5.15 Vdc)<br>logic low (<1 Vdc)|||||



Notes: 6. Position in CN4 pin 3 & pin 4 (pin 3 is INHIBIT, pin 4 is GND). 

## **PROTECTIONS** 

|**PROTECTIONS**||||||
|---|---|---|---|---|---|
|**parameter**|**conditions/description**|**min**|**typ**|**max**|**units**|
||12 Vdc output model|13.0||16.8|Vdc|
||24 Vdc output model|25.2||31.2|Vdc|
|over voltage protection|28 Vdc output model<br>36 Vdc output model|29.4<br>37.5||36.4<br>48.0|Vdc<br>Vdc|
||48 Vdc output model|50.4||62.0|Vdc|
||54 Vdc output model|56.0||68.0|Vdc|
|over current protection|auto recovery|105||150|%|
|short circuit protection|auto recovery|||||
|over temperature protection|recovery requires ac power cycle or INHIBIT pin reset|||||



## **SAFETY & COMPLIANCE** 

|**parameter**|**conditions/description**<br>**min**<br>**typ**<br>**max**<br>**units**|
|---|---|
|isolation voltage|input to output , 2 MOPP<br>4,000<br>5,656<br>Vac<br>Vdc|
||input to earth ground, 1 MOPP<br>1,500<br>2,121<br>Vac<br>Vdc|
||output to earth ground, 1 MOPP<br>1,500<br>2,121<br>Vac<br>Vdc|
|safety approvals7|certifed to 60601-1: UL, EN|
|EMI/EMC|IEC 60601-1-2 Ed4:2014, EN 60601-1-2 Ed4:2015, EN 55024, EN 55011 Class B<br>EN 55032 Class B, FCC Part 15 Class B, FCC Part 18 Class B|
|MTBF|as per Telcordia SR-332 (Bellcore) at 25°C<br>250,000<br>hours|
|RoHS|yes|
|Notes:<br>7. 2xMOPP||



**cui** .com 

**CUI Inc │ SERIES:** VOFM-280B **│ DESCRIPTION:** AC-DC POWER SUPPLY 

**date** 11/18/2024 **│ page** 3 of 6 

## **ENVIRONMENTAL** 

|**ENVIRONMENTAL**||||||
|---|---|---|---|---|---|
|**parameter**|**conditions/description**|**min**|**typ**|**max**|**units**|
|operating temperature|see derating curves|-20||70|°C|
|storage temperature||-20||85|°C|
|operating humidity|non-condensing|0||90|%|
|storage humidity|non-condensing|0||90|%|
|operating altitude||||5,000|m|



## **DERATING CURVES** 

**cui** .com 

**CUI Inc │ SERIES:** VOFM-280B **│ DESCRIPTION:** AC-DC POWER SUPPLY 

**date** 11/18/2024 **│ page** 4 of 6 

## **MECHANICAL** 

|**MECHANICAL**||||||
|---|---|---|---|---|---|
|**parameter**|**conditions/description**|**min**|**typ**|**max**|**units**|
|dimensions|open frame: 127.00 x 76.20 x 30.00<br>U-frame: 127.00 x 83.20 x 38.0||||mm<br>mm|
|weight|open frame<br>U-frame||350<br>475||g<br>g|
|cooling|forced air cooling|||||



## **MECHANICAL DRAWING** 

## **Open frame** 

units: mm 

|**Open frame**<br>units: mm|||
|---|---|---|
|CN1: Input Connector<br>JST B2P3-VH pitch: 3.96 mm or equivalent,<br>mates with JST VAR-2 or equivalent||CN4: Remote control and Standby supply<br>JST B2B-XH-A pitch: 2.5 mm or equivalent,<br>mates with JST XHP-4 or equivalent|
|PIN<br>Function||PIN<br>Function|
|1<br>AC (L)||1<br>GND|
|2<br>AC (N)||2<br>+5 VSB|
|||3<br>INHIBIT (Remote control)|
|CN2:  FAN Output Connector<br>JST B2B-XH-A pitch: 2.5 mm or equivalent,||4<br>GND|



|CN2:  FAN Output Connector<br>JST B2B-XH-A pitch: 2.5 mm or equivalent,<br>mates with JST XHP-2 or equivalent|CN2:  FAN Output Connector<br>JST B2B-XH-A pitch: 2.5 mm or equivalent,<br>mates with JST XHP-2 or equivalent|
|---|---|
|PIN|Function|
|1|GND FAN-|
|2|+12V FAN+|



INHIBIT = Logic level HIGH (5V) or Floating: Enable, Logic level LOW: Disable 

|**Molex Connector**<br>12 pin min fit pitch: 4.2 mm<br>Molex PN 39-28-1123 or<br>equivalent|**Molex Connector**<br>12 pin min fit pitch: 4.2 mm<br>Molex PN 39-28-1123 or<br>equivalent|
|---|---|
|PIN|Function|
|1|+Vout|
|2|+Vout|
|3|+Vout|
|4|GND|
|5|GND|
|6|GND|
|7|+Vout|
|8|+Vout|
|9|+Vout|
|10|GND|
|11|GND|
|12|GND|



|8<br>+Vout<br>9<br>+Vout<br>10<br>GND<br>11<br>GND<br>12<br>GND|8<br>+Vout<br>9<br>+Vout<br>10<br>GND<br>11<br>GND<br>12<br>GND|
|---|---|
|**C-Connector**<br>JST B8P-VH-B pitch: 3.96 mm<br>or equivalent, mates with JST<br>FHR-8N or equivalent||
|PIN|Function|
|1|GND|
|2|GND|
|3|GND|
|4|GND|
|5|+Vout|
|6|+Vout|
|7|+Vout|
|8|+Vout|
|||
|**Terminal Block Connector**<br>4-Pole Terminal block pitch:<br>8.25 mm, rate 20A/300V or<br>equivalent||
|PIN|Function|
|1|GND|
|2|GND|
|3|+Vout|
|4<br>~~—~~|+Vout<br>~~—~~|



**==> picture [129 x 9] intentionally omitted <==**

**----- Start of picture text -----**<br>
CN3: Main Output Connector<br>**----- End of picture text -----**<br>


**==> picture [566 x 15] intentionally omitted <==**

**----- Start of picture text -----**<br>
| —<br>**----- End of picture text -----**<br>


**cui** .com 

**CUI Inc │ SERIES:** VOFM-280B **│ DESCRIPTION:** AC-DC POWER SUPPLY 

**date** 11/18/2024 **│ page** 5 of 6 

## **MECHANICAL DRAWING (CONTINUED)** 

## **U-frame** 

units: mm 

**==> picture [393 x 153] intentionally omitted <==**

**----- Start of picture text -----**<br>
|||||
|---|---|---|---|
|CN1: Input Connector|CN4: Remote control and Standby supply|
|JST B2P3-VH pitch: 3.96 mm or equivalent,|JST B2B-XH-A pitch: 2.5 mm or equivalent,|
|mates with JST VAR-2 or equivalent|mates with JST XHP-4 or equivalent|
|PIN|Function|PIN|Function|
|1|AC (L)|1|GND|
|2|AC (N)|2|+5 VSB|
|3|INHIBIT (Remote control)|
|CN2:  FAN Output Connector|4|GND|
|JST B2B-XH-A pitch: 2.5 mm or equivalent,|
|mates with JST XHP-2 or equivalent|INHIBIT = Logic level HIGH (5V) or|
|PIN|Function|Floating: Enable, Logic level LOW: Disable|
|1|GND FAN-|
|2|+12V FAN+|

**----- End of picture text -----**<br>


**==> picture [116 x 219] intentionally omitted <==**

**----- Start of picture text -----**<br>
|||
|---|---|
|Molex Connector|
|12 pin min fit pitch: 4.2 mm|
|Molex PN 39-28-1123 or|
|equivalent|
|PIN|Function|
|1|+Vout|
|2|+Vout|
|3|+Vout|
|4|GND|
|5|GND|
|6|GND|
|7|+Vout|
|8|+Vout|
|9|+Vout|
|10|GND|
|11|GND|
|12|GND|

**----- End of picture text -----**<br>


**==> picture [125 x 163] intentionally omitted <==**

**----- Start of picture text -----**<br>
|||
|---|---|
|C-Connector|
|JST B8P-VH-B pitch: 3.96 mm|
|or equivalent, mates with JST|
|FHR-8N or equivalent|
|PIN|Function|
|1|GND|
|2|GND|
|3|GND|
|4|GND|
|5|+Vout|
|6|+Vout|
|7|+Vout|
|8|+Vout|

**----- End of picture text -----**<br>


## **CN3: Main Output Connector** 

**==> picture [117 x 107] intentionally omitted <==**

**----- Start of picture text -----**<br>
|||
|---|---|
|Terminal Block Connector|
|4-Pole Terminal block pitch:|
|8.25 mm, rate 20A/300V or|
|equivalent|
|PIN|Function|
|1|GND|
|2|GND|
|3|+Vout|
|4|+Vout|

**----- End of picture text -----**<br>


**cui** .com 

**CUI Inc │ SERIES:** VOFM-280B **│ DESCRIPTION:** AC-DC POWER SUPPLY 

**date** 11/18/2024 **│ page** 6 of 6 

## **REVISION HISTORY** 

|**rev.**|**description**|**date**|
|---|---|---|
|1.0|initial release|10/20/2024|
|1.01|features updated|11/18/2024|



The revision history provided is for informational purposes only and is believed to be accurate. 

**==> picture [115 x 37] intentionally omitted <==**

**Headquarters** 15575 SW Sequoia Pkwy #100 Portland, OR 97224 **800.275.4899** 

Fax 503.612.2383 **cui** .com techsupport@cui.com 

CUI offers a two (2) year limited warranty.  Complete warranty information is listed on our website. 

CUI reserves the right to make changes to the product at any time without notice.  Information provided by CUI is believed to be accurate and reliable.  However, no responsibility is assumed by CUI for its use, nor for any infringements of patents or other rights of third parties which may result from its use. 

CUI products are not authorized or warranted for use as critical components in equipment that requires an extremely high level of reliability.  A critical component is any component of a life support device or system whose failure to perform can be reasonably expected to cause the failure of the life support device or system, or to affect its safety or effectiveness.
Updated at April 27, 2026
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