CUI’s VOF‑180 and VOF‑225A AC-to-DC Power Supplies in 2×4 inch Open Frames

February 15, 2018 by Nick Davis

In this News Brief, we take a look at CUI’s new high-density AC/DC power supplies housed in low-profile open-frame packages.

In this News Brief, we take a look at CUI’s new high-density AC/DC power supplies housed in low-profile open-frame packages.

CUI’s Power Group announced late last year the addition of 180 W and 225 W models to its family of high-density open-frame AC-to-DC power supplies. Both the VOF-180 and VOF-225A models are compact, low-profile AC-to-DC power supplies offering high efficiency and high power density.


CUI’s new VOF-225A AC-to-DC power supply. Image taken from the datasheet (PDF).


These units come with a 12V/0.5A auxiliary fan output connector which, according to the datasheet, mates with Tyco 640440-2. By the way, if you’re in need of a cooling fan for this unit, you might consider contacting CUI and asking, nicely, if they could recommend a suitable fan based on your design requirements. So be ready to provide, if they ask, your system design parameters.

Regarding VOUT, both models offer output voltages of 12, 15, 24, 30, 48, and 58 VDC, and they have a wide universal input voltage range of 80 to 264 VAC. And while CUI touts the following features of this power supply unit, we’re rather used to seeing these almost-standard features on similar power supplies:

  • over-voltage protection
  • over-current protection
  • short-circuit protection (all with hiccup and auto-recovery features)
  • power loss hold-up time of 10ms

These power supplies have an operating temperature range of -40°C to +70°C, and depending on the cooling system (or lack thereof) they may require some derating. CUI provides some plots that help the designer to determine how much, if any, derating is necessary (see images below).


VOF-225A derating curves. Image taken from the VOF-225A datasheet (PDF).


VOF-180 derating curves. Image taken from the VOF-180 datasheet (PDF).


These two power supply models have been certified to the following standards:

  • Safety approvals: EN 60950-1, EN 60950-1 (ed.2), UL 60950 (ed.2), and CSA C22.2.
  • Conducted emissions: EN 55032 Class B
  • Input current harmonics: EN 61000-3-2, class D
  • Voltage fluctuation and flicker: EN 61000-3-3, pass
  • ESD immunity: EN 61000-4-2, level 3, criterion A


Also, CUI provides the following required mating connector information:

  • J1 input connector: Mates with JST housing VHR-3M; pins SVH-41T-P1.1 or equivalent.
  • J2 output connector:
    • Screw Type: Accepts 28 to 16 AWG wire
    • Header Type: Mates with JST housing VHR-6M; pins SVH-41T-P1.1 or equivalent
  • J3 fan connector: Mates with Tyco 640440-2


Equipped with long-life electrolytic capacitors, an industry standard 2 inch × 4 inch footprint, efficiencies up to 94% (for the VOF-225A model, and up to 92% for the VOF-180 model), power factor correction, and no-load power consumption of less than 500 mW, these AC-to-DC low-profile power supplies are ideal for space-constrained industrial, telecom, and IT equipment applications.

Keep in mind, however, that although the operating temperature range of these power supplies is -40°C to +70°C, their temperature coefficient of ±0.05 %/°C is only valid from 0°C to +50°C. So if you plan to operate these power supplies at temperatures outside the 0°C to +50°C range, you might consider contacting CUI for additional temperature coefficient information.