Transformer products
Explore VOOHU EP and EFD series for isolated DC-DC power designs in PoE powered devices. Shortlist by target output, load and package, then check the exact part's input conditions, converter topology and winding documentation. For a new design or an existing-part review, your sales engineer can coordinate FAE support.
Part number search & selector
The table uses the current English-site product records, published selection fields and part-specific technical-file links.
* Frozen Image and Part Number columns · drag horizontally to review all specifications
| Image | Datasheet | Compare | Downloads |
Package Size
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Power (W)
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Output Voltage (V)
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Output Current (A)
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Sample |
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| Image | Part number | Datasheet | Compare | Downloads | Package Size | Power (W) | Output Voltage (V) | Output Current (A) | Sample |
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ST1333WH | SPEC | EP13 Series | 12W | 12V | 0.41A~1.0A |
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ST1313WH | SPEC | EP13 Series | 13W | 13V | 0.41A~1.0A |
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ST1312WH | SPEC | EP13 Series | 12W | 12V | 0.41A~1.0A |
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ST1311WH | SPEC | EP13 Series | 10W | 13.5V | 0.41A~1.0A |
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ST1306WH | SPEC | EP13 Series | 10W | 12V | 0.41A~1.0A |
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Broaden the selected filters or clear the current search.
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Product family quick links
Counts reflect the current published product data.
How to select
The converter decides, not the network port. Settle the power stage first, then let output, core size and the datasheet narrow the candidates.
Confirm the part sits in the isolated DC-DC stage behind the PD controller, not on the Ethernet data path. Note the PoE type, the input range at the converter and any adapter input.
List each output rail with continuous and peak current, any auxiliary winding for controller bias, the switching frequency and whether the design is flyback, forward or active clamp.
Use the power, output voltage and current filters, then compare primary inductance, leakage inductance, DCR, turns ratio and the hipot condition in each PoE transformer datasheet.
Build samples into the real converter and check efficiency, temperature rise, saturation margin and EMI before release. A known part number can go straight to a sample or price request.
Key selection parameters
These four filters come from each part's catalog record. They shortlist candidates; the converter conditions behind every number are in the datasheet.
EP7, EP10 and EP13 parts are EP transformer cores; EFD15, EFD20 and EFD25 are EFD transformer cores. The name sets the core family, not mounting, height or pin layout. If you need an SMD power transformer, confirm the mounting style in each drawing.
A reference output power under stated conditions, from 3 W to 100 W across the range. It is not a PoE class label and holds only for the converter conditions given in the datasheet.
The rail the winding was designed for, such as 3.3 V, 5 V, 12 V or 24 V. The transformer does not regulate; the controller and its feedback loop set the final output.
Some entries are exact values, others are bands such as 1.08 A to 1.99 A or ≥ 2 A. A band is not an upper limit, so read the rated current in the datasheet before calculating power.
Product family comparison
Each row sums up one EP or EFD series and the power, voltage and current values that appear in it. Use it to pick a core size, then open individual parts, since one series can hold very different outputs.
Return to the selector ↑| Package Size | Parts | Power (W) | Output Voltage (V) | Output Current (A) | Action |
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| EP7 Series | 6 | 10W, 12W, 15W, 3W | 5V, 12V, 13V | 0.41A~1.0A, 1.08A~1.99A, ≥ 2A, 0.25A | Filter → |
| EP10 Series | 11 | 5W, 6W, 7W, 10W, 12W | 5V, 12V, 13.5V | 0.41A~1.0A, ≥ 2A | Filter → |
| EP13 Series | 25 | 10W, 12W, 13W, 14W, 18W, 20W, 24W, 25W, 25.2W, 30W | 5V, 12V, 13.4V, 13.5V, 13V, 14V, 24V | 0.41A~1.0A, 1.08A~1.99A, ≥ 2A, 5A | Filter → |
| EFD15 Series | 4 | 10W, 13W | 3.3V, 5V, 12V, 24V | 0.41A~1.0A, 1.08A~1.99A, ≥ 2A, 3A | Filter → |
| EFD20 Series | 5 | 30W, 60W, 100W | 5V, 12V, 24V | 1.08A~1.99A, ≥ 2A, 8.35A | Filter → |
| EFD25 Series | 4 | 45W, 60W, 72W, 90W | 12V, 15V, 24V | ≥ 2A, 3A, 3.75A | Filter → |
Technical performance & application fit
When you choose a PoE transformer for PD supplies, the load decides, not the network speed. These notes cover what to settle first in common PoE terminals; they are review prompts, not suitability claims for any listed part.
Downloads & technical resources
Enter all or part of a part number and the PoE transformer datasheet, STEP model and PCB footprint open from one row. Lay out the converter from the winding diagram and pin table in that datasheet.
Showing representative available file sets. Search to find a specific SKU.
VOOHU’s published product content is reviewed by its engineering team. Specifications, downloads and technical support information are tied to specific part numbers, so you can verify them before requesting samples or a quotation.
Category overview
A PoE power transformer, sometimes searched as a power over Ethernet transformer, is not the same part as a PoE-capable LAN transformer. Mixing the two up is the most common error in this category.
Search for a PoE Ethernet transformer and you will find two different parts. On the data side, the LAN transformer couples the signal and lets DC current flow through its center taps; Ethernet transformer PoE ratings such as PoE+ or 4PPoE describe that current and nothing more.
On the power side, the PoE power transformer sits in the isolated DC-DC converter of the powered device and turns the nominal 48 V input into the rails the electronics use. This page covers that part, which engineers also call a PoE PD transformer or simply PoE magnetics.
Because it belongs to the power stage, a PoE transformer is chosen against the converter: the input range behind the PD controller, output voltage and current, switching frequency, topology and the isolation the safety case requires. The PoE class sets the budget, but two PDs of the same class can need different DC-DC transformer designs.
Most low and mid-power PD supplies use a flyback transformer, while some higher-power 802.3bt designs move to an active clamp forward converter. Confirm the intended topology in the datasheet before treating a part as a flyback transformer for PoE.
EP and EFD describe core shapes, and each size covers a power range. In the current data, EP7 and EP10 parts carry power references up to 15 W, EP13 parts up to 30 W, and EFD20 and EFD25 parts from 30 W to 100 W. A larger core gives more winding window and lower loss at higher current, at the cost of board area and height.
Pick from output power and available space, then check temperature rise and saturation margin on the real board.
FAQ & related guides
Answers on topology, PoE class, winding ratios, isolation and samples. Treat them as review guidance and confirm values in each datasheet.
No. The LAN transformer carries Ethernet data and lets DC current pass through its center taps; the PoE power transformer sits in the DC-DC stage and converts that power. Their windings, inductance and design targets are unrelated. Identify where the part sits in the schematic first, then select from the matching category.
Only in the power it is designed for. PoE+ (IEEE 802.3at) allows up to 25.5 W at the PD input, while PoE++ (802.3bt) allows up to 51 W for Type 3 and 71.3 W for Type 4. The transformer is then chosen for the converter output at that power, so compare the catalog power reference with your rails after conversion loss.
No. A PoE flyback transformer is the usual choice for PD supplies up to the mid-power range, but forward and active clamp designs are also used, mostly at higher power. The selector has no topology filter, so check the application circuit in each datasheet, or tell us your controller and topology and our FAE team will suggest suitable parts.
Check part by part. The catalog is organised by core size and output rather than topology. If your 802.3bt design uses an active clamp forward converter, send the controller, input range, output rails and switching frequency; FAE will say whether a listed part fits or a custom design should be evaluated.
Not on its own. In a flyback the output depends on the ratio, the duty cycle and the controller's feedback, and the auxiliary winding and pin definitions also matter. Shortlist with the output voltage filter, then check every winding in the PoE transformer datasheet. A ratio is not a regulated input-to-output voltage guarantee.
No. The hipot figure is a short withstand test between stated windings, with its own AC or DC type and duration. Working insulation depends on the safety standard, creepage and the full board design. If the project needs specific compliance documents, name the standard and the part number and your sales engineer will confirm what can be supplied.
The original part number and datasheet revision, input range, output rails and load, controller and topology, and any fixed footprint or height limit. Incomplete data is fine for a first review. FAE compares candidates and lists what needs validating; there is no automatic replacement result, and the final choice is proven in your circuit.
VOOHU is a PoE transformer manufacturer and winds these parts in its own magnetics plant in Mianyang, China. Request samples from the product table, or email the part number with quantity and delivery country. Samples are available for evaluation and selected parts are free of charge, with the options confirmed by our FAE team. Quotes and lead times are set for each order.
Engineer support
Send the candidate part number and the condition you need reviewed. Sample support can be added after the selection is clear; commercial questions may be discussed in the same engineering conversation.
Include the document revision
Temperature, isolation voltage and PoE current basis
Pin count, pitch and spacing between pin rows
To help prioritize samples and evaluation
When you need candidates and a comparison of differences
Engineering review identifies candidate parts and explains the differences.
From the selector or engineering review
Prototyping / pilot build / production
Specify sample and production timing separately
Compliance documents, material declarations or third-party reports
Samples are available for evaluation, and selected parts are free of charge. Our FAE team will be glad to confirm the options for your project. Sales will respond on business days.
