EP7 PoE Power Transformer: VOOHU WHEP7995 Replacement for Sunlord TWPEP090909B300T

1. Competitor Product Overview (Sunlord Electronics Co., Ltd.)

Sunlord TWPEP090909B300T is a wire-wound power transformer with an EP9 core, horizontal SMD form and three windings. The primary is on pins 3-2 for a 33-57 V input, and the two secondary windings are 8-6 and 7-5, each for 12 V / 0.5 A. For a compact isolated supply, the input window and the two outputs are the first checks; inductance, leakage inductance and winding DCR must then be judged at their stated switching conditions.

2. VOOHU Replacement Overview (Suzhou VOOHU Electronic Technology Co., Ltd.)

VOOHU WHEP7995 is an EP7-series PoE power transformer with the same 3-2 primary and dual 12 V / 0.5 A secondaries on 8-6 and 7-5. Its 55 μH inductance, 0.8 μH maximum leakage inductance and 24:12:12 turns ratio are all specified at 500 kHz, 0.1 V. It belongs in the same selection pass for a dual-12 V isolated supply, but a changeover still calls for package, land-pattern, pin-orientation and insulation checks, followed by samples at the real load.

3. Key Parameter Comparison

Put the circuit topology, turns ratio, magnetic values and insulation conditions side by side first. The decision should not rest on one matching number; each value has to be read with its terminals and test conditions.

Notes:

1. The primary and two secondary winding assignments line up, as do the input range and the two 12 V / 0.5 A outputs. That is a valid starting point for the same selection round, not proof of mechanical compatibility.
2. Both leakage-inductance limits are 0.8 μH max. at 500 kHz and 0.1 V, but the shorting instruction is written differently. Reproduce the stated terminal condition for each part, and hold the switching frequency, drive method and fixture constant during sample tests.
3. WHEP7995 lists DCR limits of 195 mΩ, 85 mΩ and 110 mΩ, versus 180 mΩ, 80 mΩ and 100 mΩ for the reference part. Evaluate copper loss, temperature rise, PCB trace resistance and output-voltage margin at the real current.
4. The available values support an electrical selection comparison, but they do not establish pin-to-pin or land-pattern compatibility. Before a changeover, overlay the package outline, pads, pin-1 orientation, creepage and clearance, then validate samples at a 33-57 V input and real load.

4. Applications

1. 33-57 V isolated DC/DC stages in PoE powered devices, such as IP cameras, wireless access points and networked access-control or intercom terminals; start with the dual-12 V load split and controller switching frequency.
2. Auxiliary supplies in compact network equipment, including small switches, industrial gateways and data-acquisition terminals, where a PoE or 48 V-class input is converted into two isolated 12 V rails.
3. Dual-12 V power stages in video-security and communication terminals, where the two secondaries feed a camera module, processing unit or peripheral interface and both load branches need ripple and temperature checks.
4. BOM localization or multisourcing for existing boards and new designs: complete pad, height and insulation-boundary overlays first, then validate start-up, full-load behavior, temperature rise, hi-pot and conducted/radiated performance on samples.

5. FAQ

Can WHEP7995 directly replace TWPEP090909B300T?

Do not make that conclusion directly. Their winding topology, input/output arrangement, inductance and leakage-inductance values at 500 kHz, and hi-pot values are comparable, but the package, pads, pin orientation, creepage and clearance still need line-by-line confirmation and on-board samples.

Do matching inductance and leakage-inductance values prove the same high-frequency behavior?

No. Both 55 μH and 0.8 μH values are measured at 500 kHz and 0.1 V, but the leakage-inductance shorting instructions differ. Switching frequency, drive waveform, snubber network, PCB parasitics and the fixture all affect actual spike voltage, EMI and temperature rise.

How should the DCR difference be evaluated?

List the real current, permitted voltage drop and winding-temperature target for both 12 V rails, then include PCB trace resistance with the winding DCR. WHEP7995 has slightly higher DCR limits, so turns ratio or no-load output is not enough for a decision.

What should be checked first in sample validation?

Build the circuit at a 33-57 V input and real load, then check both 12 V outputs, start-up and full-load temperature rise, switching waveforms, hi-pot and EMI. Follow that with pad assembly, reflow and system-level insulation-clearance checks.

Why VOOHU?

One-stop sourcing: connectors + magnetics + interface chips, full support from selection to small-batch production.

Custom solutions: just share your application requirements and budget to get a tailored solution with professional technical support.

Fast development: direct from the manufacturer, rapid FAE response, efficient sampling, shorter time-to-market.

Core qualifications: ISO9001, ISO14001, RoHS, REACH; two in-house factories ensure delivery and quality.

For more information, visit VOOHU: China www.voohu.cn | Overseas www.voohuele.com | Technical support: song.lei@voohu.cn

Replacement Cross-Reference

Manufacturer: Sunlord Electronics Co., Ltd.; Part No.: TWPEP090909B300T; key parameters: 33-57 V primary with two 12 V / 0.5 A secondaries, 55 μH ±10% and 0.8 μH max. at 500 kHz, 0.1 V, 24:12:12 turns ratio, and a 1500 V primary-to-secondary test. Compatible VOOHU WHEP7995, replacement, visit for more information: