PoE Power Transformer Selection Comparison: VOOHU WHEP7089 vs. Coilcraft POE30P-12LD Replacement Evaluation
PoE Power Transformer Selection Comparison: VOOHU WHEP7089 vs. Coilcraft POE30P-12LD Replacement Evaluation
1. Competitor Product Overview (Coilcraft, Inc.)
Coilcraft POE30P-12LD is a 3 W flyback power transformer for PoE powered-device isolation stages in an 8-pin SMT package. Its primary accepts 36-72 Vdc; the secondary delivers 12 V / 0.25 A and includes a 12 V / 20 mA bias winding. For an existing design, turns ratio and DC resistance are only part of the decision: the paralleled-secondary connection, isolation test conditions, and PCB land pattern should be checked together.
2. VOOHU Replacement Overview (Suzhou VOOHU Electronic Technology Co., Ltd.)
VOOHU WHEP7089 uses the same eight-terminal functional topology: pins 3-4 are primary, pins 2-1 are bias, and pins 5+6 / 7+8 are tied as the secondary on the PCB. Its input and output configuration can be assessed alongside POE30P-12LD. This makes WHEP7089 a replacement-evaluation candidate, not a confirmed drop-in; verify pad geometry, keep-out area, component height, and isolation clearance before powering a sample board.
3. Key Parameter Comparison
These transformers can be compared around terminal topology, output configuration, and key electrical values. Test conditions are retained where they affect interpretation, and the engineering limits are called out below.
| Parameter | Coilcraft POE30P-12LD | VOOHU WHEP7089 |
|---|---|---|
| Terminal functions and secondary connection | 3-4 primary; 2-1 bias; 5+6 and 7+8 paralleled as secondary on PCB | 3-4 primary; 2-1 bias; 5+6 and 7+8 paralleled as secondary on PCB |
| Nominal input range | 36-72 Vdc | 36-72 V |
| Secondary output | 12 V, 0.25 A | 12 V, 0.25 A |
| Bias output | 12 V, 20 mA | 12 V, 20 mA |
| Primary inductance | 310 µH ±10% (250 kHz, 0.1 Vrms, 0 A) | 310 µH ±10% (10 kHz, 0.1 Vrms) |
| Primary DCR (3-4) | 1.04 Ω Max. (25°C) | 1.04 Ω Max. (25°C) |
| Bias DCR (2-1) | 2.01 Ω Max. (25°C) | 2.01 Ω Max. (25°C) |
| Primary : secondary turns ratio | 1 : 0.70 (secondary paralleled on PCB) | 1 : 0.698 ±3% (20 kHz, 1.0 Vrms) |
| Primary : bias turns ratio | 1 : 0.70 | 1 : 0.698 ±3% (20 kHz, 1.0 Vrms) |
| Leakage inductance | 4.25 µH Max. (3-4; all other terminals shorted) | 6.5 µH Max. (100 kHz, 0.1 Vrms; other terminals shorted) |
| Primary-to-secondary isolation test | 1500 Vrms, 1 min. | 1500 VAC, 5 mA, 1 s |
| Maximum body size (L × W × H) | 13.21 × 10.92 × 9.02 mm | 13.5 × 11.0 × 9.5 mm |
Notes:
- Both primary inductance values are nominally 310 µH, but the test frequencies are 250 kHz and 10 kHz. Confirm startup, ripple-current, and core-margin behavior at the actual switching frequency and current.
- The leakage-inductance setups are not fully aligned. WHEP7089 specifies 100 kHz and 0.1 Vrms; POE30P-12LD specifies measurement across pins 3-4 with all other terminals shorted. The values should not be ranked as a spike-voltage or EMI conclusion.
- Secondary DCR is expressed differently: POE30P-12LD is 0.700 Ω Max. per secondary winding, while WHEP7089 gives 0.35 Ω Max. for the grouped 5+6 / 7+8 terminals. It is therefore not shown as a direct comparison row.
- Both parts use a 1500 V class primary-to-secondary test, but the test duration is 1 minute versus 1 second. Apply the safety requirement and actual isolation clearance of the end equipment.
- WHEP7089 has a slightly larger body envelope. Matching terminal functions are a starting point for replacement evaluation, not proof of a pin-to-pin PCB replacement. Complete a CAD overlay, land-pattern review, reflow check, and sample validation.
- Thermal labels also differ: POE30P-12LD lists an ambient range of -40°C to +85°C, while WHEP7089 lists -40°C to +125°C operating temperature including self-temperature rise. Use measured temperature rise and the local thermal environment for the final decision.
4. Applications
- PoE isolated-power stages requiring a 36-72 V input, 12 V / 0.25 A output, and a 12 V / 20 mA bias winding.
- Low-power PoE powered devices in industrial Ethernet endpoints, wireless access equipment, security cameras, and access-control terminals; review the actual controller, rectifier, clamp, and feedback network before release.
- Alternative-source evaluation for installed POE30P-12LD boards and new projects where a CAD overlay and sample testing can be performed.
- Isolated power designs using paralleled secondary terminals and a 12 V bias winding.
5. FAQ
Can WHEP7089 directly replace POE30P-12LD?
The table alone is not enough to support that conclusion. Terminal functions, input/output configuration, and several electrical values are close, but WHEP7089 has a larger maximum body size and some test conditions differ. Review PCB pads, nearby clearance, isolation distance, and reflow behavior, then validate on a powered sample board.
What should be checked first on an existing PoE board?
At minimum input voltage, check startup and output regulation. Record switching spikes, clamp-network temperature rise, EMI, transformer temperature rise, and isolation results. Keep the 5+6 and 7+8 secondary connections consistent with the original board.
Why verify primary inductance when both are 310 µH?
The test frequencies differ, and only POE30P-12LD provides a minimum inductance at 0.3 A. Switching frequency, peak current, and bias conditions all affect core margin, so nominal inductance by itself is not enough.
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
