Bel S558-5999-T7-F Alternative: VOOHU WHS16037TG Comparison
For an industrial 10/100 port rated −40 to +85 °C, the VOOHU WHS16037TG is a functional alternative to the Bel S558-5999-T7-F — verify with samples in your design. Both are 16-pin, 1.27 mm pitch SMD LAN transformers with 1CT:1CT windings, 350 µH minimum OCL at 8 mA DC bias, common mode chokes on the line side and 1500 VAC isolation. Two items need attention before layout: the pin numbering described below, and the body length, which is 12.80 ± 0.50 mm on the WHS16037TG against 0.485 in (12.32 mm) max on the S558-5999-T7-F.
Design note:the two parts put the chip side and the line side on opposite pin numbers. On the Bel S558-5999-T7-F, pins 1–8 are the line (cable) side and pins 9–16 are the chip side; on the VOOHU WHS16037TG, pins 1–8 are the chip (PHY) side and pins 9–16 are the line side. Do not place the VOOHU part on a Bel footprint with the pin-1 marks aligned. Re-check pad assignment, placement orientation and the silkscreen pin-1 mark against both datasheets, and confirm with samples and our FAE before you reuse the layout.
Bel S558-5999-T7-F datasheet values beside the WHS16037TG
Bel publishes this part as a drawing (Rev A, 2021-01-27) with electrical data on page 1 and mechanical data on page 2; the VOOHU values come from the WHS16037TG datasheet Rev A0. Bel dimensions are in inches with millimetres in brackets, as printed on the drawing. Note that Bel writes insertion loss, return loss, crosstalk and common mode rejection as positive dB magnitudes, while VOOHU writes them as negative values; read 1.0 dB max and −1.1 dB max as loss figures of the same kind.
| Parameter | Bel S558-5999-T7-F (source) | VOOHU WHS16037TG (source) |
|---|---|---|
| Application | 10/100BASE-T, single port (Bel product page) | 10/100BASE-TX, single port (DS p1) |
| Pins / pitch | 16 / 0.050 in [1.27 mm] typ (drawing p2) | 16 / 1.27 ± 0.20 mm (DS p1) |
| Pins 1–8 | Line side: RX+ 1, RXCT 2, RX− 3; 4 and 5 not used; TX+ 6, TXCT 7, TX− 8 (drawing p1) | Chip side: TD+ 1, CT 2, TD− 3; RD+ 6, CT 7, RD− 8 (DS p1) |
| Pins 9–16 | Chip side: TX− 9, TXCT 10, TX+ 11; 12 and 13 not used; RX− 14, RXCT 15, RX+ 16 (drawing p1) | Line side: RX− 9, CT 10, RX+ 11; TX− 14, CT 15, TX+ 16 (DS p1) |
| Common mode chokes | Line side, pins 1–8 (drawing p1) | Line side, pins 9–16 (DS p1) |
| Turns ratio | 1CT:1CT (drawing p1) | 1CT:1CT ± 5% (DS p2) |
| OCL | 350 µH min @ 100 kHz, 100 mVrms, 8 mA DC bias (drawing p1) | 350 µH min @ 100 kHz, 0.1 V, 8 mA DC bias (DS p2) |
| Leakage inductance | 0.3 µH max @ 1 MHz, 20 mVrms (drawing p1) | 0.5 µH max @ 100 kHz, 0.1 V (DS p2) |
| Interwinding capacitance | 30 pF max (drawing p1) | not stated |
| DC resistance | not stated | 1400 mΩ max (DS p2) |
| Insertion loss | 1.0 dB max, 300 kHz–100 MHz (drawing p1) | −1.1 dB max, 1–100 MHz (DS p2) |
| Return loss | 18 dB min, 1–30 MHz; 18 − 20log(f/30 MHz) dB min, 30–60 MHz; 12 dB min, 60–80 MHz (drawing p1) | −18 dB min, 1–30 MHz; −14.4 dB @ 40 MHz; −13.1 dB @ 50 MHz; −12 dB min, 60–80 MHz (DS p2) |
| Crosstalk | 35 dB min, 300 kHz–100 MHz (drawing p1) | −30 dB min, 1–100 MHz (DS p2) |
| Common mode rejection | CM-CM 30 dB min; CM-DM 40 dB min; 300 kHz–100 MHz (drawing p1) | −30 dB min, 1–100 MHz; CM-DM not stated (DS p2) |
| Isolation (hipot) | Leakage current less than 1 mA at 1500 VAC; duration not stated (drawing p1) | 1500 VAC, 1 mA, 60 s (DS p2) |
| Operating temperature | −40 to +85 °C (drawing p1; product page) | −40 to +85 °C (DS p2) |
| Body length | 0.485 in [12.32 mm] max (drawing p2) | 12.80 ± 0.50 mm (DS p1) |
| Body width | 0.285 in [7.24 mm] max (drawing p2) | 6.90 ± 0.50 mm (DS p1) |
| Width across leads | 0.375 in [9.52 mm] (drawing p2) | 9.30 ± 0.50 mm (DS p1) |
| Height | 0.225 in [5.71 mm] max (drawing p2) | 5.65 ± 0.50 mm (DS p1) |
| Lead width / row pitch | 0.018 ± 0.002 in [0.46 ± 0.05 mm]; 0.35 ± 0.01 in [8.89 ± 0.25 mm] (drawing p2) | 0.46 ± 0.10 mm; 8.89 ± 0.20 mm (DS p1) |
| Recommended land pattern | Outer edge 0.425 in [10.80 mm]; pad length 0.070 in [1.78 mm]; pad width 0.025 in [0.62 mm]; 1.27 mm pitch (drawing p2) | Outer edge 10.50 mm; inner edge 7.10 mm; pad width 0.76 mm; row pitch 8.89 mm; all typical (DS p1) |
| Coplanarity | 0.004 in [0.10 mm] (drawing p2) | 0.10 mm (DS p1) |
What to check before replacing the S558-5999-T7-F
Pin numbering and orientation.Pin numbering runs the opposite way on the two parts. On the Bel S558-5999-T7-F, pins 1–8 are the line (cable) side and pins 9–16 the chip side; on the VOOHU WHS16037TG, pins 1–8 are the chip (PHY) side and pins 9–16 the line side. Do not place the VOOHU part on a Bel footprint with the pin-1 marks aligned. Re-check pad assignment, placement orientation and the silkscreen pin-1 mark against both datasheets, and confirm with samples and our FAE before reusing the layout.
Reading the two published schematics, the pin functions correspond when the VOOHU part is rotated 180° relative to the Bel pin-1 mark; this has not yet been confirmed by our FAE. Even on paper, that orientation would still need a new silkscreen pin-1 mark and a new pick-and-place rotation, and it does not change the body length or pad differences described below.
Body size.Body length: Bel 0.485 in (12.32 mm) max; VOOHU 12.80 ± 0.50 mm, so the nominal VOOHU length is 0.48 mm over the Bel maximum. Width is 0.285 in (7.24 mm) max on the Bel part and 6.90 ± 0.50 mm on the VOOHU part; height is 0.225 in (5.71 mm) max and 5.65 ± 0.50 mm respectively. Industrial boards often pack the transformer close to TVS parts and the RJ45 jack, so measure the clearance at both ends of the body.
Pads.Both drawings use an 8.89 mm row pitch and 1.27 mm lead pitch. The Bel pattern has a 0.425 in (10.80 mm) outer edge and 0.025 in (0.62 mm) wide pads 0.070 in (1.78 mm) long; the VOOHU pattern has a 10.50 mm outer edge, a 7.10 mm inner edge and 0.76 mm wide pads (typical). Size the pads to the VOOHU drawing, or confirm the Bel pads with a sample build.
Test conditions.Leakage inductance is measured at 1 MHz and 20 mVrms on the Bel drawing and at 100 kHz and 0.1 V on the VOOHU datasheet, so the 0.3 µH and 0.5 µH limits should not be set against each other. Insertion loss is 1.0 dB max from 300 kHz on the Bel drawing and −1.1 dB max from 1 MHz on the VOOHU datasheet. The Bel hipot line gives 1500 VAC with less than 1 mA leakage but no duration; the VOOHU datasheet gives 1500 VAC, 1 mA for 60 seconds. If your product file cites one of these figures, take it from the part you build with.
Temperature, LEDs, shield.Both are rated −40 to +85 °C, which is the reason this pair is worth evaluating for industrial designs. As discrete transformers they carry no LEDs or shield.
Which industrial designs suit the WHS16037TG?
The WHS16037TG targets the same 10/100 industrial ports where an S558-5999-T7-F is usually specified, as long as the layout is reviewed for the pin orientation above:
- PLCs, remote I/O and fieldbus-to-Ethernet modules
- Industrial gateways and protocol converters in control cabinets
- Energy meters and data concentrators with an Ethernet uplink
In each of these, the −40 to +85 °C rating on both datasheets is what makes the WHS16037TG a candidate; the orientation review and a sample build decide whether the swap works on your board.
VOOHU parts to evaluate
WHS16037TG— the part compared on this page: 10/100BASE-TX, −40 to +85 °C, chip side on pins 1–8.
WHS16013LF— for a version of the product that only needs 0 to +70 °C. Its datasheet also puts the chip side on pins 1–8, so the same orientation check against a Bel footprint applies.
Compare more single-port options in the10/100BASE-TX LAN transformer selector.
产品WHS16037TG
产品WHS16013LF
方案/solution-ethernet/
FAQ
Q1: What can replace Bel S558-5999-T7-F?
The VOOHU WHS16037TG is a functional alternative to the Bel S558-5999-T7-F — verify with samples in your design. Both datasheets list a 16-pin SMD 10/100 LAN transformer with 1CT:1CT windings, 350 µH minimum OCL, 1500 VAC isolation and a −40 to +85 °C rating. Pin 1 is on the chip side of the WHS16037TG and on the line side of the S558-5999-T7-F, so check orientation and pad assignment with our FAE before reusing a layout.
Q2: What is the S558-5999-T7-F pinout?
The Bel drawing shows the line side on pins 1–8 (RX+ 1, RXCT 2, RX− 3, TX+ 6, TXCT 7, TX− 8) and the chip side on pins 9–16 (TX− 9, TXCT 10, TX+ 11, RX− 14, RXCT 15, RX+ 16); pins 4, 5, 12 and 13 are not used. The common mode chokes are on the line side. This is the reverse of the WHS16037TG, whose pins 1–8 face the PHY.
Q3: Does this comparison cover S558-5999-AB-F, -AR-F, -AT-F, -Q2-F or -Z5-F?
No. Every Bel value on this page comes from the S558-5999-T7-F drawing only. The other S558-5999 suffixes have their own drawings, so check their pin assignment, temperature range and outline separately before choosing a VOOHU part. Send us the exact Bel part number and we will compare it for you.
Q4: Where do the center taps sit on each part?
On the S558-5999-T7-F the chip-side center taps are pins 10 and 15 and the line-side center taps are pins 2 and 7. On the WHS16037TG it is the other way round: chip-side center taps on pins 2 and 7, line-side center taps on pins 10 and 15. Connect the chip-side taps as your PHY reference design specifies and the line-side taps to your cable termination network, and re-check those nets whenever the part changes.
Get the orientation checked with samples
Planning to move an S558-5999-T7-F design to the WHS16037TG?Request samplesand include the transformer area of your layout and the PHY you use. 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. Our FAE team can suggest suitable parts and help check the design, including pad assignment, placement orientation and the pin-1 mark when moving from the Bel footprint. VOOHU supplies RJ45 and SFP connectors, LAN and PoE transformers and common mode chokes from Suzhou, China, to more than 1,500 customers.
