SM13072APEL AEC-Q200 10/100 Base-T LAN Transformer Discrete LAN Magnetics

The SM13072APEL is a high-reliability, surface-mount (16-Pin SOIC) discrete 10/100 Base-T Ethernet pulse transformer module engineered specifically for harsh automotive and industrial environments. Built with a fully potted construction, automated coil winding, and cable-side integrated common mode chokes, it provides continuous operation up to +125 °C, robust differential noise immunity (DCMRR: -35 dB), and dual dielectric isolation of 1500 Vrms / 2250 Vdc.

SM13072APEL Core Specifications at a Glance

SM13072APEL Electrical Characteristics

All electrical specifications below are specified at 25°C unless otherwise stated.

The published Bourns datasheet gives the same core electrical characteristics, including 350 µH OCL, 0.5 µH maximum leakage inductance, 35 pF maximum winding capacitance, -1.1 dB maximum insertion loss and 1500 Vrms isolation.

Why 350 µH OCL Matters

The open circuit inductance (OCL) is a key selection parameter for a 10/100 Ethernet transformer. SM13072APEL specifies a minimum 350 µH at 100 kHz, 0.1 V and 8 mA DC bias.

Engineers comparing alternative 10/100 LAN transformers should evaluate OCL under the same measurement conditions rather than comparing inductance values without test conditions.

Low Leakage Inductance for Signal Integrity

SM13072APEL specifies a maximum 0.5 µH leakage inductance for both transmit and receive channels. Low leakage inductance helps maintain the intended high-frequency coupling characteristics of the transformer.

The specified winding capacitance is also limited to 35 pF maximum, which is relevant when evaluating high-frequency signal behavior and transformer compatibility.

SM13072APEL LAN Magnetics Datasheet

Electrical Schematic & Pin Configuration

The SM13072APEL integrates two symmetrical 1:1 channels (Transmit TX and Receive RX). The common mode chokes (CMC) are positioned on the cable side (Pins 14/16 and 9/11) to attenuate common-mode electromagnetic noise before it enters the PCB ground system.

TRANSMIT CHANNEL (TX)                                  RECEIVE CHANNEL (RX)
 PHY Side                  Cable Side               PHY Side                  Cable Side
 Pin 1 (TD+) ───┐      ┌─── Pin 16 (TX+)           Pin 6 (RD+) ───┐      ┌─── Pin 11 (RX+)
                )      (                                          )      (
 Pin 2 (CT)  ───┤ 1:1  ├─── Pin 15 (CT)            Pin 7 (CT)  ───┤ 1:1  ├─── Pin 10 (CT)
                )      (    [Common Mode                          )      (    [Common Mode
 Pin 3 (TD-) ───┘      └───  Choke]                Pin 8 (RD-) ───┘      └───  Choke]
                           Pin 14 (TX-)                                       Pin 9 (RX-)

 *Note: Pins 4, 5, 12, and 13 are No Connect (NC).

Pin Assignment Table

Why Discrete Magnetics Outperform Integrated Magjacks in Automotive Applications?

While integrated RJ45 Magjacks are popular in consumer office equipment, SM13072APEL discrete magnetics are the preferred architecture for automotive and harsh industrial platforms due to three key factors:

Extreme Thermal Capability (-40 °C to +125 °C):
Commercial Magjacks contain internal plastic housings, LED inserts, and unpotted bobbins rated only to +70 °C or +85 °C. The SM13072APEL uses specialized automotive-grade potting epoxy and high-Curie-temperature ferrite cores, ensuring stable inductance even in high-heat engine bays.

High-Density Automated Winding:
Automated winding increases the wire pair twists per unit length. This precise winding control guarantees turns ratio accuracy (±2%) and drives leakage inductance down to an industry-leading ≤0.5 μH ensuring sharp pulse edge transitions and minimal jitter.

Flexible Layout for ESD & Surge Suppression:
Discrete transformers permit engineers to place high-energy ESD protection diodes (such as low-capacitance TVS arrays) directly between the external RJ45 connector and the transformer, isolating clamping currents away from the PHY.

Mechanical Dimensions, Solder Footprint & Process Information

Package Dimensions (16-Pin SOIC)

• Body Length: 12.80 ± 0.25 mm (0.504 ± 0.010 in)
• Body Width: 6.90 ± 0.25 mm (0.272 ± 0.010 in)
• Overall Width (Lead-to-Lead): 9.50 ± 0.25 mm (0.374 ± 0.010 in)
• Package Height: 5.65 ± 0.25 mm (0.222 ± 0.010 in)
• Lead Pitch: 1.27 ± 0.05 mm (0.050 ± 0.002 in)
• Lead Width: 0.46 ± 0.05 mm (0.018 ± 0.002 in)
• Row-to-Row Center Span: 8.89 ± 0.25 mm (0.350 ± 0.010 in)

Recommended PCB Landing Pattern

• Pad Width: 0.76 mm (0.030 in)
• Pad Pitch: 1.27 mm (0.050 in)
• Pad Row Span: 7.10 mm (0.280 in) inner span to 10.50 mm (0.413 in) outer span
• Recommended Pad Length: 1.70 mm

PCB Footprint Design Note

The recommended PCB landing pattern should be followed when designing or reviewing the SM13072APEL footprint. In particular, engineers should verify the 1.27 mm lead pitch, 8.89 mm row-to-row center span, and the recommended 0.76 mm pad width before PCB release. The manufacturer's recommended layout specifies 7.10 mm and 10.50 mm pad-row dimensions for the inner and outer spans, respectively.

Tape & Reel Specifications

• Carrier Tape Width: 24.00 ± 0.30 mm (0.945 ± 0.012 in)
• Pocket Cavity Pitch: 16.00 mm (0.630 in)
• Reel Diameter: 330.0 ± 2.0 mm (13.0 in)
• Total Reel Thickness: 30.5 mm (1.201 in) Max.
• Standard Package Quantity (SPQ): 600 pcs/reel