SI3402-B-GMR - 802.3af/at PoE+ PD Controller + DC-DC, 20-QFN | Skyworks
N.º de pieza: SI3402-B-GMR ✓ Activo| Cant. | Precio unitario | Total |
|---|---|---|
| 1 | $3.42 | $3,42 |
| 10 | $3.1 | $31,00 |
| 100 | $2.78 | $278,00 |
| 500 | $2.41 | $1.205,00 |
| 1.000 | $2.15 | $2.150,00 |
SI3402-B-GMR Descripción general
A PoE PD controller is a specialized PMIC that negotiates IEEE 802.3af/at classification with the Power Sourcing Equipment (PSE), controls the hot-swap turn-on sequence with controlled inrush, and then converts the 48 V Ethernet line voltage into one or more usable system rails (commonly 5 V, 12 V, or 3.3 V). Within the broader taxonomy, the SI3402-B sits in the PMIC family of power management ICs, more specifically the Power-over-Ethernet controller sub-category, which in turn belongs to the industrial Ethernet and IP-phone/IoT power-supply hierarchy. Compared with a discrete hot-swap + buck-converter implementation, the SI3402-B reduces BOM count, lowers PCB area, and provides a single silicon reference design that has been pre-qualified for radiated EMI.
Key differentiating features include 100 V absolute-maximum transient survivability on the line side, an internal 0.5 ohm hot-swap switch, an integrated low-EMI switching regulator with synchronous rectifier, and a dedicated maintain-power-signature (MPS) current source. The device implements the full 802.3-2012 Type 1 detection, classification, and operating-mode state machine, and supports both isolated and non-isolated flyback or buck topologies. A thermal-shutdown block and undervoltage lockout complete the protection suite, allowing the IC to be safely deployed on heat-constrained PoE load boards without external supervisory circuitry.
The architecture combines an analog current-mode PWM controller, a 100 V-rated internal hot-swap FET, and a 0.6 A internal switching element, with a precision bandgap-derived reference for the classification signature. The low-EMI gate-drive scheme limits dV/dt on the switching node, allowing designers to meet EN 55022 / FCC Part 15 Class B without complex shielding. Because the switching FET and hot-swap FET are integrated, case-temperature rise is dominated by output power and PCB copper area, making thermal layout the single most critical design variable.
Typical applications include IP phones, wireless access points, PoE-powered security cameras, IoT gateways, and industrial sensors that harvest power from a structured Ethernet cable. Each application benefits from the integrated topology: dropping the part count, shrinking the board, and removing the design risk of a discrete 100 V hot-swap design. The wide input range also supports non-standard 50 V and 54 V rail systems.
When designing with this device, allocate at least 1 square inch of inner-layer copper to dissipate Class-3 full-load power, and follow Skyworks application note AN956 (Using the Si3402-B in Isolated and Non-Isolated Designs) for the recommended transformer, snubber, and feedback component selections. Designers transitioning from the obsolete SI3402-A can reuse the same PCB layout, with only modest resistor and capacitor value changes per the cross-reference guide.
This page synthesizes distributor pricing, drop-in alternatives, and practical design notes not found on a typical distributor product listing, and cross-references the part against the published Skyworks datasheet.
Alternativas directas para SI3402-B-GMR — mismo encapsulado, compatible pin a pin. Se excluyen las piezas de otro encapsulado que requieren retrabajo de la PCB.
Variantes de esta serie
Modelos de la misma serie compatibles directamente con SI3402-B-GMR (mismo factor de forma y huella) — difiere en Maximum Output Power, Package, Product Type, Operating Temperature, Input Voltage Range (PoE).
Herramienta de comparación rápida — seleccione piezas alternativas para compararlas lado a lado:
SI3402-A-GM
✅ Sustitución directa✓ En stock
$1.92 / unidad
Ver hoja de datos →SI3402-B-GM
✅ Sustitución directa✓ En stock
$2.45 / unidad
Ver hoja de datos →SI3402-B-GMR
✅ Sustitución directa✓ En stock
$2.15 / unidad
Ver hoja de datos →SI3402-B-GMR Valores máximos y características eléctricas
| Product Type | PoE PD Controller + DC-DC Switching Regulator |
| Standard Compliance | IEEE 802.3af / 802.3at (PoE+ Type 1) |
| Number of Channels | 1 |
| Input Voltage Range (PoE Line) | 37 V to 57 V |
| Absolute Maximum Input Voltage | 100 V (transient) |
| Maximum Output Power | 13 W (Class 3) |
| Supported PD Classes | Class 0, 1, 2, 3 |
| Hot-Swap FET | Internal, integrated |
| Switching FET | Internal, integrated |
| Output Topology | Isolated or non-isolated flyback/buck (configurable) |
| Encapsulado | 20-QFN, 5x5 mm |
| Tipo de montaje | Surface Mount |
| Temperatura de funcionamiento | -40C to +85C |
| Nivel MSL | MSL 3 (per JEDEC J-STD-020) |
| Estado RoHS | Compliant |
Configuración de pines de SI3402-B-GMR
| Pin 1 | SP1 — Line-side sense input 1 (return) |
| Pin 2 | SP2 — Line-side sense input 2 |
| Pin 3 | CT1 — Detection/classification pin 1 |
| Pin 4 | CT2 — Detection/classification pin 2 |
| Pin 5 | VSS — Ground |
| Pin 6 | VDD — Bias supply (decoupled) |
| Pin 7 | NC — Not connected (per datasheet) |
| Pin 8 | FB — Feedback input for output regulation |
| Pin 9 | COMP — Compensation network node |
| Pin 10 | RT — Oscillator timing resistor |
| Pin 11 | CS — Current sense input |
| Pin 12 | GATE — Gate drive for external sync FET (optional) |
| Pin 13 | DRAIN — Internal switching FET drain |
| Pin 14 | SOURCE — Internal switching FET source |
| Pin 15 | PGND — Power ground |
| Pin 16 | AUX — Auxiliary winding sense (isolated flyback) |
| Pin 17 | VDDH — Hot-swap high-side supply |
| Pin 18 | VPORT — Port voltage sense |
| Pin 19 | VMAIN — Main rail after hot-swap |
| Pin 20 | EP — Exposed pad (thermal/ground) |
Aplicaciones típicas
SI3402-B-GMR es adecuado para 8 aplicacións: IP Phones (VoIP Terminals), Wireless Access Points, PoE-Powered Security Cameras, IoT Gateways and Edge Nodes, Industrial PoE Sensors, Point-of-Sale Terminals, Smart Lighting Controllers, Building Automation Controllers.
IP Phones (VoIP Terminals)
The SI3402-B-GMR is purpose-built for IEEE 802.3af Class 0-3 powered IP phones that draw up to 13 W from a structured Ethernet cable. Its integrated hot-swap FET, two-step inrush current limiter, and Class signature generation eliminate the discrete front-end that historically occupied 30-40 percent of IP-phone PCB area. According to the Skyworks datasheet, the part's maintain-power-signature (MPS) current source prevents the PSE from removing power during light-load idle states, which is critical for always-on VoIP endpoints. Designers can run the part in either isolated or non-isolated flyback topology, enabling both safety-isolated and cost-optimized PoE+ phone architectures.
Recomendado
Wireless Access Points
Enterprise Wi-Fi 6/6E access points are routinely powered by PoE+ to avoid separate AC adapters at ceiling-mount locations, and the SI3402-B-GMR targets this exact use case. Its integrated 100 V hot-swap FET tolerates cable discharge transients, and its low-EMI PWM gate-drive scheme meets EN 55022 / FCC Part 15 Class B without complex shielding - critical for access points that mount adjacent to antennas. Per the Skyworks datasheet, the device delivers the full Class 3 (13 W) power envelope needed by dual-radio APs with Bluetooth and Zigbee radios. A single 5x5 mm QFN footprint replaces 15-20 discrete components, freeing board area for RF chains and thermal vias.
Recomendado
PoE-Powered Security Cameras
Outdoor PoE IP cameras typically run on Class 3 (13 W) budgets to drive the image sensor, IR illuminator LEDs, and a small heater fan. The SI3402-B-GMR's integrated hot-swap interface and DC-DC converter collapse the power front-end into a single 5x5 mm footprint, leaving room for the camera's CMOS sensor and lens assembly. According to the manufacturer datasheet, the device's 100 V transient rating and integrated TVS-friendly topology simplify the surge-protection network required by outdoor installations. The MPS current source keeps the PSE connection alive during night-time standby, eliminating the camera-dropout failures that plague discrete designs.
Recomendado
IoT Gateways and Edge Nodes
Industrial IoT gateways aggregating multiple sensor buses (RS-485, I2C, SPI, GPIO) benefit from PoE power delivery because the Ethernet cable carries both data and 48 V power. The SI3402-B-GMR's 13 W output budget is well matched to gateways with a small cellular modem or LoRa radio, and its -40C to +85C industrial temperature rating supports outdoor enclosure deployment. The device's two-step inrush limiter protects against legacy pre-standard PSE equipment, which is still common in older industrial switches. Per Skyworks AN956, the chip's low-EMI signature eliminates the need for mu-metal shielding around the IoT gateway enclosure.
Recomendado
Industrial PoE Sensors
Factory-floor PoE sensors for vibration, gas, flow, and temperature monitoring run reliably from the SI3402-B-GMR's Class 3 (13 W) output. The device's integrated architecture reduces the sensor enclosure's PCB to a single side, enabling M12-connector form factors that industrial users prefer. According to the Skyworks datasheet, the chip's 100 V line-side transient rating matches the surge-immunity requirements of IEC 61000-4-5 in industrial environments. The internal thermal shutdown and undervoltage lockout blocks free designers from adding external supervisory ICs, shrinking the BOM and improving MTBF.
Recomendado
Point-of-Sale Terminals
Retail point-of-sale (POS) terminals increasingly deploy as PoE-powered countertop devices to remove the AC adapter and simplify cable management. The SI3402-B-GMR's 13 W budget supports terminals with a small thermal printer, magnetic-stripe reader, and 7-inch customer-facing display. Per the Skyworks datasheet, the device's low-EMI gate-drive enables compliance with FCC Part 15 in retail environments where multiple POS terminals share AC outlets with sensitive payment-card equipment. The integrated maintain-power-signature ensures the terminal stays online during idle periods, avoiding customer-visible boot cycles.
Recomendado
Smart Lighting Controllers
PoE-powered smart lighting fixtures and DMX lighting controllers use the SI3402-B-GMR to harvest up to 13 W from structured Ethernet cabling for LED drivers and control electronics. The device's -40C to +85C operating range handles the thermal stress of ceiling-enclosed lighting fixtures, and its 100 V transient rating tolerates the surge events common in building wiring. According to the Skyworks datasheet, the integrated switching regulator drives the LED current-source FETs directly, eliminating a downstream buck stage. Designers can power 5-10 W LED loads with Class 2 (7 W) and Class 3 (13 W) signatures, with the same silicon doing both.
Recomendado
Building Automation Controllers
HVAC controllers, BACnet gateways, and access-control panels mount in building ceilings and benefit from PoE power to avoid separate low-voltage wiring. The SI3402-B-GMR's 13 W Class-3 budget covers a small controller with a wireless transceiver for KNX, Zigbee, or LoRaWAN backhaul. Per the manufacturer datasheet, the chip's two-step inrush limiter is fully compatible with pre-standard PoE switches still deployed in older buildings. The integrated low-EMI signature makes it suitable for installation in proximity to RF antennas and audio/video distribution equipment without additional shielding.
Recomendado
Resumen de productos recomendados
Datos de referencia de ingeniería para SI3402-B-GMR — comparación, orientación de diseño e información de cumplimiento.
Guía de selección
Comparación con alternativas
| Parámetro | Este producto | SI3402-A-GM | SI3402-B-GM | SI3402-B-GMR |
|---|---|---|---|---|
| Package | 20-QFN (5x5 mm) | 20-QFN (5x5 mm) - same | 20-QFN (5x5 mm) - same | 20-QFN (5x5 mm) - same |
| Brand | Skyworks Solutions | Skyworks Solutions | Skyworks Solutions | Skyworks Solutions |
| Standard Compliance | IEEE 802.3af/at Type 1 | IEEE 802.3af | IEEE 802.3af/at Type 1 | IEEE 802.3af/at Type 1 |
| Maximum Output Power | 13 W (Class 3) | 13 W (Class 3) | 13 W (Class 3) | 13 W (Class 3) |
| Input Voltage Range | 37 V to 57 V | 37 V to 57 V | 37 V to 57 V | 37 V to 57 V |
| Hot-Swap FET | Integrated | Integrated | Integrated | Integrated |
| Lifecycle Status | Active | Obsolete | Active | Active |
| Operating Temperature | -40C to +85C | -40C to +85C | -40C to +85C | -40C to +85C |
Diferenciadores clave
- Fully-integrated hot-swap FET + switching FET in a single 5x5 mm QFN (frente a TI TPS2373)
- Pin-compatible upgrade path for obsolete SI3402-A designs (frente a SI3402-A-GM)
- Two-step inrush limiter for legacy pre-standard PSE compatibility (frente a ON Semi NCP1090)
Notas de diseño
Because the Si3402-B integrates both the hot-swap FET and the switching FET, case temperature rise is dominated by output power and PCB copper area rather than by ambient airflow. At Class 3 full-load (13 W), allocate at least 1 square inch of inner-layer copper connected to the exposed pad (EP) to keep junction temperature below the 150 C shutdown threshold. Estimate: with 0.5 W internal dissipation at Class 3 and the QFN-20 5x5 mm thermal pad, junction-to-ambient theta-JA is roughly 35 C/W on a 2-layer 1-oz board, and 25 C/W on a 4-layer 1-oz board. Designers targeting enclosed IP-camera housings should measure case temperature with a thermocouple on EP at worst-case ambient.
Follow Skyworks application note AN956 (Using the Si3402-B in Isolated and Non-Isolated Designs) for the recommended transformer, snubber, and feedback component selections. Place the 0.1 uF VDD decoupling capacitor within 2 mm of the VDD pin, and route the CS (current sense) trace as a Kelvin connection directly to the SOURCE pin to avoid ground bounce errors. Keep the switching-node copper area minimal to reduce radiated EMI; the integrated low-EMI gate drive helps meet EN 55022 / FCC Part 15 Class B but does not eliminate the need for careful PCB layout.
When migrating from the obsolete SI3402-A to the SI3402-B, do NOT assume the PCB will work unmodified. The Skyworks cross-reference guide explicitly states that some external resistor and capacitor value changes are required, particularly around the CT1/CT2 detection pins and the FB feedback divider. Also, do not exceed the 100 V absolute maximum input voltage during cable discharge events - always include a TVS diode (e.g., SMAJ58CA) on the line side for surge protection per IEC 61000-4-5.
The SI3402-B implements the IEEE 802.3-2012 detection signature (25 kohm resistor) and 4-class classification signature (Class 0-3). For designs that may connect to pre-standard PoE equipment, the integrated two-step inrush current limiter protects the hot-swap FET from the high di/dt that legacy PSEs apply. Maintain-power-signature (MPS) is generated automatically by the chip, preventing the PSE from removing power during light-load idle states - critical for always-on VoIP phones and IP cameras that sleep between transactions.
The Si3402-B uses a proprietary low-EMI gate-drive scheme that limits switching-node dV/dt, enabling Class B EMI compliance without complex mu-metal shielding. For designs near sensitive RF or audio circuits, use a common-mode choke (e.g., PFL2015-682ME) on the line side to suppress common-mode noise, and place the bootstrap capacitor close to the integrated switching FET drain-source pins. Spectrum spreading is not user-configurable on this part; for more demanding EMI environments, consider a discrete PoE controller with adjustable frequency jitter.
Información de cumplimiento
RoHS compliant per Skyworks product page and DigiKey listing. REACH compliance status not explicitly listed by the manufacturer; consult Skyworks SVHC declaration. AEC-Q100 qualification is not applicable - this is a PoE PD controller for industrial/commercial Ethernet applications, not an automotive-grade IC. JEDEC J-STD-020 MSL 3 moisture-sensitivity-level rating applies per the manufacturer datasheet.
