W55RP20-S2E - Serial-to-Ethernet MCU, 2MB Flash | WIZnet
MPN: W55RP20-S2E ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $4.21 | $4.21 |
| 10 | $3.88 | $38.80 |
| 100 | $3.58 | $358.00 |
| 500 | $3.31 | $1,655.00 |
| 1,000 | $3.05 | $3,050.00 |
W55RP20-S2E Overview
An application-specific communications microcontroller, or ioMCU, is a device that combines a general-purpose MCU core with dedicated network hardware. In the W55RP20-S2E, the integration hierarchy runs: serial-to-Ethernet chip -> communications controller MCU -> Ethernet IC -> power/networking semiconductor. Unlike software TCP/IP stacks that consume MCU cycles, the integrated W5500-style hardwired TCP/IP core offloads protocol processing in silicon.
Key features include the SiP integration of Raspberry Pi's RP2040 microcontroller and WIZnet's W5500 Ethernet controller, 264kB on-chip SRAM organized in six independent banks, a 12-channel DMA controller supporting memory-to-peripheral, peripheral-to-memory, and memory-to-memory transfers, and a USB 2.0 full-speed (12 Mbps) controller usable as host or device. The serial-to-Ethernet firmware supports serial speeds up to 921,600 bps, letting any UART-equipped device gain Ethernet connectivity without protocol development.
The dual Cortex-M0+ architecture lets one core handle application logic while the other manages network I/O, and the hardwired TCP/IP stack supports 8 independent sockets with minimal latency. Because the TCP/IP, MAC, and PHY functions are hardened in silicon, software stack bugs and CPU load from protocol handling are essentially eliminated.
Typical applications include adding Ethernet to legacy industrial equipment with UART ports, IoT smart-device connectivity, and networked sensor or control nodes. The pre-programmed firmware approach removes firmware certification and development risk for serial-to-Ethernet designs.
Design consideration: since this is a pre-programmed part, use the bare W55RP20 if custom firmware is required; the S2E variant is optimized for UART-to-Ethernet bridging with minimal development effort.
This page synthesizes distributor pricing, drop-in alternatives, and practical design notes not found in the manufacturer datasheet.
Drop-in alternatives for W55RP20-S2E — same package, pin-to-pin compatible. Different-package parts requiring PCB rework are excluded.
Variants in this series
Same-series models that are drop-in compatible with W55RP20-S2E (same form factor and footprint) — differing in Product Type, SRAM.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
W55RP20
✅ Drop-In✓ In Stock
$2.45 / Unit
View Datasheet →W55RP20-2S2E
✅ Drop-In📋 Reference alternative (not in catalog)
W55RP20-S2E Maximum Ratings & Electrical Characteristics
| Core Processor | ARM Cortex-M0+ (dual core) |
| Core Clock Frequency | 133 MHz |
| Flash Memory | 2 MB on-chip |
| SRAM | 264 kB (six independent banks) |
| DMA Channels | 12 independent channels |
| Ethernet | 10/100 Mbps hardwired TCP/IP (W5500 core) |
| Serial Interface Speed | Up to 921,600 bps (UART) |
| USB Controller | USB 2.0 full speed (12 Mbps), host/device |
| Product Type | Pre-programmed Serial-to-Ethernet (S2E) chip |
| MAC Address | Unique MAC from WIZnet OUI block (pre-programmed) |
| Package | 68-VFQFN Exposed Pad |
| Mounting Type | Surface Mount |
| Integration | RP2040 MCU + W5500 Ethernet controller + 2MB Flash SiP |
| Firmware | WIZnet Serial-to-Ethernet (S2E) firmware pre-loaded |
W55RP20-S2E 68-vfqfn exposed pad Pin Configuration Guide
Pin configuration for W55RP20-S2E (68-vfqfn exposed pad package). This digital IC includes GPIO, communication interfaces (UART, SPI, I2C), and power pins. Refer to the manufacturer datasheet for alternate pin functions and configuration options. Essential for embedded system design and PCB layout.
No detailed pinout data available for W55RP20-S2E.
Refer to the datasheet for full pin configuration.
Typical Applications
W55RP20-S2E is suitable for 6 applications: Legacy Industrial Equipment Ethernet Retrofit, IoT Smart Device Connectivity, Serial Device Servers and Gateways, Networked Sensor and Control Nodes, Embedded Systems with USB and Ethernet, PoE-Ready Access and Building Automation Devices.
Legacy Industrial Equipment Ethernet Retrofit
The W55RP20-S2E fits equipment retrofits where legacy machines expose only a UART debug or control port. Its S2E firmware bridges serial data to TCP/IP at up to 921,600 bps, far exceeding typical legacy 115,200 bps links, while the hardwired TCP/IP core keeps protocol latency independent of firmware complexity. Engineers mount the 68-VFQFN on the existing controller board, wire the UART crosswise, and configure IP settings over the network - no host software changes. Because TCP, IP, MAC, and PHY are hardened in silicon, retrofit certification is simplified versus software-stack solutions.
Recommended
IoT Smart Device Connectivity
Smart devices need reliable wired networking without burdening the main MCU. The W55RP20-S2E's dual Cortex-M0+ cores at 133 MHz let one core run application logic while the other services the network, and the 2MB Flash accommodates feature-rich application code alongside S2E firmware data. The 264kB SRAM in six independent banks supports buffering for bursty sensor traffic, and the 12-channel DMA moves data without CPU intervention. The hardwired 10/100 Mbps TCP/IP engine delivers deterministic response times that Wi-Fi-based IoT devices cannot match, at the lowest possible power for the network function.
Recommended
Serial Device Servers and Gateways
Serial device servers concentrate multiple RS-232/RS-485 endpoints onto Ethernet. The W55RP20-S2E's hardwired TCP/IP controller supports 8 independent sockets, enabling multi-session serial tunneling on one chip, and the W55RP20-2S2E variant natively bridges two UARTs. UART throughput to 921,600 bps covers high-speed fieldbus links. The USB 2.0 full-speed controller adds a local service port for configuration. Compared with software-stack MCUs, the silicon TCP/IP engine eliminates stack-update maintenance and reduces jitter, important for Modbus RTU-to-TCP gateway timing budgets.
Recommended
Networked Sensor and Control Nodes
Distributed sensing and control nodes benefit from the W55RP20-S2E's integration level: MCU, Ethernet MAC/PHY, TCP/IP engine, USB, and 2MB Flash in one 68-VFQFN reduce board area and BOM lines versus an MCU-plus-W550m module stack. RP2040 peripherals (including programmable I/O) capture sensor streams, DMA channels push data to the Ethernet controller, and the 133 MHz dual core runs local control loops with millisecond determinism. The unique pre-provisioned MAC address simplifies fleet deployment since every node is network-unique out of the box.
Recommended
Embedded Systems with USB and Ethernet
Designs requiring both USB and wired Ethernet - test fixtures, data loggers, networked instruments - normally need two ICs plus a bridge. The W55RP20-S2E integrates a USB 2.0 full-speed (12 Mbps) controller that operates as host (supporting low-speed 1.5 Mbps and full-speed devices) or device, alongside the 10/100 Mbps Ethernet engine, on a single die. The dual Cortex-M0+ cores partition USB and network tasks cleanly, and 2MB Flash stores logging payloads or web-server assets. This consolidation shortens layout, shrinks the power tree, and cuts qualification effort for dual-interface products.
Recommended
PoE-Ready Access and Building Automation Devices
Building automation endpoints - access controllers, lighting gateways, HVAC interfaces - demand always-on wired links. The W55RP20-S2E's 10/100 Mbps Ethernet with hardwired TCP/IP guarantees continuous connectivity without watchdog-driven stack resets, and the 133 MHz dual Cortex-M0+ handles door, lighting, and schedule logic concurrently. WIZnet's documented customization path on the W55RP20-2S2E platform allows initial settings, MAC addressing, and added protocols to be factory-programmed, letting building-automation vendors ship application-specific silicon without maintaining their own firmware line.
Recommended
Recommended Products Summary
Engineering reference data for W55RP20-S2E — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | W55RP20 | W55RP20-2S2E |
|---|---|---|---|
| Package | 68-VFQFN Exposed Pad | 68-VFQFN Exposed Pad - same | 68-VFQFN Exposed Pad - same |
| Brand | WIZnet | WIZnet | WIZnet |
| Core | Dual ARM Cortex-M0+ @ 133 MHz | Dual ARM Cortex-M0+ @ 133 MHz | Dual ARM Cortex-M0+ @ 133 MHz |
| Flash Memory | 2 MB | 2 MB | 2 MB |
| SRAM | 264 kB (6 banks) | 264 kB (6 banks) | 264 kB (6 banks) |
| Ethernet | 10/100 Mbps hardwired TCP/IP | 10/100 Mbps hardwired TCP/IP | 10/100 Mbps hardwired TCP/IP |
| Pre-programmed Firmware | S2E serial-to-Ethernet firmware + unique MAC | None (user-programmed) | 2-port S2E firmware, customizable |
| Serial Ports Supported | 1 (up to 921,600 bps) | User-defined | 2 |
| DMA Channels | 12 | 12 | 12 |
| USB | USB 2.0 full speed (12 Mbps) host/device | USB 2.0 full speed (12 Mbps) host/device | USB 2.0 full speed (12 Mbps) host/device |
Key Differentiators
- Zero-firmware-development serial-to-Ethernet deployment (vs W55RP20)
- Dual-serial-port capability on identical silicon (vs W55RP20-2S2E)
- SiP consolidation versus MCU + W5500 two-chip designs (vs W5500)
Design Notes
The W55RP20-S2E ships with fixed S2E firmware and a provisioned MAC address - it cannot be re-flashed for custom applications like a bare W55RP20. If there is any chance the product roadmap requires custom protocol behavior, two UART-to-Ethernet ports, or a different firmware stack, design in the bare W55RP20 and load the open-source S2E firmware from the WIZnet-ioNIC/W55RP20-S2E GitHub repository instead. Verify the required serial port count before committing to S2E vs 2S2E.
The 68-VFQFN exposed pad is the primary thermal and ground path. Connect the exposed pad to a solid ground plane with an array of vias (typically 4x4 or more) directly under the package. Route the Ethernet MDI pairs (TX+/TX-, RX+/RX-) as 100-ohm differential pairs with length matching, and place the magnetics/RJ45 within 25 mm of the chip. Decouple each supply pin with 100 nF ceramics placed within 2 mm of the pin, plus bulk 10 uF per rail.
UART lines from the host device can be long in retrofit applications. Keep the serial traces under 15 cm at 921,600 bps; for longer runs, add series resistors (22-100 ohm) and consider level shifting if the host is a 5V system, since RP2040-based silicon is not 5V tolerant. Confirm the host UART logic levels against the W55RP20 datasheet supply voltage before wiring. Ground the cable shield at one point to avoid ground loops between the legacy device and Ethernet equipment.
Estimated: the SiP combines an RP2040 at 133 MHz plus a W5500 Ethernet PHY; worst-case combined consumption is on the order of a few hundred milliamps at the core supply, so size the local regulator and decoupling with margin and verify against the W55RP20 datasheet power tables for your clock configuration. Power the PHY rail cleanly and separately from noisy digital loads on the board; PHY supply ripple appears directly as Ethernet jitter.
Compliance Information
Compliance status not stated in the provided web data; consult the WIZnet product page or datasheet for RoHS/REACH declarations.
