W5500 vs W5100: Ethernet Module Comparison

Selecting the right Ethernet controller chip for embedded projects can significantly impact both development speed and final product performance. The WIZnet W5500 vs W5100 comparison represents a decision point facing many engineers working with Arduino and other microcontroller platforms. Both chips provide hardware-implemented TCP/IP stacks, eliminating the need for software networking layers that consume valuable MCU resources. However, the architectural improvements in the W5500 deliver substantial performance gains over its predecessor, the W5100.

As someone who has designed PCBs incorporating both chips and debugged countless network connectivity issues, I’ve learned that understanding the technical differences between W5500 vs W5100 extends beyond specification sheets. This comparison examines real-world performance characteristics, implementation challenges, cost considerations, and compatibility factors that influence the choice between these two popular Ethernet controllers.

Technical Specifications: W5500 vs W5100

The core differences between W5500 vs W5100 become immediately apparent when examining their fundamental specifications. WIZnet introduced significant improvements in the W5500 that address the limitations experienced with W5100 in demanding applications.

Core Performance Comparison

Specification	W5100	W5500	Advantage
Manufacturing Process	0.18µm	0.13µm	W5500 (smaller die, lower cost)
Core Voltage	3.3V	1.2V internal (3.3V I/O)	W5500 (lower power)
Internal Buffer	16KB	32KB	W5500 (2x capacity)
Number of Sockets	4	8	W5500 (2x concurrent connections)
SPI Speed (Max)	14 MHz	80 MHz	W5500 (5.7x faster)
Operating Current (Active)	132mA	132mA	Equal
Standby Current	40mA	40mA	Equal
Power Down Mode	900µA	<1µA	W5500 (better sleep mode)
Package Options	80-LQFP	48-LQFP, 48-QFN	W5500 (easier soldering)

The manufacturing process improvement from 0.18µm to 0.13µm enabled WIZnet to double the internal buffer and socket count while reducing die size. This translates directly to lower production costs, which explains why W5500 modules now cost less than W5100 despite superior performance.

Buffer Architecture and Memory Organization

The internal buffer architecture represents one of the most significant W5500 vs W5100 differences. The W5100 provides 16KB total buffer memory organized as 8KB TX and 8KB RX, distributed across four sockets. Each socket receives 2KB TX and 2KB RX by default, though this can be reconfigured.

The W5500 doubles this capacity to 32KB total (16KB TX, 16KB RX) distributed across eight sockets. Default allocation provides each socket with 2KB TX and 2KB RX, but the W5500 allows flexible reallocation. For high-throughput applications, developers can allocate 8KB to a single socket while reducing buffer sizes for less critical connections.

Buffer Configuration Flexibility:

W5100: Fixed 4 sockets × 4KB = 16KB total

W5500: Configurable 8 sockets with dynamic allocation up to 32KB

This flexibility proves critical in applications like web servers handling multiple simultaneous client connections or data logging systems maintaining persistent connections to cloud services.

SPI Communication Performance

The SPI interface represents the bottleneck in any MCU-to-Ethernet controller communication. The W5500 vs W5100 comparison reveals dramatic improvements in this critical interface.

SPI Protocol Enhancements

The W5100 supports SPI speeds up to 14MHz, which limits maximum theoretical throughput to approximately 1.75MB/s (assuming perfect conditions with no protocol overhead). In practice, achievable throughput rarely exceeds 8-10 Mbps due to:

• SPI frame overhead (address, control bytes)
• MCU interrupt latency
• Buffer management delays
• Protocol processing time

The W5500 increases maximum SPI clock to 80MHz – a 5.7x improvement. More importantly, WIZnet simplified the SPI frame format, reducing protocol overhead. The W5500 achieves practical throughput exceeding 13 Mbps when paired with capable MCUs running at 42MHz SPI clock.

SPI Frame Format Comparison

Aspect	W5100	W5500
Frame Components	OP Code + Address + Data	Address + Control + Data
Variable Length Support	Limited	Full support
Burst Transfer	Restricted	Optimized
Overhead per Transaction	Higher	Lower

The W5500’s improved SPI protocol allows variable-length data transfers without frame length specification, reducing overhead and simplifying implementation. This enhancement becomes particularly noticeable in applications transmitting many small packets, such as MQTT brokers or RESTful API clients.

Socket Management and Concurrent Connections

The expansion from 4 to 8 independent hardware sockets in the W5500 vs W5100 comparison addresses a fundamental limitation in multi-client server applications.

Real-World Socket Usage Scenarios

W5100 Limitations (4 Sockets):

Consider a web server application:

• Socket 0: HTTP server listening
• Socket 1: Active client connection serving webpage
• Socket 2: Active client connection serving image
• Socket 3: DNS query for external API call

At this point, all sockets are allocated. A fifth client attempting to connect receives no response until a socket becomes available. This limitation severely restricts W5100 capability in applications requiring:

• Multiple simultaneous web clients
• Persistent cloud service connections
• Combined server and client operations
• Multi-protocol support (HTTP + MQTT + DNS)

W5500 Advantages (8 Sockets):

The same web server with W5500:

• Sockets 0-3: HTTP server handling four simultaneous clients
• Socket 4: MQTT connection to cloud service
• Socket 5: NTP time synchronization
• Socket 6: DNS query resolution
• Socket 7: Available for expansion

This flexibility enables more sophisticated network architectures without complex socket management code or connection queuing algorithms.

Socket Configuration Flexibility

Configuration Option	W5100	W5500
Maximum Sockets	4	8
Per-Socket Buffer Reallocation	Limited	Full flexibility
Maximum Single Socket Buffer	8KB TX/RX	16KB TX/RX
Independent Protocol Selection	Yes	Yes

The W5500 allows extreme configurations like allocating all 16KB TX buffer to a single socket for high-speed data streaming, while maintaining minimal buffers on monitoring sockets.

Power Consumption Analysis

Power efficiency has become increasingly critical for IoT and battery-powered applications. The W5500 vs W5100 power consumption comparison reveals mixed results depending on operating mode.

Active Operation Power Draw

Both W5100 and W5500 draw approximately 132mA during active network operation at 3.3V (approximately 435mW). This similarity exists because both integrate the same 10/100 Mbps Ethernet PHY, which dominates power consumption during active transmission and reception.

The W5500’s smaller 0.13µm process and 1.2V core voltage don’t significantly reduce active power because the Ethernet PHY operates at fixed voltages regardless of process node.

Sleep Mode Power Efficiency

The dramatic difference appears in low-power modes:

Power Mode	W5100	W5500	Improvement
Standby (link up)	40mA	40mA	Equal
Power Down	900µA	<1µA	900x better

Battery-powered applications leveraging sleep modes between transmission bursts benefit enormously from the W5500’s <1µA power-down current. For a sensor node transmitting once per minute and sleeping between transmissions:

W5100 Power Budget (1-minute cycle):

• Active 2 seconds: 132mA × 2s = 264mAs
• Sleep 58 seconds: 0.9mA × 58s = 52.2mAs
• Average current: 5.27mA

W5500 Power Budget (1-minute cycle):

• Active 2 seconds: 132mA × 2s = 264mAs
• Sleep 58 seconds: 0.001mA × 58s = 0.058mAs
• Average current: 4.4mA

This 16.5% power reduction extends battery life proportionally – critical for deployed sensors running on coin cells or solar harvesting.

PCB Design and Hardware Implementation

The W5500 vs W5100 comparison from a PCB design perspective reveals important practical differences affecting manufacturing and reliability.

Package Options and Assembly

W5100 Package:

• 80-LQFP (Low-profile Quad Flat Package)
• 12mm × 12mm footprint
• 0.5mm pin pitch
• 80 pins total

W5500 Package Options:

• 48-LQFP: 7mm × 7mm footprint, 0.5mm pitch
• 48-QFN: 7mm × 7mm footprint, 0.5mm pitch

The W5500’s smaller package with fewer pins offers multiple advantages:

1. Reduced PCB area: 40% smaller footprint saves board space
2. Easier hand soldering: 48 pins vs 80 pins
3. Better thermal performance: QFN package option provides superior heat dissipation
4. Lower component count: Fewer required external components

External Component Requirements

Both chips require similar supporting components:

Component	W5100	W5500	Notes
Decoupling Capacitors	Multiple values	Multiple values	Standard practice
Crystal/Oscillator	25MHz	25MHz	Can share with MCU
Ethernet Transformer	Required	Required	Magnetic isolation
RJ45 Connector	Standard	Standard	With integrated magnetics option
Reset Circuit	Optional	Optional	Recommended for reliability

The W5500’s reduced pin count stems from eliminating parallel bus interface pins (present in W5100 but rarely used) and improved internal multiplexing.

Software Compatibility and Development

The W5500 vs W5100 software compatibility question concerns many developers considering migration or new projects.

Arduino Ethernet Library Support

The Arduino Ethernet library has evolved to support both chips transparently:

Library Version Requirements:

• W5100: All versions (legacy support)
• W5500: Requires Ethernet library 2.0.0 or newer

Modern Arduino IDE installations include updated Ethernet libraries that automatically detect chip type at runtime using hardware status queries. The same sketch runs on both W5100 and W5500 shields without modification:

#include <SPI.h>

#include <Ethernet.h>

byte mac[] = { 0xDE, 0xAD, 0xBE, 0xEF, 0xFE, 0xED };

IPAddress ip(192, 168, 1, 177);

EthernetServer server(80);

void setup() {

  Ethernet.begin(mac, ip);

  server.begin();

  // Library automatically detects W5100 or W5500

  Serial.print(“Chip: “);

  if (Ethernet.hardwareStatus() == EthernetW5100) {

    Serial.println(“W5100”);

  } else if (Ethernet.hardwareStatus() == EthernetW5500) {

    Serial.println(“W5500”);

  }

}

Performance Differences in Practice

While the API remains identical, developers report noticeable W5500 vs W5100 behavioral differences:

Stability Improvements: Multiple community reports indicate the W5500 exhibits fewer random disconnections and better recovery from network errors. This likely stems from improved internal state machine logic and the doubled buffer capacity reducing overflow conditions.

Speed Perception: Users consistently report “faster” behavior with W5500, attributable to the higher SPI clock capability and improved protocol efficiency. Page loads from Arduino web servers feel more responsive.

Connection Handling: The W5500’s 8 sockets eliminate scenarios where web browsers opening multiple parallel connections exhaust available sockets, a common W5100 frustration.

Cost Analysis and Availability

The W5500 vs W5100 cost comparison has shifted dramatically since the W5500’s introduction, making it the clear economic choice for new designs.

Chip Pricing (1000+ quantity)

Chip	Price per Unit	Year Introduced
W5100	$4.32	2008
W5500	$2.64	2014

The W5500 costs 39% less than W5100 despite superior specifications. This price advantage stems from:

• Smaller die size (0.13µm vs 0.18µm process)
• Reduced package size (48 vs 80 pins)
• Higher manufacturing volumes
• Market maturation

Module Pricing

Pre-assembled modules available on marketplaces show similar pricing:

Module Type	Typical Price
W5100 Basic Module	$8-12
W5500 Basic Module	$3.50-8
W5100 Arduino Shield	$15-25
W5500 Arduino Shield	$12-20

The W5500’s cost advantage extends beyond the chip to complete modules, making it the economical choice for both prototyping and production.

Migration Considerations

For engineers maintaining existing W5100-based products, the W5500 vs W5100 migration decision involves several factors.

Reasons to Migrate

Upgrade Triggers:

• Need for more simultaneous connections (>4 sockets)
• Performance bottlenecks from 14MHz SPI limitation
• Battery life concerns in sleep mode applications
• Supply chain issues obtaining W5100 chips
• Cost reduction initiatives in production

Migration Challenges

PCB Redesign: Different footprints require PCB layout changes. The smaller W5500 package usually simplifies layout but necessitates design verification.

Firmware Compatibility: Using Arduino Ethernet library ensures code portability. Custom firmware directly accessing registers may require updates to accommodate W5500’s slightly different register map.

Testing Requirements: Complete regression testing ensures W5500 behavior matches W5100 in all operating scenarios, particularly edge cases like rapid connection cycling and error recovery.

Practical Recommendations

Based on extensive experience with both chips, here are specific recommendations for the W5500 vs W5100 decision:

Choose W5500 When:

• Starting new designs (superior specs, lower cost)
• Building web servers handling multiple clients
• Developing battery-powered IoT nodes
• Working with faster MCUs (>50MHz) that benefit from 80MHz SPI
• Requiring more than 4 concurrent network connections
• Cost-sensitive production runs

Consider W5100 When:

• Maintaining legacy designs already validated
• Using existing W5100 Arduino shields
• PCB redesign costs exceed savings
• No supply chain constraints

Realistic Assessment: The W5100 remains a capable chip for simple applications, but no compelling technical or economic reasons exist for specifying W5100 in new designs. The W5500’s advantages in performance, cost, and power consumption make it the clear choice for modern projects.

Useful Resources and Documentation

Official WIZnet Documentation

Resource	Description	Access
W5100 Datasheet	Complete technical specifications	WIZnet.io
W5500 Datasheet	Complete technical specifications	WIZnet.io
Application Notes	Implementation guides and examples	WIZnet Developer Forum
Migration Guide	W5100 to W5500 migration assistance	WIZnet Documentation Portal

Arduino Libraries and Examples

Library	Repository	Purpose
Ethernet Library	Built into Arduino IDE	Primary networking library
WIZnet ioLibrary	GitHub – Wiznet	Low-level driver library
W5500-EVB Examples	WIZnet GitHub	Evaluation board examples

Development Modules

Module	Features	Typical Price
W5500 Ethernet Shield	Arduino-compatible shield	$12-20
WIZ850io	Compact W5500 module	$15-25
W5500-EVB-Pico	RP2040 + W5500 integrated	$12-18

Frequently Asked Questions

1. Can I directly replace a W5100 with W5500 on existing PCBs?

No, direct replacement is not possible due to different package sizes and pin counts. The W5100 uses an 80-LQFP package while W5500 uses 48-LQFP or 48-QFN. Pin functions also differ, requiring PCB redesign. However, at the software level, the Arduino Ethernet library provides transparent compatibility, so existing sketches typically run without modification once hardware is updated.

2. Will my Arduino sketches need modification when switching from W5100 to W5500?

Most Arduino sketches require zero modification when using the standard Ethernet library (version 2.0.0 or newer). The library automatically detects chip type at runtime and adjusts accordingly. Custom code directly accessing hardware registers may require updates, but socket-level programming using standard Client/Server classes remains identical between W5500 vs W5100.

3. Why does the W5500 cost less despite better performance?

The W5500’s lower cost stems from manufacturing process improvements. The 0.13µm fabrication process (vs 0.18µm for W5100) produces smaller dies, reducing silicon cost. The 48-pin package (vs 80-pin) further reduces manufacturing costs. Combined with higher production volumes since introduction, these factors enable WIZnet to price W5500 approximately 39% lower than W5100 while maintaining profit margins.

4. Does the faster 80MHz SPI of W5500 require special consideration?

Most modern Arduino boards (Uno, Mega, Due, ESP32) support 80MHz SPI clock rates without issues. However, practical throughput depends on MCU speed – a 16MHz Arduino Uno won’t benefit from 80MHz SPI capability. The W5500 gracefully operates at any SPI speed from 1MHz to 80MHz, automatically adapting. Even at lower MCU speeds, the improved SPI protocol efficiency provides performance benefits over W5100.

5. Which chip is better for battery-powered IoT applications?

The W5500 dramatically outperforms W5100 for battery applications due to its <1µA power-down current (vs 900µA for W5100). This 900x improvement in sleep mode significantly extends battery life in duty-cycled applications. During active network operation, both chips draw similar current (~132mA), but IoT sensors typically spend the majority of time sleeping between transmissions where W5500’s advantage becomes critical.

Conclusion

The W5500 vs W5100 comparison clearly favors the newer W5500 for virtually all applications. The doubled buffer memory, eight independent sockets, 5.7x faster SPI interface, and 39% lower cost make the W5500 the superior choice for modern embedded networking projects. While the W5100 served admirably as the Arduino community’s introduction to hardware Ethernet controllers, the W5500 represents a significant evolutionary step forward.

For engineers maintaining legacy W5100 designs, migration to W5500 should be evaluated based on specific project constraints – PCB redesign costs, production volumes, and performance requirements. For new projects, the decision is straightforward: specify W5500. The combination of improved performance, lower cost, better power efficiency, and smaller footprint makes W5500 the clear winner in this comparison.

The Arduino Ethernet library’s transparent support for both chips ensures software compatibility, reducing migration risk and enabling developers to focus on application development rather than low-level networking protocols. As the embedded networking landscape continues evolving, the W5500 provides a proven, cost-effective foundation for projects ranging from simple web servers to complex IoT gateways.