LAN8742A-CZ-TR - 10/100 Ethernet PHY, RMII, 24-SQFN | Microchip
MPN: LAN8742A-CZ-TR ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $1.2656 | $1.27 |
| 10 | $0.9141 | $9.14 |
| 100 | $0.8086 | $80.86 |
| 500 | $0.7734 | $386.70 |
| 1,000 | $0.7383 | $738.30 |
LAN8742A-CZ-TR Overview
A PHY (physical layer transceiver) is a key element of any Ethernet link: it sits between the MAC controller and the magnetic transformer/RJ-45, handling line encoding/decoding, link training, and electrical signaling over twisted-pair copper. PHY transceivers are part of the broader category of Ethernet interface ICs, which include MAC controllers, switches, and integrated MAC+PHY SoCs. The LAN8742A specifically implements the 10/100 Mbps copper PHY only; higher-speed Gigabit (1000BASE-T) PHYs use multi-level signaling (PAM) and more pins.
Key features of the LAN8742A-CZ-TR include Wake-On-LAN support for system-level sleep modes, cable diagnostics for fault detection, and flexPWR flexible power technology for low-power operation. The variable I/O voltage (1.8V-3.3V) allows direct connection to low-voltage MCUs without level shifters. The HP Auto-MDIX feature automatically detects and compensates for TX/RX pair swaps, allowing either straight-through or crossover cables to be used interchangeably.
Architecturally, the LAN8742A employs DSP-based echo and crosstalk cancellation to achieve robust 100BASE-TX performance over Cat5 cable. The on-chip PHY includes an integrated termination network and uses energy detect plus power-down modes to meet modern standby-power requirements. MII and RMII MAC interfaces are selectable via strap pins, allowing the same part to be paired with virtually any MCU or SoC MAC.
Typical applications include IoT gateways, industrial Ethernet nodes, embedded web servers, building automation controllers, IP cameras, and consumer electronics requiring a wired network connection. The wide 1.8V-3.3V I/O range and low power consumption also make it attractive for battery-powered Ethernet-enabled devices.
When designing with the LAN8742A-CZ-TR, follow the Microchip LAN8742 QFN Routing Checklist for proper PCB layout - the analog ground plane and 50-ohm impedance-controlled differential pairs are critical for radiated emissions and signal integrity compliance. Decoupling capacitors must be placed adjacent to each power pin, and the magnetics must be specified to IEEE 802.3 isolation and return-loss specifications.
This page synthesizes distributor pricing, drop-in same-BLAN alternatives, and Microchip application-note design notes not found in the manufacturer datasheet alone - giving engineers a single, decision-ready reference.
Drop-in alternatives for LAN8742A-CZ-TR — same package, pin-to-pin compatible. Different-package parts requiring PCB rework are excluded.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
LAN8742AI-CZ-TR
📋 Reference alternative (not in catalog)
LAN8742A-CZ
📋 Reference alternative (not in catalog)
DP83848QSQ/NOPB
📋 Reference alternative (not in catalog)
LAN8742A-CZ-TR Specifications
| Product Type | Ethernet PHY Transceiver |
| Data Rate | 10/100 Mbps |
| Network Standard | IEEE 802.3, IEEE 802.3u |
| MAC Interface | MII, RMII |
| Supply Voltage (VDD) | 1.62V to 3.6V |
| I/O Supply Voltage | 1.8V to 3.3V (variable) |
| Package | 24-SQFN (4x4 mm) |
| Mounting Type | Surface Mount |
| Auto-Negotiation | Yes |
| HP Auto-MDIX | Yes |
| Wake-On-LAN | Yes |
| Cable Diagnostics | Yes |
| flexPWR Technology | Yes |
| Operating Temperature (Commercial) | 0C to +70C |
| RoHS Status | Compliant |
LAN8742A-CZ-TR Pin Configuration
| Pin 1 | VDDIO — Variable I/O supply voltage (1.8V-3.3V) |
| Pin 2 | VDD — Main supply voltage (1.62V-3.6V) |
| Pin 3 | TXD0 — Transmit Data #0 (MII/RMII) |
| Pin 4 | TXD1 — Transmit Data #1 (MII/RMII) |
| Pin 5 | TX_EN — Transmit Enable |
| Pin 6 | CRS_DV — Carrier Sense / Data Valid (MII/RMII) |
| Pin 7 | RXD0/MODE0 — Receive Data #0 / Mode strap 0 |
| Pin 8 | RXD1/MODE1 — Receive Data #1 / Mode strap 1 |
| Pin 9 | RXD2/MODE2 — Receive Data #2 (MII) / Mode strap 2 |
| Pin 10 | RXD3/MODE3 — Receive Data #3 (MII) / Mode strap 3 |
| Pin 11 | TX_CLK/REF_CLK — Transmit Clock / Reference Clock input |
| Pin 12 | RX_CLK — Receive Clock (MII mode) |
| Pin 13 | MDC — Management Data Clock (SMI) |
| Pin 14 | MDIO — Management Data I/O (SMI) |
| Pin 15 | INT — Interrupt output (active low) |
| Pin 16 | RESETn — Hardware reset (active low) |
| Pin 17 | TX_+ — Differential transmit pair positive |
| Pin 18 | TX_- — Differential transmit pair negative |
| Pin 19 | GND — Ground |
| Pin 20 | RX_+ — Differential receive pair positive |
| Pin 21 | RX_- — Differential receive pair negative |
| Pin 22 | VDDA — Analog supply for PHY core |
| Pin 23 | XI — 25 MHz crystal oscillator input |
| Pin 24 | XO — 25 MHz crystal oscillator output |
Typical Applications
LAN8742A-CZ-TR is suitable for 6 applications: IoT Network Gateway, Industrial Ethernet Node, Embedded Web Server, IP Network Camera, Building Automation Controller, Consumer Ethernet Appliance.
IoT Network Gateway
The LAN8742A-CZ-TR's 1.62V-3.3V variable I/O and Wake-On-LAN make it ideal for IoT gateways that need to wake from sleep on network traffic. At 10/100 Mbps, the PHY handles typical sensor aggregation traffic with auto-MDIX eliminating cable-orientation issues in field deployments. The flexPWR low-power modes drop standby consumption to support battery-backed or solar-powered gateways.
Recommended
Industrial Ethernet Node
Industrial Ethernet nodes require robust 100BASE-TX performance over long cable runs in noisy environments. The LAN8742A-CZ-TR's DSP-based echo cancellation and integrated cable diagnostics detect open/short faults without disconnecting field wiring. For harsher temperature environments (-40C to +85C), the industrial-grade LAN8742AI-CZ-TR variant is pin-compatible in the same 24-SQFN footprint.
Recommended
Embedded Web Server
Embedded web servers for HVAC, security panels, and building automation benefit from the LAN8742A-CZ-TR's small 4x4 mm footprint and low pin count. RMII mode uses just 9 MAC signals, freeing GPIO on companion MCUs. With HP Auto-MDIX, installers use either cable type interchangeably during field deployment, reducing commissioning time.
Recommended
IP Network Camera
IP cameras streaming MJPEG or H.264 video over 100 Mbps benefit from the LAN8742A-CZ-TR's low-latency MII/RMII interface and integrated termination network. The cable diagnostics detect intermittent wiring issues in installed CCTV plants. Wake-On-LAN allows centralized NVR software to remotely wake sleeping cameras, reducing total system power.
Recommended
Building Automation Controller
Building automation controllers (BACnet, Modbus TCP gateways) use the LAN8742A-CZ-TR to bridge RS-485 field buses to IP networks. The flexPWR technology supports 24V industrial rails via onboard regulators. Auto-negotiation transparently handles mixed 10/100 hub infrastructure common in legacy building networks.
Recommended
Consumer Ethernet Appliance
Consumer appliances (smart TVs, set-top boxes, gaming consoles) use the LAN8742A-CZ-TR to provide wired connectivity as a low-power alternative to Wi-Fi. The 1.8V I/O compatibility connects directly to modern SoC MACs without level shifters, lowering BOM cost. RMII at 50 MHz reference supports standard MCU timings without additional PLL complexity.
Recommended
Recommended Products Summary
Engineering reference data for LAN8742A-CZ-TR — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | LAN8742AI-CZ-TR | LAN8742A-CZ | DP83848QSQ/NOPB |
|---|---|---|---|---|
| Brand | Microchip Technology | Microchip Technology | Microchip Technology | Texas Instruments |
| Package | 24-SQFN (4x4 mm) | 24-SQFN (4x4) - same | 24-SQFN (4x4) - same | 40-QFN - DIFFERENT |
| Data Rate | 10/100 Mbps | 10/100 Mbps | 10/100 Mbps | 10/100 Mbps |
| MAC Interface | MII, RMII | MII, RMII | MII, RMII | MII, RMII, SNI |
| Operating Temperature | 0C to +70C (Commercial) | -40C to +85C (Industrial) | 0C to +70C (Commercial) | -40C to +105C (Industrial) |
| HP Auto-MDIX | Yes | Yes | Yes | Yes |
| Cable Diagnostics | Yes | Yes | Yes | No |
| Wake-On-LAN | Yes | Yes | Yes | No |
Key Differentiators
- Wide 1.62V-3.6V supply with variable 1.8V-3.3V I/O (vs DP83848QSQ/NOPB)
- HP Auto-MDIX eliminates crossover cable requirement (vs DP83848QSQ/NOPB)
- Integrated cable diagnostics for fault detection (vs DP83848QSQ/NOPB)
- Wake-On-LAN for power-sensitive designs (vs LAN8720A)
Design Notes
Follow Microchip's LAN8742 QFN Routing Checklist (LAN8742_QFN_Rev_A) for proper PCB layout. Place the 24-SQFN on a continuous ground plane with the exposed pad soldered directly to GND for thermal dissipation. Route the MDI differential pairs (TX_+/-, RX_+/-) as 100-ohm differential impedance-controlled traces with matched length within 50 mils. Keep the 25 MHz crystal traces short and surround them with ground guard traces to minimize EMI.
Place 0.1uF decoupling capacitors within 2 mm of each VDD and VDDIO pin, plus a 10uF bulk capacitor near the analog VDD supply. The flexPWR technology requires both VDDIO (1.8V-3.3V) and VDD (1.62V-3.6V) rails; these may share a common supply in 3.3V-only designs but must be separate in mixed-voltage systems. Power-up sequencing requires VDDIO before VDD if voltages are different.
The MII/RMII MAC interface signals should be length-matched within a clock period to avoid setup/hold violations. For RMII at 50 MHz reference, keep MAC traces under 50 mm and series-terminate if longer than 25 mm. The MDIO bus operates at up to 2.5 MHz; pull-up resistors of 1.5-10 kohm are required on both MDIO and MDC lines for proper SMI management interface operation.
Do not omit the 25 MHz crystal or external clock - the LAN8742A-CZ-TR requires a stable +/-50 ppm reference for proper 100BASE-TX operation. Strapping pins (MODE0-MODE3) must be pulled to defined logic levels at reset via 4.7k resistors; floating straps select undefined modes. The cable diagnostics feature requires specific TDR register access via MDIO - see datasheet section on cable fault detection.
Compliance Information
RoHS compliant per Microchip product page and distributor listings. Industrial variant LAN8742AI-CZ-TR is suitable for industrial environments but not AEC-Q100 automotive qualified.
