LAN8720i SMSC [SMSC Corporation], LAN8720i Datasheet - Page 6

• Manufacturer Part Number: LAN8720i
• Description: Small Footprint RMII 10/100 Ethernet Transceiver with HP Auto-MDIX Support
• Manufacturer: SMSC [SMSC Corporation]

Small Footprint RMII 10/100 Ethernet Transceiver with HP Auto-MDIX Support
Datasheet
List of Figures
Figure 1.1 LAN8720/LAN8720i System Block Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
Figure 1.2 LAN8720/LAN8720i Architectural Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
Figure 2.1 LAN8720/LAN8720i 24-QFN Pin Assignments (TOP VIEW). . . . . . . . . . . . . . . . . . . . . . . . . 12
Figure 4.1 100Base-TX Data Path . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
Figure 4.2 Receive Data Path . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
Figure 4.3 Relationship Between Received Data and Specific MII Signals . . . . . . . . . . . . . . . . . . . . . . 23
Figure 4.4 External 50MHz clock sources the REF_CLK . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27
Figure 4.5 LAN8720 sources REF_CLK from a 25MHz crystal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28
Figure 4.6 LAN8720 Sources REF_CLK from External 25MHz Source . . . . . . . . . . . . . . . . . . . . . . . . . 29
Figure 4.7 Direct Cable Connection vs. Cross-over Cable Connection . . . . . . . . . . . . . . . . . . . . . . . . . 32
Figure 4.8 nINTSEL Strapping on LED2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33
Figure 4.9 REGOFF Configuration on LED1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33
Figure 4.10 MDIO Timing and Frame Structure - READ Cycle. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35
Figure 4.11 MDIO Timing and Frame Structure - WRITE Cycle . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35
Figure 5.1 Near-end Loopback Block Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52
Figure 5.2 Far Loopback Block Diagram. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52
Figure 5.3 Connector Loopback Block Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53
Figure 6.1 SMI Timing Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55
Figure 6.2 100M RMII Receive Timing Diagram (50MHz REF_CLK IN). . . . . . . . . . . . . . . . . . . . . . . . . 56
Figure 6.3 100M RMII Transmit Timing Diagram (50MHz REF_CLK IN) . . . . . . . . . . . . . . . . . . . . . . . . 57
Figure 6.4 10M RMII Receive Timing Diagram (50MHz REF_CLK IN). . . . . . . . . . . . . . . . . . . . . . . . . . 58
Figure 6.5 10M RMII Transmit Timing Diagram (50MHz REF_CLK IN) . . . . . . . . . . . . . . . . . . . . . . . . . 59
Figure 6.6 100M RMII Receive Timing Diagram (50MHz REF_CLK OUT). . . . . . . . . . . . . . . . . . . . . . . 60
Figure 6.7 100M RMII Transmit Timing Diagram (50MHz REF_CLK OUT) . . . . . . . . . . . . . . . . . . . . . . 61
Figure 6.8 10M RMII Receive Timing Diagram (50MHz REF_CLK OUT). . . . . . . . . . . . . . . . . . . . . . . . 62
Figure 6.9 10M RMII Transmit Timing Diagram (50MHz REF_CLK OUT) . . . . . . . . . . . . . . . . . . . . . . . 63
Figure 6.10 Reset Timing Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 64
Figure 8.1 Simplified Application Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 73
Figure 8.2 High-Level System Diagram for Power . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 74
Figure 8.3 High-Level System Diagram for Power . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 74
Figure 8.4 Copper Interface Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 74
Figure 8.5 Copper Interface Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 74
Figure 9.1 LAN8720/LAN8720i-EZK 24-QFN Package Outline, 4 x 4 x 0.9 mm Body (Lead-Free) . . . . 76
Figure 9.1 QFN, 4x4 Taping Dimensions and Part Orientation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 77
Figure 9.2 Reel Dimensions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 78
Revision 1.0 (05-28-09)
6
SMSC LAN8720/LAN8720i
DATASHEET