KS8993M Micrel Inc, KS8993M Datasheet - Page 27
![IC SWITCH 10/100 3PORT 128PQFP](/photos/6/81/68152/576-128-pqfp_sml.jpg)
KS8993M
Manufacturer Part Number
KS8993M
Description
IC SWITCH 10/100 3PORT 128PQFP
Manufacturer
Micrel Inc
Specifications of KS8993M
Applications
*
Mounting Type
Surface Mount
Package / Case
128-MQFP, 128-PQFP
Number Of Primary Switch Ports
3
Internal Memory Buffer Size
32
Operating Supply Voltage (typ)
1.8/2.5/3.3V
Fiber Support
Yes
Integrated Led Drivers
Yes
Phy/transceiver Interface
MII/SNI
Power Supply Type
Analog/Digital
Package Type
PQFP
Data Rate (typ)
10/100Mbps
Vlan Support
Yes
Operating Temperature (max)
70C
Operating Temperature (min)
0C
Pin Count
128
Mounting
Surface Mount
Jtag Support
No
Operating Supply Voltage (max)
1.89/3.465V
Operating Supply Voltage (min)
1.71/3.135V
Power Dissipation
800mW
Supply Current
0.1/0.19A
Operating Temperature Classification
Commercial
Data Rate
100Mbps
Lead Free Status / RoHS Status
Lead free / RoHS Compliant
For Use With
576-1013 - BOARD EVAL EXPERIMENT KS8993M
Lead Free Status / RoHS Status
Not Compliant, Lead free / RoHS Compliant
Available stocks
Company
Part Number
Manufacturer
Quantity
Price
Part Number:
KS8993M
Manufacturer:
MICREL/麦瑞
Quantity:
20 000
Functional Overview: MAC and Switch
Address Lookup
The internal lookup table stores MAC addresses and their associated information. It contains a 1K uni-cast
address table plus switching information. The KSZ8993M is guaranteed to learn 1K addresses and distinguishes
itself from hash-based lookup tables, which depending on the operating environment and probabilities, may not
guarantee the absolute number of addresses that can be learned.
Learning
The internal lookup engine will update its table with a new entry if the following conditions are met:
1. The received packet's SA does not exist in the lookup table.
2. The received packet is good; the packet has no receiving errors, and is of legal length.
The lookup engine will insert the qualified SA into the table, along with the port number and time stamp. If the
table is full, the last entry of the table will be deleted to make room for the new entry.
Migration
The internal lookup engine also monitors whether a station has moved. If so, it will update the table accordingly.
Migration happens when the following conditions are met:
1. The received packet's SA is in the table but the associated source port information is different.
2. The received packet is good; the packet has no receiving errors, and is of legal length.
The lookup engine will update the existing record in the table with the new source port information.
Aging
The lookup engine will update the time stamp information of a record whenever the corresponding SA appears.
The time stamp is used in the aging process. If a record is not updated for a period of time, the lookup engine will
remove the record from the table. The lookup engine constantly performs the aging process and will continuously
remove aging records. The aging period is about 200 seconds. This feature can be enabled or disabled through
Global Register 3 (0x03).
Forwarding
The KSZ8993M will forward packets using the algorithm that is depicted in the following flowcharts. Figure 4
shows stage one of the forwarding algorithm where the search engine looks up the VLAN ID, static table, and
dynamic table for the destination address, and comes up with “port to forward 1” (PTF1). PTF1 is then further
modified by spanning tree, IGMP snooping, port mirroring, and port VLA processes to come up with “port to
forward 2” (PTF2), as shown in Figure 5. The packet is sent to PTF2.
Micrel, Inc.
October 2008
27
M9999-020606
KSZ8993M/ML