78Q2120C09
10/100BASE-TX Transceiver
MII Evaluation Board Design Kit
UM 78Q2120C09 v1-2
User Manual
April 2007
© 2007 Teridian Semiconductor Corporation, Proprietary and Confidential
- 1 -
Rev_1.2
DESCRIPTION
The 78Q2120C09-DB is a design example for a
10/100BASE-TX Mbit/second Fast Ethernet MII
Interface adaptor. The 78Q2120C09 transceiver
provides the network physical interface and MII
(Medium Independent Interface) interface.
Teridian Semiconductor’s 78Q2120C09 is an auto-
sensing, auto-switching 10/100BASE-TX Fast
Ethernet transceiver with full duplex operation
capability. The device interfaces directly to the
IEEE-802.3u MII port. Full-featured MII
management functions are included along with an
extended register set. A five bit configurable PHY
address is provided for multiple PHY architectures.
The 78Q2120C09 interfaces to CAT5 UTP cable via
a 1:1 transformer.
The transceiver’s transmitter includes on-chip the
pulse shaper and low power line driver. The
receiver incorporates a sophisticated combination of
real-time adaptive equalization, an adaptive DC
offset adjustment circuit and baseline wander
correction. Smart squelch circuitry further improves
the receiver’s noise rejection. Full featured auto-
negotiation or parallel detect modes are supported.
Using 0.18
µ
m CMOS technology, the 78Q2120C09
operates at +3.3V. Intelligent power management
and power down modes minimize power
consumption. The demo board requires operation
with a +3.3V power supply.
Design Kit contains:
√
78Q2120C09 MII Demo Board
√
Demo Board Parts List
√
P.C.B. Gerber Files
√
Demo
Board
schematic
√
78Q2120C09 Data Sheet
100Base-TX Interface
RJ45 Pin Assignment
Pin Signal
Pin Signal
1 TX+
5 N/C
2 TX-
6 RX-
3 RX+
7 N/C
4 N/C
8 N/C
MII: Medium Independent Interface
Pin Assignment:
(40 Pin Male Subminiature D, 0.050)
Pin Signal
Pin Signal
1 +3.3V
21 +3.3V
2 MDIO
22 COMMON
3 MDC
23 COMMON
4 RXD3
24 COMMON
5 RXD2
25 COMMON
6 RXD1
26 COMMON
7 RXD0
27 COMMON
8 RXDV
28 COMMON
9 RXCLK
29 COMMON
10 RXER
30 COMMON
11 TXER
31 COMMON
12 TXCLK
32 COMMON
13 TXEN
33 COMMON
14 TXD0
34 COMMON
15 TXD1
35 COMMON
16 TXD2
36 COMMON
17 TXD3
37 COMMON
18 COL
38 COMMON
19 CRS
39 COMMON
20 +3.3V
40 +3.3V
