AC101LKQT Broadcom, AC101LKQT Datasheet - Page 9

• Manufacturer Part Number: AC101LKQT
• Manufacturer: Broadcom

Specifications of AC101LKQT

• Number Of Receivers: 1
• Data Rate: 10/100Mbps
• Package Type: TQFP
• Operating Temperature Classification: Industrial
• Mounting: Surface Mount
• Pin Count: 48
• Operating Temperature (max): 85C
• Operating Temperature (min): -40C
• Lead Free Status / Rohs Status: Not Compliant

Preliminary Data Sheet
AC101L
03/10/03
S e c t io n 1 : F un c t i o na l D e s c r ip t io n
The AC101L is a single-chip, Fast Ethernet transceiver. It performs all of the physical layer interface functions for
100BASE-TX full-duplex or half-duplex on Category 5 twisted-pair cable, and 10BASE-T full-duplex or half-duplex on
Category 3 cable. It can be configure for 100BASE-FX full- or half-duplex transmission over fiber optic cable when pair with
an external fiber optic line driver and receiver.
The chip performs 4B5B, MLT3, NRZI, encoder/decoder, link monitor, auto-negotiation selection, adaptive equalization,
clock/data recovery, baseline wander correction, multi-mode transmitter, scrambler/descrambler, far-end fault (FEF), and
auto-MDI/MDIX. It can be connected to a MAC switch controller through the MII on one side, and connects directly to the
media on the other side through a transformer for twisted-pair (TP) mode, or fiber-optic module for FX mode. It is fully
compliant with the IEEE 802.3 and 803.3u standards.
E
/D
NCODER
ECODER
In 100BASE-TX and 100BASE-FX modes, the AC101L transmits and receives data stream on twisted-pair or fiber-optic
cable. When the MII transmit enable is asserted, nibble wide (4 bit) data from transmit data pins is encoded into 5-bit code
groups and inserted into transmit data stream. The 4B5B encoding is shown in
Section 6: “4B/5B Code Group” on page
31.
The transmit packet is encapsulated by replacing the first 2 nibbles of preamble with a start of stream delimiter (J/K codes)
and appending an end of stream delimiter (T/R codes) to the end of packet. When the MII transmit error input is asserted
during a packet, the error code group (H) is sent in place of the corresponding data code group. The transmitter sends
repeatedly the idle code group between packets.
In 100BASE-TX mode, the encode data stream is scrambled by a stream cipher block and then serialized and encoded into
an MLT3 signal level. A multi mode transmit DAC (digital to analog converter) is used to drive the MLT3 data onto twisted-
pair cable. Following are baseline wander correction, adaptive equalization and clock/data recovery in 100BASE-TX mode,
the receive data stream is converted from MLT3 to serial NRZ data. The NRZ data is descrambled by the stream cipher block
and then deserialized and aligned into 5-bit code groups.
In 100BASE-FX mode, the scrambling function is bypassed and the data is NRZII encoded. The multi mode transmit DAC
drives differential Positive ECL (PECL) levels to an external fiber optic transmitter. Baseline wander correction, adaptive
equalization, stream cipher descrambling functions are bypass and NRZI decoding is used instead of MLT3.
The 5-bit code groups are decoded into 4 bit data nibbles. The start of stream delimiter is replaced with preamble nibbles
and the end of stream delimiter and idle codes are replaced with all zeros. The decoded data is driven onto the MII receive
data pins. When an invalid code group or bad SSD is detected in the data stream, the AC101L asserts the MII RXER signal.
In 10BASE-T mode, Manchester encoding and decoding is performed on the data stream. The multi mode transmit DAC
performs pre-equalization for 100 meters of Category 3 cable.
L
M
INK
ONITOR
In 100BASE-TX mode, receive signal energy is detected by monitoring the receive pair for transitions in the signal level. The
signal levels are qualified using squelch detect circuits. When no signal or certain valid signal is detected on the receive pair
for a minimum period of time, the link monitor enter the link pass state and the transmit and receive functions are enabled.
B roa dcom
Document
AC101L-DS05-R
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