83C694 Datasheet, PDF (4/33 Pages) List of Unclassifed Manufacturers – TWISTED PAIR INTERFACE AND MACHESTER ENCODER/DECODER

INTRODUCTION
83C694D
1.0 INTRODUCTION
1.1 DOCUMENT SCOPE
This document describes the function and opera-
tion of the 83C694D Twisted-Pair Interface and
Manchester Encoder/Decoder. It includes a de-
scription of external logic necessary for the efficient
use of this device and its proper role in the chip set
which includes the 83C690 and 83B692 as shown
in Figure 1-1. Figure 1-2 provides a functional block
diagram of the 83C694D chip itself.
1.2 FEATURES
Features of the 83C694D include:
• Twisted-Pair interface solution for IEEE 802.3
10BaseT Standard
• Compatible with Ethernet II (10BASE5) and
Cheapernet (10BASE2) IEEE 802.3 Stand-
ards
• Smart Squelch^© digital noise filter at receive
and collision inputs to reject noise and digital
noise on twisted-pair receive inputs.
• Direct connection to the transceiver (AUI) ca-
ble
• 16V fault protection at the AUI transmitter in-
terface
• 10 Mbps Manchester encoding/ decoding with
receive clock recovery
• Low power, 1.25µ CMOS technology
• TTL/MOS-compatible controller interface
• Externally-selectable half- or full-step modes
of operation at AUI TX± outputs
• Loopback capability for diagnostics
• Single station interface operation
• Link test generation and digital equalization for
twisted-pair transmitter
• Automatic phase detection
• AUI/TP autoselect
• Built-in LED drivers for transmit, receive, link
test and polarity status indicators
1.3 GENERAL DESCRIPTION
The 83C694D is used for applications where
Twisted-Pair Interface (TPI) and/or Attachment Unit
Interface (AUI) functions are required. Its two main
functions are to:
1. Receive a digital data stream from a low-level
input signal and
2. Convert a digital output data stream into an
analog high-current signal for transmission
across a network cable.
This means that the 83C694D serves as the logical
link between a network cable on one end and a
digital controller chip (such as the 83C690) on the
other end.
To accomplish these two functions, the 83C694D
consists of these components: Manchester en-
coder/decoder, balanced drivers and receivers, on-
board crystal oscillator, signal translator, diagnostic
circuit, and protocol timers and state machines.
The remainder of this data sheet contains the fol-
lowing information:
Section 2 discusses the system architecture in-
cluding an explanation of all chip circuits.
Section 3 provides pin descriptions.
Section 4 provides DC Operating Characteristics.
Section 5 provides AC Operating Characteristics
including Interface Timing diagrams.
Section 6 provides the PLCC package diagram of
this chip.
1