Gigabit Ethernet and
Fibre Channel SerDes ICs
Technical Data
Features
• IEEE 802.3z Gigabit Ethernet
Compatible
• ANSI x3.230-1994 Fibre
Channel Compatible (FC-O)
• Supports Serial Data Rates of
1062.5 MBd (Fibre Channel)
& 1250 MBd (Gigabit
Ethernet)
• Low Power Consumption,
630 mW Typical
• Transmitter and Receiver
Functions Incorporated onto
a Single IC
• Three Package Sizes
Available:
– 10 mm TQFP (HDMP-T1636A)
– 10 mm PQFP (HDMP-1636A)
– 14 mm PQFP (HDMP-1646A)
• 10-Bit Wide Parallel TTL
Compatible I/Os
• Single +3.3 V Power Supply
• 5-Volt Tolerant I/Os
• 2 kV ESD Protection on All
Pins
HDMP-1636A Transceiver
HDMP-1646A Transceiver
HDMP-T1636A Transceiver
Description
The HDMP-1636A/46A/T1636A
transceiver is a single integrated
circuit packaged in a plastic QFP
package. It provides a low-cost,
low-power physical layer solution
for 1250 MBd Gigabit Ethernet,
1062.5 MBd Fibre Channel, and
proprietary link interfaces. It
provides complete Serialize/
Deserialize (SerDes) for copper
transmission, incorporating the
Gigabit Ethernet/Fibre Channel
transmit and receive functions
into a single device.
This chip is used to build a high
speed interface (as shown in
Figure 1) while minimizing board
space, power and cost. It is
compatible with the IEEE 802.3z
specification.
The transmitter section accepts
10-bit wide parallel TTL data and
serializes this data into a high
speed serial data stream. The
parallel data is expected to be
“8B/10B” encoded data, or equiv-
alent. This parallel data is latched
into the input register of the
transmitter section on the rising
edge of the reference clock (used
as the transmit byte clock). A
1062.5 MHz reference clock is
used in Fibre Channel operation,
whereas a 125 MHz reference
clock is used in Gigabit Ethernet
operation.
The transmitter section’s PLL
locks to the user supplied
reference byte clock. This clock
is then multiplied by 10 to gener-
ate the high speed serial clock
used to generate the high speed
output. The high speed outputs
are capable of interfacing directly
to copper cables for electrical
transmission or to a separate
fiber optic module for optical
transmission.
The receiver section accepts a
serial electrical data stream at
1062.5 MBd or 1250 MBd and
recovers the original 10-bit wide
parallel data. The receiver PLL
locks onto the incoming serial
signal and recovers the high
speed serial clock and data. The
serial data is converted back into
10-bit parallel data, recognizing
the 8B/10B comma character to
establish byte alignment.
Applications
• 1250 MBd Gigabit Ethernet
Interface
• 1062.5 MBd Fibre Channel
Interface
• Mass Storage System I/O
Channel
• Work Station/Server I/O
Channel
• Backplane Serialization
• FC Interface for Disk Drives
and Arrays
CAUTION: As with all semiconductor ICs, it is advised that normal static precautions be taken in handling and assembly
of this component to prevent damage and/or degradation which may be induced by electrostatic discharge (ESD).
2
HDMP-16x6A
TRANSMITTER SECTION
SERIAL DATA OUT
PLL
PROTOCOL DEVICE
RBC0
RBC1
PLL
RECEIVER SECTION
SERIAL DATA IN
BYTSYNC
REFCLK
ENBYTSYNC
Figure 1. Typical Application Using the HDMP-1636A/1646A/T1636A.
INPUT
LATCH
DATA BYTE
TX[0-9]
FRAME
MUX
OUTPUT
SELECT
INTERNAL
LOOPBACK
± DOUT
LOOPEN
TXCAP0
TXCAP1
TX
PLL/CLOCK
GENERATOR
INTERNAL
TX CLOCKS
INPUT
SELECT
± DIN
REFCLK
RXCAP0
RXCAP1
RBC0
RBC1
RX
PLL/CLOCK
RECOVERY
SIGNAL
DETECT
SIG_DET
OUTPUT
DRIVER
DATA BYTE
RX[0-9]
FRAME
DEMUX
AND
BYTE SYNC
INTERNAL
RX CLOCKS
INPUT
SAMPLER
BYTSYNC
ENBYTSYNC
Figure 2. HDMP-1636A/1646A/T1636A Transceiver Block Diagram.
3
The recovered parallel data is
presented to the user at TTL
compatible outputs. The receiver
section also recovers two receiver
byte clocks which are 180
degrees out of phase with each
other. For Gigabit Ethernet,
these clocks are 62.5 MHz,
whereas for Fibre Channel, they
are 53.125 MHz. The parallel
data is properly aligned with the
rising edge of alternating clocks.
For test purposes, the transceiver
provides for on-chip local loop-
back functionality, controlled
through an external input pin.
Additionally, the byte
synchronization feature may be
disabled. This may be useful in
proprietary applications which
use alternative methods to align
the parallel data.
INPUT LATCH
The transmitter accepts 10-bit
wide TTL parallel data at inputs
TX[0..9]. The user-provided
reference clock signal, REFCLK,
is also used as the transmit byte
clock. The TX[0..9] and REFCLK
signals must be properly aligned,
as shown in Figure 3.
TX PLL/CLOCK GENERATOR
The transmitter Phase Locked
Loop and Clock Generator (TX
PLL/CLOCK GENERATOR) block
is responsible for generating all
internal clocks needed by the
transmitter section to perform its
functions. These clocks are based
on the supplied reference byte
clock (REFCLK). REFCLK is
used as both the frequency
reference clock for the PLL and
the transmit byte clock for the
incoming data latches. It is
expected to be properly aligned
to the incoming parallel data (see
Figure 3). This clock is then
multiplied by 10 to generate the
high speed clock necessary for
clocking the high speed serial
outputs.
FRAME MUX
The FRAME MUX accepts the 10-
bit wide parallel data from the
INPUT LATCH. Using internally
generated high speed clocks, this
parallel data is multiplexed into
the high speed serial data stream.
The data bits are transmitted
sequentially, from the least
significant bit (TX[0]) to the
most significant bit (TX[9]).
OUTPUT SELECT
The OUTPUT SELECT block
provides for an optional internal
loopback of the high speed serial
signal for testing purposes.
In normal operation, LOOPEN is
set low and the serial data stream
is placed at +/- DOUT. When
wrap-mode is activated by setting
LOOPEN high, the +/- DOUT
pins are held static at logic 1 and
the serial output signal is
internally wrapped to the INPUT
SELECT box of the receiver
section.
INPUT SELECT
The INPUT SELECT block
determines whether the signal at
+/- DIN or the internal loop-back
serial signal is used. In normal
operation, LOOPEN is set low
and the serial data is accepted at
+/- DIN. When LOOPEN is set
high, the high speed serial signal
is internally looped-back from the
transmitter section to the
receiver section. This feature
allows for loop back testing
exclusive of the transmission
medium.
RX PLL/CLOCK RECOVERY
The RX PLL/CLOCK RECOVERY
block is responsible for frequency
and phase locking onto the
incoming serial data stream and
recovering the bit and byte
clocks. An automatic locking
feature allows the Rx PLL to lock
onto the input data stream
without external PLL training
controls. It does this by
continually frequency locking
onto the reference clock, and
then phase locking onto the input
data stream. An internal signal
detection circuit monitors the
presence of the input, and
invokes the phase detection as
the data stream appears. Once bit
locked, the receiver generates the
high speed sampling clock for the
input sampler, and recovers the
HDMP-1636A/1646A/
T1636A Block Diagram
The HDMP-1636A/1646A/
T1636A was designed to transmit
and receive 10-bit wide parallel
data over a single high-speed
line. The parallel data applied to
the transmitter is expected to be
8B/10B encoded. In order to
accomplish this task, the HDMP-
1636A/1646A/T1636A
incorporates the following:
• TTL Parallel I/Os
• High Speed Phase Locked
Loops
• Parallel to Serial Converter
• High Speed Serial Clock and
Data Recovery Circuitry
• Comma Character Recognition
Circuitry as per 8B/10B
Specifications
• Byte Alignment Circuitry
• Serial to Parallel Converter
4
two receiver byte clocks
(RBC1/RBC0). These clocks are
180 degrees out of phase with
each other, and are alternately
used to clock out the 10-bit
parallel output data.
INPUT SAMPLER
The INPUT SAMPLER is respon-
sible for converting the serial
input signal into a retimed serial
bit stream. In order to accom-
plish this, it uses the high speed
serial clock recovered from the
RX PLL/CLOCK RECOVERY
block. This serial bit stream is
sent to the FRAME DEMUX and
BYTE SYNC block.
FRAME DEMUX AND BYTE
SYNC
The FRAME DEMUX AND BYTE
SYNC block is responsible for
restoring the 10-bit parallel data
from the high speed serial bit
stream. This block is also
responsible for recognizing the
comma character (or a K28.5
character) of positive disparity
(0011111xxx). When recognized,
the FRAME DEMUX AND BYTE
SYNC block works with the RX
PLL/CLOCK RECOVERY block to
properly align the receive byte
clocks to the parallel data. When
a comma character is detected
and realignment of the receiver
byte clocks (RBC1/RBC0) is
necessary, these clocks are
stretched, not slivered, to the
next possible correct alignment
position. These clocks will be
fully aligned by the start of the
second 2-byte ordered set. The
second comma character
received shall be aligned with the
rising edge of RBC1. As per the
8B/10B encoding scheme,
comma characters must not be
transmitted in consecutive bytes
to allow the receiver byte clocks
to maintain their proper
recovered frequencies.
OUTPUT DRIVERS
The OUTPUT DRIVERS present
the 10-bit parallel recovered data
byte properly aligned to the
receive byte clocks (RBC1/RBC0),
as shown in Figure 5. These
output data buffers provide TTL
compatible signals.
SIGNAL DETECT
The SIGNAL DETECT block
examines the differential
amplitude of the inputs
±
DIN.
When this input signal is too
small, it outputs a logic 0 at
SIG_DET (refer to SIG_DET pin
definition for detection
thresholds), and at the same
time, forces the parallel output
RX[0]..RX[9] to all logic one
(1111111111). The main
purpose of this circuit is to
prevent the generation of random
data when the serial input lines
are disconnected. When the
signal at
±
DIN is of a valid
amplitude, SIG_DET is set to
logic 1, and the output of the
INPUT SELECT block is passed
through.
HDMP-1636A/1646A/T1636A (Transmitter Section) – Gigabit Ethernet
Timing Characteristics
T
A
= 0°C to +70°C, V
CC
= 3.15 V to 3.45 V
Symbol
Parameter
t
setup
Setup Time
t
hold
Hold Time
t_txlat
[1]
Transmitter Latency
Units
nsec
nsec
nsec
bits
Min.
1.5
1.0
Typ.
Max.
3.5
4.4
Note:
1. The transmitter latency, as shown in Figure 4, is defined as the time between the latching in of the parallel data word (as triggered
by the rising edge of the transmit byte clock, REFCLK) and the transmission of the first serial bit of that parallel word (defined by
the rising edge of the first bit transmitted).
5
HDMP-1636/1646A/T1636A (Transmitter Section) – Fibre Channel
Timing Characteristics
T
A[1]
= 0°C to +70°C, V
CC
= 3.15 V to 3.45 V
Symbol
Parameter
t
setup
Setup Time
t
hold
Hold Time
t_txlat
[2]
Transmitter Latency
Units
nsec
nsec
nsec
bits
Min.
2
1.5
Typ.
Max.
4.2
4.4
Notes:
1. Device tested and characterized under T
A
conditions specified, with T
C
monitored at approximately 20° higher than T
A
.
2. The transmitter latency, as shown in Figure 4, is defined as the time between the latching in of the parallel data word (as triggered
by the rising edge of the transmit byte clock, REFCLK) and the transmission of the first serial bit of that parallel word (defined by
the rising edge of the first bit transmitted).
REFCLK
1.4 V
2.0 V
TX[0]-TX[9]
DATA
DATA
DATA
DATA
DATA
0.8 V
t
SETUP
t
HOLD
Figure 3. Transmitter Section Timing.
DATA BYTE A
DATA BYTE B
± DOUT
T5
T6
T7
T8
T9
T0
T1
T2
T3
T4
T5
T6
T7
T8
T9
T0
T1
T2
T3
T4
T5
t_TXLAT
TX[0]-TX[9]
DATA BYTE B
DATA BYTE C
REFCLK
1.4 V
Figure 4. Transmitter Latency.
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