SY58621L
Precision 3.2Gbps CML/LVPECL Backplane
Transceiver with Integrated Loopback
Precision Edge is a registered trademark of Micrel, Inc.
MLF and
Micro
LeadFrame are trademarks of Amkor Technology, Inc.
Micrel Inc. 2180 Fortune Drive San Jose, CA 95131 USA tel +1 (408) 944-0800 fax + 1 (408) 474-1000 http://www.micrel.com
September 2005
M9999-093005-A
hbwhelp@micrel.com
or (408) 955-1690
General Description
The SY58621L is a low jitter, high-speed transceiver
with a variable swing LVPECL transmitter buffer and a
CML high-gain receiver optimized for precision telecom
and enterprise server transmission line and backplane
data management. The SY58621L distributes data to
3.2Gbps guaranteed over temperature and voltage.
The SY58621L transmitter differential input includes
Micrel's unique, patented 3-pin input termination
architecture that directly interfaces to any (AC- or DC-
coupled) differential signal as small as 100mV
(200mV
PP
) without any termination resistor network in
the signal path. The receiver differential input is
optimized to interface directly to AC-coupled signals as
small as 10mV (20mV
PP
). The receiver output is 50
source-terminated CML and the transmitter output is
variable swing 80mV to 800mV LVPECL with extremely
fast rise/fall time.
To support remote self-testing, the SY58621L features a
high-speed loopback test mode. The input control signal
LOOPBACK enables an internal loopback path from the
transmitter input to the receiver output.
The SY58621L operates from a 3.3V 10% supply and
is guaranteed over the full industrial temperature range
of 40C to +85C. The SY58621L is part of Micrel's
high-speed, Precision Edge
product line. For
applications that requires a CML receiver and
transmitter, consider the SY58620L.
All support documentation can be found on Micrel's web
site at:
www.micrel.com
.
Applications
Backplane management
Active cable transceivers
SONET/SDH data/clock applications
4X Fibre Channel applications
Precision Edge
Features
Guaranteed AC performance over temperature and
voltage:
- Maximum Throughput 3.2Gbps
- <160ps
t
r
/t
f
time
Transmitter
- Patented input termination directly interfaces to AC-
or DC-coupled differential inputs
- Variable swing LVPECL output
Receiver
- 32dB high-gain Input
- Internal
50 input termination
- Accepts AC-coupled input signals as small as 10mV
(20mv
PP
)
- 400mV
(800mV
PP
) differential CML output swing
Loss-of-Signal (LOS)
- High-gain, TTL-compatible LOS output with internal
4.75k pull-up
- Programmable LOS level set
Ultra-low jitter design
-
<5ps
RMS
random jitter
Patent-pending MUX isolates the receiver and the
transmitter channels minimizing on crosstalk
Selectable loopback diagnostic mode
Output enables on transmitter and receiver outputs
Power supply +3.3V 10%
Industrial temperature range -40C to +85C
Available in 24-pin (4mm x 4mm) MLFTM
Markets
Precision telecom
Enterprise server
ATE
Test and measurement
Micrel, Inc.
SY58621L
September 2005
2
M9999-093005-A
hbwhelp@micrel.com
or (408) 955-1690
Typical Applications
Functional Block Diagram
Note:
It is recommended that R
LOSLVL
10k. See the "Typical Operating Characteristics" section for more details.
Micrel, Inc.
SY58621L
September 2005
3
M9999-093005-A
hbwhelp@micrel.com
or (408) 955-1690
Ordering Information
(1)
Part Number
Package
Type
Operating
Range
Package Marking
Lead Finish
SY58621LMG
MLF-24
Industrial
621L with Pb-Free bar-line indicator
NiPdAu
Pb-Free
SY58621LMGTR
(2)
MLF-24
Industrial
621L with Pb-Free bar-line indicator
NiPdAu
Pb-Free
Notes:
1. Contact factory for die availability. Dice are guaranteed at T
A
= 25C, DC Electricals only.
2.
Tape
and
Reel.
Pin Configuration
24-Pin MLFTM (MLF-24)
Micrel, Inc.
SY58621L
September 2005
4
M9999-093005-A
hbwhelp@micrel.com
or (408) 955-1690
Pin Description
Inputs
Pin Number
Pin Name
Pin Description
23 LOOPBACK
LOOPBACK Mode Control. TTL/CMOS control input. LOOPBACK is an active HIGH signal
used to control the LOOPBACK MUX. LOOPBACK is internally connected to a 25k
pull-
down resistor and will default to a LOW state if left open. V
TH
= V
CC
/2.
20 /RXEN
Receiver Output Control. TTL/CMOS control input. /RXEN is an active LOW signal used to
enable the receiver outputs. /RXEN is internally connected to a 25k
pull-down resistor and will
default to a LOW state if left open. V
TH
= V
CC
/2.
1, 2
RXIN, /RXIN
Receiver Differential Input. Input accepts AC differential signals as small as 10mV (20mV
PP
).
Each pin internally terminates to V
CC_RXIN
-1.3V (internal voltage reference) through 50
. Input
will default to an indeterminate state if left open. See figure 6b.
7 /TXEN
Transmitter Output Control. TTL/CMOS control input. /TXEN is an active LOW signal used to
enable the transmitter output. /TXEN is internally connected to a 25k
pull-down resistor and
will default to a LOW state if left open. V
TH
= V
CC
/2.
14, 13
TXIN, /TXIN
Transmitter Differential Input. Input accepts AC- or DC-coupled differential signals as small as
100mV (200mV
PP
). Each pin terminates to the TXVT
pin through 50
. Note that this input will
default to an indeterminate state if left open. See figure 6a.
9 TXVCTRL
Transmitter Output Swing Control. Input that controls the output amplitude of the transmitter.
The operating range of the control input is from V
REF_CTRL
(max swing) to V
CC
(min swing).
Control of the output swing can be obtained by using a variable resistor between V
REF_CTRL
and
V
CC_TXQ
through a wiper driving TXVCTRL. Setting TXVCTRL to V
CC_TXQ
sets the output swing
to min swing. Refer to the "Interface Applications" and "Output Stage" sections for more
details.
11 TXVT
Input Termination Center-Tap. Each side of the transmitter differential input pair terminates to
the TXVT
pin. The TXVT
pin provides a center-tap to a termination network for maximum
interface flexibility. Refer to the "Input Stage" section for more details.
Micrel, Inc.
SY58621L
September 2005
5
M9999-093005-A
hbwhelp@micrel.com
or (408) 955-1690
Outputs
Pin Number
Pin Name
Pin Description
22 LOS
Loss-of-Signal Output. TTL-compatible output with internal 4.75k
pull-up resistor. Loss-of-
Signal asserts to logic HIGH when the receiver input amplitudes fall below the threshold set
by LOSLVL.
19
LOSLVL
RX Loss-of-Signal Level Set. A resistor (R
LOSLVL
) connected between LOSLVL and V
CC
sets
the threshold for the data input amplitude at which the LOS output is asserted. Default is max
sensitivity. LOSLVL is used to set the Loss-of-Signal (LOS) voltage. It is internally connected
to a 2.8k
pull-down resistor to an internal V
REF
voltage source. See "Typical Operating
Characteristics," and "Application Implementation" sections for more details.
17, 16
RXQ, /RXQ
Receiver Differential Output. Output is CML compatible. Refer to the "Truth Table" and
"Output Stage" sections for more details. Unused output pair may be left open. The output is
designed to drive 400mV (800mV
PP
) into 50
to V
CC
or 100
across the pair.
5, 6
TXQ, /TXQ
Transmitter differential Variable Swing Output. Output is LVPECL-compatible. Please refer
to the "Truth Table" section for details. Unused output pair may be left open. Each output is
designed to drive 80mV (min) to 800mV (typ) into 50 to V
CC
-2V depending on TXVCTRL.
8 VREF_CTRL
Transmitter Output Reference Voltage. Output biases to V
CC
_
TXQ
-1.3V. Connecting V
REF_CTRL
to TXVCTRL sets the transmitter output swing to max swing.
10 TXVREF-AC
Transmitter Input Reference Voltage. This output biases to V
CC
-1.3V. It is used when AC
coupling the transmitter input. For AC-coupled applications, connect TXVREF-AC to the
TXVT pin and bypass with a 0.01F low ESR capacitors to V
CC
. See "Input Stage" section for
more details. Maximum sink/source current is 1.5mA.
Power Pins
Pin Number
Pin Name
Pin Description
3, 24
GND,
Exposed Pad
Ground. GND pins and exposed pad must be connected to the same ground plane.
12, 15, 18
VCC
3.3V 10% Positive Power Supply. Bypass with 0.1F//0.01F low ESR capacitors and place
as close to each V
CC
pins as possible. Power pins are not connected internally and must be
connected to the same power supply externally.
21 VCC_RXIN
3.3V 10% Receive Input Power Supply. Bypass with 0.1F//0.01F low ESR capacitors and
place as close to the V
CC_RXIN
pin as possible. Power pins are not connected internally and
must be connected to the same power supply externally.
4 VCC_TXQ
3.3V 10% Output Transmit Power Supply. Bypass with 0.1F//0.01F low ESR capacitors
and place as close to the V
CC_TXQ
pin as possible. Power pins are not connected internally
and must be connected to the same power supply externally.
Truth Table
LOOPBACK RXQ
TXQ
0 RXIN TXIN
1 TXIN RXIN
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