SY58620L
Precision 4.25Gbps CML Backplane
Transceiver with Integrated Loopback
General Description
The SY58620L is a low jitter, high-speed transceiver
with a variable swing CML transmitter buffer and a CML
high-gain receiver optimized for precision telecom and
enterprise server transmission line and backplane data
management. The SY58620L distributes data to
4.25Gbps guaranteed over temperature and voltage.
The SY58620L transmitter differential input includes
Micrel’s unique, 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
Ω
(20mV
PP
). The outputs are 50
source
-terminated CML
with extremely fast rise/fall time.
To support remote self-testing, the SY58620L 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 SY58620L operates from a 3.3V ±10% supply and
is guaranteed over the full industrial temperature range
of –40°C to +85°C. The SY58620L is part of Micrel’s
®
high-speed, Precision Edge product line.
All support documentation can be found on Micrel’s web
site at:
www.micrel.com.
Precision Edge
®
Features
•
Guaranteed AC performance over temperature and
voltage:
- Maximum Throughput 4.25Gbps
- <120ps t
r
/t
f
time
•
Transmitter
- Patented input termination directly interfaces to AC-
or DC-coupled differential inputs
- Variable swing CML output
•
Receiver
- 32dB high-gain Input
- Internal 50Ω
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
4.75kΩ
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 enable
•
Power supply +3.3V ±10%
•
Industrial temperature range -40°C to +85°C
•
Available in 24-pin (4mm x 4mm) QFN
Applications
•
•
•
•
Backplane management
Active cable transceivers
SONET/SDH data/clock applications
4X Fibre Channel applications
Typical Applications
Markets
•
•
•
•
Precision telecom
Enterprise server
ATE
Test and measurement
United States Patent No. RE44,134
Precision Edge is a registered trademark of Micrel, 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
January 2006
M9999-012006-C
hbwhelp@micrel.com
or (408) 955-1690
Micrel, Inc.
SY58620L
Functional Block Diagram
Note:
It is recommended that R
LOSLVL
≤10kΩ.
See the “Typical Operating Characteristics” section for more details.
January 2006
2
M9999-012006-C
hbwhelp@micrel.com
or (408) 955-1690
Micrel, Inc.
SY58620L
Ordering Information
(1)
Part Number
SY58620LMG
SY58620LMGTR
Notes:
1. Contact factory for die availability. Dice are guaranteed at T
A
= 25ºC, DC Electricals only.
2. Tape and Reel.
(2)
Package
Type
QFN-24
QFN-24
Operating
Range
Industrial
Industrial
Package Marking
620L with Pb-Free bar-line indicator
620L with Pb-Free bar-line indicator
Lead Finish
NiPdAu
Pb-Free
NiPdAu
Pb-Free
Pin Configuration
24-Pin QFN
January 2006
3
M9999-012006-C
hbwhelp@micrel.com
or (408) 955-1690
Micrel, Inc.
SY58620L
Pin Description
Inputs
Pin Number
23
Pin Name
LOOPBACK
Pin Description
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 25kΩ pull-
down resistor and will default to a LOW state if left open. V
TH
= V
CC
/2.
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 25kΩ pull-down resistor and will
default to a LOW state if left open. V
TH
= V
CC
/2.
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 50Ω. Input
will default to an indeterminate state if RXIN inputs are left open. See figure 6b.
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 25kΩ pull-down resistor and
will default to a LOW state if left open. V
TH
= V
CC
/2.
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 50Ω. Input will default to an
indeterminate state if TXIN inputs are left open. See figure 6a.
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 is obtained with 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.
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.
20
/RXEN
1, 2
RXIN, /RXIN
7
/TXEN
14, 13
TXIN, /TXIN
9
TXVCTRL
11
TXVT
January 2006
4
M9999-012006-C
hbwhelp@micrel.com
or (408) 955-1690
Micrel, Inc.
SY58620L
Outputs
Pin Number
22
Pin Name
LOS
Pin Description
Loss-of-Signal Output. TTL-compatible output with internal 4.75kΩ pull-up resistor. Loss-of-
Signal asserts to logic HIGH when the receiver input amplitudes falls below the threshold set
by 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 2.8kΩ pull-down resistor to an internal V
REF
voltage source. See “Typical Operating
Characteristics,” and “Application Implementation” sections for more details.
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 50Ω to V
CC
or 100Ω across the pair.
Transmitter Differential Variable Swing Output. Output is CML compatible. Please 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 80mV (160mV
PP
) min swing to 400mV (800mV
PP
) typ.
swing into 50Ω to V
CC_TXQ
or drive 100Ω across the pair depending on TXVCTRL.
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.
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 0.01µF low ESR capacitors to V
CC
. See “Input Stage” section for
more details. Maximum sink/source current is ±1.5mA.
19
LOSLVL
17, 16
RXQ, /RXQ
5, 6
TXQ, /TXQ
8
VREF_CTRL
10
TXVREF-AC
Power Pins
Pin Number
3, 24
12, 15, 18
Pin Name
GND,
Exposed Pad
VCC
Pin Description
Ground. GND pins and exposed pad must be connected to the same ground plane.
3.3V ±10% Positive Power Supply. Bypass with 0.1µF//0.01µF 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.
3.3V ±10% Receive Input Power Supply. Bypass with 0.1µF//0.01µF 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.
3.3V ±10% Output Transmit Power Supply. Bypass with 0.1µF//0.01µF 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.
21
VCC_RXIN
4
VCC_TXQ
Truth Table
LOOPBACK
0
1
RXQ
RXIN
TXIN
TXQ
TXIN
RXIN
January 2006
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or (408) 955-1690
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