SY58620L

Precision 4.25Gbps CML 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-B

hbwhelp@micrel.com

or (408) 955-1690

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

) 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

). 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

Applications

· Backplane management
· Active cable transceivers
· SONET/SDH data/clock applications
· 4X Fibre Channel applications

Typical Applications

Precision Edge

Features

· Guaranteed AC performance over temperature and

voltage:
- Maximum Throughput 4.25Gbps

- <120ps

time

· Transmitter
- Patented input termination directly interfaces to AC-

or DC-coupled differential inputs

- Variable swing CML output
· Receiver
- 32dB high-gain Input
- Internal

50 input termination

- Accepts AC-coupled input signals as small as 10mV

(20mV

)

- 400mV

(800mV

) 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 enable
· Power supply +3.3V ±10%
· Industrial temperature range -40°C to +85°C
· Available in 24-pin (4mm x 4mm) MLFTM

Markets

· Precision telecom
· Enterprise server
· ATE
· Test and measurement

Micrel, Inc.

SY58620L

September 2005

M9999-093005-B

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

= V

/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

= V

/2.

1, 2

RXIN, /RXIN

Receiver Differential Input. Input accepts AC differential signals as small as 10mV (20mV

Each pin internally terminates to V

CC_RXIN

-1.3V (internal voltage reference) through 50

. Input

will default to an indeterminate state if RXIN inputs are 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

= V

/2.

14, 13

TXIN, /TXIN

Transmitter Differential Input. Input accepts AC- or DC-coupled differential signals as small as
100mV (200mV

). Each pin terminates to the TXVT

pin through 50

. Input will default to an

indeterminate state if TXIN inputs are 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

(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.

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.

SY58620L

September 2005

M9999-093005-B

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 falls below the threshold set
by LOSLVL.

LOSLVL

RX Loss-of-Signal Level Set. A resistor (R

LOSLVL

) connected between LOSLVL and V

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

) into 50

to V

or 100

across the pair.

5, 6

TXQ, /TXQ

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

) min swing to 400mV (800mV

) typ.

swing into 50

to V

CC_TXQ

or drive 100

across the pair depending on TXVCTRL.

8 VREF_CTRL

Transmitter Output Reference Voltage. Output biases to V

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

-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

. 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 0.1µF//0.01µF low ESR capacitors and place
as close to each V

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 0.1µF//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.

4 VCC_TXQ

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.

Truth Table

LOOPBACK RXQ

TXQ

0 RXIN TXIN
1 TXIN RXIN

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