Microsemi

Integrated Products Division

11861 Western Avenue, Garden Grove, CA. 92841, 714-898-8121, Fax: 714-893-2570

Page 4

Copyright

© 2000

Rev. 1.0c, 2005-02-08

LX5261

27-Line LVD SCSI Source/Sink Regulator

TM

®

BLOCK DI AGRAM

+

-

6

7

3

VTERM

1.3V

Reference

+

-

1.75V

Reference

+

-

0.75V

Reference

1.3V +/- 0.1V

1.75V +/- 0.05V

200mA source/sink

0.75V +/- 0.05V

200mA source/sink

2

4

GND

DIFSENS

VOUT1

VOUT2

Figure 1 – LX5261 Block Diagram

APPLI CATI ON I N FORMATI O N

LVD SCSI with Resistor Stack

The LX5261 is used with a LVD resistor network (475Ω, 121Ω, 475Ω) to meet LVD SCSI performance. Connecting the top side of the

voltage required by the SPI-2 through SPI-4 SCSI specification (see Figure 2. below). The LX5261 is designed to drive up to 27 LVD

pairs.

6

3

+

-

+

-

1.75V +/- 0.05V

200mA source/sink

0.75V +/- 0.05V

200mA source/sink

VOUT1

VOUT2

475

1%

475

1%

121

1%

Ln-

Ln+

1 of 27

LVD Pairs

4.7uF

4.7uF

27

27

Common Mode Impedance

Differential Bias Voltage

Common Mode Voltage

Differential Impedance

112.9

107.3

237

1.25

100 to 110

100 to 125

100 to 300

1.2 to 1.3

Parameter

LX5261

SCSI Standard

Units

ohm

mV

V

ohm

Figure 2 – LX5261 with LVD Resistor Stack