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DS2127
(Rev.:2004)

Ultra3 LVD/SE SCSI 14-Line Terminator

Maxim Integrated 

Rev 1; 3/04

Ultra3 LVD/SE SCSI 14-Line Terminator

General Description

The DS2127 Ultra3 LVD/SE SCSI terminator provides

low-voltage differential (LVD)/single-ended (SE) termi-

nations for 14 SCSI lines. Through the voltage on the

DIFF_CAP pin, the device detects the types of drivers

on the bus. If the device is connected in an LVD-only

bus, the DS2127 provides LVD termination. If any sin-

gle-ended devices are connected to the bus, the

DS2127 uses SE termination. If any high-voltage differ-

ential (HVD) devices are connected to the bus, the

DS2127 isolates itself from the SCSI bus. The mode

change has a built-in delay that is determined by an

integrated SPI-3 mode change filter/delay. The termi-

nating resistors can also be disconnected from the bus

by asserting the ISO pin.

For the LVD termination, the DS2127 provides 14 pre-

cisely trimmed resistors. Each resistor is biased with

two current sources to a fail-safe state. For SE termina-

tion, the DS2127 provides 14 precision 110Ω resistors

and one regulator for active-negation bias.

Applications

SCSI Array Backplane

SCSI Cables

Features

♦ Fully Compliant with Ultra2, Ultra3, Ultra160, and

Ultra320 SCSI Standards

♦ Provides LVD/SE Termination for 14 Signal Pairs

♦ Auto-Selection of LVD or SE Termination

♦ 5% Tolerance on SE and LVD Termination

Resistance

♦ Low 3pF Power-Down Capacitance

♦ Built-In Mode-Change Filter/Delay

♦ On-Board Thermal-Shutdown Circuitry

♦ SCSI Bus Hot-Plug Compatible

♦ Fully Supports Actively Negated SE SCSI Signals

PART

DS2127

Ordering Information

TEMP RANGE

0°C to +70°C

PIN-

PACKAGE

48 LQFP

TOP

MARK

DS2127

Pin Configuration

TOP VIEW

R2P 13

R2N 14

R3P 15

R3N 16

R4P 17

R4N 18

R5P 19

R5N 20

R6P 21

R6N 22

R7P 23

R7N 24

DS2127

48 R13N

47 R13P

46 R12N

45 R12P

44 R11N

43 R11P

42 R10N

41 R10P

40 R9N

39 R9P

38 R8N

37 R8P

LQFP

______________________________________________ Maxim Integrated Products 1

For pricing, delivery, and ordering information, please contact Maxim/Dallas Direct! at

1-888-629-4642, or visit Maxim’s website at www.maxim-ic.com.

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