Microsemi Corporation LX5218CPW, LX5218CDW Datasheet

LIN DOC #:

5218

UltraMAX

9-CHANNEL PLUG AND PLAY SCSI TERMINATOR

THE INFINITE POWER OF INNOVATION

DESCRIPTION KEY FEATURES

The LX5218 SCSI terminator is part of Linfinity's UltraMAX family of high-performance, adaptive, nonlinear mode SCSI products, which are designed to deliver true UltraSCSI performance in SCSI applications. The low voltage BiCMOS architecture employed in their design offers superior performance to older linear passive and active techniques. Linfinity's UltraMAX architecture employs high-speed adaptive elements for each channel, thereby providing the fastest response possible — typically 35MHz, which is 100 times faster than the older linear regulator/terminator approach used by other manufacturers. Products using this older linear regulator approach have bandwidths which are dominated by the output capacitor and which are limited to 500KHz (see further discussion in the Functional Description section). The UltraMAX architecture also eliminates the output compensation capacitor typical in earlier terminator designs. It is approved for use with SCSI1, -2, -3, UltraSCSI and beyond — providing the highest performance alternative available today.

Another key improvement offered by the LX5218 lies in its ability to insure reliable, error free communications even in systems which do not adhere to recommended SCSI hardware design guidelines, such as the use of improper cable lengths and

IMPORTANT: For the most current data, consult LinFinity's web site: http://www.linfinity.com.

impedances. Frequently, this situation is not controlled by the peripheral or host designer and, when problems occur, they are the first to be made aware of the problem. The LX5218 architecture is much more tolerant of marginal system integrations.

The LX5218 has two disconnect pins for SCSI Plug and Play (PnP) applications. Quiescent current is typically less than (275µA) in disable mode, while the output capacitance is also less than 3pF. The obvious advantage of extended battery life for portable systems is inherent in the product's sleepmode feature. Additionally, the disable function permits factory-floor or production-line configurability, reducing inventory and product-line diversity costs. Field configurability can also be accomplished without physically removing components which, often times results in field returns due to mishandling.

Reduced component counts is also inherent in the LX5218 architecture. Traditional termination techniques require large stabilization and transient protection capacitors of up to 20µF in value and size. The LX5218 architecture does not require these components, allowing all the cost savings associated with inventory, board space, assembly, reliability, and component costs.

P RODUCTION DATA SHEET

LX5218

■ SCSI PLUG AND PLAY, DUAL LOW

DISCONNECT, LOGIC LOW COMMAND DISCONNECTS ALL TERMINATION LINES

■ HOT SWAP COMPATIBLE

■ ULTRA-FAST RESPONSE FOR FAST-20

SCSI APPLICATIONS

■ 35MHz CHANNEL BANDWIDTH

■ 3.5V OPERATION

■ LESS THAN 3pF OUTPUT CAPACITANCE

■ DISABLE-MODE CURRENT LESS THAN

275µA

■ THERMALLY SELF LIMITING

NO EXTERNAL COMPENSATION

■

CAPACITORS

WIDE

■ IMPLEMENTS 8-BIT OR 16-BIT (

APPLICATIONS

■ COMPATIBLE WITH ACTIVE NEGATION

DRIVERS (60mA / CHANNEL)

■ COMPATIBLE WITH PASSIVE AND

ACTIVE TERMINATIONS

■ APPROVED FOR USE WITH SCSI-1, -2, -3

AND ULTRASCSI

■ CONSULT FACTORY FOR APPLICATION

TEST REPORT

)

PRODUCT HIGHLIGHT

DRIVING WAVEFORM - 20MHZRECEIVING WAVEFORM - 20MHZ

Receiver

1 Meter, AWG 28

LX5218 LX5218

LX5268 LX5268

PACKAGE ORDER INFORMATION

(°C)

Plastic SOWB

DW PW

16-pin

0 to 70 LX5218CDW LX5218CPW

Note: All surface-mount packages are available in Tape & Reel.

Append the letter "T" to part number. (i.e. LX5218CDWT)

Driver

Plastic TSSOP 20-pin

NOTE:

For An In-Depth

Discussion On Applying

SCSI, Request Linfinity

Application Note:

"Understanding The

Single-Ended SCSI Bus"

L INFINITY MICROELECTRONICS INC.

11861 WESTERN AVENUE, GARDEN GROVE, CA. 92841, 714-898-8121, FAX: 714-893-2570

PRODUCT DATABOOK 1996/1997

LX5218

9-CHANNEL PLUG AND PLAY SCSI TERMINATOR

RODUCTION DATA SHEET

ABSOLUTE MAXIMUM RATINGS (Note 1)

Continuous Termination Voltage .......................................................................... 10V

Continuous Output Voltage Range .............................................................. 0 to 5.5V

Continuous Disable Voltage Range ............................................................. 0 to 5.5V

Operating Junction Temperature ........................................................... 0°C to 125°C

Storage Temperature Range ............................................................. -65°C to +150°C

Solder Temperature (Soldering, 10 seconds) ................................................... 300°C

Note 1. Exceeding these ratings could cause damage to the device.

THERMAL DATA

DW PACKAGE:

x θ

θθ

THERMAL RESISTANCE-JUNCTION TO AMBIENT,

PW PACKAGE:

THERMAL RESISTANCE-JUNCTION TO AMBIENT,

Junction Temperature Calculation: TJ = TA + (P

numbers are guidelines for the thermal performance of the device/pc-board system.

The θ

All of the above assume no ambient airflow.

95°C/W

144°C/W

UltraMAX

PACKAGE PIN OUTS

TERM POWER

GND

TERM POWER

N.C. N.C.

D0 D1 D2 D3 D4

N.C.

GND

1 16

215

N.C.

314

413

512

611

710

DW PACKAGE

(Top View)

219

318

417

516

615

714

813

912 10 11

TERM POWER DISC1 DISC2 D8 D7 D6 D5 GND

TERM POWER DISC1 DISC2 D8 D7 N.C. D6 D5 N.C. GND

PW PACKAGE

(Top View)

Rev. 1.7 12/97

PRODUCT DATABOOK 1996/1997

UltraMAX

LX5218

9-CHANNEL PLUG AND PLAY SCSI TERMINATOR

P RODUCTION DATA SHEET

RECOMMENDED OPERATING CONDITIONS (Note 2)

Parameter

Termination Voltage V High Level Disable Input Voltage V

Low Level Disable Input Voltage V

Operating Virtual Junction Temperature Range

LX5218C

Note 2. Range over which the device is functional.

Symbol

TERM

ELECTRICAL CHARACTERISTICS

Term Power = 4.75V unless otherwise specified. Unless otherwise specified, these specifications apply at the recommended operating ambient temperature of T

= 25°C. Low duty cycle pulse testing techniques are used which maintains junction and case temperatures equal to the ambient temperature.

Parameter

Output High Voltage V

TermPwr Supply Current I

Output Current I Disable Input Current I

Output Leakage Current I

Capacitance in Disabled Mode C Channel Bandwidth BW Termination Sink Current, per Channel I

Symbol

OUT

OUTVOUT

SINKVOUT

Test Conditions Units

All data lines = open All data lines = 0.5V DISC1 Pin = DISC2 Pin = 0V

= 0.5V DISC1 Pin = DISC2 Pin = 4.75V

DISC1 Pin = DISC2 Pin = 0V DISC1 Pin = DISC2 Pin = 0V, VO = 0.5V

= 0V, frequency = 1MHz

= 4V

Recommended Operating Conditions

Min. Typ. Max.

3.5 5.5 V 2V

0 0.8 V

0 125 °C

TERM

LX5218

Min. Typ. Max.

2.65 2.85 V

69mA 215 225 mA

275 µA

-21 -23 -24 mA 90 µA

-10 nA 10 nA

3pF 35 MHz 60 mA

Units

PRODUCT DATABOOK 1996/1997

LX5218

DISC1 DISC2

TERM POWER

THERMAL

LIMITING

CIRCUIT

9-CHANNEL PLUG AND PLAY SCSI TERMINATOR

RODUCTION DATA SHEET

BLOCK DIAGRAM

CURRENT

BIASING

CIRCUIT

24mA CURRENT

LIMITING CIRCUIT

2.85V

UltraMAX

DATA OUTPU PIN DB(0)

1 OF 9 CHANNELS

FUNCTIONAL DESCRIPTION

Cable transmission theory suggests to optimize signal speed and quality, the termination should act both as an ideal voltage reference when the line is released (deasserted) and as an ideal current source when the line is active (asserted). Common active terminators, which consist of Linear Regulators in series with resistors (typically

110Ω), are a compromise. As the

line voltage increases, the amount of current decreases linearly by the equation V = I * R. The LX5218, with its unique new architecture applies the maximum amount of current regardless of line voltage until the termination high threshold (2.85V) is reached.

Acting as a near ideal line terminator, the LX5218 closely reproduces the optimum case when the device is enabled. To enable the device the DISC1 and DISC2 Pins must be pulled logic High, Open, or any combination of both High and Low. During this mode of operation, quiescent current is 6mA and the device will

POWER UP / POWER DOWN FUNCTION TABLE

DISC1 DISC2

H H Enabled 6mA H L Enabled 6mA

L H Enabled 6mA L L Disabled 275µA

Open Open Enabled 6mA

respond to line demands by delivering 24mA on assertion and by imposing 2.85V on deassertion. In order to disable the device, the DISC1 and DISC2 pins must be driven logic Low. This mode of operation places the device in a sleep state where

a meager 275µA of quiescent current is consumed. Additionally, all outputs are in a Hi-Z (impedance)

Outputs

LX5218 has been optimized to have only 3pF of capacitance per output in the sleep state.

An additional feature of the LX5218 is its compatibility with active negation drivers. The device handles up to 60mA of sink current for drivers which exceed the 2.85V output high.

Quiescent

Current

state. Sleep mode can be used for

power conservation or to completely eliminate the terminator from the SCSI chain. In the second case, termination node capacitance is important to consider. The ter-

minator will appear as a parasitic distributed capacitance on the line, which can detract from bus performance. For this reason, the

Rev. 1.7 12/97

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