DS2108S/T&R Maxim Integrated Products, DS2108S/T&R Datasheet

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DS2108S/T&R

Manufacturer Part Number
DS2108S/T&R
Description
IC TERM SCSI DIFF/SWITCH 24-SOIC
Manufacturer
Maxim Integrated Products
Type
SCSI, HVD, SEr
Datasheet

Specifications of DS2108S/T&R

Number Of Terminations
9
Voltage - Supply
4 V ~ 5.25 V
Operating Temperature
0°C ~ 70°C
Mounting Type
Surface Mount
Package / Case
24-SOIC (7.5mm Width)
Lead Free Status / RoHS Status
Contains lead / RoHS non-compliant

Available stocks

Company
Part Number
Manufacturer
Quantity
Price
Part Number:
DS2108S/T&RDS2108S/T&R
Manufacturer:
DALLAS
Quantity:
20 000
FEATURES
DESCRIPTION
The DS2108 SCSI Terminator has been specifically designed for High Voltage Differential (HVD) SCSI
systems requiring switchable termination. The DS2108 integrates eighteen 330-ohm and nine 150-ohm
precise switched termination resistors into a monolithic IC. The surface mount SOIC package saves board
space over conventional resistor SIPs. The termination resistors can be isolated from the SCSI bus under
software or hardware control. While in the powered down mode, the DS2108 isolates the nine terminator
blocks from the bus while adding only 6 pF capacitance to each signal line of the SCSI bus.
FUNCTIONAL DESCRIPTION
The DS2108 consists of power-down circuitry, eighteen 330-ohm and nine 150-ohm termination resistors
(Figure 1). The DS2108 can be removed from the circuit by bringing the power down pin (PD) low. The
power down capacitance on the terminating resistors is 6 pF, well below the SCSI-3 allotment of 25 pF.
The DS2108 supports SCSI signal voltages of -7 to +12 volts when powered on or off. When all lines
settle into the quiescent state (no signal transitions), 56 mA is typically consumed. Only 1 mA is
typically consumed in the powered down mode.
www.dalsemi.com
Fully compliant with SCSI, SCSI-2 and SCSI-
3 standards
Conforms to EIA RS-485 standard
Provides differential termination for 9 pairs of
signal lines
Operates with SCSI signal voltages of -7 to
+12 Volts
Laser-trimmed 330 and 150-ohm termination
resistors have ±5% tolerance over full
temperature range
Switchable power-down mode
Low power down capacitance of 6 pF
24-pin plastic SOIC (DS2108S)
Differential SCSI Switchable Terminator
1 of 5
PIN ASSIGNMENT
TPWR
TPWR
R4N
R9N
R1N
R2N
R3N
R5N
R6N
R7N
R8N
DS2108S 24-Pin SOIC (300-mil)
NC
1
10
11
12
2
3
5
6
7
8
9
4
23
22
20
19
18
17
16
15
14
13
24
21
GND
R1P
R2P
R3P
R4P
R5P
R6P
R7P
R8P
R9P
GND
PD
DS2108
112099

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DS2108S/T&R Summary of contents

Page 1

FEATURES Fully compliant with SCSI, SCSI-2 and SCSI- 3 standards Conforms to EIA RS-485 standard Provides differential termination for 9 pairs of signal lines Operates with SCSI signal voltages +12 Volts Laser-trimmed 330 and 150-ohm termination ...

Page 2

DS2108 BLOCK DIAGRAM Figure DS2108 ...

Page 3

TYPICAL DIFFERENTIAL SCSI BUS CONFIGURATION Figure 2 NOTES: 1. Two DS2108s required per 8–bit SCSI device and three DS2108s per 16–bit SCSI device. 2. Mid–bus termination effectively removed by grounding 3. Termination power to be provided as specified in SCSI–3 ...

Page 4

ABSOLUTE MAXIMUM RATINGS* Voltage on Any Pin Relative to Ground Operating Temperature Storage Temperature Soldering Temperature * This is a stress rating only and functional operation of the device at these or any other conditions above those indicated in the ...

Page 5

SOIC (300-MIL) The chamfer on the body is optional not present, a terminal 1 identifier must be positioned so that ½ or more of its area is contained in the hatched zone. PKG 24-PIN DIM MIN ...

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