DS21S07AE Datasheet Download

Part No.:
DS21S07AE
Download:
Download Datasheet
Description:
[SCSI Terminator]
File Size:
89 K
Page:
10 Pages
Logo:
Manufacturer:
MAXIM [ MAXIM INTEGRATED PRODUCTS ]
PCB Prototype
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DS2109
DS2109
Plug and Play SCSI Terminator
FEATURES
PIN ASSIGNMENT
PDI
R1
R2
R3
R4
R5
HS–GND
HS–GND
PDO
R6
R7
R8
R9
TPWR
1
2
3
4
5
6
7
8
9
10
11
12
13
14
28
27
26
25
24
23
22
21
20
19
18
17
16
15
GND
R18
R17
R16
R15
R14
TCS
HS–GND
PDE
R13
R12
R11
R10
V
REF
Fully
SCSI
compliant with SCSI–1, Fast SCSI and Ultra
Compatible with Plug and Play SCSI Profile
Functionally compatible with DS21S07A
Provides active termination for 18 signal lines
2%
tolerance on termination resistors and voltage
regulator
Bus termination sensing
Low power down capacitance of 3 pF
Onboard thermal shutdown circuitry
DS2109, DS2109S 28–PIN SOIC (300 MIL)
DESCRIPTION
The DS2109 is intended for one chip Plug and Play
(PnP) SCSI termination. Plug and Play SCSI requires
the exit–point terminator on computer motherboards or
host bus adapters to automatically switch off if an exter-
nal device is connected to the system. The DS2109 sat-
isfies this requirement by offering the engineer a choice
of onboard current sensing circuitry or onboard ground
detect circuitry. If an external device is connected, the
DS2109 will automatically be isolated from the SCSI
bus thereby maintaining proper system termination.
The DS2109 integrates a low drop–out regulator, 18
precise switched 110 ohm termination resistors, and
bus termination sensors into a 28–pin 300 mil SOIC
package. Active termination provides: greater immu-
nity to voltage drops on the TERMPWR (TERMination
PoWeR) line, enhanced high–level noise immunity,
intrinsic TERMPWR decoupling, and very low quies-
cent current consumption. The DS2109 contains an
output port that can control the power down pin of addi-
tional terminators (DS21S07A) for Wide SCSI applica-
tions.
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