DS2109S/T&R Maxim Integrated Products, DS2109S/T&R Datasheet - Page 3

• Manufacturer Part Number: DS2109S/T&R
• Description: IC TERM SCSI PLUG/PLAY 28-SOIC
• Manufacturer: Maxim Integrated Products
• Type: SCSIr

Specifications of DS2109S/T&R

• Number Of Terminations: 18
• Voltage - Supply: 4 V ~ 5.25 V
• Operating Temperature: 0°C ~ 70°C
• Mounting Type: Surface Mount
• Package / Case: 28-SOIC (7.5mm Width)
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant

The DS2109 consists of 3 major functional blocks,
Figure 2:
When the Bus Ground Sensing Circuitry or Bus Current
Sensing Circuitry determine that the SCSI bus is prop-
DS2109 BLOCK DIAGRAM Figure 2
Voltage reference, terminating resistors, and isolation
switches
Bus current sensing circuitry
Bus ground sensing circuity
PDO
PDE
PDI
REFERENCE
BANDGAP
BUS GROUND
CIRCUITRY
SENSING
DISABLE
+
–
BUFFER
POWER
DOWN
DISABLE
erly terminated without the DS2109, the power down
buffer isolates the resistors from the SCSI bus and dis-
ables the power amp, thereby placing the DS2109 in a
low power mode (the bus sensing circuitry always stays
active). The PDO (Power Down Output) pin can be con-
nected to the pin of a DS21S07A SCSI terminator for
Wide SCSI configurations, Figure 8.
BUS CURRENT
CIRCUITRY
SENSING
110 OHMS
110 OHMS
110 OHMS
TCS
R14
R18
R1
V
REF
022698 3/10
DS2109