MAXIM DS2127 Technical data

General Description
The DS2127 Ultra3 LVD/SE SCSI terminator provides low-voltage differential (LVD)/single-ended (SE) termi­nations 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 sin­gle-ended devices are connected to the bus, the DS2127 uses SE termination. If any high-voltage differ­ential (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 termi­nating resistors can also be disconnected from the bus by asserting the ISO pin.
For the LVD termination, the DS2127 provides 14 pre­cisely trimmed resistors. Each resistor is biased with two current sources to a fail-safe state. For SE termina­tion, the DS2127 provides 14 precision 110resistors 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
DS2127
Ultra3 LVD/SE SCSI 14-Line Terminator
______________________________________________ Maxim Integrated Products 1
Pin Configuration
Ordering Information
Rev 1; 3/04
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.
查询DS2127供应商
PART TEMP RANGE
PIN­PACKAGE
DS2127 0°C to +70°C 48 LQFP DS2127
TOP
MARK
TOP VIEW
REF
R1N
R1P
V
HS_GND
HS_GND
HS_GND
HS_GND
HS_GND
HS_GND
TPWR
R14N
R14P
12111098765432
13
R2P
14
R2N
15
R3P
16
R3N
17
R4P
18
R4N
19
R5P R5N R6P R6N R7P R7N
20
21
22
23
24
2526272829303132333435
SE
GND
LVD
DS2127
HS_GND
HS_GND
HS_GND
LQFP
HS_GND
HS_GND
HS_GND
DIFFSENS
DIFF_CAP
1
36
ISO
48
R13N
47
R13P
46
R12N
45
R12P
44
R11N
43
R11P
42
R10N
41
R10P
40
R9N
39
R9P
38
R8N
37
R8P
DS2127
Ultra3 LVD/SE SCSI 14-Line Terminator
2 _____________________________________________________________________
ABSOLUTE MAXIMUM RATINGS
ELECTRICAL CHARACTERISTICS
(TPWR = V
TPWR(MIN)
to V
TPWR(MAX)
, TA= 0°C to +70°C, unless otherwise noted.)
Stresses beyond those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. These are stress ratings only, and functional operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to absolute maximum rating conditions for extended periods may affect device reliability.
Voltage Range on All Pins Relative to Ground ......-0.3V to +6.0V
V
REF
Continuous Output Current....................................±200mA
Operating Temperature Range...............................0°C to +70°C
Junction Temperature......................................................+150°C
Storage Temperature Range .............................-65°C to +160°C
Soldering Temperature .......................................See IPC/JEDEC
J-STD-020A Specification
PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS
TPWR Operating Supply Range (Note 1)
TPWR SUPPLY CURRENT
TPWR Supply Current (All Lines Open)
LVD TERMINATION (Applies to each line pair, 1 to 14 in LVD mode)
Differential-Mode Termination Resistance
Common-Mode Termination Resistance
Differential-Mode Bias V
Common-Mode Bias V
SE TERMINATION (Applies to single-ended terminators, 1 to 14 in SE mode)
Single-Ended Mode Termination Resistance
Termination Current I
SE Voltage Reference V
Pin Leakage With ISO high 400 nA
Single-Ended GND Resistance R
TERMINATOR PIN CAPACITANCE
Terminator Pin Capacitance C
V
REGULATOR
REF
1.25V Regulator Output Voltage V
1.25V Regulator Short-Circuit
Source Current
1.25V Regulator Short-Circuit
Sink Current
V
TPWR
I
TPWR_LVD
I
TPWR_SE
I
TPWR_ISO
R
DM
R
CM
DM
CM
R
SE
REF
GND
REF_LVD
I
SOURCE
I
SINK
LVD 2.7 3.3 5.5
SE 4 5.0 5.5
LVD SCSI mode 32
SE SCSI mode 10
ISO mode (terminators disabled) 750 µA
100 110
RP and RN shorted together (V
CM(MAX)
All lines open 100 125 mV
RP and RN shorted together (Note 1) 1.15 1.25 1.35 V
RSE = (VLX - 0.2) / ILX, where VLX = voltage at terminator pin with pin unloaded and
SE
I
LX
the pin forced to 0.2V
Signal level at 0.2V, all lines low -21 -24 -25.4
Signal level at 0.5V -18 -22.4
Measured at RP pins, I = 10mA 20 60
With ISO high (Note 2) 3 pF
IN
0.5V ≤ V
and RN lines simultaneously
V
REF
V
REF
= 2V, V
= current for each terminator pin with
2.0V, VCM applied to all R
CM
= 0V -375 -700 -1000 mA = 3.3V 170 300 700 mA
CM(MIN)
= 0.5V)
P
110 165
104.5 110 115.5
2.7 2.85 3.0 V
1.15 1.25 1.35 V
mA
mA
V
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