Multimode SCSI 14 Line Terminator
UCC5628
FEATURES
Auto Selection Single Ended (SE) or
•
Low Voltage Differential (LVD)
Termination
Meets SCSI-1, SCSI-2, SCSI-3, SPI,
•
Ultra (Fast-20), Ultra2 (SPI-2 LVD)
and Ultra3 Standards
2.7V to 5.25V Operation
•
Differential Failsafe Bias
•
Thermal packaging for low junction
•
temperature and better MTBF.
BLOCK DIAGRAM
2.15V
DESCRIPTION
The UCC5628 Multimode SCSI Terminator provides a smooth transition
into the next generation of the SCSI Parallel Interface (SPI-2). It automati
cally senses the bus, via DIFFB, and switches the termination to either sin
gle ended (SE) or low voltage differential (LVD) SCSI, dependent on which
type of devices are connected to the bus. The UCC5628 can not be used
on a HVD, EIA485, differential SCSI bus. If the UCC5628 detects a HVD
SCSI device, it switches to a high impedance state.
The Multimode terminator contains all functions required to terminate and
auto detect and switch modes for SPI-2 bus architectures. Single Ended
and Differential impedances and currents are trimmed for maximum effec
tiveness. Fail Safe biasing is provided to insure signal integrity. Device/Bus
type detection circuitry is integrated into the terminator to provide automatic
switching of termination between single ended and LVD SCSI and a high
impedance for HVD SCSI. The multimode function provides all the per
formance analog functions necessary to implement SPI-2 termination in a
single monolithic device.
The UCC5628 is offered in a 48 pin LQFP package for a temperature
range of 0°C to 70°C.
(NOISE LOAD)
HPD
–15mA ≤I
50µA ≤I
SOURCE
SINK
≤–5mA
≤200µA
REF
1.3V
1.3V
35 DIFFSEN
-
-
-
-
DISCNCT
34DIFFB
0.6V
REF
2.7V
REF
1.25V
10µA
36
3TRMPWR
HS/GND
25
GND
4-9
SOURCE/SINK REGULATOR
SE
LVD
HS/GND
ALL SWITCHES
UP
DOWN
OPEN
28-33
MODE
DISCNCT
10
REG
4.7µF .
110
124
110
124
56mV
–+
56mV
+–
SE GND SWITCH
56mV
–+
56mV
+–
SE GND SWITCH
52.5
52.5
52.5
52.5
27
LVD
SE
26
L1–
12
L1+
11
L14–
2
L14+
1
UDG-98099
SLUS302A - SEPTEMBER 1999
UCC5628
ABSOLUTE MAXIMUM RATINGS
TRMPWR Voltage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . +6V
Signal Line Voltage . . . . . . . . . . . . . . . . . . . . . 0V to TRMPWR
Package Dissipation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2W
Storage Temperature . . . . . . . . . . . . . . . . . . . –65°C to +150°C
Junction Temperature. . . . . . . . . . . . . . . . . . . –55°C to +150°C
Lead Temperature (Soldering, 10 sec.) . . . . . . . . . . . . . +300°C
Recommended Operating Conditions . . . . . . . . . 2.7V to 5.25V
Currents are positive into negative out of the specified terminal.
Note: Consult Packaging Section of Databook for thermal limi
-
tations and considerations of package.
RECOMMENDED OPERATING CONDITIONS
TRMPWR Voltage . . . . . . . . . . . . . . . . . . . . . . . . 2.7V to 5.25V
Temperature Ranges . . . . . . . . . . . . . . . . . . . . . . 0°C to +70°C
CONNECTION DIAGRAMS
(TOP VIEW)
FQP Package
HS/GND
HS/GND
HS/GND
REG
L1+
L1–
12
10
GND
LVD
HS/GND
HS/GND
HS/GND
L2+
L2–
L3+
L3–
L4+
L4–
L5+
L5–
L6+
L6–
L7+
L7–
SE
11
13
14
15
16
17
18
19
20
21
22
23
24
25
26
8
7
9
27
29
30
28
6
5
313233
HS/GND
HS/GND
HS/GND
TRMPWR
L14–
L14+
2
4
3
1
L13–
48
47
L13+
L12–
46
L12+
45
L11–
44
L11+
43
L10–
42
L10+
41
L9–
40
L9+
39
38
L8–
37
35
34
L8+
36
DISCNCT
DIFFSENS
DIFFB
HS/GND
HS/GND
HS/GND
ELECTRICAL CHARACTERISTICS
Unless otherwise stated, these specifications apply for TA=TJ= 0°C to 70°C,
TRMPWR = 3.3V.
PARAMETER TEST CONDITIONS MIN TYP MAX UNITS
TRMPWR Supply Current Section
TRMPWR Supply Current LVD Mode 20 25 mA
SE Mode 1.6 10 mA
Disabled Terminator 250 400
Regulator Section
1.25V Regulator LVD Mode 1.15 1.25 1.35 V
1.25V Regulator Source Current V
1.25V Regulator Sink Current V
= 0V –375 –700 –1000 mA
REG
= 3.3V 170 300 700 mA
REG
1.3V Regulator Diff Sense 1.2 1.3 1.4 V
1.3V Regulator Source Current V
1.3V Regulator Sink Current V
= 0V –15 –5 mA
REG
= 3.3V 50 200 µA
REG
2.7V Regulator SE Mode 2.5 2.7 3.0 V
2.7V Regulator Source Current V
2.7V Regulator Sink Current V
= 0V –375 –700 –1000 mA
REG
= 3.3V 170 300 700 mA
REG
Differential Termination Section
Differential Impedance 100 105 110
Common Mode Impedence (Note 2) 110 150 165 Ω
Differential Bias Voltage 100 125 mV
Common Mode Bias 1.15 1.25 1.35 V
Output Capacitance Single Ended Measurement to Ground (Note 1) 3 pF
µA
Ω
2