GMT G218A

G218A
Global Mixed-mode Technology Inc.
Multi-mode LVD/SE SCSI Terminator
Features
General Description
„Auto-selectable multi-mode Single-Ended
The G218A Multi-mode LVD/SE SCSI terminator provides a smooth transition into the next generation of
the SCSI Parallel Interface (SPI-2). It automatically
senses the bus, via DIFFSENS, and switches the termination to either single-ended (SE) or low voltage
differential (LVD) SCSI, dependent on which type of
devices are connected to the bus. If the G218A detects a HVD SCSI device, it switches to a high impedance state. For a 16-bit Wide SCSI bus to be operational, three G218A terminators are needed.
or LVD Termination
„Meets SCSI-1, SCSI-2, SCSI-3 SPI Ultra
(Fast-20), Ultra 2(SPI-2 LVD), Ultra160 standards.
„Supports active negation
„Current limit and thermal protection
„Hot-Swap compatible (Single-Ended)
„5% tolerance on SE and LVD termination
resistance
„28 and 36 pin SSOP package
„28 Pin SSOP: Pin Compatible with DS2119
„36 Pin SSOP: Pin Compatible with DS2118,
LX5241 and UCC5630
The Multi-mode terminator contains all functions required to terminate and auto detect and switch modes
for SCSI parallel Interface (SPI-2) bus architectures.
For the SE termination, one regulator and nine precision 110ohm resistors are used. For the LVD termination, the G218A integrates two regulated supplies with
nine precision resistor strings.
Applications
„Server and workstation
„High-end PC
„Industrial PC
„Disk Array (RAID)
„SCSI cable
Pin Configuration
(Top View)
G218A
G218A
TPWR
VREF
NC
1
36
2
35
HVD
NC
3
34
LVD
R1+
4
33
SE
R1-
5
32
R9-
6
31
R9+
7
30
R8-
VREF
1
28
TPWR
R1+
2
27
R1-
3
26
TPWR
R9-
R2+
R2-
4
25
R9+
R2+
R2-
5
24
R8-
HS/GND
8
29
NC
6
23
R8+
28
R3+
7
22
NC
HS/GND 9
HS/GND 10
R8+
HS/GND
27
HS/GND
R3-
8
21
R7-
R3+
11
26
HS/GND
R4+
9
20
R7+
R3-
12
25
R4-
10
19
R6-
R4+
13
24
R7R7+
R6+
R4-
14
23
R6-
R5+
15
22
R6+
R5-
16
21
DIFFB
DISCNCT
17
20
GND 18
19
DIFFSENSE
M/S
R5+
11
18
R5-
12
17
DIFFB
DISCNCT
13
16
DIFFSENSE
GND
14
15
M/S
28Pin SSOP/TSSOP
36Pin SSOP
Ver 3.3
Sep 11, 2001
TEL: 886-3-5788833
http://www.gmt.com.tw
1
Global Mixed-mode Technology Inc.
G218A
Ordering Information
PART NUMBER
TEMP. RANGE
PIN-PACKAGE
FEATURE
G218AT-S4
G218AR-S4
0ºC-70ºC
0ºC-70ºC
SSOP-28 pin / Tube
SSOP-28 pin / Tape & Reel
DISCNCT does not disable VREF
DISCNCT does not disable VREF
G218AT-S5
G218AR-S5
G218AT-D3
G218AR-D3
0ºC-70ºC
0ºC-70ºC
0ºC-70ºC
0ºC-70ºC
SSOP-36 pin / Tube
SSOP-36 pin / Tape & Reel
TSSOP-28 pin / Tube
TSSOP-28 pin / Tape & Reel
DISCNCT does not disable VREF
DISCNCT does not disable VREF
DISCNCT does not disable VREF
DISCNCT does not disable VREF
Functional Description
The DIFFSENSE pin can also drive the SCSI
DIFFSENS line (when M/S=1) to determine the SCSI
bus operating mode. The G218A switches to the termination mode that is appropriate for the bus based on
the value of the DIFFSENS voltage. These modes are:
The G218A combines LVD and SE termination with
DIFFSENS sourcing and detection. The LVD termination section consists of two source/sink amplifiers
(VTOP, VBOT), biasing circuitry and nine precision
resistor strings (RTOP, RMID, RBOT). The SE termination section consists of a 2.85V source/sink regulator with 9 precision 110ohm resistor. The DIFFSENSE
section consists of a 1.3V, 5mA driver and a sensing
circuit (Figure 1)
LVD mode LVD termination is provided by a precision
resistor string with two amplifiers. This configuration
yields a 105Ω differential and 150Ω common mode
impedance. A fail safe bias of 112mV is maintained
when no drivers are connected to the SCSI bus.
DIFFSENSE is used by multi-mode transceiver
(LVD/SE) to determine if the device is connected to a
single-ended, LVD or HVD SCSI bus. If the voltage on
DIFFSENSE is between 0-0.5V the bus is single-ended; if it is between 0.7-1.9V the bus is LVD;
and if it is greater than 2.4V, the bus is HVD.
SE mode When the external driver for a given signal
line turns off, the active terminator will pull that signal
line to 2.85 volts (quiescent state). When used with an
active negation driver, the power amp can sink 22mA
per line.
while keeping the voltage reference in regulation. The
terminating resistors maintain their 110Ω value.
The G218A DIFFB pin monitors the DIFFSENS line to
determine the proper operating mode of the device;
this mode is indicated by the SE/LVD/HVD outputs.
power trace length, thereby resulting in less input capacitance and reflections which can degrade the bus
signals.
HVD Isolation Mode The G218A identifies that there
is an HVD (high voltage differential) device on the
SCSI bus and isolates the termination pins from the
bus.
To maintain the specified regulation, a 4.7µF capacitor
is required between the VREF pin and ground of each
G218A. A high frequency cap (0.1µF ceramic recommended) can also be placed on the VREF pin in applications that use fast rise/fall time drivers. A typical
SCSI bus configuration is shown in Figure2.
When DISCNCT=1, the termination pins are isolated
from the SCSI bus, and the bus mode indicators
(SE/LVD/HVD) as well as VREF remains active. During thermal shutdown, the termination pins are isolated
from the SCSI bus and VREF becomes high impedance. The DIFFSENSE driver is shut down during either of these two events.
An internal pull down resistor assures that the G218A
will be terminating the bus if the DISCNCT pin is left
floating.
To ensure proper operation, the TPWR pin should be
connected to the SCSI bus TERMPWR line. As with all
analog circuitry, the TERMPWR and VDD lines should
be bypassed locally. A 2.2µF capacitor and a 0.01µF
high frequency capacitor is recommended between
TPWR and ground and placed as close as possible to
the G218A. The G218A should be placed as close as
possible to the SCSI connector to minimize signal and
Note:
DIFFSENSRefers to the SCSI bus signal.
DIFFSENSERefers to the G218A pin name and internal circuitry relating to differential sensing.
DIFFBRefers to the G218A pin name and internal
circuitry relating to monitoring the DIFFSENS line.
Ver 3.3
Sep 11, 2001
TEL: 886-3-5788833
http://www.gmt.com.tw
2
G218A
Global Mixed-mode Technology Inc.
G218A Block Diagram
(Figure 1)
( 36pin SSOP only )
DIFFSENSE
DISCNCT M/S
SE LVD HVD
THERMAL
SHUTDOWN
CIRCUITRY
SE
LVD
HVD
DIFFSENSE
CIRCUITRY
DIFFB
CONTROL
LOGIC
VREF
VREF
+
_
R1-
110 Ohms
R9110 Ohms
BANDGAP
REFERENCE
+
_
VTOP
RTOP
R1-
R1R9R9-
RMID
R1+
R1+
R9+
R9+
RBOT
+
_
VBOT
SE
GND
DRIVER
Ver 3.3
Sep 11, 2001
TEL: 886-3-5788833
http://www.gmt.com.tw
3
G218A
Global Mixed-mode Technology Inc.
SCSI Bus Configuration (Figure 2)
CONTROL LINES (9)
TERMPWR
2.2µF
TERMPWR
TPWR
M/S
DISCNCT
TPWR
M/S
DISCNCT
G218A
G218A
DIFFSENS
DIFFSENSE
VREF
20K
20K
2.2µF
DIFFSENSE
DIFFB
VREF
DIFFB
0.1µF
0.1µF
4.7µF
4.7µF
DATA LINES (9)
TPWR
TPWR
M/S
M/S
DISCNCT
G218A
DIFFB
DIFFB
VREF
4.7µF
4.7µF
2.2µF
2.2µF
DISCNCT
G218A
VREF
2.2µF
DATA LINES (9)
TPWR
TPWR
M/S
DISCNCT
M/S
DISCNCT
G218A
VREF
2.2µF
G218A
DIFFB
DIFFB
VREF
4.7µF
4.7µF
Ver 3.3
Sep 11, 2001
TEL: 886-3-5788833
http://www.gmt.com.tw
4
Global Mixed-mode Technology Inc.
Pin Description
G218A
(for 28pin SSOP)
PIN
SYMBOL
DESCRIPTION
1
VREF*
2-5,7-12,
18-21, 23-26
Rx+, Rx-
Reference Voltage. 2.85-volt reference; a regulator bypass, must be connected to a 4.7µF capacitor.
Signal Termination. (X=1,2,3,…..9)
Rx+: Ground line for single-ended or positive line for differential applications for the SCSI bus.
Rx-: Signal line/active line for single-ended or negative line in differential applications for the SCSI
bus.
6,22
13
14
NC
DISCNCT
GND
15
M/S
16
17
27,28
No Connect. Do not connect these pins.
Disconnect. When pulled high, the G218 isolates its bus pins (Rx+, Rx-) from the SCSI bus.
Ground. Terminator ground pin. Connected to ground.
Master/slave. Used to select which terminator is the controlling device. M/S pin high enables the
DIFFSENSE driver.
DIFFSENSE Output to drive the SCSI bus DIFFSENS line.
DIFFB pin should be connected to a 0.1µF capacitor to GND and 20k resistor to SCSI/Bus
DIFFB
DIFFSENS line. An input pin to detect the type of device (differential or single-ended) on the SCSI
bus.
TPWR
Terminator Power. Connect to the SCSI TERMPWR line and de-couple with a 2.2µF capacitor.
*The VREF keeps the level at 2.85 volt, despite the DISCNCT pin is asserted or not; even the termination mode is changed.
(36pin SSOP)
PIN
SYMBOL
1
VREF*
2,3
4-7,11-16,
22-25,
29-32
8, 9,10,26,
27,28
17
NC
DISCNCT
18
GND
19
20
21
Rx+
RxHS/GND
DESCRIPTION
Reference Voltage. 2.85-volt reference; a regulator bypass, must be connected to a 4.7µF capacitor.
No Connect. Do not connect these pins.
Signal Termination. (X=1,2,3,…..9)
Rx+: Ground line for single-ended or positive line for differential applications for the SCSI bus.
Rx-: Signal line/active line for single-ended or negative line in differential applications for the SCSI bus.
Heat Sink Ground. Connect to large area PC board traces to increase power dissipation capability.
Disconnect. When pulled high, the G218 isolates its bus pins (Rx+, Rx-) from the SCSI bus.
Ground. Terminator ground pin. Connected to ground.
Master/slave. Mode select for the non controlling terminator.
M/S
MSTR enables the DIFFSENSE driver.
DIFFSENSE Output to drive the SCSI bus DIFFSENS line.
DIFFB pin should be connected to a 0.1µF capacitor to GND and 20k resistor to SCSI/Bus
DIFFB
DIFFSENS line. An input pin to detect the type of device (differential or single-ended) on the SCSI
bus.
33
34
SE
LVD
35
HVD
36
TPWR
Single ended mode indicator. It is HIGH when terminator is operating in SE mode.
Low Voltage Differential mode indicator. It is HIGH when terminator is operating in LVD mode.
High Voltage Differential mode indicator. It is HIGH when terminator is operating in HVD mode
or thermal shutdown.
Terminator Power. Connect to SCSI bus TERMPWR line and decouple with 2.2µF capacitor.
*The VREF keeps the level at 2.85 volt, despite the DISCNCT pin is asserted or not; even the termination mode is changed.
Ver 3.3
Sep 11, 2001
TEL: 886-3-5788833
http://www.gmt.com.tw
5
G218A
Global Mixed-mode Technology Inc.
Recommended Operating Conditions
SYMBOL
MIN
TYP
MAX
UNITS
Termpower Voltage
PARAMETER
Vtpwr
4.5
5
5.50
V
Logic 0
Logic 1
Operating Temperature
Vil
Vih
Tamb
-0.3
2.0
0
+0.8
Vtpwr+0.3
70
V
V
°C
NOTES
(0°C to 70°C)
Single Ended Characteristics
SYMBOL
MIN
TYP
MAX
UNITS
NOTES
SE Termination Resistance
PARAMETER
Rse
104.5
110
115.5
Ohms
Vline = 0-3.0 volts
SE Voltage Reference
SE output Current
Vref
Iose
2.79
2.85
2.93
25.4
Volts
mA
Vline = 0.2 volts
(0°C to 70°C)
Low Voltage Differential Characteristics
PARAMETER
SYMBOL
MIN
TYP
MAX
UNITS
Differential Mode Termination Resistance
Common Mode Termination Resistance
Rdm
Rcm
100
110
105
150
110
190
Ohms
Ohms
Differential Mode Bias
Common Mode Bias
Vdm
Vcm
100
1.125
112
1.25
125
1.375
mV
V
All lines Open
(0°C to 70°C)
DC Characteristics
PARAMETER
SYMBOL
MIN
Termpower Current
Input Leakage High
Itpmr
Iih
-1.0
Input Leakage Low
Output Current High
Output Current Low
DIFFSENS SE Operating Range
Iil
Ioh
Iol
Vseor
-1.0
4.0
-0.3
DIFFSENS LVD Operating Range
DIFFSENS HVD Operating Range
DIFFSINS Driver Output Voltage
DIFFSENSE Driver Source Current
Vlvdor
Vhvdor
Vdso
Idsh
0.7
2.4
1.2
Idsl
20
DIFFSENSE Driver Sink Current
TYP
MAX
35
1.0
5
UNITS
NOTES
mA
µA
All lines Open
0.5
µA
mA
mA
V
1.9
Vtpwr+0.3
1.4
15
V
V
V
mA
M/S=1; Ids = 0-5mA
M/S = 1; Vdso=0V
200
µA
M/S=1; Vdso=2.75V
Vout = 2.4 volts;SE/LVD/HVD Pins only
Vout=0.4 volts;SE/LVD/HVD Pins only
(0°C to 70°C)
Regulator Characteristics
PARAMETER
Line Regulation
Load Regulation
Current Limit
Sink Current
NOTES
SYMBOL
MIN
LIREG
LOREG
ILIM
ISINK
200
TYP
MAX
UNITS
1.0
1.3
350
2.0
3.0
%
%
mA
NOTES
mA
Ver 3.3
Sep 11, 2001
TEL: 886-3-5788833
http://www.gmt.com.tw
6
G218A
Global Mixed-mode Technology Inc.
Package Information (28 pin SSOP)
0.25
C
D
L
28
E1
E
1.00 REF
1
θ
A2
A
A1
b
e
Min.
Dimension in mm
Typ.
Max.
Min.
Dimension in inch
Typ.
A
1.35
1.60
1.75
0.053
0.064
0.069
A1
A2
b
C
0.10
----0.20
0.19
----1.45
0.25
-----
0.25
----0.30
0.25
0.004
----0.008
0.007
----0.057
0.010
-----
0.010
----0.012
0.010
D
E
E1
e
9.80
5.80
3.80
-----
------------0.64
10.00
6.20
4.00
-----
0.386
0.228
0.150
-----
------------0.025
0.394
0.244
0.157
-----
L
y
θ
0.40
----0º
-------------
1.27
0.10
8º
0.016
----0º
-------------
0.050
0.004
8º
Symbol
Ver 3.3
Sep 11, 2001
Max.
TEL: 886-3-5788833
http://www.gmt.com.tw
7
G218A
Global Mixed-mode Technology Inc.
36 pin SSOP
C
L
E1 E
h x 45°
θ
D
A
A1
0.004 C
SEATING PLANE
b
e
Symbol
Min.
Dimension in mm
Typ.
Max.
Min.
Dimension in inch
Typ.
Max.
A
A1
b
c
2.413
0.203
0.300
0.127
2.591
0.305
2.794
0.406
0.450
0.254
0.095
0.008
0.012
0.005
0.102
0.012
0.110
0.016
0.018
0.010
D
e
E
E1
15.748
15.875
0.800 BASIC
16.002
0.620
0.625
0.032 BASIC
0.630
10.668
7.595
0.395
0.291
h
L
θ
0.381
0.508
0
0.635
1.016
8
0.015
0.020
0
10.033
7.391
7.493
Ver 3.3
Sep 11, 2001
0.295
0.420
0.289
0.025
0.040
8
TEL: 886-3-5788833
http://www.gmt.com.tw
8
G218A
Global Mixed-mode Technology Inc.
28 pin TSSOP
C
D
28
L
E1
E
1
θ
A
A2
A1
e
b
Note:
1. Package body sizes exclude mold flash protrusions or gate burrs
2. Tolerance ±0.1mm unless otherwise specified
3. Coplanarity : 0.1mm
4. Controlling dimension is millimeter converted inch dimensions are not necessarily exact.
5. Followed from JEDEC MO-153
SYMBOL
MIN.
DIMENSION IN MM
NOM.
MAX.
MIN.
DIMENSION IN INCH
NOM.
MAX.
A
-----
-----
1.20
-----
-----
0.048
A1
A2
b
C
0.05
0.80
0.19
0.09
----1.00
---------
0.15
1.05
0.30
0.20
0.002
0.031
0.007
0.004
----0.039
---------
0.006
0.041
0.012
0.008
D
E
E1
e
9.60
----4.30
-----
9.70
6.40
4.40
0.65
9.80
----4.50
-----
0.378
----0.169
-----
0.382
0.252
0.173
0.026
0.386
----0.177
-----
L
y
θ
0.45
----0º
0.60
---------
0.75
0.10
8º
0.018
----0º
0.024
---------
0.030
0.004
8º
Taping Specification
Feed Direction
Typical SSOP, TSSOP Package Orientation
Ver 3.3
Sep 11, 2001
TEL: 886-3-5788833
http://www.gmt.com.tw
9