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參數(shù)資料
| 型號： | G219R-D3 |
| 廠商： | Electronic Theatre Controls, Inc. |
| 英文描述： | Ultra320 Multi-mode LVD/SE SCSI Terminator |
| 中文描述： | Ultra320的多模內(nèi)徑/東南的SCSI終結(jié)者 |
| 文件頁數(shù)： | 2/9頁 |
| 文件大小： | 130K |
| 代理商： | G219R-D3 |
Ver 1.2
Feb 08, 2002
TEL: 886-3-5788833
http://www.gmt.com.tw
2
G219
Global Mixed-mode Technology Inc.
Ordering Information
PART NUMBER
TEMP. RANGE
0oC-70oC
0oC-70oC
PIN-PACKAGE
G219T-D3
G219R-D3
TSSOP-28 pin / Tube
TSSOP-28 pin / Tape & Reel
Note:
DIFFSENS
Refers to the SCSI bus signal.
DIFFSENSE
Refers to the G219 pin name and internal circuitry relating to differential sensing.
DIFFB
Refers to the G219 pin name and internal circuitry relating to monitoring the DIFFSENS line.
Functional Description
The G219 is used in multi-mode active termination
applications, where single ended (SE) and low voltage
differential (LVD) devices might coexist. The LVD ter-
mination section consists of 18 source/sink amplifiers
(VTOP, VBOT), biasing circuitry and nine precision
resistor strings (RTOP, RMID, RBOT). The SE termi-
nation section consists of a 2.85V source/sink regula-
tor with 9 precision 110ohm resistor. The DIFFSENSE
section consists of a 1.3V, 5mA driver and a sensing
circuit (Figure 1)
DIFFSENS is used to identify which types of SCSI
devices are present on the bus. If the voltage on
DIFFSENS 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.
The G219 DIFFB pin monitors the DIFFSENS line to
determine the proper operating mode of the device.
HVD Isolation Mode
The G219 identifies that there is
an HVD (high voltage differential) device on the SCSI
bus and isolates the termination pins from the bus.
When DISCNCT is pulled high, the termination pins
are isolated from the SCSI bus, and VREF is
grounded. During thermal shutdown, the termination
pins are isolated from the SCSI bus and VREF is
grounded. The DIFFSENSE driver is shut down during
either of these two events.
To ensure proper operation, the TPWR pin should be
connected to the SCSI bus TERMPWR line. As with all
analog circuitry, the TERMPWR lines should be by-
passed 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
G219. The G219 should be placed as close as possi-
ble to the SCSI connector to minimize signal and
power trace length, thereby resulting in less input ca-
pacitance and reflections which can degrade the bus
signals.
The DIFFSENSE pin can drive the SCSI DIFFSENS
line (when M/S is pulled high) to determine the SCSI
bus operating mode. The G219 switches to the termi-
nation mode that is appropriate for the bus based on
the value of the DIFFSENS voltage. These modes are:
LVD mode
LVD termination is provided by a precision
resistor string with two amplifiers. This configuration
yields a 105
differential and 150
common mode
impedance. A fail safe bias of 112mV is maintained
when no drivers are connected to the SCSI bus.
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 regula-
tion. The terminating resistors maintain their 110
value.
To maintain the specified regulation, a 4.7μF capacitor
is required between the VREF pin and ground of each
G219. A high frequency cap (0.1μF ceramic recom-
mended) can also be placed on the VREF pin in ap-
plications that use fast rise/fall time drivers. A typical
SCSI bus configuration is shown in Figure2.
An internal pull down resistor assures that the G219
will be terminating the bus if the DISCNCT pin is left
floating.
DIFFSENS noise filtering
The G219 incorporates a internal digital filter to re-
move the noise signal on the DIFFSENS control line,
thereby eliminating erroneous switching between
modes. The external filter may be used in addition to
the internal digital filter.
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相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| G219T-D3 | 制造商:未知廠家 制造商全稱:未知廠家 功能描述:Ultra320 Multi-mode LVD/SE SCSI Terminator |
| G2-1A02-ST | 功能描述:固態(tài)繼電器-PCB安裝 SPST 150MA 6 PIN SMD RoHS:否 制造商:Omron Electronics 控制電壓范圍: 負載電壓額定值:40 V 負載電流額定值:120 mA 觸點形式:1 Form A (SPST-NO) 輸出設(shè)備:MOSFET 封裝 / 箱體:USOP-4 安裝風(fēng)格:SMD/SMT |
| G2-1A02-TT | 制造商:M.E.C. Relays 功能描述: |
| G2-1A03-ST | 功能描述:固態(tài)繼電器-PCB安裝 SPST 150MA 6 PIN SMD RoHS:否 制造商:Omron Electronics 控制電壓范圍: 負載電壓額定值:40 V 負載電流額定值:120 mA 觸點形式:1 Form A (SPST-NO) 輸出設(shè)備:MOSFET 封裝 / 箱體:USOP-4 安裝風(fēng)格:SMD/SMT |
| G2-1A03-TT | 功能描述:固態(tài)繼電器-PCB安裝 SPST 150MA 6 DIP RoHS:否 制造商:Omron Electronics 控制電壓范圍: 負載電壓額定值:40 V 負載電流額定值:120 mA 觸點形式:1 Form A (SPST-NO) 輸出設(shè)備:MOSFET 封裝 / 箱體:USOP-4 安裝風(fēng)格:SMD/SMT |
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