Global Mixed-mode Technology Inc.
Pin Description
PIN
1
2-5,7-12,
18-21, 23-26
6,22
13
14
15
16
17
27,28
VREF*
G218A
(for 28pin SSOP)
DESCRIPTION
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.
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.
SYMBOL
Rx+, Rx-
NC
DISCNCT
GND
M/S
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
1
2,3
4-7,11-16,
22-25,
29-32
8, 9,10,26,
27,28
17
18
19
20
21
33
34
35
36
SYMBOL
VREF*
NC
Rx+
Rx-
HS/GND
DISCNCT
GND
DESCRIPTION
Reference Voltage.
2.85-volt reference; a regulator bypass, must be connected to a 4.7µF capaci-
tor.
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 capabil-
ity.
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.
SE
LVD
HVD
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
GMT [ GLOBAL MIXED-MODE TECHNOLOGY INC ]
