Global Mixed-mode Technology Inc.
Pin Description
PIN
1
VREF*
G218B
(for 28pin SSOP/TSSOP)
DESCRIPTION
SYMBOL
Reference Voltage.
2.85-volt reference; must be connected to a 4.7µF capacitor.
Signal Termination.
(X=1,2,3,…..9)
2-5,7-12,
Rx+: Ground line for single-ended or positive line for differential applications for the SCSI bus.
Rx+, Rx-
18-21, 23-26
Rx-: Signal line/active line for single-ended or negative line in differential applications for the SCSI
bus.
6,22
NC/ HS GND
No Connect/ HS GND.
Should be grounded for heat sinking purpose.
13
DISCNCT
Disconnect.
When pulled high, the G218B isolates its bus pins (Rx+, Rx-) from the SCSI bus.
Ground.
Terminator ground pin. Connected to ground.
14
GND
Master/slave.
Used to select which terminator is the controlling device. M/S pin high enables the
15
M/S
DIFFSENSE driver.
16
DIFFSENSE Output to drive the SCSI bus DIFFSENS line.
17
27,28
DIFFB
TPWR
DIFFB pin should be connected to a 0.1µF capacitor to GND and 20k resistor to SCSI/Bus
DIFFSENS line. An input pin to detect the type of device (differential or single-ended) on the SCSI
bus.
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-
DESCRIPTION
Reference Voltage.
2.85-volt reference; 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 capabil-
HS/GND
ity.
DISCNCT
Disconnect.
When pulled high, the G218 isolates its bus pins (Rx+, Rx-) from the SCSI bus.
Ground.
Terminator ground pin. Connected to ground.
GND
Master/slave.
Used to select which terminator is the controlling device. M/S pin high enables the
M/S
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.
Single ended mode indicator.
It is HIGH when terminator is operating in SE mode.
SE
Low Voltage Differential mode indicator.
It is HIGH when terminator is operating in LVD mode.
LVD
High Voltage Differential mode indicator.
It is HIGH when terminator is operating in HVD mode
HVD
Terminator Power.
Connect to SCSI bus TERMPWR line and decouple with 2.2µF capacitor.
TPWR
*The VREF keeps the level at 2.85 volt, despite the DISCNCT pin is asserted or not; even the termination mode is changed.
Ver 1.4
Apr 07, 2005
TEL: 886-3-5788833
http://www.gmt.com.tw
8
GMT [ GLOBAL MIXED-MODE TECHNOLOGY INC ]
