DS2108 Dallas Semiconducotr, DS2108 Datasheet - Page 3

• Manufacturer Part Number: DS2108
• Description: Differential SCSI Switchable Terminator
• Manufacturer: Dallas Semiconducotr

TYPICAL DIFFERENTIAL SCSI BUS CONFIGURATION Figure 2
NOTES:
1. Two DS2108s required per 8–bit SCSI device and three DS2108s per 16–bit SCSI device.
2. Mid–bus termination effectively removed by grounding
3. Termination power to be provided as specified in SCSI–3 Parallel Interface (SPI) document.
4. Local TERMPWR bypassing is recommended by the SPI document with values shown. The bypass
PIN DESCRIPTION Table 1
2, 3, 4, 5, 6,
14, 15, 16,
17, 18, 19,
7, 8, 9, 10
20, 21, 22
capacitors should be located as close as possible to the DS2108s. Only one pair of capacitors is
required per SCSI device (may be shared between DS2108s on same device).
13, 23
1, 11
PIN
12
24
R1N…R9N Signal Termination Negative. Connect to –SIGNAL of SCSI bus.
R1P…R9P
SYMBOL
TPWR
GND
NC
PD
DESCRIPTION
Termination Power. Should be connected to the SCSI TERMPWR line.
Bypass with a 2.2 µF cap in parallel with a 0.1 µF cap as shown in Figure
2.
No Connect. Do not connect any signal to this pin.
Ground. Signal ground; 0.0V.
Signal Termination Positive. Connect to +SIGNAL of SCSI bus.
Power Down. When tied low, the DS2108 enters a power-down mode.
Contains an internal 50K pull-up. Strap low to deactivate the DS2108,
leave open circuited to activate the DS2108.
3 of 5
PD
pin.
DS2108