参数资料
型号: DS21S07AE
厂商: MAXIM INTEGRATED PRODUCTS INC
元件分类: Bus Terminator
英文描述: 9-LINE 110 ohm SCSI BUS TERMINATOR, PDSO20
封装: 4.40 MM, PLASTIC, TSSOP-20
文件页数: 2/8页
文件大小: 448K
代理商: DS21S07AE
DS21S087A
2 of 8
FUNCTIONAL DESCRIPTION
The DS21S07A consists of a bandgap reference, buffer amplifier, and nine termination resistors
(Figure 1). The bandgap reference circuit produces a precise 2.55V level that is fed to a buffer amplifier.
The buffer produces a 2.85V level and can source at least 24mA into each of the termination resistors
when the signal line is low (active). When the driver for a given signal line turns off, the terminator pulls
the signal line to 2.85V (quiescent state). To handle actively negated SCSI signals, the buffer can sink at
least 200mA, and VREF will move less than 60mV. When all lines settle in the quiescent state, the
regulator consumes about 2.5mA. When the DS21S07A is put into power-down mode by bringing
PD
low, the power-down circuitry turns off the transistors on each signal line. This isolates the DS21S07A
from the signal lines and effectively removes it from the circuit. The power-down pin (
PD) has an internal
50k
pullup resistor. To place the DS21S07A into an active state, the PD pin should be left open
circuited. When installed on disk drives or RAID system components, the DS21S07A will not affect the
SCSI bus during a hot plug operation.
To ensure proper operation, both the TERMPWR1 and TERMPWR2 pins must be connected to the SCSI
bus TERMPWR line and both the VREF1 and VREF2 pins must be tied together externally. Each
DS21S07A requires a 4.7
F capacitor connected between the VREF pins and ground. Figure 2 details a
typical SCSI bus configuration. In an 8-bit-wide SCSI bus arrangement (“A” Cable), two DS21S07A’s
would be needed at each end of the SCSI cable to terminate the 18 active signal lines. In a 16-bit-wide
SCSI bus arrangement (“P” Cable), three DS21S07A’s would be needed at each end of the SCSI cable to
terminate the 27 active signal lines.
Figure 1. DS21S087A Block Diagram
相关PDF资料
PDF描述
DS21T05S 9-LINE 110 ohm SCSI BUS TERMINATOR, PDSO16
DS21T05Z 9-LINE 110 ohm SCSI BUS TERMINATOR, PDSO16
DS21T07E 9-LINE 110 ohm SCSI BUS TERMINATOR, PDSO20
DS21T07S 9-LINE 110 ohm SCSI BUS TERMINATOR, PDSO16
DS21T09S 18-LINE 110 ohm SCSI BUS TERMINATOR, PDSO28
相关代理商/技术参数
参数描述
DS21S07AE/T 制造商:MAXIM 制造商全称:Maxim Integrated Products 功能描述:SCSI Terminator
DS21S07AE/T&R 制造商:Rochester Electronics LLC 功能描述: 制造商:Maxim Integrated Products 功能描述: 制造商:Maxim Integrated Products 功能描述:IC TERMINATOR SCSI 20-TSSOP
DS21S07AE/T&R 功能描述:SCSI 接口集成电路 RoHS:否 制造商:Texas Instruments 工作电源电压:2.7 V to 5.25 V 电源电流:13 mA 最大工作温度:+ 70 C 最小工作温度:0 C 安装风格:SMD/SMT 封装 / 箱体:SSOP-36 封装:Tube
DS21S07AE/TR 制造商:MAXIM 制造商全称:Maxim Integrated Products 功能描述:SCSI Terminator
DS21S07AE+ 功能描述:SCSI 接口集成电路 RoHS:否 制造商:Texas Instruments 工作电源电压:2.7 V to 5.25 V 电源电流:13 mA 最大工作温度:+ 70 C 最小工作温度:0 C 安装风格:SMD/SMT 封装 / 箱体:SSOP-36 封装:Tube