74VCX163245GX 查看數據表（PDF） - Fairchild Semiconductor

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74VCX163245GX

Low Voltage 16-Bit Dual Supply Translating Transceiver with 3-STATE Outputs

Fairchild Semiconductor 

VCX163245 Translator Power Up Sequence Recommendations

To guard against power up problems, some simple guide-

lines need to be adhered to. The VCX163245 is designed

so that the control pins (T/Rn, OEn) are supplied by VCCB.

Therefore the first recommendation is to begin by powering

up the control side of the device, VCCB. The OEn control

pins should be ramped with or ahead of VCCB, this will

guard against bus contentions and oscillations as all A Port

and B Port outputs will be disabled. To ensure the high

impedance state during power up or power down, OEn

should be tied to VCCB through a pull up resistor. The mini-

mum value of the resistor is determined by the current

sourcing capability of the driver. Second, the T/Rn control

pins should be placed at logic LOW (0V) level, this will

ensure that the B-side bus pins are configured as inputs to

help guard against bus contention and oscillations. B-side

Data Inputs should be driven to a valid logic level (0V or

VCCB), this will prevent excessive current draw and oscilla-

tions. VCCA can then be powered up after VCCB, however

VCCA must be greater than or equal to VCCB to ensure

proper device operation. Upon completion of these steps

the device can then be configured for the users desired

operation. Following these steps will help to prevent possi-

ble damage to the translator device as well as other system

components.

Logic Diagrams

Please note that these diagrams are provided only for the understanding of logic operations and should not be used to estimate propagation delays.

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