SCLS087F December 1982 – June 2021 SN54HC21 , SN74HC21
PRODUCTION DATA
请参考 PDF 数据表获取器件具体的封装图。
The positive supply voltage is used to produce the output HIGH voltage. Drawing current from the output will decrease the output voltage as specified by the VOH specification in the Section 6.4. Similarly, the ground voltage is used to produce the output LOW voltage. Sinking current into the output will increase the output voltage as specified by the VOL specification in the Section 6.4.
Unused outputs can be left floating. Do not connect outputs directly to VCC or ground.
Refer to Section 8.3 for additional information regarding the outputs for this device.