1 Features
• Buffered inputs and outputs
• Typical propagation delay: 13ns at VCC = 5V, CL =
15pF, TA = 25oC
• Fanout (over temperature range)
– Bus driver outputs: 15 LSTTL loads
• Wide operating temperature range: -55oC to 125oC
• Balanced propagation delay and transition times
• Significant power reduction compared to LSTTL
logic ICs
• HC types
– 2V to 6V Operation
– High noise immunity: NIL = 30%, NIH = 30% of
VCC at VCC = 5V
• HCT types
– 4.5V to 5.5V Operation
– Direct LSTTL input logic compatibility, VIL= 0.8V
(Max), VIH = 2V (Min)
– CMOS input compatibility, Il ≤ 1μA at VOL, VOH

2 Description
The CDx4HC147 and CD74HCT147 are 9-input
priority encoders. These devices provide the 10-line to
4-line priority encoding function by use of the implied
decimal “zero.”