The CD40147B CMOS encoder features priority encoding of the inputs to ensure that only the highest-order data line is encoded. Ten data input lines (0-9) are encoded to four-line (8, 4, 2, 1) BCD. The highest priority line is line 9. All four output lines are logic 1 (VSS) when all input lines are logic 0. All inputs and outputs are buffered, and each output can drive one TTL low-power Schottky load. The CD40147B is functionally similar to the TTL54/74147 if pin 15 is tied low.