The HEF4049B provides six inverting buffers with high current output capability suitable
for driving TTL or high capacitive loads. Since input voltages in excess of the buffers’
supply voltage are permitted, the buffers may also be used to convert logic levels of up to
15 V to standard TTL levels. Their guaranteed fan-out into common bipolar logic elements
is shown in Table 3. It operates over a recommended VDDpower supply range of 3 V to 15 V referenced to VSS (usually ground). Unused inputs must be connected to VDD, VSS, or another input.