The CD4049UB device is an inverting hex buffer; the CD4050B device is a noninverting hex buffer. These devices do logic-level conversions and have a high sink current that can drive two TTL loads. These devices also have low input current of 1 µA across the full temperature range at 18 V.

The CD4049UB and CD4050B devices are designated as replacements for CD4009UB and CD4010B devices, respectively. Because the CD4049UB and CD4050B require only one power supply, they are preferred over the CD4009UB and CD4010B and should be used in place of the CD4009UB and CD4010B in all inverter, current driver, or logic-level conversion applications. In these applications the CD4049UB and CD4050B are pin compatible with the CD4009UB and CD4010B respectively, and can be substituted for these devices in existing as well as in new designs. Pin 16 (NC) is not connected internally on the CD4049UB or CD4050B, therefore, connection to this terminal is of no consequence to circuit operation. TI recommends the CD4069UB hex inverter is recommended for applications not requiring high sink-current or voltage conversion.