The Texas Instruments TP3420AV309 is an ISDN S/T Interface Device, functioning as a transceiver. It operates with a supply voltage of 4.75-5.25V and is available in a 20-PLCC package.
The Microchip Technology MT9075BP1 is a telecom interface IC designed for surface mount applications. It operates within a voltage range of 4.75V to 5.25V.