Piezoelectric component connection circuit
C1 prevents Ag migration in high humidity with DC across piezo
R1 C1 also matches impedance of this buzzer ... 10nF, 1kΩ (30%), (6.3kHz)
D1, D2 protects LSI chip if the board is dropped producing large V which may wound chip.
R2   reduces DC


maybe MMBD7000L dual diode is ok for you 

Regarding differential drive from MCU , that is fine as 20mm piezo disks are typically 1 kOhm and less if above +/-10. So +/-3.3 or 5V is no sweat.  You may want to use a natural resonant frequency in a self oscillating loop to improve loudness. For even louder sound an SMT stepup transformer can be used.

Sometimes you have to dig around on the JP site to get more details not in the English datasheet. They hold back broadcasting some information for at least 5 yrs and in many cases even special parts are not available for export for the same period.  That's been going on for as long as I have practised.