I don't know what I'm doing wrong...
here's my html:
<div class="col-md-2">
<label class="label-form" for="dataNascimento">Data de Nascimento:</label>
<input matInput [matDatepicker]="picker" class="input-form" [formControl]="_dataNascimento" type="text" id="dataNascimento" value="">
<mat-datepicker-toggle matSuffix [for]="picker"></mat-datepicker-toggle>
<mat-datepicker #picker></mat-datepicker>
</div>