Set a pattern for min and max length of fields, combined with the required field option.

CF-patterns-examples.php

<?php
//Use caldera_forms_field_attributes filter hook
add_filter( 'caldera_forms_field_attributes', function( $attrs, $field, $form ){

//REPLACE fld_******* BY YOUR OWN FIELD IDs

	//Min and max 5
	if( 'fld_4009904' === $field[ 'ID' ] ) {
			$attrs[ 'pattern' ] = ".{5,5}";
	}
	//Min and max 10
	if( 'fld_*******' === $field[ 'ID' ] ) {
			$attrs[ 'pattern' ] = ".{10,10}";
	}
	
	return $attrs;
	
}, 20, 3 );