ini_set('display_errors', 1);
error_reporting(1);

try {
    $db = new PDO("sqlsrv:Server=localhostSQLEXPRESS,1433;Database=DB_NAME;Host=PC2_IP", "USER", "PASSWORD");
    $db->setAttribute(PDO::ATTR_EMULATE_PREPARES, false );
    die("try");
} catch (PDOException $e){
    echo $e->getMessage();

    die("catch");
}

<?php
$dsn  = "sqlsrv:Server=PC2_IP\SQLEXPRESS,1433;Database=DB_NAME";
$user = "USER";
$pass = "PASS";
$opts = [
    PDO::ATTR_ERRMODE            => PDO::ERRMODE_EXCEPTION,
    PDO::ATTR_EMULATE_PREPARES   => false,
    PDO::ATTR_DEFAULT_FETCH_MODE => PDO::FETCH_ASSOC,
];
try {
    $db = new PDO($dsn, $user, $pass, $opts);
    die("try");
} catch (PDOException $e){
    echo $e->getMessage();
    die("catch");
}