July 6 (Reuters) - Chinese smartphone maker Xiaomi Corp (1810.HK) will mandate 12 banks to lead a U.S. dollar bond issue, according to a term sheet seen by Reuters. Goldman Sachs, Credit Suisse, J.P. Morgan, China International Capital Corp, CLSA Ltd, Morgan Stanley, Citigroup, HSBC, Bank of China, China Construction Bank Corp, ICBC and AMTD will lead the bond issue, the document showed.