MCP3020/MOC3020IC MCP3021 MCP3021 模拟IC MCP3021A0T-E/OT MCP3021A0T-E/OTVAO MCP3021A1T-E/OT MCP3021A1T-E/OTVAO MCP3021A2T-E/OT MCP3021A2T-E/OTVAO MCP3021A3T-E/OT