Another set of features that further lowers the power consumption is the low power serial interfaces. The LPC54100 contains a low power 12-bit ADC with high sampling speed. It consumes just 1.3 mA base current and can operate at a maximum speed of 4.8 Msps across the entire operating voltage of 1.62 to 3.6 V. The nearest competing part, on the other hand, consumes 1.6 mA base current and requires that the sampling speed be reduced when the operating voltage is reduced below a certain value. With this comparison in mind, you can save up to 40% ADC current to achieve the same sampling speed as the competing part by operating the LPC54100 at a lower voltage. Some battery-operated applications can now extend usable battery voltage range without having to disable or sacrifice ADC performance. The Serial interfaces are also designed with low power consumption in mind. The USART, SPI and I2C peripherals can be configured to operate from a clock that is asynchronous from the CPU clock – in other words, these peripherals can operate from a clock source such as 32 kHz RTC oscillator or 500 kHz internal oscillator while the CPU can operate from a 12 MHz internal oscillator or external clock with or without PLL. In many instances, serial interface bit rate is significantly slower than the CPU speed and can be clocked at a separate very slow clock. Since the peripheral consumption is proportional to the clock speed, the total MCU consumption can be lowered without reducing the system performance.