NCP1011ST100T3

NCP1011ST100T3 is part of On Semiconductor’s AC/DC Converters, Offline Switchers product family. It is a 700mA step-down converter that is well-suited for powering low-power, always-on industrial and consumer applications.

The NCP1011ST100T3 operates from an input voltage of 4.5V to 36V and provides an adjustable output voltage from 0.6V to 33V. It also includes a host of features including output voltage programming, input undervoltage lockout, over-current protection, adjustable frequency up to 1MHz, power-good flag, separate enable, auto-restart, short-circuit protection and thermal protection.The NCP1011ST100T3 monolithic converter is designed using ON Semiconductor’s proprietary high-voltage BCDMOS process technology ideal for applications requiring higher operating voltages. It is available in a 3mm x 3mm PowerPAD™ or SOT-23-5 packages and is rated over the industrial temperature range of -40°C to +85°C.

Application Field

The NCP1011ST100T3 is ideally suited for low-power, always-on and portable industrial and consumer applications. Applications include handheld devices, embedded power supply for set-top and cable boxes, point-of-load (POL) DC/DC converter, PDAs and high-end cellular phones. The NCP1011ST100T3 also works well in 5V and 3.3V buck regulators, standby power supplies and mobile device chargers.

Working Principle

The NCP1011ST100T3 uses a two-phase, synchronous buck topology in a current-mode control structure. The two-phase topology allows for a faster response to load and line stimuli, which is needed in applications with low quiescent current or low operating frequency. The input voltage is connected to a high-frequency voltage divider, and the voltage difference is used to control the outer current loop. The current passes through an inductor, and then to the ground through a switch. When the switch is turned off, the inductor stores energy and transfers the energy, which is regulated by the inner voltage loop, into the output capacitor for storage.

The NCP1011ST100T3 can be supplied in a shutdown mode, where the bias and power are reduced to an extremely low level. When in shutdown mode, the NCP1011ST100T3 draws only 1μA of quiescent current, which makes it an ideal choice for applications requiring a low-power, always-on mode. Additionally, the device features an adjustable operating frequency with a range from 500kHz to 1MHz, which allows the system designer to select the switching frequency that reduces the EMI footprint.

The NCP1011ST100T3 features a user-adjustable output voltage and a power-good flag for superior system diagnostics. The thermal protection feature prevents damage to the device in case of extreme die temperature to ensure reliable operation. In addition, the device has short-circuit protection and a separate enable pin for easy control.

Overall, the NCP1011ST100T3 is a robust, feature-rich AC/DC power converter perfect for applications requiring low quiescent current, low EMI and always-on operation at step-down voltages from 4.5V to 36V.