NCP3230MNTXG

The NCP3230 is a high current, high efficiency, voltage−feed− forward voltage−mode synchronous buck converter which operates from 4.5 V to 18 V input and generates output voltages down to 0.6 V at up to 30 A load. The NCP3230 is a 500 kHz, high efficiency, high current PWM synchronous buck converter. It operates with a single supply voltage from 4.5 to 18 V and can provide output current as high as 30 A. NCP3230 utilizes voltage mode with voltage feed−forward control to respond instantly to Vin changes and provide for easier compensation over the supply range of the converter. The device also includes pre−bias startup capability to allow monotonic startup in the event of a pre−biased output condition. Protection features include overcurrent protection (OCP), output over and under voltage protection (OVP, UVP), and power good. The enable function is highly programmable to allow for adjustable startup voltages at higher input voltages. There is also an adjustable soft−start, an over− temperature comparator, and internal thermal shutdown. The NCP3230 incorporates an internal reference that allows output voltages as low as 0.6 V. The tolerance of the internal reference is guaranteed over the entire operating temperature range of the controller. The reference voltage is trimmed using a test configuration that accounts for error amplifier offset and bias currents. The ramp waveform is a saw tooth formed at the PWM frequency with a peak−to−peak amplitude of VCC/6.3, offset from GND by typically 0.64 V. The PWM duty cycle is limited to a typical 94%, allowing the bootstrap capacitor to charge during each cycle. The error amplifier’s primary function is to regulate the converter’s output voltage using a resistor divider connected from the converter’s output to the FB pin of the controller. A type III compensation network must be connected around the error amplifier to stabilize the converter. It has a bandwidth of greater than 24 MHz, with open loop gain of at least 60 dB. An external capacitor connected from the SS pin to ground sets up the soft start period, which can limit the start−up inrush current. The soft start period can be programmed based on the Equation 1. OCP is the only fault that is active during a soft−start. In a synchronous buck converter, a certain dead time is required between the low side drive signal and high side drive signal to avoid shoot through. During the dead time, the body diode of the low side FET freewheels the current. NCP3230 implements adaptive dead time control to minimize the dead time, as well as preventing shoot through.

Applications

• Cellular Base Stations
• ASIC, FPGA, DSP and CPU Core and I/O Supplies
• Telecom and Network Equipment
• Server and Storage System

Key features

• Wide Input Voltage Range from 4.5 V to 18 V
• 0.6 V Internal Reference Voltage
• 500 kHz Switching Frequency
• External Programmable Soft−start
• Lossless Low−side FET Current Sensing
• Output Over−voltage Protection and Under−voltage Protection
• System Over−temperature Protection using a Thermistor or Sensor
• Hiccup Mode Operation for All Faults
• Pre−bias Start−up
• Adjustable Output Voltage
• Power Good Output
• Internal Over−temperature Protection
• This is a Pb−Free Device