LP3220SAB5F

The LP3220S is a 1.5MHz constant frequency current mode PWM step-down converter. It is ideal for portable equipment which requires very high current up to 1.0A from single-cell Lithium-ion batteries while still achieving over 94% efficiency during peak load conditions. The LP3220S also can run at 100% duty cycle for low dropout operation, extending battery life in portable systems while light load operation provides very low output ripple for noisy sensitive applications. The LP3220S can supply up to 1.0A output load current from at VIN = 3V and has an input voltage 2.2V to 5.5V and the output voltage can be regulated as low as 0.6V. The high switching frequency minimizes the size of external components while keeping switching losses low. The internal slope compensation setting allows the device to operate with smaller inductor values to optimize size and provide efficient operation. The LP3220S is a high output current switch-mode step-down DC-DC converter. The device operates at a fixed 1.5MHz switching frequency, and uses a slope compensated current mode architecture. This step-down DC-DC converter can supply up to 1A output current from at VIN = 3V and has an input voltage range from 2.2V to 5.5V. It minimizes external component and optimizes efficiency at the heavy load range. The slope compensation allows the device to remain stable over a wider range of inductor values so that smaller values (2.2μH to 4.7μH) with lower DCR can be used to achieve higher efficiency. Apart from the small bypass input capacitor, only a small L-C filter is required at the output. The device can be programmed with external feedback to any voltage, ranging from 0.61V to near the input voltage. It uses internal MOSFETs to achieve high efficiency and can generate very low output voltages by using an internal reference of 0.6V. At dropout, the converter duty cycle increases to 100% and the output voltage tracks the input voltage minus the low RDS(ON) drop of the P-channel high-side MOSFET and the inductor DCR. The internal error amplifier and compensation provides excellent transient response, load and line regulation. Internal soft start eliminates any output voltage over-shoot when the enable or the input voltage is applied.

Applications

• Portable Instruments
• DSP Core Supplies
• Cellular Phone and Smart mobile phone
• PDA
• GPS Applications

Key features

• Input Voltage Range: 2.2V to 5.5V
• Output Voltage Range: 0.61V to VIN
• 1.0A Output Current
• High Efficiency: Up to 94%
• 100% Duty Cycle in Dropout
• Low Shutdown Current: <1uA
• 1.5MHz Switching Frequency
• Soft star Function
• Short Circuit Protection
• Thermal Fault Protection
• SOT23-5 Package
• RoHS Compliant and 100% Lead (Pb)-Free