The MP3398L is a step-up controller with 4 current channels, which is designed to drive WLED arrays for large-size LCD-panel backlighting applications. It is flexible to expand the number of LED channels by two or more ICs in parallel sharing a single inductive power source. The MP3398L uses peak-current mode with fixed switching frequency. The frequency is programmable by an external setting resistor. The MP3398L drives an external MOSFET to boost up the output voltage from a 5V to 28V input supply. It regulates the current in each LED string to the value set by an external current-setting resistor. The MP3398L applies 4 internal current sources for current balance. The current matching can achieve 2.5% regulation accuracy between strings. Its low regulation voltage on LED current sources reduces power loss. The MP3398L can support both analog and PWM dimming independently to meet the different dimming-mode request. In addition, rich protection modes are also integrated including OCP, OTP, UVP, OVP, LED short/open protection, inductor/diode short protection. The MP3398L is available in SOIC16 package.4-String, Max 350mA/String WLED Driver 4.5V to 28V Input Voltage Range 2.5% Current Matching Accuracy Between Strings Programmable Switching Frequency PWM and Analog Dimming Mode Cascading Capability with a Single Power Source LED Open and Short LED Protection Programmable Over-Voltage Protection Recoverable Thermal Shutdown Protection Over Current Protection Inductor/Diode short Protection Under-Voltage Lockout SOIC16 Package