Features: 95% efficiency, synchronous operation Adjustable output voltage from 0.8V to vin-14.5V to 5.5V Input voltage range up to 2A output current Fixed frequency 1.3MHz PWM operation 100 % duty cycle Low dropout operation (LDO) Soft-Start Function Excellent Load Transient Response Power Good Flag Overvoltage, Undervoltage Lockout, Short Circuit and Thermal Shutdown Protection 3x3mm Six-Lead MLP Package

Application: Hard Disk Drive Set Top Box Power Laptop Communication Equipment Description: Fan 2013 is a high efficiency, low noise, low voltage synchronous pulse width modulation (pwm) current mode dc-dc converter application. It provides continuous loads up to 2A. Current from 4.5V to 5.5V input. The output voltage can be passed through an external voltage divider. When the input voltage on the VIN (vin) pin exceeds the UVLO threshold. A fast transient current mode control loop response ensures good line and load regulation. The fixed 1.3MHz switching frequency makes the designer choose a small, inexpensive external inductor and capacitor. Filtering widgets can be done, reducing space and cost. Protection features include input under-voltage lockout, short-circuit protection and thermal shutdown. Soft-start limits the inrush current during start-up conditions. The unit has a 3x3mm 6-wire MLP.

Typical performance characteristics

Ta=25°C, Cin=10μF, Cout=40μF, L=2.2μH, Vin=5V, Vout=1.2V unless otherwise stated.

Detailed operating instructions: FAN2013 is a buck pulse width modulated (pwm) current mode converter with fixed switch frequency 1.3MHz. On each rising edge of the clock cycle, the P-channel transistor turns on until the PWM comparator trips or the current limit is reached. During the turn-on time, the inductor current rise is monitored by an internal current-mode control loop. After the shortest dead time, the n-channel transistor turns on and the inductor current drops. As the clock cycle completes, the n-channel switch is turned off and the next clock cycle begins. The duty cycle is given by the ratio of the output voltage to the input voltage. At output, the converter operates at a minimum duty cycle with minimum voltage and maximum input voltage, approaching the output voltage when the input voltage is 100%, as described below. 100% Duty Cycle Operation When the input voltage approaches the output voltage with a duty cycle exceeding the typical 95%, the converter keeps the P-channel transistor energized. In this mode, the output voltage is equal to the input voltage, minus the voltage drop across the P-channel transistor: VOUT=VIN – ILOAD X (Radio data system on + rear left) (1) rds_on=P-channel on resistance ILOAD= Output Current rl = Inductor DC Resistor UVLO and Soft Start Internal Voltage Reference, VREF and IC remain reset until VIN reaches the 3.7V UV low threshold.

The FAN2013 has an internal soft-start circuit that limits inrush current at startup. This prevents input voltage and eliminates output voltage overshoot. Soft-start is implemented as a digital circuit, increasing the switch current in four steps to the P-channel current limit (3.5A). Typical start-up time for a 40µf output capacitor is 800µs at 2.0A load current. Output Over-Voltage Protection When the output voltage vout reaches approximately 7% higher than nominal, the device turns off the PChannel switch and turns on a portion of the N-channel transistor with a built-in current limit of approximately 400 mA. The device starts switching normally in closed loop when VOUT reaches approximately 2% hysteresis. The IF output voltage is limited by the external voltage source through a current limit above the typical 400mA, and the output voltage is maintained at the external voltage source level. Overvoltage protection is designed to limit the output voltage excursion from full load to minimum load during transient response. The output short-circuit protection switch peak current is limited cycle-by-cycle to a typical short circuit at an output voltage of 3.5A, the device operates at 400kHz and a minimum duty cycle, allowing typical input current. 45A. Thermal shutdown resets when the mold temperature exceeds 150°C when the mold cools to 130°C, allowing the circuit to restart.

Application Information: Set the output voltage internal voltage reference to 0.8V. The output is divided by the voltage divider, r1 and r2 to the fb pin. The output voltage is: VUT V reference 1 r1 r2 = + - (2) According to this equation, assuming a desired output voltage of 1.2V, and given r2 = 10KΩ as the recommended resistance for any output voltage setting, the calculated value for r1 is 5kΩ. Inductor selection The inductance parameter performance directly related to the device is saturation current and DC resistance. The typical inductance value of FAN2013 is 2.2μh. The lower the DC resistance, the better the efficiency. For saturation current, the inductance is rated above the maximum load current, plus the inductor ripple current, calculated as:

PCB Layout Recommendations The inherently high peak currents and switching power frequencies require careful PCB layout design. For best results, use wide traces for high current paths and place the input capacitor inductance and output capacitor as close as possible to the IC terminals. To minimize voltage spikes on the device due to the presence of electron spin resonance using low input bypass capacitors. Note that the peak amplitude of the switching peak depends on the load current; the higher the load current, the higher the switching peak. The resistor divider that sets the output voltage should be kept away from the inductor to avoid RF coupling. The ground plane on the bottom of the PCB acts as an EMI shield to reduce EMI. This recommended PCB layout is shown in Fig.