GENERAL DESCRIPTION The DT9111 is a 5V in 12V 1A Out step-up DC/DC converter The DT9111 incorporates a 30V 6A N-channel MOSFET with low 60mΩ RDSON. The externally adjustable peak inductor current limit feature provides good over-current protection. Besides, the DT9111 features various other protection functions, such as soft-start, UVLO, etc. The DT9111 is available in ESOP8 package. FEATURES Wide Operating Voltage Range: 3~7.5V Maximum Output Voltage: 24V Deliver up to 12Vx1A from 3.6V Up to 92% Efficiency 400KHz Fixed Switching Frequency 1.25V Feedback Voltage Adjustable Current Limit Soft-Start UVLO ESOP8 Package APPLICATIONS Power Supply TYPICAL APPLICATION CIRCUIT PIN ASSIGNMENT ORDER INFORMATION FULL CODE PACKAGE OPTION DT9111SOEHx S: Sub-category, S=Standard OEH: Package Type, OEH=ESOP8 x: Package Material Option, 1=Copper Wire TAPE & REEL, 2500EA/REEL DT9111 Datasheet Rev1.01, Dec 2015 Page 1
PIN DESCRIPTION PIN NO SYMBOL DESCRIPTTION 1 FB Feedback input. 2 COMP Compensation 3 CS Current Limit Setup 4 CS Current Limit Setup 5 SW Switch Output 6 VIN Power Supply Input 7 EN Chip Enable 8 GND Ground Exposed PAD Switch Output ABSOLUTE MAXIMUM RATINGS (Note 1) SYMBOL ITEMS VALUE UNIT V IN Input Voltage -0.3~8 V V IO All Other I/O Pins GND-0.3 to VDD+0.3 V P DMAX Power Dissipation 2.5 W P TR1 Thermal Resistance,ESOP8, Θ JA 40 /W T J Junction Temperature -40~125 Tstg Storage Temperature -65 to 150 Tsolder Package Lead Soldering Temperature 260, 10s Note 1: Absolute Maximum Ratings indicate limits beyond which damage to the device may occur. Recommended Operating Range indicates conditions for which the device is functional, but do not guarantee specific performance limits. Electrical Characteristics state DC and AC electrical specifications under particular test conditions which guarantee specific performance limits. This assumes that the device is within the Operating Range. Specifications are not guaranteed for parameters where no limit is given, however, the typical value is a good indication of device performance. RECOMMANDED OPERATING RANGE SYMBOL ITEMS VALUE UNIT V IN VIN Supply Voltage 3.0 to 7.5 V T OPT Operating Temperature -40 to +85 DT9111 Datasheet Rev1.01, Dec 2015 Page 2
ELECTRICAL CHARACTERISTICS The following specifications apply for V IN = V EN =3.6V T A =25 o C, unless specified otherwise. SYMBOL ITEMS CONDITIONS MIN TYP MAX UNIT V IN Input Voltage 3.0 7.5 V V FB FB Pin Voltage 1.225 1.25 1.275 mv I FB FB Pin Input Bias Current 0.05 1 µa I SHDN Shutdown Current 0.1 1 µa I Q Quiescent Current V FB =0.4V 400 500 µa F SW Switching Frequency 400 KHz D MAX Maximum Duty Cycle V FB =0V 90 % RDSON ON Resistance of MOSFET 60 mω VCS Current Limit Threshold Voltage 80 mv V EN_H EN Minimum High Level 1.5 V V EN_L EN Maximum Low Level 0.4 V I EN EN Input Bias Current 0.1 1 µa T SS Soft Start Time V IN Power On 6 ms SIMPLIFIED BLOCK DIAGRAM OPERATION DESCRIPTIONS The DT9111 is a 5V Boost DC-DC converter capable of deliver up to 24V output. The 60mΩ built-in Power MOSFET delivers up to 12Vx1A Output from 3.6V Power Supply. The DT9111 has built-in soft-start to limit the inrush current during startup and to limit the amount of overshoot on the output. Protection features in the DT9111 include soft-start, cycle-by-cycle current limit protection and UVLO. The Current Limit is externally adjustable. DT9111 Datasheet Rev1.01, Dec 2015 Page 3
TYPICAL OPERATING CHARACTERISTICS VIN=5V, VOUT=12V, Tested under TA=25 C, unless otherwise specified 1. Efficiency 2. Line Regulation 3. Load Regulation DT9111 Datasheet Rev1.01, Dec 2015 Page 4
4. SW Waveform and Output Ripple at 12V/No Load 5. SW Waveform and Output Ripple at 12V/100mA 5. SW Waveform and Output Ripple at 12V/1A DT9111 Datasheet Rev1.01, Dec 2015 Page 5
6. Inductor Current at 12V/0.5A 7. Transient Response at 0.1A/1A/0.5ms 8. Soft Start DT9111 Datasheet Rev1.01, Dec 2015 Page 6
APPLICATION INFORMATION Inductor Selection A 2.2~10μH inductor is recommended for most applications. If high efficiency is a critical requirement, a low DCR inductor should be selected. The inductor s saturation current rating should also exceed the peak input current, especially for high load current application. Capacitor Selection Small size ceramic capacitors are ideal for DT9111 application. A combination of 470uF input capacitor and 470uF output capacitor is suggested for most applications. For better voltage filtering, ceramic capacitors with low ESR are recommended. X5R and X7R types are suitable because of their wider voltage and temperature ranges. Diode Selection Using a Schottky diode is recommended in DT9111 applications because of its low forward voltage drop and fast reverse recovery time. The current rating of the Schottky diode should exceed the peak current of the boost converter. The voltage rating should also exceed the target output voltage. Output Voltage Setting Output Voltage is determined by the feedback resistor. The feedback voltage is internally set at 1.25V. For accurate Output Voltage settings, precision 1% resistors are recommended. The formula is shown below: VOUT = (1+R2/R1)*VFB Selection R1=100KΩ, then R2 can be derived from the above formula. Power Sequence In order to assure the normal soft start function for suppressing the inrush current the input voltage should be ready before EN pulls high. Soft-Start The function of soft-start is made for suppressing the inrush current to an acceptable value at the beginning of power on. The DT9111 provides a built-in soft-start function by clamping the output voltage of error amplifier so that the duty cycle of the PWM will be increased gradually in the soft-start period. Current Limiting The current flow through inductor as charging period is detected by a current sensing circuit through the CS pin. As the value comes across the current limiting threshold, the external N-MOSFET will be turned off so that the inductor will be forced to leave charging stage and enter discharging stage. Therefore, the inductor current will not increase over the current limiting threshold. The threshold voltage VCS is 80mV. UVLO The Under-Voltage Lock Out function disables the DT9111 from malfunctioning when the power supply is too low, and recovers when the power supply goes high. DT9111 Datasheet Rev1.01, Dec 2015 Page 7
Layout Considerations PCB layout is very important for high frequency switching regulators in order to keep the loop stable and minimize noise. For best performance of the DT9111, the following guidelines must be strictly followed. Input and Output capacitors should be placed close to the IC and connected to ground plane to reduce noise coupling. The GND pin should be connected to a strong ground plane for heat sinking and noise protection. Keep the main current traces as possible as short and wide. The DRV node is with high frequency voltage swing. It should be kept in a smallest area. Place the cs (on CS pin) and feedback components (on FB pin) as close as possible to the IC and keep away from the noisy devices. DT9111 Datasheet Rev1.01, Dec 2015 Page 8
PACKAGE OUTLINE ESOP8 DT9111 Datasheet Rev1.01, Dec 2015 Page 9