UD05021G-AF5-R

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UNISONIC TECHNOLOGIES CO., LTD UD05021 CMOS IC www.unisonic.com.tw 1 of 7 Copyright © 2016 Unisonic Technologies Co., Ltd QW-R115-010.A 2.0A 1.5MHZ SYNCHRONOUS BUCK CONVERTER  DESCRIPTION The UTC UD05021 is a monolithic synchronous buck regulator with a built in internal power MOSFET. It achieves 2A continuous output current fix switching frequenc y with excellent load and line regulation. Current mode operation provides fast transient response and eases of loop stabilization. Fault condition protection includes cycle-by-cycle current limiting, output short circuit protection and thermal shutdown. In shutdown mode the regulator draws less than 1 μA of supply current. Internal soft-start minimizes the inrush supply current at initial startup.  FEATURES * 2.5V~5.5V input voltage range * Up to 2A Output Current * 150/120mΩ Internal Power MOSFET Switch * Stable with Low ESR Output Ceramic Capacitors * Up to 95% Efficiency * Less than 1μA Shutdown Current * 1.5Mhz Switching Frequency * Thermal Shutdown Protection * Current limit and short circuit protections. * Output Adjustable from 1V to V IN * Build-in soft start function  ORDERING INFORMATION Ordering Number Package Packing UD05021G-AF5-R SOT-25 Tape Reel  MARKING

UNISONIC TECHNOLOGIES CO., LTD 2 of 7 www.unisonic.com.tw Q W - R 1 1 5 - 0 1 0 . A  PIN CONFIGURATION 12 3 EN GND SW FB VCC  PIN DESCRIPTION PIN NO. PIN NAME DESCRIPTION 1 EN Chip enable pin. Active high.

2 GND Ground pin

3 SW Switching pin

4 V CC V CC input pin

5 FB Feedback pin

 BLOCK DIAGRAM EN FB GND SW VCC -EA0.6V UVLO and POR Reference And bias softatart COMP Thermal shutdown Driver OSCILLATOR ILimit PWM Control logic P-switch ISEN

UNISONIC TECHNOLOGIES CO., LTD 3 of 7 www.unisonic.com.tw Q W - R 1 1 5 - 0 1 0 . A  ABSOLUTE MAXIMUM RATING (TA= 25°C, unless otherwise specified) PARAMETER SYMBOL RATINGS UNIT VCC Pin Voltage V IN -0.3~7 V SW Pin Voltage V SW -0.7 ~ V IN+0.3 V EN, FB Pins Voltage -0.3 ~ V IN+0.3 V Continuous Power Dissipation P D (T J-TA) /θJA mW Junction Temperature T J -40 ~ +125 °C Storage Temperature T STG -65 ~ +150 °C Notes: 1. Absolute maximum ratings are those values beyond which the device could be permanently damaged. Absolute maximum ratings are stress ratings only and functional device operation is not implied. 2. Stresses exceed those ratings may damage the device.  THERMAL CHARACTERISTICS PARAMETER SYMBOL RATINGS UNIT Junction to Ambient θJA 250 °C/W Junction to Case θJC 110 °C/W Note: θJA is measured with the PCB copper are (need connect to GND of the UTC UD05021) of approximately 1 in2 (Multi-layer).  ELECTRICAL CHARACTERISTICS (VIN=5V, VEN=5V, VOUT=3.3V, TA= 25°C) PARAMETER SYMBOL TEST CONDITIONS MIN TYP MAX UNIT Input Voltage Range V IN 2.5 5.5 V Input UVLO UVLO I OUT=0A 1.8 2.2 2.5 V Input OVLO OVLO I OUT=0A 6.0 V Quiescent Current I CCQ V EN=1V 250 350 μA Shutdown Current I SD V EN=0V 0.1 1 μA FB Pin Voltage V FB 0.588 0.6 0.612 V FB Pin Current (Note) I FB ±50 nA Load Regulation 0A<I OUT<1.5A 0.6 % Load Regulation 2.5V<V IN<5.5V 0.3 %/V EN Pin Voltage High V ENH 1.5 V EN Pin Voltage Low V ENL 0.4 V EN Pin Leakage Current V EN=3V 0.1 1 uA Switching Frequency F OSC 1.1 1.5 1.9 MHz Current Limit C L VIN=3V, VFB=0.5Vor VOUT=90%, Duty Cycle<35% 2.2 2.5 A Switching Maximum Duty Dmax 100 % Minimum Duty Dmin 0 % P-Switch RDS(ON) R DS(ON)-P 150 m Ω N-Switch RDS(ON) (Note) R DS(ON)-N 120 m Ω Low Side Discharger 60 Ω Thermal Shutdown T SD 155 °C Thermal Shutdown Protection hysteresis T SH 30 °C Note: Guaranteed by design.

UNISONIC TECHNOLOGIES CO., LTD 4 of 7 www.unisonic.com.tw Q W - R 1 1 5 - 0 1 0 . A  TYPICAL APPLICATION CIRCUIT 1.8V≦VOUT≦4.4V EN GND FB SWVCCVIN 10uF OFF ON CFB 22P Option 10uF ×2 2.2~4.7uH V OUT VOUT=0.6x(1+R1/R2) option VOUT=VFB × (1+R1/R2), VFB=0.6V, R2 suggest 60k~300kΩ 1.0V≦VOUT≦1.6V EN GND FB SWVCCVIN 10uF OFF ON 22uF 2.2uH VOUT VOUT=0.6x(1+R1/R2) option 22uF

UNISONIC TECHNOLOGIES CO., LTD 5 of 7 www.unisonic.com.tw Q W - R 1 1 5 - 0 1 0 . A  FUNCTION DESCRIPTION Normal Operation The UD05021 uses a user adjustable frequency, current mode, synchronous step-do wn architecture with internal paver switch. During normal operation, the internal power switch is turned on each cycle when the oscillator sets the SR latch, and turned off when the comparator resets the SR latch. The peak inductor cu rrent at which comparator resets the SR latch is controlled by t he output of error amplifier EA. While the high-side switch is off, the external schottky diode turns on until either the inductor current starts to reverse or the beginning of the next switching cycle. Dropout Operation As the input supply voltage decreases to a value approaching the output voltage, the duty cycle increases toward the maximum on-time. Further reduction of the supply voltage forces the high-side switch to remain on for more than one cycle until it reaches 100% duty cycle. The output voltage is dropped from the input supply for the voltage which across the high-side switch. Setting the Output Voltage Application circuit item shows the basic application circuit with adjustable output version. The external resistor sets the output voltage according to the following equation: VOUT=VFB× (1+R1 / R2), VFB=0.6V, R2 suggest 60kΩ ~ 300kΩ Table 1 Resistor select for output voltage setting VOUT R1 R2 1.0V 100K 150K 1.2V 100K 100K 1.5V 150K 100K 1.8V 200K 100K 2.5V 470K 150K 3.3V 450K 100K Over Temperature Protection In most applications the UD05021 does not dissipate much heat due to high efficiency. But, in applications where the UD05021 is running at high ambient temperature with low supply voltage and high duty cycles, such as in dropout, the heat dissipated may exceed the maximum junction temperature of the part. If the junction temperature reaches approximately 155°C, the inter nal high-side power switch will be turned off and the LX node will become high impedance. Over Current Protection The UD05021 cycle-by-cycle limits the peak inductor current to protect embedded switch from damage. Hence the maximum output current (the average of inductor current) is also limited. In case the load increases, the inductor current is also increase. Whenever t he current limit level is reached, t he output voltage can not be regulated and starting to drop. Soft-Start The UD05021 employs internal soft-start circuitry to reduce supply inrush current during startup conditions. When the device exits under-voltage lockout or shut-down mode, t he soft-start circuitry will slowly ramp up the output voltage. Short-circuit Protection Short-circuit protection will activate once the feedback voltage falls below, and the operating frequency will be reducing normal switching frequency to reduce power delivered from input to output.

UNISONIC TECHNOLOGIES CO., LTD 6 of 7 www.unisonic.com.tw Q W - R 1 1 5 - 0 1 0 . A  TYPICAL CHARACTERISTICS Efficiency vs. Output Current Efficiency (%) Output Current, VOUT (V) 100 Quiescent Current vs. Input Voltage Quiescent Current, ICCQ (mA) Input Voltage, VIN (V) 0.05 0.1 0.2 0.25 0.3 1.2 Power ON VIN=5V, VOUT=3.3V, IOUT=0A ISW VIN Power ON VIN=5V, VOUT=3.3V, IOUT=2A SW VOUT ISW VIN SW Load Transient Response VIN=5V, VOUT=3.3V, IOUT=50mA→500mA IOUT VOUT Load Transient Response VIN=5V, VOUT=3.3V, IOUT=500mA→1.5A IOUT VOUT 0.6 0.8 1.81.4 75 0.15 VIN=5V, VOUT=3.3V VOUT

UNISONIC TECHNOLOGIES CO., LTD 7 of 7 www.unisonic.com.tw Q W - R 1 1 5 - 0 1 0 . A  TYPICAL CHARACTERISTICS (Cont.) UTC assumes no responsibility for equipment failures that result from using products at values that exceed, even momentarily, rated values (such as maximum ratings, operating condition ranges, or other parameters) listed in products specifications of any and all UTC products described or contained herein. UTC products are not designed for use in life support appliances, devices or systems where malfunction of these products can be reasonably expected to result in personal injury. Reproduction in whole or in part is prohibited without the prior written consent of the copyright owner. The information presented in this document does not form part of any quotation or contract, is believed to be accurate and reliable and may be changed without notice.