UNISONIC TECHNOLOGIES CO., LTD UC3550 CMOS IC PWM CONTROLLED， PWM/PFM SWITCHABLE STEP-UP DC-DC CONTROLLER 3 2 1 DESCRIPTION The UTC UC3550 series is a compact, high efficiency, step-up DC/DC controllers includes an error amplifier, oscillator, PWM comparator, skip cycle comparator, voltage reference, soft-start, and high speed lower ON-resistance driver for driving external power devices (NMOS or NPN) ,Additionally, a CE (chip enable) function that reduces power consumption during shut-down mode. That typically operated from a single-or dual-cell battery packs. It have a driver pin ,ext pin, for connecting to an external transistor （NMOS or NPN）. a lower ON-resistance external transistor can obtain larger output current. With only external components, this series allow a simple means to accommodate high output current applications. The UTC UC3550 series goes automatically into skip switching cycles under light load condition to maintain high efficiency. 5 4 SOT-25 *Pb-free plating product number: UC3550L FEATURES * Input voltage range：0.9~8V * Output voltage range：1.8~6V programmable in 0.1V with high accuracy ± 2.5% * High efficiency 88%（typ.） * Low start-up voltage of 0.9V typical at IOUT = 1.0mA * Oscillator frequency: 300kHz.（±20%） * Chip enable pin with pull-up current source * High output current up to 1000mA (VIN = 2.0V, VOUT =3.3V) ORDERING INFORMATION Order Number Normal Lead Free Plating UC3550-xx-AF5-R UC3550L-xx-AF5-R UC3550L-xx-AF5-R Package Packing SOT-25 Tape Reel (1)Packing Type (1) R: Tape Reel (2)Package Type (2) AF5: SOT-25 (3)Voltage Code (3) xx: reference to Marking Information (4)Lead Plating (4) L: Lead Free Plating, Blank: Pb/Sn www.unisonic.com.tw Copyright © 2005 Unisonic Technologies Co., Ltd 1 of 10 QW-R502-082,A UC3550 CMOS IC MARKING INFORMATION PACKAGE VOLTAGE CODE MARKING 3 SOT-25 33:3.3V 50:5.0V 2 1 U5XX Voltage Code Lead Plating 4 5 PIN CONFIGURATION NC OUT CE 3 2 1 4 5 GND EXT PIN DESCRIPTION PIN NO PIN NAME 1 CE 2 3 4 5 OUT NC GND EXT DESCRIPTION Chip Enable: The chip is enabled if a voltage equal to or greater than 1.0V or left floating is applied. The chip is disabled if a voltage less than 0.3V is applied. Output voltage monitor, IC internal power supply No connection Ground External transistor drive UNISONIC TECHNOLOGIES CO., LTD www.unisonic.com.tw 2 of 10 QW-R502-082,A UC3550 CMOS IC BLOCK DIAGRAM OUT 2 + - NC 3 ~5mV PWM COMP Error Amplifier + Buffer driver 5 EXT Ramp Oscillator Skip COMP 120nA Voltage reference and soft start GND 4 CE 1 UNISONIC TECHNOLOGIES CO., LTD www.unisonic.com.tw 3 of 10 QW-R502-082,A UC3550 CMOS IC ABSOLUTE MAXIMUM RATING PARAMETER SYMBOL RATINGS Supply Voltage VOUT -0.3~8 -0.3 ~ 8 VEXT EXT Voltage EXT Sink/Source Current IEXT -150 ~ +150 CE Input Voltage Range VCE -0.3 ~ 12.0 CE Input Current Range ICE -155 ~ 155 Power Dissipation (Ta=25℃) PD 500 Junction Temperature TJ +150 Operating Temperature TOPR -40 ~ +85 Storage Temperature TSTG -55 ~ +150 Note: 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. UNIT V V mA V mA mW ℃ ℃ ℃ THERMAL DATA PARAMETER Thermal Resistance Junction to Air SYMBOL θJA RATINGS 250 UNIT ℃/W ELECTRICAL CHARACTERISTICS (Ta=25℃, fOSC＝300kHz, unless otherwise specified) UC3550-3.3V PARAMETER OSCILLATOR Frequency Frequency Temperature Coefficient Maximum PWM Duty Cycle Minimum Start-up Voltage Minimum Start-up Voltage Minimum Start-up Voltage Temperature Coefficient Minimum Operation Hold Voltage Soft-Start Time CE (PIN 1) CE Input Voltage： High State, Device Enabled Low State, Device Disabled CE Input Current： High State, Device Enabled Low State, Device Disabled SYMBOL fOSC △f DMAX VSTART1 VSTART2 TEST CONDITIONS VOUT=VSET×0.96 Ta=-40℃ ~ 85℃ VOUT=VSET×0.96 IOUT=0mA IOUT=1mA MIN TYP MAX UNIT 240 300 0.10 80 800 900 360 kHz %/℃ % mV mV 70 △VSTART Ta=-40℃ ~ 85℃ VOPR tSS IOUT=0mA VOUT=VSET VCEH VCEL VOUT=VSET×0.96 ICEH VOUT=VCE=5.0V ICEL VOUT=5.0V, VCE=0V 90 900 1000 -1.6 600 60 mV/℃ 700 250 mV ms 680 mV mV 900 µA -0.5 0 0.5 0 0.15 0.5 µA 11 8 15 12 Ω Ω 3.3 3.383 EXT (PIN 5) ON Resistance EXT “H” EXT “L” TOTAL DEVICE Output Voltage Output Voltage temperature coefficient Operating Current Stand-by Current Off-State Current Efficiency REXTH REXTL VEXT=VOUT-0.4V VEXT=0.4V VOUT 3.218 △VOUT Ta=-40 ~ 85℃ 150 IDD ISTN-BY VOUT=VCE=VSET×0.96 VOUT=VCE=VSET+0.5V VOUT=5.0V, VCE=0V, Ta=-40 ~ +85℃ IOUT = 200mA, VIN = 2.0V 103 15 160 38 µA µA 0.6 1.5 µA IOFF η UNISONIC TECHNOLOGIES CO., LTD www.unisonic.com.tw V 80 88 ppm/℃ % 4 of 10 QW-R502-082,A UC3550 CMOS IC ELECTRICAL CHARACTERISTICS (Cont.) UC3550-5.0V PARAMETER OSCILLATOR Frequency Frequency Temperature Coefficient Maximum PWM Duty Cycle Minimum Start-up Voltage Minimum Start-up Voltage Minimum Start-up Voltage Temperature Coefficient Minimum Operation Hold Voltage Soft-Start Time CE (PIN 1) CE Input Voltage ： High State, Device Enabled Low State, Device Disabled CE Input Current ： High State, Device Enabled Low State, Device Disabled SYMBOL fOSC △f DMAX VSTART1 VSTART2 TEST CONDITIONS VOUT=VSET×0.96 Ta=-40℃ ~ 85℃ VOUT=VSET×0.96 IOUT=0mA IOUT=1mA MIN TYP MAX UNIT 240 300 0.1 80 800 900 360 kHz %/℃ % mV V 70 △VSTART Ta=-40℃ ~ 85℃ VOPR tSS IOUT=0mA VOUT=VSET VCEH VOUT=VSET×0.96 -1.6 600 60 VOUT=VCE=5.0V VOUT=5.0V, VCE=0V REXTH REXTL VEXT=VOUT-0.4V VEXT=0.4V mV/℃ 700 200 mV ms 680 mV 0 0.15 0.5 0.5 µA µA 6 6 10 10 Ω Ω 5 5.125 900 mV VCEL ICEH ICEL 90 900 1 -0.5 0 EXT (PIN 5) ON Resistance EXT “H” EXT “L” TOTAL DEVICE Output Voltage Output Voltage temperature coefficient Operating Current Stand-by Current Off-State Current Efficiency VOUT 4.875 △VOUT Ta=-40 ~ 85℃ 150 IDD ISTN-BY VOUT=VCE=VSET×0.96 VOUT=VCE=VSET+0.5V VOUT=5.0V, VCE=0V, Ta=-40 ~ +85℃ IOUT = 200mA, VIN = 2.0V 136 15 220 38 µA µA 0.6 1.5 µA IOFF η UNISONIC TECHNOLOGIES CO., LTD www.unisonic.com.tw V 80 88 ppm/℃ % 5 of 10 QW-R502-082,A UC3550 CMOS IC TYPICAL STEP-UP CONVERTER APPLICATION 10uH V IN V OUT 220uF CE EXT 1 5 OUT UTC UC3550 2 10uF NC 0.1µ 3 GND 4 Step -up Converter using external MOSFET 10uH VIN VOUT Cb 3000P 1 OUT 2 10uF NC 0.1µ 3 220 uF EXT CE 5 UTC UC3550 Rb 560 GND 4 Step -up Converter using external NPN Recommended components NmosTr ：XP161A0390PR/ (Torex) or NTGS3446T1（ON SEMI） ：10Uh(sunida CD54 fosc＝300kHz) L ：MA737, or MBRM110L SD ：10V 10uF (tantalum) Cin ：16V220uF (tantalum) CL NPN Tr type Tr ：2SD1628(Sanyo)，MMJT9410 Rb ：500～1000Ω(Adjust according to load and Tr. hFE levels) Cb ：3000p（ceramic type） UNISONIC TECHNOLOGIES CO., LTD www.unisonic.com.tw 6 of 10 QW-R502-082,A UC3550 CMOS IC EXTERNAL COMPONENT SELECTION Inductor Selection An inductor value of 10uH performs well in most application. The UC3550 series also work with inductors in the 4.7uH to 12uH range. An inductor with higher peak inductor current tends a higher output voltage ripple（IPEAK x output filter capacitor ESR）. The inductor’s DC resistance significantly affects efficiency. Output Capacitor Selection The output ripple voltage（IPEAK x output filter capacitor ESR）is the product of the peak inductor current and the output capacitor Equivalent Series Resistance (ESR). Best performances are obtained with good high frequency characteristics capacitors and low ESR. The best compromise for the value of the Output Capacitance is 220F Tantalum Capacitor. The output capacitor as close as possible to the device pins. Input Capacitor Selection The Input Capacitor is required to compensate, if present, the series impedance between the Supply Voltage Source and the Input Voltage of the Application. A value of 10 F is enough to guarantee stability for distances less than 2". In any case we suggest to connect both capacitors, The input capacitor as close as possible to the device pins. Diode Selection The Schottky diode with an high switching speed and a very low Forward Voltage (VF) is needed. Higher VF may cause lost power as heat in the diode, with a decrease of the Efficiency. Moreover, since the Output Voltage pin is also used as the device Supply Voltage, the Start-up Voltage (see related plots) is strictly due to the diode Forward Voltage at the rated Forward Current. External Component Selection An enhancement N-channel MOSFET or a bipolar NPN transistor can be used as the external switch transistor. since enhancement N-channel MOSFET is a voltage driven device, it is a more efficient switch than a BJT transistor. However, he MOSFET requires a higher voltage to turn on as compared with BJT transistor For enhancement N-channel MOSFET ( it is especially importance for RDS(ON),typically<0.1Ω, threshold voltage, VGS(TH) must be<VOUT, typically<1.5V. For bipolar NPN transistor, continuous collector current typically 1A to 4A and VCE(SAT)<0.2V. the driving capability is determined by the DC current gain, HFE, of the transistor and the base resistor, Rb. Moreover, a speed-up capacitor, Cb should be connected in paralled with Rb to reduce switch loss and improve efficiency. UNISONIC TECHNOLOGIES CO., LTD www.unisonic.com.tw 7 of 10 QW-R502-082,A UC3550 CMOS IC TYPICAL CHARACTERISTICS VOUT=5.0V 0.1 VOUT=3.0V 2 3 4 Input Voltage, VIN (V) 10 0.1 VOUT=3.0V, R b=560Ω 5.2 VCE = 0 V 0.8 Open-Loop Test 0.6 0.4 0.2 2 6 3 4 5 Input Voltage, VIN (V) Output Voltage vs. Output Current 5.1 VIN=2.0V 5.0 VIN=3.0V 4.9 VIN=0.9V 4.8 Ta=25℃ 0.0 1 2 3 4 5 4.7 0 6 VOUT (V) 100 3.4 3.3 3.2 VIN=0.9V VIN=1.2V VIN=2.0V 3.1 3.0 0 200 400 600 800 1000 Output Current, IOUT (mA) Maximum Duty Cycle vs. Temperature Output Voltage vs. Output Current 200 400 600 800 Output Current, I O (mA) 1000 UNISONIC TECHNOLOGIES CO., LTD www.unisonic.com.tw Maximum Duty Cycle, D MAX (%) 3.5 Output Voltage, VOUT (V) VOUT=5.0V, R b=560Ω 1 0.01 1 5 Off-State Current vs. VOUT 1.0 OFF-State Current, IOFF (µA) NO Load Input Current, I IN (mA) 1 0.01 1 No Load Input Current vs. Input Voltage (Using BJT) 100 Output Voltage, VOUT (V) NO Load Input Current, IIN (mA) No Load Input Current vs. Input Voltage (Using MOSFET) 10 90 80 70 60 50 0-50 Open- Loop Test -25 0 25 50 75 100 Temperature (℃) 8 of 10 QW-R502-082,A UC3550 CMOS IC TYPICAL CHARACTERISTICS(Cont.) Efficiency vs Output Current (5.0V) Startup/Hold Voltage, V start/Vhold (V) 100 Efficiency (%) VIN=3.0V 80 VIN=2.0V 60 VIN=0.9V 40 20 0 0. 01 0.1 1 10 100 1000 Startup/Hold Voltage vs Output Current (Using MOSFET) Output Current (3.3V) 2.0 Vstart 1.6 1.2 0.8 Vnold 0.4 0.0 20 0 Output Current, IOUT (mA) EXT ON -Resistance vs Temperature 20 15 VOUT=5.0V×0.96 VEXT=VOUT-0.4V Open-Loop Test 10 VOUT=5.0V×0.96 VEXT =0.4V Open-Loop Test 5 0 -50 25 - 0 25 50 75 180 160 80 100 VIN=2.0V 140 120 100 VIN=3.0V VIN=1.5V 80 60 40 VIN=4.5V 20 0 100 Temperature℃ 0 200 400 600 800 1000 Output Current, IOUT (mA) Oscillator Frequency vs. Temperature Oscillator Frequency vs. Temperature 600 600 VOUT=3.3V Oscilator Frequency, fosc (KHz) Oscilator Frequency, fosc (KHz) 60 Ripple Voltage vs Output Current 200 Ripple Voltage, VRIPPLE (mV) ON-Resistance, (Ω) 25 40 Output Current, IC (mA) 500 400 300 200 100 0 -50 -25 0 25 50 75 100 UNISONIC TECHNOLOGIES CO., LTD www.unisonic.com.tw VOUT=5V 500 400 300 200 100 0 -50 -25 0 25 50 Temperature (℃) 75 100 9 of 10 QW-R502-082,A UC3550 CMOS IC 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. UNISONIC TECHNOLOGIES CO., LTD www.unisonic.com.tw 10 of 10 QW-R502-082,A