AP1518 300KHz, 3A PWM Buck DC/DC Converter Features General Description - Adjustable version output voltage range, 0.8V to 18V+4% - 300KHz +15% fixed switching frequency - Voltage mode non-synchronous PWM control - Thermal-shutdown and current-limit protection The AP1518 series are monolithic IC designed for a step-down DC/DC converter, and own the ability of driving a 3A load without external transistor. Due to reducing the number of external component, the board space can be saved easily. The external shutdown function can be controlled by logic level and then come into standby mode. The internal compensation makes feedback control have good line and load regulation without external design. Regarding protected function, thermal shutdown is to prevent over temperature operating from damage, and current limit is to prevent over current operating of the output switch. If current limit function occurred and VFB is down to 0.5V below, the switching frequency will be reduced. The AP1518 series operate at a switching frequency of 300KHz thus allowing smaller sized filter components than what would be needed with lower frequency switching regulators. Other features include a guaranteed +4% tolerance on output voltage under specified input voltage and output load conditions, and +15% on the oscillator frequency. The packages are available in a standard 5-lead TO-220 package or a 5-lead TO-263. - ON /OFF shutdown control input - Operating voltage can be up to 22V - Output load current: 3A - TO220-5L and TO263-5L Pb-Free packages - Low power standby mode - Built-in switching transistor on chip Applications - Simple High-efficiency step-down regulator - On-card switching regulators - Positive to negative converter Pin Assignments Pin Descriptions ( Top View ) Metal Tab GND Name VIN 5 SD 4 FB 3 Gnd 2 Output 1 VIN Output GND TO263-5L Description Operating voltage input Switching output Ground FB Output voltage feedback control SD ON /OFF Shutdown ( Top View ) 5 SD 4 FB 3 Gnd 2 Output 1 VIN TO220-5L This datasheet contains new product information. Anachip Corp. reserves the rights to modify the product specification without notice. No liability is assumed as a result of the use of this product. No rights under any patent accompany the sale of the product. Rev.1.1 Oct 29, 2004 1/12 AP1518 300KHz, 3A PWM Buck DC/DC Converter Ordering Information AP1518 X X Package Packing T5: TO220-5L K5: TO263-5L T5R: TO220-5L(R) Blank : Tube A : Taping Block Diagram SD VIN 200mV Current Source bias 0.8V Reference 2.5V Regulator 220mV Start up + Comp _ _ Comp + Amp _ _ + FB Frequecy compensation Comp + Pre-driver 3A Switch Output 300kHz OSC. Anachip Corp. www.anachip.com.tw Thermal Shutdown Gnd Rev.1.1 Oct 29, 2004 2/12 AP1518 300KHz, 3A PWM Buck DC/DC Converter Absolute Maximum Ratings Symbol VCC VSD VFB VOUT PD TST TOP VOP Parameter Rating Supply Voltage ON /OFF Pin input voltage Feedback Pin voltage Output voltage to Ground Power dissipation Storage temperature Operating temperature Operating voltage Unit +24 V -0.3 to +18 V -0.3 to +18 -1 Internally limited -65 to +150 -40 to +125 +4.5 to +22 V V W o C o C V Electrical Characteristics (All Output Voltage Versions) Unless otherwise specified, VIN=12V, ILOAD = 0.5A Symbol IFB Parameter Feedback bias current Conditions VFB=0.8V (Adjustable version only) Min. Typ. -10 FOSC Oscillator frequency 255 220 300 FSCP Oscillator frequency short circuit protect 10 30 VSAT DC ICL IL IQ ISTBY VIL VIH of When current limit occurred o and VFB < 0.5V, Ta=25 C IOUT=3A Saturation Voltage No outside circuit VFB=0V force driver on Max. Duty Cycle (ON) VFB=0V force driver on Min. Duty Cycle (OFF) VFB=12V force driver off Peak current Current limit No outside circuit VFB=0 force driver on Output No outside circuit Output = 0V leakage VFB=12 force driver off current VIN=22V Output =-1V Quiescent Current VFB=12 force driver off Standby Quiescent ON /OFF pin=5V Current VIN=22V Low (regulator ON) ON /OFF pin logic input High (regulator OFF) threshold voltage 4.5 V 1.7 % A 6.5 -200 -5 5 70 2.0 1.3 IL ON /OFF pin input current VLOGIC=0.5V (ON) -0.1 TO220-5L TO263-5L TO220-5L 2.5 3.5 28 Thermal Resistance With copper area of approximately 3 in2 KHz KHz 5.5 3.6 VLOGIC=2.5V (OFF) ΘJA 50 nA 100 0 ON /OFF pin logic input current Thermal Resistance Unit 1.6 1.4 IH ΘJC Max. -50 -100 345 345 uA mA mA 10 150 200 0.6 - uA V -0.01 uA TO263-5L Junction to case Junction to ambient 23 -1 o C/W o C/W Specifications with boldface type are for full operating temperature range, the other type are for TJ=25ºC. Anachip Corp. www.anachip.com.tw Rev.1.1 Oct 29, 2004 3/12 AP1518 300KHz, 3A PWM Buck DC/DC Converter Electrical Characteristics (Continued) AP1518 Sym. Parameter Conditions Typ. Limit Unit VFB Output Feedback 5V < VIN < 22V 0.2A < ILOAD < 3A 0.8 0.784/0.768 0.816/0.832 V VMIN VMAX η Efficiency η Efficiency η Efficiency η Efficiency VOUT programmed for 3V VIN = 12V, ILOAD=3A VOUT programmed for 3.3V VIN = 12V, ILOAD=3A VOUT programmed for 5V VIN = 12V, ILOAD=3A VOUT programmed for 12V VIN = 16V, ILOAD = 3A 74 % 75 % 80 % 89 % Specifications with boldface type are for full operating temperature range, the other type are for TJ=25ºC. Anachip Corp. www.anachip.com.tw Rev.1.1 Oct 29, 2004 4/12 AP1518 300KHz, 3A PWM Buck DC/DC Converter Typical Performance Characteristics AP1518 Efficiency v.s. Temperature (Vin=12V,Vout=3.3V,Io=3A) 78 83 82 81 80 79 78 77 76 75 74 73 72 77 76 Efficiency (%) Efficiency (%) AP1518 Efficiency v.s. Temperature (Vin=12V,Vout=5V,Io=3A) 75 74 73 72 71 70 -50 -30 -10 10 30 50 70 90 110 130 150 -50 -30 -10 10 Temperature (TA) (°C) AP1518 Saturation Voltage v.s. Temperature (Vcc=12V,Vfb=0V,VSD=0) 50 70 90 110 130 150 AP1518 Switch Current Limit v.s. Temperature (Vcc=12V,Vfb=0V) 1.6 Switch Current Limit (A) 5.5 1.5 Saturation Voltage (V) 30 Temperature (TA) (°C) 3A 1.4 1.3 2A 1.2 1A 1.1 0.5A 1 0.9 0.8 0.7 -50 -25 0 25 50 75 100 5 4.5 4 3.5 3 -50 125 Temperature (TA) (°C) -30 -10 10 30 50 70 90 Temperature (TA) (°C) 15 14 13 12 11 10 9 8 7 6 5 60 Supply Current (uA) Supply Current (mA) AP1518 Supply Current v.s. Temperature (Vcc=12V , No Load ,Von/off =0V(Switch ON) ,Von/off =5V(Switch OFF)) Switch ON -50 -30 -10 10 30 50 70 90 110 130 150 55 50 45 Switch OFF 40 35 30 -50 -30 -10 10 30 50 70 90 110 130 150 Temperature (TA) (°C) Temperature (TA) (°C) Anachip Corp. www.anachip.com.tw Rev.1.1 Oct 29, 2004 5/12 AP1518 300KHz, 3A PWM Buck DC/DC Converter Typical Performance Characteristics (Continued) AP1518 ON/OFF Current v.s. ON/OFF Voltage (Vin=12V) AP1518 Threshold Voltage v.s. Temperature (Vcc=12V , Io=100mA) 1.7 10 0 -10 -20 -30 -40 -50 -60 -70 -80 -90 -100 1.6 ON/OFF Current (nA) Threshold Voltage (V) 1.5 1.4 1.3 1.2 1.1 1 0.9 0.8 -50 -30 -10 10 30 50 70 0 90 110 130 150 Temperature (TA) (°C) 10 310 0 Feedback Current (nA) Frequency (KHz) 9 12 15 18 21 AP1518 Feedback Current v.s. Temperature (Vcc=12V , Vout=5V,Vfb=0.8V) 320 300 290 280 270 50 6 ON/OFF Voltage (V) AP1518 Frequency v.s. Temperature (Vcc=12V , Io=500mA ,Vout=5V) 260 -50 -30 -10 10 30 3 -10 -20 -30 -40 -50 70 90 110 130 150 -50 -30 -10 10 30 50 70 90 110 130 150 Temperature (TA) (°C) Temperature (TA) (°C) Vout (V) AP1518 Output Voltage v.s. Temperature (Vin=12V ,Io=3A) 3.5 3.45 3.4 3.35 3.3 3.25 3.2 3.15 3.1 3.05 3 2.95 2.9 -40 -20 0 20 40 60 80 100 120 140 160 Temperature (TA) (°C) Anachip Corp. www.anachip.com.tw Rev.1.1 Oct 29, 2004 6/12 AP1518 300KHz, 3A PWM Buck DC/DC Converter Typical Application Circuit (1) Normal Circuit R1 R2 FB 12V DC Input L1 10uH 4 1 Vin AP1518 5 SD Cin Capacitor 2 Output 1V/ 2A Output Load 3 Gnd Vout = VFB × (1 + D1 Schottky Diode R1 R2 Co Capacitor ) VFB = 0.8V R2 = 1K ~ 3K (2) Delay Start Circuit R2 R1 FB 12V DC Input 4 Vin Cin Capacitor CDELAY 0.1uF 1 AP1518 5 2 Output L1 10uH 1V/ 2A Output Load 3 SD RDELAY 10K Gnd D1 Schottky Diode Anachip Corp. www.anachip.com.tw Co Capacitor Rev.1.1 Oct 29, 2004 7/12 AP1518 300KHz, 3A PWM Buck DC/DC Converter Function Description of 25oC (still air). These temperature rise numbers are all approximate and there are many factors that can affect these temperatures. Higher ambient temperatures require more heat sinking. Pin Functions +VIN This is the positive input supply for the IC switching regulator. A suitable input bypass capacitor must be present at this pin to minimize voltage transients and to supply the switching currents needed by the regulator. The TO-263 surface mount package tab was designed to be soldering to the copper on a printed circuit board. The copper and the board are the heat sink for this package and the other heat producing components, such as the catch diode and inductor. The PC board copper area that the package is soldered to should be at least 0.8 in2, and ideally should have 2 or more square inches of 2 oz. Additional copper area improves the thermal characteristics, but with copper areas greater than approximately 6 in2, only small improvements in heat dissipation are realized. If further thermal improvements are needed, double sided, multi-layer PC board with large copper areas and/or airflow will be recommended. Ground Circuit ground. Output Internal switch. The voltage at this pin switches between (+VIN – VSAT) and approximately – 0.5V, with a duty cycle of approximately VOUT / VIN. To minimize coupling to sensitive circuitry, the PC board copper area connected to this pin should be kept a minimum. Feedback (FB) Senses the regulated output voltage to complete the feedback loop. The AP1518 (TO-263 package) junction temperature rises above ambient temperature with a 2A load for various input and output voltages. This data was taken with the circuit operating as a buck-switching regulator with all components mounted on a PC board to simulate the junction temperature under actual operating conditions. This curve can be used for a quick check for the approximate junction temperature for various conditions, but be aware that there are many factors that can affect the junction temperature. When load currents higher than 3A are used, double sided or multi-layer PC boards with large copper areas and/or airflow might be needed, especially for high ambient temperatures and high output voltages. ON /OFF (SD) Allows the switching regulator circuit to be shutdown using logic level signals thus dropping the total input supply current to approximately 150uA. Pulling this pin below a threshold voltage of approximately 1.3V turns the regulator on, and pulling this pin above 1.3V (up to a maximum of 18V) shuts the regulator down. If this shutdown feature is not needed, the ON /OFF pin can be wired to the ground pin. Thermal Considerations The AP1518 is available in two packages: a 5-pin TO-220 and a 5-pin surface mount TO-263. For the best thermal performance, wide copper traces and generous amounts of printed circuit board copper should be used in the board layout. (Once exception to this is the output (switch) pin, which should not have large areas of copper.) Large areas of copper provide the best transfer of heat (lower thermal resistance) to the surrounding air, and moving air lowers the thermal resistance even further. The TO-220 package needs a heat sink under most conditions. The size of the heatsink depends on the input voltage, the output voltage, the load current and the ambient temperature. The AP1518 junction temperature rises above ambient temperature for a 3A load and different input and output voltages. The data for these curves was taken with the AP1518 (TO-220 package) operating as a buck-switching regulator in an ambient temperature Anachip Corp. www.anachip.com.tw Rev.1.1 Oct 29, 2004 8/12 AP1518 300KHz, 3A PWM Buck DC/DC Converter Function Description (Continued) the size, quantity and spacing of other components on the board, as well as whether the surrounding air is still or moving. Furthermore, some of these components such as the catch diode will add heat to the PC board and the heat can vary as the input voltage changes. For the inductor, depending on the physical size, type of core material and the DC resistance, it could either act as a heat sink taking heat away from the board, or it could add heat to the board. Package thermal resistance and junction temperature rise numbers are all approximate, and there are many factors that will affect these numbers. Some of these factors include board size, shape, thickness, position, location, and even board temperature. Other factors are, trace width, total printed circuit copper area, copper thickness, single or double-sided, multi-layer board and the amount of solder on the board. The effectiveness of the PC board to dissipate heat also depends on Marking Information (1) TO263-5L (2) TO220-5L ( Top view ) ( Top view ) Logo Part Number 1518 YY WW X Logo ID code Xth week: 01~52 Year: "01" = 2001 "02" = 2002 Part Number 1518 YY WW X ~ ID code Xth week: 01~52 Year: "01" = 2001 "02" = 2002 ~ Anachip Corp. www.anachip.com.tw Rev.1.1 Oct 29, 2004 9/12 AP1518 300KHz, 3A PWM Buck DC/DC Converter Package Information (1) Package Type: TO220-5L E A F L D H1 Q ΦP b e C J1 e1 Symbol A b C D E e e1 F H1 J1 L Øp Q Dimensions In Millimeters Min. Nom. Max. 4.07 4.45 4.82 0.76 0.89 1.02 0.36 0.50 0.64 14.22 14.86 15.50 9.78 10.16 10.54 1.57 1.71 1.85 6.68 6.81 6.93 1.14 1.27 1.40 5.46 6.16 6.86 2.29 2.74 3.18 13.21 13.97 14.73 3.68 3.81 3.94 2.54 2.73 2.92 Anachip Corp. www.anachip.com.tw Dimensions In Inches Min. Nom. Max. 0.160 0.030 0.014 0.175 0.035 0.020 0.190 0.040 0.025 0.560 0.385 0.062 0.263 0.045 0.215 0.090 0.520 0.145 0.100 0.585 0.400 0.067 0.268 0.050 0.243 0.108 0.550 0.150 0.107 0.610 0.415 0.073 0.273 0.055 0.270 0.125 0.580 0.155 0.115 Rev.1.1 Oct 29, 2004 10/12 AP1518 300KHz, 3A PWM Buck DC/DC Converter Package Information (Continued) (2) Package Type: TO263-5L E 2.5 L D 15.7 9.1 L2 10.9 1.0 1.7 C2 A B C e Land Pattern Recommendation (Unit: mm) L1 Symbol A B C C2 D E e L L1 L2 Dimensions In Millimeters Min. Nom. Max. 4.07 4.46 4.85 0.66 0.84 1.02 0.36 0.50 0.64 1.14 1.27 1.40 8.65 9.15 9.65 9.78 10.16 10.54 1.57 1.71 1.85 14.61 15.24 15.88 2.29 2.54 2.79 2.92 Anachip Corp. www.anachip.com.tw Dimensions In Inches Min. Nom. Max. 0.160 0.176 0.191 0.026 0.033 0.040 0.014 0.020 0.025 0.045 0.050 0.055 0.341 0.360 0.380 0.385 0.400 0.415 0.062 0.068 0.073 0.575 0.600 0.625 0.090 0.100 0.110 0.115 Rev.1.1 Oct 29, 2004 11/12 AP1518 300KHz, 3A PWM Buck DC/DC Converter Package Information (Continued) (3) Package Type: TO220-5L(R) Mechanical drawing A E F Q H1 D d1 H2 H3 d2 J1 b J2 e J3 J3 J2 A J1 E Symbol A b D d1 d2 E e F H1 H2 H3 J1 J2 J3 Q Dimensions In Millimeters Min. Nom. Max. 4.4 4.6 4.7 0.7 0.8 0.9 8.4 8.7 8.9 1.0 6.3 9.91 10.16 10.41 1.6 1.7 1.8 1.2 1.25 1.3 6.4 20.8 21.6 22.4 23.9 24.7 25.5 2.7 3.7 4.5 5.3 8.4 2.5 2.8 3.0 Anachip Corp. www.anachip.com.tw Dimensions In Inches Min. Nom. Max. 0.175 0.180 0.185 0.027 0.032 0.037 0.330 0.340 0.350 0.039 0.248 0.390 0.400 0.410 0.062 0.067 0.072 0.048 0.050 0.052 0.250 0.820 0.850 0.880 0.942 0.972 1.002 0.105 0.147 0.177 0.207 0.331 0.100 0.110 0.120 Rev.1.1 Oct 29, 2004 12/12