AP1519 300KHz, 2A 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 - ON/OFF shutdown control input - Operating voltage can be up to 22V - Output load current: 2A - SOP-8L Pb-Free packages - Low power standby mode - Built-in switching transistor on chip The AP1519 is monolithic IC designed for a step-down DC/DC converter, and own the ability of driving a 2A load without additional transistor. It saves board space. The external shutdown function can be controlled by logic level and then come into standby mode. The internal compensation makes feedback control having 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 against over current operating of the output switch. If current limit function occurs and VFB is down below 0.5V, the switching frequency will be reduced. The AP1519 series operates at a switching frequency of 300KHz thus allows 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 chips are available in a standard 8-lead SOP-8 package. Applications - Simple High-efficiency step-down regulator - On-card switching regulators - Positive to negative converter Pin Assignments Pin Descriptions Name (Top View) VIN Output FB SD 1 2 3 4 8 7 6 5 VIN GND GND GND GND Output GND SOP-8L Description Operating voltage input Switching output Ground FB Output voltage feedback control SD ON/OFF Shutdown 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.1.0 Oct 5, 2004 1/9 AP1519 300KHz, 2A PWM Buck DC/DC Converter Ordering Information AP1519 X X Package Packing S: SOP-8L Blank : Tube A : Taping Block Diagram SD VIN 200mV Current Source bias 0.8V Reference 2.5V Regulator 220mV Start up + Comp _ _ Comp + Frequecy compensation _ FB + Amp _ Comp + Pre-driver 2A Switch Output 300kHz OSC. Thermal Shutdown Gnd Anachip Corp. www.anachip.com.tw Rev.1.0 Oct 5, 2004 2/9 AP1519 300KHz, 2A PWM Buck DC/DC Converter Absolute Maximum Ratings Symbol Parameter Rating Unit +24 V ON/OFF Pin input voltage -0.3 to +18 V Feedback Pin voltage -0.3 to +18 V VCC Supply Voltage VSD VFB VOUT Output voltage to Ground PD Power dissipation TST Storage temperature -1 V Internally limited W -65 to +150 o C o C TOP Operating temperature -40 to +125 VOP Operating voltage +4.5 to +22 V Electrical Characteristics (All Output Voltage Versions) Unless otherwise specified, VIN=12V. ILOAD = 0.5A Symbol IB 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 IH IL ΘJC ΘJA of When current limit occurred and VFB < 0.5V, Ta=25 oC IOUT=2A 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=0V force driver on Output No outside circuit Output = 0 leakage VFB=12V force driver off VIN=22V Output = -1 current Quiescent Current VFB=12V force driver off Standby Quiescent ON/OFF pin=5V Current VIN=22V Low (regulator ON) ON/OFF pin logic input threshold voltage High (regulator OFF) ON/OFF pin logic input VLOGIC=2.5V (OFF) current ON/OFF pin input current VLOGIC=0.5V (ON) Junction to Thermal Resistance SOP-8L case Thermal Resistance Junction to With copper area of SOP-8L ambient 2 approximately 3 in Max. -50 -100 345 345 Unit 50 KHz nA KHz 1.4 1.25 V 1.5 100 0 % 3 A -200 -5 5 70 2.0 1.3 uA mA mA 10 150 200 0.6 uA V -0.01 -0.1 uA -1 15 o 70 o C/W C/W Anachip Corp. www.anachip.com.tw Rev.1.0 Oct 5, 2004 3/9 AP1519 300KHz, 2A PWM Buck DC/DC Converter Electrical Characteristics (Continued) AP1519 Sym. Parameter Conditions Typ. Limit Unit VFB Output Feedback 5V < VIN < 22V 0.2A < ILOAD < 2A 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=2A VOUT programmed for 3.3V VIN = 12V, ILOAD=2A VOUT programmed for 5V VIN = 12V, ILOAD=2A VOUT programmed for 12V VIN = 16V, ILOAD = 2A 75 % 76 % 81 % 90 % Specifications with boldface type are for full operating temperature range, the other type are for TJ=25ºC. Anachip Corp. www.anachip.com.tw Rev.1.0 Oct 5, 2004 4/9 AP1519 300KHz, 2A PWM Buck DC/DC Converter Typical Application Circuit (1) Normal Circuit R1 250 Ω R2 1K FB 12V DC Input L1 22uH 3 Vin 1 AP1519 2 Output Inductor 5 6 7 8 4 SD Gnd Gnd Gnd Gnd Cin Capacitor 1V/2A Output Load D1 Schottky Diode Vout = VFB × (1 + R1 R2 Co Capacitor ) (2) Delay Start Circuit R1 250 Ω R2 1K 12V DC Input FB 3 Vin CDELAY 0.1uF Cin Capacitor RDELAY 10K 1 AP1519 4 5 6 2 7 Output L1 22uH 1V/2A Output Load Inductor 8 SD Gnd Gnd Gnd Gnd D1 Schottky Diode Co Capacitor Anachip Corp. www.anachip.com.tw Rev.1.0 Oct 5, 2004 5/9 AP1519 300KHz, 2A PWM Buck DC/DC Converter Typical Performance Characteristics AP1519 Efficiency v.s. Temperature (Vin=12V,Vout=3.3V,Io=2A) 86 85 84 83 82 81 80 79 78 77 76 75 81 80 79 Efficiency (%) Efficiency (%) AP1519 Efficiency v.s. Temperature (Vin=12V,Vout=5V,Io=2A) 78 77 76 75 74 73 -50 -30 -10 10 30 50 70 -50 -30 -10 10 90 110 130 150 AP1519 Saturation Voltage v.s. Temperature (Vcc=12V,Vfb=0V,VSD=0) 70 90 110 130 150 5 Switch Current Limit (A) Saturation Voltage (V) 50 AP1519 Switch Current Limit v.s. Temperature (Vcc=12V,Vfb=0V) 1.4 1.3 1.2 2A 1.1 1A 1 0.5A 0.9 0.8 0.7 -50 30 Temperature (TA) (°C) Temperature (TA) (°C) 4.5 4 3.5 3 2.5 -25 0 25 50 75 100 -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) AP1519 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.1.0 Oct 5, 2004 6/9 AP1519 300KHz, 2A PWM Buck DC/DC Converter Typical Performance Characteristics (Continued) AP1519 Threshold Voltage v.s. Temperature (Vcc=12V , Io=100mA) AP1519 ON/OFF Current v.s. ON/OFF Voltage (Vin=12V) 1.7 10 0 -10 -20 -30 -40 -50 -60 -70 -80 -90 -100 1.5 ON/OFF Current (nA) Threshold Voltage (V) 1.6 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) 6 9 12 15 18 21 ON/OFF Voltage (V) AP1519 Frequency v.s. Temperature (Vcc=12V , Io=500mA ,Vout=5V) AP1519 Feedback Current v.s. Temperature (Vcc=12V , Vout=5V,Vfb=0.8V) 320 10 310 0 Feedback Current (nA) Frequency (KHz) 3 300 290 280 270 -10 -20 -30 -40 -50 260 -50 -30 -10 10 30 50 70 -50 -30 -10 10 90 110 130 150 Temperature (TA) (°C) 30 50 70 90 110 130 150 Temperature (TA) (°C) Vout (V) AP1519 Output Voltage v.s. Temperature (Vin=12V ,Io=2A) 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.1.0 Oct 5, 2004 7/9 AP1519 300KHz, 2A PWM Buck DC/DC Converter Function Description Pin Functions +VIN This is the positive input supply for the IC switching regulator. A suitable input bypass capacitor must be presented at this pin to minimize voltage transients and to supply the switching currents needed by the regulator. Thermal Considerations The SOP-8 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 AP1519 junction temperature rises above ambient temperature for a 2A load and different input and output voltages. The data for these curves was taken with the AP1519 (SOP-8 package) operating as a buck-switching regulator in an ambient temperature of 25oC (still air). These temperature increments are all approximate and are affected by man factors. Higher ambient temperatures requires more heat sinker. 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 minimized. For the best thermal performance, wide copper traces and generous amounts of printed circuit board copper should be used in the board layout. (One exception 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. Feedback Senses the regulated output voltage to complete the feedback loop. 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 SD pin can be wired to the ground pin. Package thermal resistance and junction temperature increments are all approximate. The increments are affected by a lot of factors. 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 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. Anachip Corp. www.anachip.com.tw Rev.1.0 Oct 5, 2004 8/9 AP1519 300KHz, 2A PWM Buck DC/DC Converter Marking Information SOP-8L (Top view) Logo Part Number 1519 YY WW X Date Code X: Internal code WW: Nth week YY: Year Package Information H E Package Type: SOP-8L L VIEW "A" D 0.015x45 C B A1 e 7 (4X) A A2 7 (4X) VIEW "A" y Symbol A A1 A2 B C D E e H L y θ Dimensions In Millimeters Min. Nom. Max. 1.40 1.60 1.75 0.10 0.25 1.30 1.45 1.50 0.33 0.41 0.51 0.19 0.20 0.25 4.80 5.05 5.30 3.70 3.90 4.10 1.27 5.79 5.99 6.20 0.38 0.71 1.27 0.10 0O 8O Anachip Corp. www.anachip.com.tw Dimensions In Inches Min. Nom. Max. 0.055 0.063 0.069 0.040 0.100 0.051 0.057 0.059 0.013 0.016 0.020 0.0075 0.008 0.010 0.189 0.199 0.209 0.146 0.154 0.161 0.050 0.228 0.236 0.244 0.015 0.028 0.050 0.004 0O 8O Rev.1.0 Oct 5, 2004 9/9