AP1530 18V 3A 300KHz BUCK CONVERTER General Description Features • • • • • • • • • • AP1530 consists of step-down switching regulator with PWM control. These devices include a reference voltage source, oscillation circuit, error amplifier and internal PMOS. Input voltage: 3.6V to 18V. Output voltage: 0.8V to VCC. Duty ratio: 0% to 100% PWM control Oscillation frequency: 300kHz typ. Current Limit, Enable function Thermal Shutdown function Built-in internal SW P-channel MOS Lead Free package: SOP-8L SOP-8L: Available in “Green” Molding Compound (No Br, Sb) (Note 1) Lead Free Finish/ RoHS Compliant (Note 2) AP1530 provides low-ripple power, high efficiency, and excellent transient characteristics. The PWM control circuit is able to vary the duty ratio linearly from 0 up to 100%. This converter also contains an error amplifier circuit. An enable function, an over current protection and a short circuit protection are built inside, and when OCP or SCP happens, the operation frequency will be reduced from 300kHz to 50kHz. Also, an internal compensation block is built in to minimum external component count. With the addition of an internal P-channel Power MOS, a coil, capacitors, and a diode connected externally, these ICs can function as step-down switching regulators. They serve as ideal power supply units for portable devices when coupled with the SOP-8L package, providing such outstanding features as low current consumption. Since this converter can accommodate an input voltage up to 18V, it is also suitable for the operation via an AC adapter. Applications • • • • • • • • • PCD Motherboard LCD Monitor Graphic Card DVD-Video Player Telecom Equipment ADSL Modem Printer and other Peripheral Equipment Microprocessor core supply Networking power supply Typical Application Circuit Vcc VIN Output ROCSET COCSET Option 3K C IN OCSET 470uF CVcc 0.1uF R EN 100K 22uH Cc AP 1530 EN VOUT = 5V/3A L1 Option RA 6.8K + FB V SS D1* C + 0.1uF - COUT 470uF RB 1.3K C EN 0.1uF VOUT = V FB x (1+ R A /RB ) R B = 0.7K~5K ohm * Suggested DIODES Power Schottky P/N: B340 series or PDS340. AP1530 Rev. 7 DS31092 1 of 12 www.diodes.com NOVEMBER 2009 © Diodes Incorporated AP1530 18V 3A 300KHz BUCK CONVERTER Ordering Information AP 1 5 3 0 S X - 13 Device AP1530SL-13 AP1530SG-13 Notes: Package Lead Free S : SOP-8L L : Lead Free G : Green Package Code S S Packaging (Note 2) SOP-8L SOP-8L Packing 13 : Tape & Reel 13” Tape and Reel Quantity Part Number Suffix 2500/Tape & Reel -13 2500/Tape & Reel -13 1. EU Directive 2002/95/EC (RoHS). All applicable RoHS exemptions applied. Please visit our website at http://www.diodes.com/products/lead_free.html. 2. Pad layout as shown on Diodes Inc. suggested pad layout document AP02001, which can be found on our website at http://www.diodes.com/datasheets/ap02001.pdf. Pin Assignments (1) SOP-8L ( Top View ) AP1530 Rev. 7 DS31092 Vss FB 1 8 EN 2 7 Vss OCSET 3 6 Output VCC 4 5 Output 2 of 12 www.diodes.com NOVEMBER 2009 © Diodes Incorporated AP1530 18V 3A 300KHz BUCK CONVERTER Pin Descriptions Pin Name Pin No. Description FB 1 Feedback pin EN 2 Power-off pin H: Normal operation (Step-down operation) L: Step-down operation stopped (All circuits deactivated) OCSET 3 Add an external resistor to set max output current VCC 4 IC power supply pin Output 5, 6 Switch Pin. Connect external inductor/diode here. Minimize trace area at this pin to reduce EMI VSS 7, 8 GND Pin Block Diagram Output Oscillation Circuit Reference Voltage Source Vcc + PWM-Switched Control Circuit FB - Thermal Shutdown VEN EN AP1530 Rev. 7 DS31092 3 of 12 www.diodes.com 100uA Vss OCSET NOVEMBER 2009 © Diodes Incorporated AP1530 18V 3A 300KHz BUCK CONVERTER Absolute Maximum Ratings Symbol ESD HBM ESD MM VCC VFB VEN VOUTPUT PD TJ TST Parameter Human Body Model ESD Protection Machine Model ESD Protection VCC Pin Voltage Feedback Pin Voltage EN Pin Voltage Switch Pin Voltage Power Dissipation Operating Junction Temperature Range Storage Temperature Range Rating 5 500 VSS - 0.3 to VSS + 20 VSS - 0.3 to VCC VSS - 0.3 to VIN + 0.3 VSS - 0.3 to VIN + 0.3 Internally limited -40 to +125 -65 to +150 Unit KV V V V V V mW o C o C Caution: The absolute maximum ratings are rated values exceeding which the product could suffer physical damage. These values must therefore not be exceeded under any conditions. Recommended Operating Conditions Symbol VIN IOUT TA AP1530 Rev. 7 DS31092 Parameter Input Voltage Output Current Operating Ambient Temperature 4 of 12 www.diodes.com Min 3.6 0 -20 Max 18 3 85 Unit V A o C NOVEMBER 2009 © Diodes Incorporated AP1530 18V 3A 300KHz BUCK CONVERTER Electrical Characteristics (VIN = 12V, TA=25°C, unless otherwise specified) Symbol Parameter Conditions Min VFB Feedback Voltage IOUT=0.1A 0.784 IFB Feedback Bias Current IOUT=0.1A ISW Switch Current -3.5 Current Consumption During ISHDN VEN =0V Power Off ∆VOUT Line Regulation VIN=5V~18V /VIN ∆VOUT Load Regulation IOUT=0.1 to 3A /VOUT fOSC Oscillation Frequency Measure waveform at SW pin 240 Frequency of Current Limit or fOSC1 Measure waveform at SW pin Short Circuit Protection VIH Evaluate oscillation at SW pin 2.0 EN Pin Input Voltage VIL Evaluate oscillation stop at SW pin IENH -EN Pin Input Leakage Current IENL -IOCSET OCSET Pin Bias Current -75 TSS Soft-Start Time -0.3 TSHDN Thermal shutdown threshold THYS Thermal shutdown hysteresis VIN=5V, VFB=0V RDSON Internal MOSFET RDS(ON) VIN=12V, VFB=0V VIN=12V, VOUT = 5V EFFI Efficiency IOUT=3A Thermal Resistance θJA SOP-8L (Note 3) Junction-to-Ambient Thermal Resistance θJC SOP-8L (Note 3) Junction-to-Case Notes: Typ. 0.8 0.1 - Max 0.816 0.5 - Unit V µA A 10 - µA 1 2 % 0.2 0.5 % 300 360 kHz 50 - kHz 20 -10 90 2 150 55 110 70 0.8 105 5 150 100 92 - 134 - o C/W 22 - o C/W V µA µA µA ms °C °C mΩ % 3. Test condition SOP-8L: Device mounted on FR-4 substrate 2oz copper, minimum recommended pad layout, and single side. For better thermal performance, please arrange larger copper pad of layout for heatsink. AP1530 Rev. 7 DS31092 5 of 12 www.diodes.com NOVEMBER 2009 © Diodes Incorporated AP1530 18V 3A 300KHz BUCK CONVERTER 340 338 336 334 332 330 328 326 324 322 320 VIN vs. Frequency VIN vs. VFB (VOUT=3.3V; IOUT=0.2A) (VOUT=3.3V; IOUT=0.1A) 0.820 0.815 0.810 0.805 0.800 0.795 0.790 0.785 0.780 VFB (V) FOSC (kHz) Typical Performance Characteristics 2 4 6 8 10 12 14 VIN (V) 16 18 20 2 22 4 6 VOUT (A) VOUT (V) (VOUT=3.3V; IOUT=0.2A) 2 4 6 8 10 10 12 14 VIN (V) 16 18 20 22 Load Regulation Line Regulation 3.40 3.35 3.30 3.25 3.20 3.15 3.10 3.05 3.00 8 12 14 VIN (V) 16 18 20 (VIN=12V; VOUT=5V) 5.00 4.99 4.98 4.97 4.96 4.95 4.94 4.93 4.92 22 0 0.5 1 1.5 IOUT (A) 2 2.5 3 Efficiency (%) Efficiency VIN=5V; VOUT=3.3V 100% 90% 80% 70% 60% 50% 40% 30% 20% 10% 0% 0 AP1530 Rev. 7 DS31092 0.5 1 1.5 IOUT (A) 2 2.5 3 6 of 12 www.diodes.com NOVEMBER 2009 © Diodes Incorporated AP1530 18V 3A 300KHz BUCK CONVERTER Typical Performance Characteristics (Continued) AP1530 Vout Ripple (Vin= 12V; Vout= 3.3V; Iout= 3A) AP1530 Vout Ripple (Vin= 12V; Vout= 3.3V; Iout= 0.1A) Test Circuit VCC OUTPUT FB Oscillation open open OCSET A EN + - VSS Enable function test VCC + - A OUTPUT VCC OUTPUT OCSET EN FB VSS Feedback function test FB OCSET EN VSS + V - Operation function test AP1530 Rev. 7 DS31092 7 of 12 www.diodes.com NOVEMBER 2009 © Diodes Incorporated AP1530 18V 3A 300KHz BUCK CONVERTER Functional Description PWM Control The AP1530 is a DC/DC converter that employs pulse width modulation (PWM) scheme. Its pulse width varies in the range of 0% to 99%, based on the output current loading. The output ripple voltage caused by the PWM high frequency switching can easily be reduced through an output filter. Therefore, this converter provides a low ripple output supply over a broad range of input voltage & output current loading Inductor Selection For most designs, the operates with inductors of 22µH to 33µH. The inductor value can be derived from the following equation: Under Voltage Lockout The under voltage lockout circuit of the AP1530 assures that the high-side MOSFET driver remains in the off state whenever the supply voltage drops below 3.3V. Normal operation resumes once VCC rises above 3.5V. Where ΔIL is inductor Ripple Current. Large value inductors lower ripple current and small value inductors result in high ripple current. Choose inductor ripple current approximately 15% of the maximum load current 3A, ∆IL=0.45A. The DC current rating of the inductor should be at least equal to the maximum load current plus half the ripple current to prevent core saturation (3A+0.225A). Current Limit Protection The current limit threshold is set by external resistor ROCSET connected from VCC supply to OCSET pin. The internal sink current IOCSET (90uA typical) across this resistor sets the voltage at OCSET pin. When the PWM voltage is less than the voltage at OCSET, an over-current condition is triggered. The current limit threshold is given by the following equation: IPEAK × RDS(ON) = IOCSET × R OCSET ( ΔI) IPEAK > IOUT (MAX) + 2 VIN − VOUT FSxL x Input Capacitor Selection This capacitor should be located close to the IC using short leads and the voltage rating should be approximately 1.5 times the maximum input voltage. The RMS current rating requirement for the input capacitor of a buck regulator is approximately 1⁄2 the DC load current. A low ESR input capacitor sized for maximum RMS current must be used. A 470µF low ESR capacitor for most applications is sufficient. VOUT VIN IPEAK is the output peak current; RDS (ON) is the MOSFET ON resistance; FS is the PWM frequency (300KHz typical). Also, the inductor value will affect the ripple current ΔI. The above equation is recommended for input voltage range of 5V to 18V. For input voltage lower than 5V or ambient temperature over 100°C, higher ROCSET is recommended. The recommended minimum ROCSET value is summarized below: VIN (V) 4 5 12 18 AP1530 Rev. 7 DS31092 VOUT (V) 0.8 3.3 5 12 ROCSET (Ω) 3.9K 3.0K 3.0K 3.0K VIN − VOUT VOUT × fs × ΔI VIN Output Capacitor Selection The output capacitor is required to filter the output voltage and provides regulator loop stability. The important capacitor parameters are the 100KHz Equivalent Series Resistance (ESR), the RMS ripples current rating, voltage rating and capacitance value. For the output capacitor, the ESR value is the most important parameter. The output ripple can be calculated from the following formula. where, ΔI = L= V RIPPLE = ΔIL × ESR The bulk capacitor’s ESR will determine the output ripple voltage and the initial voltage drop after a high slew-rate transient. An aluminum electrolytic capacitor's ESR value is related to the capacitance and its voltage rating. In most case, higher voltage electrolytic capacitors have lower ESR values. Most of the time, capacitors with much higher voltage ratings may be needed to provide the low ESR values required for low output ripple voltage. PCB Layout Guide If you need low TC & TJ or large PD (Power Dissipation), The dual SW pins(5& 6) and Vss pins(7& 8)on the SOP-8L package are internally connected to die pad, The evaluation board should be allowed for maximum copper area at output (SW) pins. 1. Connect FB circuits (R1, R2, C1) as closely as possible and keep away from inductor flux for pure VFB. 2. Connect C3 to Vcc and Vss pin as closely as possible to get good power filter effect. 3. Connect R4 to Vcc and OCSET pin as closely as possible. 4. Connect ground side of the C2 & D1 & C4 as closely as possible and use ground plane for best performance. 8 of 12 www.diodes.com NOVEMBER 2009 © Diodes Incorporated AP1530 18V 3A 300KHz BUCK CONVERTER Functional Description (Continued) Keep the gap of exposed pads from short circuit. Recommended exposed-pads gap: 30~40mil (0.75~1mm) Top Side Layout Guide Use vias to conduct the heat into the backside of PCB layer. The heat sink at output (SW) pins should be allowed for maximum solder-painted area. Brown: IC exposed pads. Red: recommended layout. Reference pads layout dimension: Output: 90 x 50 mil Vss: 90 x 60 mil Bottom Side Layout Guide AP1530 Rev. 7 DS31092 9 of 12 www.diodes.com NOVEMBER 2009 © Diodes Incorporated AP1530 18V 3A 300KHz BUCK CONVERTER Functional Description (Continued) Vcc VIN Output C7 Option R4 C2 C1 Option AP1530 VOUT R1 + FB OCSET V SS EN C3 L1 R5 D1 C8 + C4 - R2 C6 Figure: Layout numbering comparison Marking Information (1) SOP-8L ( Top View ) 8 5 Logo Part Number AP1530 YY WW X X 1 AP1530 Rev. 7 DS31092 4 10 of 12 www.diodes.com L : Lead Free G : Green YY : Year : 08, 09,10~ WW : Week : 01~52; 52 represents 52 and 53 week X : Internal Code NOVEMBER 2009 © Diodes Incorporated AP1530 18V 3A 300KHz BUCK CONVERTER Package Information ( All Dimensions in mm ) 0.254 0.10/0.20 3.85/3.95 5.90/6.10 (1) Package Type: SOP-8L Gauge Plane Seating Plane 0.62/0.82 Detail "A" 7°~9° 0.15/0.25 1.30/1.50 1.75max. 0.35max. 45° 7°~9° Detail "A" 0°/8° 0.3/0.5 1.27typ 4.85/4.95 5.4 8x-0.60 8x-1.55 6x-1.27 Land Pattern Recommendation (Unit: mm) AP1530 Rev. 7 DS31092 11 of 12 www.diodes.com NOVEMBER 2009 © Diodes Incorporated AP1530 18V 3A 300KHz BUCK CONVERTER IMPORTANT NOTICE DIODES INCORPORATED MAKES NO WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, WITH REGARDS TO THIS DOCUMENT, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE (AND THEIR EQUIVALENTS UNDER THE LAWS OF ANY JURISDICTION). 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