AP1512/A 50KHz, 2A/3A PWM BUCK DC/DC CONVERTER General Description Features • • • • • • • • • • • Output voltage: 3.3V, 5V, 12V and adjustable output version Adjustable version output voltage range, 1.23V to 37V+4% 50KHz +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 60V Output load current: 2A (for AP1512) 3A (for AP1512A) Low power standby mode Built-in switching transistor on chip Lead Free Finish/ RoHS Compliant (Note 1) The AP1512/A is a monolithic IC designed for use as a step-down DC/DC converter with the ability of driving a 2A (3A for AP1512A) load without additional transistor components. The board space is reduced since AP1512/A requires few external components. The external shutdown function is controlled by logic level and can be put into standby mode. The internal compensation ensures feedback control has good line and load regulation without external design. Both an integrated Thermal shutdown and Current Limit function are provided to prevent damage from exceeding temperature operation and against exceeding the current operating of the output switch. The AP1512/A operates at a switching frequency of 50KHz 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% tolerance on the oscillator frequency. The AP1512/A offers fixed output voltages of 3.3V, 5V, 12V, plus Adjustable. The package is available in a standard 5-lead TO263 package. Applications • • • Simple High-efficiency step-down regulator On-card switching regulators Positive to negative converter Ordering Information AP1512 X - XX XX X X Output Version Part Number Blank : 2A A : 3A Lead-free Blank : Adjustable 33 : 3.3V 50 : 5.0V 12 : 12V Device Package Code Packaging (Note 2) AP1512X-XXK5 K5 TO263-5L Notes: Package K5 : TO263-5L Lead Free Packing L : Lead Free -U : Tube -13 : Tape & Reel Tube Part Number Quantity Suffix 50 -U 13” Tape and Reel Part Number Quantity Suffix 800/Tape & Reel -13 1. EU Directive 2002/95/EC (RoHS). All applicable RoHS exemptions applied, see EU Directive 2002/95/EC Annex Notes. 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. AP1512/A Rev. 4 1 of 12 www.diodes.com MAY 2008 © Diodes Incorporated AP1512/A 50KHz, 2A/3A PWM BUCK DC/DC CONVERTER Pin Descriptions Pin Assignments ( Top View ) Name 5 SD 4 FB 3 GND 2 Output 1 VIN Description VIN Operating voltage input Output GND Metal Tab GND TO263-5L Switching output Ground FB Output voltage feedback control SD ON/OFF Shutdown Block Diagram SD VIN 200mV Current Source bias 1.235V Reference 2.5V Regulator 220mV Start up + Comp _ _ Comp + FB _ Amp Frequecy compensation _ + Comp + Pre-driver 2A Switch (3A for AP1512A) Output 50KHz OSC. AP1512/A Rev. 4 2 of 12 www.diodes.com Thermal Limit Gnd MAY 2008 © Diodes Incorporated AP1512/A 50KHz, 2A/3A PWM BUCK DC/DC CONVERTER Absolute Maximum Ratings Symbol ESD HBM ESD MM VCC VSD VFB VOUT TST TJ VOP Parameter Human Body Model ESD Protection Machine Model ESD Protection Supply Voltage ON/OFF Pin Input Voltage Feedback Pin Voltage Output Voltage to Ground Storage Temperature Operating Junction Temperature Operating Voltage Rating 4.5 450 +63 -0.3 to +40 -0.3 to +40 -1 -65 to +150 -40 to +125 +4.5 to +60 Unit KV V V V V V o C o C V Recommended Operating Conditions Symbol VIN IOUT TA AP1512/A Rev. 4 Parameter Input Voltage Output Current Operating Ambient Temperature 3 of 12 www.diodes.com Min 4.5 0 -20 Max 60 2 85 Unit V A o C MAY 2008 © Diodes Incorporated AP1512/A 50KHz, 2A/3A PWM BUCK DC/DC CONVERTER Electrical Characteristics (All Output Voltage Versions) Unless otherwise specified, VIN = 30V for all version. ILOAD = 0.5A Specifications with boldface type are for full operating temperature range, the other type are for TA = 25ºC. Symbol IB FOSC VSAT DC ICL ICL IL IQ ISTBY VIL VIH IH IL Parameter Feedback Bias Current Conditions Min VFB = 1.3V (Adjustable version only) 5 42.5 40 Oscillator Frequency IOUT = 2A 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 for AP1512 no outside circuit VFB = 0V force driver on peak current Current Limit for AP1512A no outside circuit VFB = 0V force driver on no outside circuit Output = 0 Output VFB = 12V force driver off leakage VIN = 60V Output = -1 current Quiescent Current VFB = 12V force driver off ON/OFF pin = 5V VIN = 60V ON/OFF pin logic input threshold voltage Low (regulator ON) High (regulator OFF) ON/OFF pin logic VLOGIC = 2.5V (OFF) input current ON/OFF pin input current VLOGIC = 0.5V (ON) θJC Thermal Resistance TO263-5L Junction to case θJA Thermal Resistance With copper area of approximately 3 in2 TO263-5L Junction to ambient AP1512/A Rev. 4 4 of 12 www.diodes.com 50 1.3 Saturation Voltage Standby Quiescent Current Typ. Max 8 10 57.5 60 1.4 Unit μA KHz V 1.5 100 0 % 4.5 2.5 3 3.2 4 A 5.5 5 -2 5 350 2.0 A 6 -250 uA -60 10 450 500 mA mA 1.3 0.6 - 0 -5 -0.8 2.5 3.5 28 -10 uA V uA o C/W o 23 C/W MAY 2008 © Diodes Incorporated AP1512/A 50KHz, 2A/3A PWM BUCK DC/DC CONVERTER Electrical Characteristics (Continued) AP1512 Symbol Parameter Conditions VMIN Typ. VMAX Unit Output Feedback 10V < VIN < 60V 0.2A < ILOAD < 2A VOUT programmed for 3V 1.193 1.18 1.23 1.267 1.28 V AP1512-ADJ VFB AP1512-3.3V VOUT Output voltage 10V < VIN < 60V 0.2A < ILOAD < 2A 3.168 3.135 3.3 3.432 3.465 V AP1512-5V VOUT Output voltage 10V < VIN < 60V 0.2A < ILOAD < 2A 4.8 4.75 5 5.2 5.25 V VOUT Output voltage 15V < VIN < 60V 0.2A < ILOAD < 2A 11.52 11.4 12 12.48 12.6 V Efficiency VIN = 30V, ILOAD = 2A AP1512-12V η 83 % Specifications with boldface type are for full operating temperature range, the other type are for TA = 25ºC. AP1512A Symbol Parameter Conditions VMIN Typ. VMAX Unit Output Feedback 10V < VIN < 60V 0.2A < ILOAD VOUT programmed for 3V 1.193 1.18 1.23 1.267 1.28 V AP1512A-ADJ VFB AP1512A-3.3V VOUT Output voltage 10V < VIN < 60V 0.2A < ILOAD 3.168 3.135 3.3 3.432 3.465 V AP1512A-5V VOUT Output voltage 10V < VIN < 60V 0.2A < ILOAD 4.8 4.75 5 5.2 5.25 V VOUT Output voltage 15V < VIN < 60V 0.2A < ILOAD 11.52 11.4 12 Efficiency VIN = 30V, ILOAD = 3A AP1512A-12V η 80 12.48 12.6 V % Specifications with boldface type are for full operating temperature range, the other type are for TA = 25ºC. AP1512/A Rev. 4 5 of 12 www.diodes.com MAY 2008 © Diodes Incorporated AP1512/A 50KHz, 2A/3A PWM BUCK DC/DC CONVERTER Typical Performance Characteristics 4 3.9 3.8 3.7 3.6 3.5 3.4 3.3 3.2 3.1 3 -50 AP1512A Efficiency vs. Supply Voltage ( Vout = 5V, Iout = 3A ) Efficiency(%) Current Limit (A) AP1512A Current Limit vs. Temperature ( Vcc = 60V, Vout = 5V ) 0 50 100 100 90 80 70 60 50 40 30 20 10 0 150 0 12 24 Temperature (TA) (°C) AP1512 Efficiency vs. Temperature ( Vin = 12V, Vout = 5V, Io = 2A ) 90 80 80 Efficiency (%) 100 90 Efficiency (%) 70 60 50 40 30 60 70 60 50 40 30 20 20 10 10 30 50 70 48 AP1512 Efficiency vs. Temperature ( Vin = 12V, Vout = 3.3V, Io = 2A ) 100 0 -50 -30 -10 10 36 Supply Voltage(V) 0 -50 -30 -10 10 30 90 110 130 150 Temperature (TA) (°C) 50 70 90 110 130 150 Temperature (TA) (°C) AP1512 Supply Current vs. Temperature ( Vcc = 12V, No Load, Von/off = 0V (Switch ON), Von/off = 5V (Switch OFF)) 100 8 90 6 Supply Current (uA) Supply Current (mA) 7 Sw itch ON 5 4 3 2 70 60 50 40 30 20 10 1 0 -40 -25 -10 5 20 35 50 65 80 95 110 125 0 -40 -25 -10 5 20 35 50 65 80 95 110 125 Temperature (TA) (°C) Temperature (TA) (°C) AP1512/A Rev. 4 Sw itch OFF 80 6 of 12 www.diodes.com MAY 2008 © Diodes Incorporated AP1512/A 50KHz, 2A/3A PWM BUCK DC/DC CONVERTER Typical Performance Characteristics (Continued) AP1512 Current Limit vs. Temperature ( Vcc = 60V, Vout = 5V ) 60 3.6 55 3.4 Current Limit (A) Frequency (KHz) AP1512 Frequency vs. Temperature ( Vcc = 12V, Io = 1A, Vout = 5V ) 50 45 40 -50 -30 -10 10 30 50 70 90 110 130 150 3.2 3 2.8 -50 0 50 100 150 Temperature (TA) (°C) Temperature (TA) (°C) AP1512 Quiescent Current vs. Supply Voltage ( force driver off ) Quiescent Current (A) 6.2 6 5.8 5.6 5.4 5.2 0 12 24 36 48 60 Supply Voltage(V) AP1512/A Rev. 4 7 of 12 www.diodes.com MAY 2008 © Diodes Incorporated AP1512/A 50KHz, 2A/3A PWM BUCK DC/DC CONVERTER Typical Application Circuit (1) Adjustable Type Circuit A. Vin = 10V~60V, Vout = 5V; Iout = 0.3A~2A, Iout below 0.3A DCM 1 Vin Vin OUTPUT L1 1 2 2 Vout 47uH AP1512/A 5 C1 C2 100uF/100V 1u SD ON/OFF FB GND 3 4 R2 3K D1 B360/B C5 1n C7 C3 0.1u 470uF/16V R3 1K B. Vin = 10V~60V, Vout = 3.3V, Iout = 0.3A~2A, Iout below 0.3A DCM 1 Vin Vin OUTPUT 2 1 L1 2 Vout 47uH AP1512/A 5 C1 C2 100uF/100V 1u ON/OFF SD GND 3 FB 4 D1 B360/B R2 2K C5 1n C7 C3 0.1u 470uF/16V R3 1.2K AP1512/A Rev. 4 8 of 12 www.diodes.com MAY 2008 © Diodes Incorporated AP1512/A 50KHz, 2A/3A PWM BUCK DC/DC CONVERTER Typical Application Circuit ( Continued ) (2) Fixed Type Circuit A. Vin = 10V~60V, Vout = 5V, Iout = 0.7A~2A, Iout below 0.7A DCM 1 Vin Vin OUTPUT 2 1 L1 2 Vout 47uH AP1512/A 5 C1 C2 100uF/100V 1u SD GND 3 ON/OFF FB 4 D1 B360/B C7 C3 10n 470uF/16V B. Vin = 10V~60V, Vout = 3.3V, Iout = 0.7A~2A, Iout below 0.7A DCM 1 Vin Vin OUTPUT 2 1 L1 2 Vout 33uH AP1512/A 5 C1 220uF/100V AP1512/A Rev. 4 C2 3.3u ON/OFF SD GND 3 FB 4 9 of 12 www.diodes.com D1 B360/B C7 3.3u C3 1500uF/16V MAY 2008 © Diodes Incorporated AP1512/A 50KHz, 2A/3A PWM BUCK DC/DC CONVERTER Functional Description +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. 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 Senses the regulated output voltage to complete the feedback loop. ON/OFF 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 40V) shuts the regulator down. If this shutdown feature is not needed, the SD pin can be wired to the ground pin or it can be left open, in either case the regulator will be in the ON condition. Thermal Considerations The AP1512/A is available in a 5-pin surface mount TO-263 package. The TO-263 surface mount package tab is designed to be soldered 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 2 copper area that the package is soldered to should be at least 0.4 in , and ideally should have 2 or more square inches of 2 oz. Additional 2 copper area improves the thermal characteristics, but with copper areas greater than approximately 6 in , only small improvements in heat dissipation are realized. If further thermal improvements are needed, double sided, multilayer PC boards with large copper areas and/or airflow are recommended. The AP1512/A (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 2A are used, double sided or multilayer PC boards with large copper areas and/or airflow might be needed, especially for high ambient temperatures and high output voltages. 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. 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, multilayer 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. AP1512/A Rev. 4 10 of 12 www.diodes.com MAY 2008 © Diodes Incorporated AP1512/A 50KHz, 2A/3A PWM BUCK DC/DC CONVERTER Marking Information (1) TO263-5L (Top view) Output Type: 1512: ADJ 1512-33: 3.3V 1512-50: 5.0V 1512-12: 12V 1512X-XX YY WW X X Logo L : Lead Free Internal code Xth week: 01~52 Year: "07" = 2007 "08" = 2008 ~ Package Information (All Dimensions in mm) (1) Package Type: TO263-5L AP1512/A Rev. 4 11 of 12 www.diodes.com MAY 2008 © Diodes Incorporated AP1512/A 50KHz, 2A/3A PWM BUCK DC/DC CONVERTER IMPORTANT NOTICE Diodes Incorporated and its subsidiaries reserve the right to make modifications, enhancements, improvements, corrections or other changes without further notice to any product herein. Diodes Incorporated does not assume any liability arising out of the application or use of any product described herein; neither does it convey any license under its patent rights, nor the rights of others. The user of products in such applications shall assume all risks of such use and will agree to hold Diodes Incorporated and all the companies whose products are represented on our website, harmless against all damages. LIFE SUPPORT Diodes Incorporated products are not authorized for use as critical components in life support devices or systems without the expressed written approval of the President of Diodes Incorporated. AP1512/A Rev. 4 12 of 12 www.diodes.com MAY 2008 © Diodes Incorporated