ELM612DA 3A 36V PWM step down DC/DC converter ■General description ELM612DA is a of step-down switching regulator with PWM control, reference voltage source, oscillation circuit, error amplifier, internal PMOS, etc. ELM612DA provides low-ripple power, high efficiency, and excellent transient characteristics; PWM control circuit is able to vary the duty ratio linearly from 0 up to 100%. ELM612DA also contains error amplifier circuit as well as soft-start circuit that prevents overshoot at during startup. Internal enable function, over current protect function and short circuit protect function will reduce the operation frequency from 150kHz to 30kHz when overmuch current or short circuit occurs. Meanwhile, internal compensation block is able to minimize the quantity of required external component. With internal P-channel Power MOS, and externally connected coil, capacitor, and diode, ELM612DA is able to function as stepdown switching regulator. By the small package of SOP-8, ELM612DA is capable of working as ideal power supply units for many devices while providing outstanding features such as low current consumption. Since this converter accommodates input voltage up to 36V, ELM612DA is also suitable for AC adapter applications. ■Features ■Application • Input voltage : 5.5V to 36V • Output voltage : 0.8V to Vin • Output current : 3.0A • Duty ratio : 0% to 100% • Constant frequency : Typ.150kHz • Soft-start • Thermal shutdown protection • Short circuit protection • Built-in internal P-channel MOS • Package : SOP-8 • • • • • • • • • PC motherboard LCD monitor Graphic card DVD, Blu-ray player Telecom equipment ADSL modem Printer and other peripheral equipment Microcomputer power supply Network power supply ■Maximum absolute ratings Parameter VIN power supply voltage Apply voltage to FB Apply voltage to EN Apply voltage to SW Apply voltage to VC Power dissipation Operating temperature range Storage temperature range Symbol Vin Vfb Ven Vsw Vc Pd Top Tstg Limit -0.3 to +40 GND-0.3 to Vin GND-0.3 to Vin+0.3 GND-0.3 to Vin+0.3 Vin-20 to Vin+0.3 300 -40 to +85 -65 to +150 Caution: Permanent damage to the device may occur when ratings above maximum absolute ones are used. 8- 1 Unit V V V V V mW °C °C Rev.1.1 ELM612DA 3A 36V PWM step down DC/DC converter ■Selection guide ELM612DA-N Symbol a b c Package Product version Taping direction ELM612DA - N ↑↑ ↑ ab c D: SOP-8 A N: Refer to PKG file * Taping direction is one way. ■Pin configuration SOP-8(TOP VIEW) 8 7 6 5 Pin No. 1 2 3 4 1 2 3 4 5, 6 7, 8 Pin name Pin description FB Feedback(0.82V operation) Enable / Disable EN H: Normal operation mode.(Step-down operation) L: Shutdown mode.(All circuits deactivated) Add an external capacitor to VIN. VC The voltage is set to Vin -7V VIN IC power supply Switch. Connect external inductor/diode to here. SW Minimize trace area at this pin to reduce EMI. GND GND ■Standard circuit VIN FB ELM612DA 24V + - EN Cc= 0.1µF/16V VC L=47µH SW GND Cin=330µF/50V Cout= 330µF/16V D=5A/40V Vout R1 R2 Vout=Vfb(1+R1/R2) 8- 2 Rev.1.1 ELM612DA 3A 36V PWM step down DC/DC converter ■Block diagram Vin VC Oscillation circuit SW PWM control circuit Thermal shutdown protection ■Electrical characteristics EN pin input voltage (*1) Feedback voltage Feedback bias current Current limit Quiescent current (switch off) Current consumption during power off Voltage clamp Oscillation frequency Frequency of current limit or short circuit protect Reference voltage source and soft start EN GND Parameter Input voltage FB Error amplifier Symbol Vin Venh Venl Vfb Ifb Icl Ignd Vin=24V, Top=25°C, unless otherwise specified Condition Min. Typ. Max. Unit 5.5 36.0 V Evaluate oscillation at SW pin 2.0 V Evaluate oscillation stop at SW pin 0.8 Iout=0.1A 0.803 0.820 0.836 V Iout=0.1A 0.1 0.5 µA 2.0 A EN ≥ Ven_h, Vfb=1V 1 2 mA 1 10 µA Vin-6 120 Vin-7 150 Vin-8 180 V kHz 20 30 40 kHz 1 2 % 0.2 0.5 % 80 87 100 mΩ % 50 μS Ignd_off EN ≤ Ven_l Vc Fosc No load Foscl ΔVout Vin=12V to 36V, Iout=0.2A Vout ΔVout Load regulation Iout=0.1 to 1.3A Vout Internal MOSFET Rdson Rds(on) Vfb=0V, Iout=1A Efficiency η Vin=24V, Vout=5V, Iout=3.0A (*1) : Rise time and fall time of the EN pin use under the following conditions, please. EN pin rise time & fall time tr, tf Ven=VenI to VenH Line regulation 8- 3 Rev.1.1 ELM612DA 3A 36V PWM step down DC/DC converter ■Application notes PWM Control ELM612DA is DC/DC converter which consists pulse-width modulation (PWM) system. In converters of ELM612DA, the pulse width varies according toe the load current, within the range from 0 to 100%. The ripple voltage produced by switching can easily be removed through the filter since switching frequency remains constant; ELM612DA is capable of providing low-ripple power within broad ranges of input voltage and load current. ■Test circuits 4 2 Cc= 0.1�F Vin Cin= 330�F 3 VIN FB EN SW 1 L=47�H ELM612DA VC Vout 5, 6 R1 GND 7, 8 RL D Cout= 330�F C1 C2 R2 ■Marking SOP-8 ELM 612DA abc Mark ELM612DA Content Product name abc Assembly lot No.: 000 to 999 repeated 8- 4 Rev.1.1 ELM612DA 3A 36V PWM step down DC/DC converter ■Typical characteristics • Vout=3.3V : Cin=330µF, Cout=330µF, R1=4kΩ, R2=1.3kΩ, C1=0.1μF, C2=0.1μF, L=47µH, • D=5A/40V, V=3.3V Top=25°C Vout-Iout 3.4 EFFICIENCY-Iout 100 Vin=12V Vin=6V Vin=12V 3.1 4.0 10 1 100 Iout (mA) 1000 Vin=24V 40 20 0 0.1 10000 1 10 1000 10000 Start Response Vout-Vin Ven=2V, Vin=12V, No load 4 Iout=1mA Iout=100mA Iout=1A 3 2 1 Iout=10mA 2.0 100 Iout (mA) 3.0 Vout (V) Vin=6V 60 Vout (V) 3 80 0 2 1.0 1 0 0 4 8 0 12 16 20 24 28 32 36 Vin (V) 8- 5 1 2 Time (ms) 3 Ven (V) Vout (V) 3.2 EFFICIENCY (%) Vin=24V 3.3 4 Rev.1.1 ELM612DA 3A 36V PWM step down DC/DC converter Load Transient Response 4 Vin=12V, Iout=100mA�1A 4 3.5 Vout (V) 3 2.5 3.5 3 2.5 1 0.5 0.5 0 5 0 10 Time (ms) 15 Iout (A) 1 0 20 0 5 10 Time (ms) 15 Iout (A) Vout (V) Load Transient Response Vin=12V, Iout=10mA�1A 20 Vfb-Top Vin=12V, Iout=0.1A 0.82 0.81 Vfb (V) 0.8 0.79 0.78 0.77 0.76 -40 -20 0 20 40 60 80 Top (�) 8- 6 Rev.1.1 ELM612DA 3A 36V PWM step down DC/DC converter • Vout=5.0V : Cin=330µF, Cout=330µF, R1=6.8kΩ, R2=1.3kΩ, C1=0.1μF, C2=0.1μF, L=47µH, • D=5A/40V, V=5.0V Top=25°C Vout-Iout 5.2 Vin=12V EFFICIENCY (%) Vin=24V 5.1 Vin=12V 4.8 Vin=6V 4.7 4.6 6.0 10 1 100 Iout (mA) 1000 80 60 Vin=24V 40 20 0 0.1 10000 1 10 100 1000 10000 Iout (mA) Start Response Vout-Vin Ven=2V, Vin=12V, No load Iout=1mA 5 5.0 4 Iout=100mA 4.0 Iout=10mA Vout (V) Vout (V) Vin=6V Iout=1A 3.0 3 2 1 0 2.0 2 1.0 1 0 0 4 8 0 12 16 20 24 28 32 36 Vin (V) 8- 7 1 2 Time (ms) 3 Ven (V) Vout (V) 5 4.9 EFFICIENCY-Iout 100 4 Rev.1.1 ELM612DA 3A 36V PWM step down DC/DC converter Load Transient Response 4 10 Time (ms) 15 4 1 0.5 0.5 Iout (A) 1 0 5 5 0 20 0 5 10 Time (ms) 15 Iout (A) 5 0 Vin=12V, Iout=100mA�1A 6 Vout (V) 6 Vout (V) Load Transient Response Vin=12V, Iout=10mA�1A 20 Vfb-Top Vin=12V, Iout=0.1A 0.82 0.81 Vfb (V) 0.8 0.79 0.78 0.77 0.76 -40 -20 0 20 40 60 80 Top (�) 8- 8 Rev.1.1