ACE701

ACE701 ACE | Alldatasheet

Document overview

• Manufacturer or author: Provided By alldatasheet.com(free datasheet download site)
• PDF pages: 13

Technical content

Features

• Deliver 200mA at 3.3V Output voltage with 1.8V input Voltage
• The converter output voltage can be adjusted from 2.5V～6.0V(In 0.1V step)
• Only three external components are necessary: An inductor, a Schottky diode and an output filter capacitor
• High power conversion efficiency---85％ Application
• Power source for PDA. DSC. MP3 Player. electronic toy and wireless mouse
• Power source for a single or dual-cell battery-powered equipments
• Power source for LED Absolute Maximum Ratings Parameter Symbol Max Unit Input supply voltage V IN -0.3~12 V Input voltage V I(LX) -0.3~Vout+0.3 V CE pin voltage -0.3~Vout+0.3 Lx pin output current 0.7 A Power Dissipation SOT-89-3 SOT-23-5 SOT-23-3 0.5 0.15 0.15 W Junction temperature T J 150 O C Storage temperature T S - 40 to 125 O C Operating free-air temperature -20 ~ 80 O C

Technology PFM STEP-UP DC/DC Converter with High Efficiency and Low Noise VER 1.2 2 Packaging Type S O T - 8 9 - 3 S O T - 2 3 - 3 S O T - 2 3 - 5 S O T - 8 9 - 5 3 5 4 5 4 1 2 3 1 2 1 2 3 1 2 3 Pin SOT-89-3 SOT-23-3 SOT-23-5 SOT-89-5 Function VSS(GND) 1 1 4 4 Ground pin VOUT 2 2 2 2 Output pin, power supply for internal circuits LX(Ext) 3 3 5 5 Switching pin NC 3 3 CE 1 1 Chip enable pin (active high)

Ordering information

Output Voltage : Function Description : 1 : Internal Tr. Driver, Without Enable circuit 2 : Internal Tr. Driver, With Enable circuit 3 : External Tr. Driver, Without Enable circuit 4 : External Tr. Driver, With Enable circui Pb - free BN : SOT-23-5 BM : SOT-23-3 AM : SOT-89-3 AN : SOT-89-5 Halogen - free

Technology PFM STEP-UP DC/DC Converter with High Efficiency and Low Noise VER 1.2 3 Block Diagram ACE701 Recommended Work Conditions Item Min Nom Max Unit Input Voltage Range 0.8 Vout V Inductor 10 27 100 μH Input capacitor 0 ≧10 μF Output capacitor 47 100 220 μF Operating junction temperature -20 85 ℃ *Suggestion: Use tantalum capacitor to reduce the ripple of the output voltage.

Electrical Characteristics

Parameter Symbol Test Conditions Min Typ Max Unit 2.45 2.5 2.55 2.646 2.7 2.754 2.94 3.0 3.06 3.234 3.3 3.366 3.528 3.6 3.672 3.92 4.0 4.08 4.9 5.0 5.1 Output Voltage Vout 5.88 6.0 6.12 V Input Voltage Vin 12 V Input Current Lin Iout=0mA, Vin=Vout*0.6 12 15 uA Start-up voltage Vstart Iout=1mA, Vin:0 Æ2V 0.8 0.9 V Hold-on voltage Vhold Iout=1mA, Vin:2 Æ0V 0.6 0.7 V Quiescent current drawn from power source IDD Without external components, Vout=Vout x 1.05 4 7 uA Switch ON Resistance Rswon 0.4 0.5 Ω

Technology PFM STEP-UP DC/DC Converter with High Efficiency and Low Noise VER 1.2 4 LX leakage current I LXleak Vout=Vlx=6V 1.0 uA CE “H” threshold voltage V CEH V CE: 0Æ2V 0.6 0.9 V CE “L” threshold voltage V CEL V CE: 2Æ0V 0.3 0.6 V Oscillator frequency F OSC LX on “L” side Vout=Vout * 0.96 300 350 400 Khz Oscillator duty cycle Maxdty On (Vlx “L”) side 70 75 80 % Efficiency η 85 % Note : 1. Diode: Schottky type, such as: 1N5817, 1N5819, 1N5822 2. Inductor: 27uH(R<0.5 Ω) 3. Capacitor: 100uF (Tantalum type) Typical Application Circuit D 1N5819 V i n V o u t L 2 7 u H L X L X O U T I o u t Cin 47uF ACE701 G N D C o u t R l o a d 1 0 0 u F T a n Detailed Description The ACE701 series are boost structure, voltage-type pulse-frequency modulation(PFM) step-up DC-DC converter. Only three external components are nece ssary: an inductor, an output filter capacitor and a schottky diode. And the converter’s low noise and low ripple output voltage can be adjusted from 2.5V to 5.0V, 0.1V step. By using the depletion technics, the quiescent current drawn from power source is lower than 7uA. The high efficiency device consists of resistors for output voltage detection and trimming, a start-up voltage circuit, an oscillator, a reference circuit, a PFM control circuit, a switch protection circuit and a driver transistor. The PFM control circuit is the core of the ACE701 IC. This block controls power switch on duty cycle to stabilize output voltage by calculating results of other blocks which sense input voltage, output voltage, output current and load conditions. In PFM modulation system, the frequency and pulse width is fixed. The duty cycle is adjusted by skipping pulses, so t hat switch on-time is changed based on the conditions such as input voltage, output current and load. The oscillate block inside ACE701 provides fixed frequency and pulse width wave. The reference circuit provides stable reference voltage to output stable output voltage. Because internal trimming technology is used, The chip output change less than ±2%. At the same time ，the problem of temperature-drift coefficient of output voltage is consi dered in design, so temperature-drift coefficient of output voltage is less than 100ppm/℃。

Technology PFM STEP-UP DC/DC Converter with High Efficiency and Low Noise VER 1.2 5 High-gain differential error amplifier guarantees stable output voltage at difference input voltage and load. In order to reduce ripple and noise, the error amplifier is designed with high band-with. Though at very low load condition, the quiescent current of chip do effect efficiency certainly. The four main energy loss of Boost structure DC-DC converter in full load are the ESR of inductor, the voltage of Schottky diode, on resistor of internal N-channel MOSFET and its driver. In order to improve the efficiency, ACE701 integrates low on-resistor N-channel MOSFET and well design driver circuits. The switch energy loss is limited at very low level. Selection of the External Components Thus it can be seen, the inductor and schottky diode affect the conversion efficiency greatly. The inductor and the capacitor also have great influence on the output voltage ripple of the converter. So it is necessary to choose a suitable inductor, a capacitor and a right schottky diode, to obtain high efficiency, low ripple and low noise. Before discussion，we define D≣Vout-Vin / Vout (1)Inductor Selection Above all, we should define the minimum value of the inductor that can ensure the boost DC-DC to operate in the continuous current-mode condition. Lmin≧D(1-D) 2RL / 2f The above expression is got under conditions of continuous current mode, neglect Schottky diode’s voltage, ESR of both inductor and capacitor. The actual value is greater that it. If inductor’s value is less than Lmin，the efficiency of DC-DC converter will drop greatly, and the DC-DC circuit will not be stable. Secondly, consider the ripple of the output voltage, ΔI=D‧Vin / Lf Im ax=Vin / (1-D) 2RL + DVin / 2Lf If inductor value is too small, the current ripple through it will be great. Then the current through diode and power switch will be great. Because the power switch on chip is not ideal switch, the energy of switch will improve. The efficiency will fall. Thirdly，in general, smaller inductor values supply more output current while larger values start up with lower input voltage and acquire high efficiency. An inductor value of 3uH to 1mH works well in most applications. If DC-DC converter delivers large output current (for example: output current is great than 50mA), large inductor value is recommended in order to improve efficiency. If DC-DC must output very large current at low input supply voltage, small inductor value is recommended. The ESR of inductor will effect efficiency greatly. Suppose ESR value of inductor is r L，Rload is load resistor，then the energy can be calculated by following expression: Δη≈ RL / Rload (1-D)2

Technology PFM STEP-UP DC/DC Converter with High Efficiency and Low Noise VER 1.2 6 For example: input 1.5V, output is 3.0V, Rload=20Ω, rL=0.5Ω, The energy loss is 10%. Consider all above ，inductor value of 47uH 、ESR<0.5Ω is recommended in most applications. Large value is recommended in high efficiency applications and smaller value is recommended (2)Capacitor Selection Ignore ESR of capacitor，the ripple of output voltage is: R= ΔVout / Vout=D / R load Cf So large value capacitor is needed to reduce ripple. But too large capacitor value will slow down system reaction and cost will improve. So 100uF capacitor is recommended. Larger capacitor value will be used in large output current system. If output current is small (<10mA), small value is needed. Consider ESR of capacitor，ripple will increase： r'=r+Imax ‧R ESR / Vout When current is large, ripple caused by ESR will be main factor. It may be greater than 100mV。The ESR will affects efficiency and increase energy loss. So low-ESR capacitor (for example: tantalum capacitor) is recommend or connect two or more filter capacitors in parallel. (3)Diode Selection Rectifier diode will affects efficiency greatly，Though a common diode (such as 1N4148) will work well for light load，it will reduce about 5%~10% efficiency for heavy load，For optimum performance, a Schottky diode (such as 1N5817、1N5819、1N5822) is recommended. (4)Input Capacitor If supply voltage is stable, the DC-DC circuit can output low ripple, low noise and stable voltage without input capacitor. If voltage source is far away from DC-DC circuit, input capacitor value greater than 10uF is recommended. Test Circuits (1) Output voltage test circuit (I load=1mA) ACE701

Technology PFM STEP-UP DC/DC Converter with High Efficiency and Low Noise VER 1.2 7 (2) Start-up voltage test circuit (Iload=1mA) ACE701 (3) Hold-on voltage test circuit (I load=1mA) ACE701 (4) Quiescent current test circuit ACE701 Note: Vout=Vout*1.05, R=1KΩ, C=0.1uF

Technology PFM STEP-UP DC/DC Converter with High Efficiency and Low Noise VER 1.2 8 (5) Oscillator frequency and duty cycle test circuit ACE701 Oscillograph Note: Vin=Vout*0.95, R=1KΩ Typical Characteristic (Recommended operating conditions: Cin=47uF, Cout=47uF, Topt=25℃, unless otherwise noted) 1.Output Voltage VS. Output Current 2.Output Voltage VS. Output Current ACE701125AM+ Output Voltage VS. Output Current ACE701133AM+ Output Voltage VS. Output Current O u t p u t C u r r e n t ( m A ) O u t p u t C u r r e n t ( m A ) 3.Output Voltage VS. Output Current 4.Efficiency VS. Output Current ACE701140AM+ Output Voltage VS. Output Current ACE701125AM+ Efficiency VS. Output Current O u t p u t C u r r e n t ( m A ) O u t p u t C u r r e n t ( m A )

Technology PFM STEP-UP DC/DC Converter with High Efficiency and Low Noise VER 1.2 9 5. Efficiency VS. Output Current 6.Efficiency VS. Output Current ACE701133AM+ Efficiency VS. Output Current ACE701140AM+ Efficiency VS. Output Current O u t p u t C u r r e n t ( m A ) O u t p u t C u r r e n t ( m A ) 7. Ripple VS. Output Current 8.Ripple VS. Output Current ACE701125AM+ Ripple Voltage VS. Output Current ACE701133AM+ Ripple Voltage VS. Output Current O u t p u t C u r r e n t ( m A ) O u t p u t C u r r e n t ( m A ) 9. Ripple VS. Output Current 10.Ino load VS. Input Voltage ACE701140AM+ Ripple Voltage VS. Output Current ACE701 Quie scent Current (Ino load) VS. Input Voltage Output Current (mA) Input Voltage (V)

Technology PFM STEP-UP DC/DC Converter with High Efficiency and Low Noise VER 1.2 10 Packing Information SOT-89-3

Technology PFM STEP-UP DC/DC Converter with High Efficiency and Low Noise VER 1.2 11 Packing Information SOT-23-3

Technology PFM STEP-UP DC/DC Converter with High Efficiency and Low Noise VER 1.2 12 Packing Information SOT-23-5

Technology PFM STEP-UP DC/DC Converter with High Efficiency and Low Noise VER 1.2 13 Notes ACE does not assume any responsibility for use as critical components in life support devices or systems without the express written approval of the president and general counsel of ACE Electronics Co., LTD. As sued herein: 1. Life support devices or systems are devices or systems which, (a) are intended for surgical implant into the body, or (b) support or sustain life, and shoes failure to perform when properly used in accordance with instructions for use provided in the labeling, can be reasonably expected to result in a significant injury to the user. 2. A critical component is any component of a life support device or system whose failure to perform can be reasonably expected to cause the failure of the life support device or system, or to affect its safety or effectiveness. ACE Technology Co., LTD. http://www.ace-ele.com/