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ACE701
Technology PFM STEP-UP DC/DC Converter with High Efficiency and Low Noise Description
The ACE701 series are CMOS-based PFM step-up DC-DC Converter. The converter can start up by supply voltage as low as 0.8V, and capable of delivering maximum 200mA output current at 3.3V output with 1.8V input Voltage. Quiescent current drawn from power source is as low as 5.5uA. All of these features make ACE701 series be suitable for the portable devices, which are supplied by a single battery to four-cell batteries. To reduce the noise caused by the switch regulator, ACE701 is well considerated in circuit design and manufacture. So that the interferer to other circuits by the device is reduced greatly. ACE701 integrates stable reference circuits and trimming technology, so it can afford high precision and low temperature-drift coefficient of the output voltage. ACE701 is available in SOT-89-3SOT-23-3SOT-89-5 and SOT-23-5 packages which is PB free. And in 5-pin packages, such as SOT-23-5 and SOT-89-5, the device can be switch on or off easily by CE pin, to minimize the standby supply current.
Features
* * * * * * * * * * *
Deliver 200mA at 3.3V Output voltage with 1.8V input Voltage Low start-up voltage (when the output current is 1mA)--------------------------0.8V The converter output voltage can be adjusted from 2.5V6.0V(In 0.1V step) Output voltage accuracy -----------2 Low temperature-drift coefficient of the output voltage------------------100ppm/ Only three external components are necessary: An inductor, a Schottky diode and an output filter capacitor High power conversion efficiency---85 Low quiescent current drawn from power source------------------------------------- <5.5uA
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 Input supply voltage Input voltage CE pin voltage Lx pin output current Power Dissipation SOT-89-3 SOT-23-5 SOT-23-3 Junction temperature Storage temperature Operating free-air temperature Symbol VIN VI(LX) Max Unit -0.3~12 V -0.3~Vout+0.3 V -0.3~Vout+0.3 0.7 A 0.5 0.15 0.15 150 - 40 to 125 -20 ~ 80 W
O O
TJ TS
C C O C
VER 1.2
1

Technology PFM STEP-UP DC/DC Converter with High Efficiency and Low Noise Packaging Type
SOT-89-3 SOT-23-3
3
ACE701
SOT-23-5
5 4
SOT-89-5
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 VSS(GND) 1 1 4 4 VOUT LX(Ext) NC CE 2 3 2 3 2 5 3 1 2 5 3 1
Function Ground pin Output pin, power supply for internal circuits Switching pin Chip enable pin (active high)
Ordering information
Selection Guide ACE701 X XX XX + H Halogen - free Pb - free BN : SOT-23-5 BM : SOT-23-3 AM : SOT-89-3 AN : SOT-89-5 Output Voltage : 2.5V / 3.0V ..... 6.0V 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
VER 1.2
2

Technology PFM STEP-UP DC/DC Converter with High Efficiency and Low Noise Block Diagram
ACE701
ACE701
Recommended Work Conditions
Item Min Nom Max Unit Input Voltage Range 0.8 Vout V Inductor 10 27 100 H Input capacitor 0 10 F Output capacitor 47 100 220 F 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 V 3.528 3.6 3.672 3.92 4.0 4.08 4.9 5.0 5.1 5.88 6.0 6.12 12 V 12 15 uA 0.8 0.9 V 0.6 0.7 V 4 0.4 7 0.5
VER 1.2
Output Voltage
Vout
Input Voltage Input Current Start-up voltage Hold-on voltage Quiescent current drawn from power source Switch ON Resistance
Vin Lin Vstart Vhold IDD Rswon
Iout=0mA, Vin=Vout*0.6 Iout=1mA, Vin:0 2V Iout=1mA, Vin:2 0V Without external components, Vout=Vout x 1.05
uA
3

Technology PFM STEP-UP DC/DC Converter with High Efficiency and Low Noise
LX leakage current CE "H" threshold voltage CE "L" threshold voltage Oscillator frequency Oscillator duty cycle Efficiency
Note : 1. 2. 3. Diode: Schottky type, such as: 1N5817, 1N5819, 1N5822 Inductor: 27uH(R<0.5) Capacitor: 100uF (Tantalum type)
ACE701
1.0
ILXleak VCEH VCEL FOSC Maxdty
Vout=Vlx=6V VCE: 0 2V VCE: 2 0V LX on "L" side Vout=Vout * 0.96 On (Vlx "L") side
0.6 300 70
0.9 0.3 350 75 85
0.6 400 80
uA V V Khz % %
Typical Application Circuit
D 1N5819 Vin L 27uH LX LX OUT ACE701 GND Iout Cout 100uF Rload Tan Vout
Cin 47uF
Detailed Description
The ACE701 series are boost structure, voltage-type pulse-frequency modulation(PFM) step-up DC-DC converter. Only three external components are necessary: 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 that 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 timethe problem of temperature-drift coefficient of output voltage is considered in design, so temperature-drift coefficient of output voltage is less than 100ppm/
VER 1.2
4

Technology PFM STEP-UP DC/DC Converter with High Efficiency and Low Noise 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.
ACE701
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 discussionwe define DVout-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. LminD(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 Lminthe 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, I=DVin / 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. Thirdlyin 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 rLRload is load resistorthen the energy can be calculated by following expression: RL / Rload (1-D)2
VER 1.2 5

Technology PFM STEP-UP DC/DC Converter with High Efficiency and Low Noise
For example: input 1.5V, output is 3.0V, Rload=20, rL=0.5, The energy loss is 10%. Consider all aboveinductor value of 47uHESR<0.5 is recommended in most applications. Large value is recommended in high efficiency applications and smaller value is recommended (2)Capacitor Selection Ignore ESR of capacitorthe ripple of output voltage is: R=Vout / Vout=D / Rload 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 capacitorripple will increase r'=r+ImaxRESR / Vout When current is large, ripple caused by ESR will be main factor. It may be greater than 100mVThe 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 greatlyThough a common diode (such as 1N4148) will work well for light loadit will reduce about 5%~10% efficiency for heavy loadFor optimum performance, a Schottky diode (such as 1N58171N58191N5822) 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.
ACE701
Test Circuits
(1) Output voltage test circuit (Iload=1mA)
ACE701
VER 1.2
6

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

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

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

Technology PFM STEP-UP DC/DC Converter with High Efficiency and Low Noise Packing Information
SOT-89-3
ACE701
VER 1.2
10

Technology PFM STEP-UP DC/DC Converter with High Efficiency and Low Noise Packing Information
SOT-23-3
ACE701
VER 1.2
11

Technology PFM STEP-UP DC/DC Converter with High Efficiency and Low Noise Packing Information
SOT-23-5
ACE701
VER 1.2
12

Technology PFM STEP-UP DC/DC Converter with High Efficiency and Low Noise
ACE701
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/
VER 1.2
13

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