AS1308A 1.2MHz, 2.0A Sync. Buck Converter FEATURES GENERAL DESCRIPTION High Efficiency：Up to 95% The AS1308A is a 1.2MHz constant frequency 1.2MHz Constant Switching Frequency current mode PWM step-down converter. It is ideal 2.0A available Load Current for portable equipment requiring very high current up 2.5V to 6.0V Input Voltage Range: to 2A from single-cell lithium batteries while still Output Voltage as low as 0.6V achieving over 90% efficiency during peak load 100% Duty Cycle In Dropout conditions. The AS1308A also can run at 100% duty Low RDS(ON) Internal Switch:0.15Ω cycle for low dropout operation, extending battery life Current Mode Control for Excellent Line & Load in portable systems while light load operation Regulation provides very low output ripple for noise sensitive Short Circuit and Thermal Fault Protection applications. The AS1308A can supply up to 2A Soft Start & Shutdown Current <1μA output load current from a 2.5V to 6.0V input voltage Space Saving Package:TDFN33-10L, and the output voltage can be regulated as low as MSOP-10L 0.6V. The high switching frequency minimizes the size of external components while keeping switching losses low. The internal slope compensation setting APPLICATIONS allows the device to operate with smaller inductor Cellular & Smart Phones values to optimize size and provide efficient Microprocessors and DSP Core Supplies operation. The AS1308A is available in adjustable Wireless and DSL Modems and fixed output voltage. PDAs & Portable Equipments The device is available in a TDFN-10L(3x3mm) & MSOP-10L package and is rated over the -40°C to 85°C temperature range. TYPICAL APPLICATION INPUT 2.5V – 5.5V 2 IN 3 IN C1 22uF OFF ON AS1308A 8 LX 7 LX OUT/FB 1 EN 6 GND 4 GND PGND PGND L1 2.2uH C3 22pF 5 10 9 R2 316 K 1% R1 634K 1% OUTPUT 1.8V/2A C2 22uF High efficiency sync. step-down Converter AS1308A Rev.1.0 10/25/2008 www.anisem.com ANISEM Proprietary Information. Unauthorized Photocopy and Duplication Prohibited. © 2008 ANISEM All Rights Reserved. 1 AS1308A 1.2MHz, 2.0A Sync. Buck Converter ABSOLUTE MAXIMUM RATINGS PACKAGE/ORDER INFORMATION (Note1) TOP VIEW VIN Voltage ………………………..….. -0.3V to 6V VEN, VFB Voltage ………….…. -0.3V to VIN +0.3V VLX, VOUT Voltage ………….…. -0.3V to VIN +0.3V PGND,AGND Ground Voltage………-0.3V to 6V Operating Temperature Range...… -40℃ to 85℃ PD Power Dissipation …………………..2.2W(Note2) ΘJA Thermal Resistance…………………………...45°C/W Storage Temperature Range …... -65℃ to 150℃ Lead Temperature(Soldering, 10sec.) ……300℃ Note 1: Absolute Maximum Ratings are those values beyond which the life of a device may be impaired. PART NUMBER PACKAGE OPERATING TEMP. AS1308AEPT TDFN-10L -40°C to 85°C AS1308AEFT MSOP-10L -40°C to 85°C Note 2: TJ is calculated from the ambient temperature TA and power dissipation PD according to the following formula: TJ = TA + PD x ΘJA ELECTRICAL CHARACTERISTICS VIN = VEN =3.6V, TA = 25°C Unless otherwise noted. PARAMETER CONDITIONS MIN TYP MAX Input Voltage Range 2.5 - 6.0 Output Voltage Range 0.6 - VIN PWM Mode, VFB = 0.5V or VOUT=90% - 300 500 Power Saving Mode, VFB = 0.63V - 40 80 Shutdown Mode, VFB = 0V, VAIN = 5.5V - 0.1 1.0 TA = 25°C 0.5880 0.6000 0.6120 TA = 0°C ≤ TA ≤ 85°C 0.5865 0.6000 0.6135 TA = -40°C ≤ TA ≤ 85°C 0.5850 0.6000 0.6150 Input Supply Current Regulated Feedback Voltage UNITS V μA V FB Input Bias Current VFB = 0.65V - - ±30 nA Line Regulation VIN = 2.5V to 5.5V, IOUT = 10mA - 0.1 0.2 %/V Load Regulation IOUT = 10mA to 2.0A - 0.2 - %/A 2.5 3.5 - A 0.96 1.2 1.44 MHz VIN=3V, VFB= 0.5V or VOUT = 90%; Peak Inductor Current Duty Cycle <35% Oscillator Frequency VFB = 0.6V or VOUT = 100% P-CH MOSFET RDS(ON) VIN = 3.6V - 0.135 0.20 N-CH MOSFET RDS(ON) VIN=3.6V - 0.095 0.15 LX Leakage VEN=0V, VLX=0V or 5V, VIN=5V ±0.01 ±1 uA Enable Threshold TA = -40°C ≤ TA ≤ 85°C 1.0 1.5 V Enable Leakage Current VIN=VEN=5.5V ±0.01 ±1 μA 0.3 Ω Note: 100% production test at +25℃; Specification over the temperature range are guaranteed by design. AS1308A Rev.1.0 10/25/2008 www.anisem.com ANISEM Proprietary Information. Unauthorized Photocopy and Duplication Prohibited. © 2008 ANISEM All Rights Reserved. 2 AS1308A 1.2MHz, 2.0A Sync. Buck Converter TYPICAL PERFORMANCE CHARACTERISTICS L=2.2uH, Cin=Cout=22uF; TA = 25°C; Unless otherwise noted. 100 QUIESCENT CURRENT vs SUPPLY VOLTAGE 1.6 1.4 EN THRESHOLD VOLTAGE (V) 90 QUIESCENT CURRENT (uA) EN THRESHOLD VOLTAGE vs SUPPLY VOLTAGE 80 70 60 50 40 30 1.2 1.0 0.8 0.6 0.4 20 0.2 10 0.0 2.0 0 2.0 3.0 4.0 5.0 6.0 3.0 4.0 5.0 6.0 5.0 6.0 SUPPLY VOLTAGE (V) SUPPLY VOLTAGE (V) 1.3 FREQUENCY vs. SUPPLY VOLTAGE FREQUENCY (MHz) 1.28 1.26 1.24 1.22 1.2 1.18 1.16 2.0 3.0 4.0 SUPPLY VOLTAGE (V) AS1308A Rev.1.0 10/25/2008 www.anisem.com ANISEM Proprietary Information. Unauthorized Photocopy and Duplication Prohibited. © 2008 ANISEM All Rights Reserved. 3 AS1308A 1.2MHz, 2.0A Sync. Buck Converter TYPICAL PERFORMANCE CHARACTERISTICS L=2.2uH, Cin=Cout=22uF; TA = 25°C; Unless otherwise noted. OUTPUT VOLTAGE (V) 1.9 OUTPUT VOLTAGE vs. SUPPLY VOLTAGE 1.85 Vout=1.8V Iout=1.0A 1.8 1.75 1.7 2.0 3.0 4.0 5.0 6.0 SUPPLY VOLTAGE (V) Vin=4.2V, Vout=1.8V, Iout=800mA AS1308A Rev.1.0 10/25/2008 Vin=3.3V, Vout=1.8V, Iout=800mA www.anisem.com ANISEM Proprietary Information. Unauthorized Photocopy and Duplication Prohibited. © 2008 ANISEM All Rights Reserved. 4 AS1308A 1.2MHz, 2.0A Sync. Buck Converter PIN FUNCTIONS PIN NUMBER PIN NAME FUNCTION Enable control input. Forcing this pin above 1.5V enables the part. Forcing 1 this pin below 0.3V shuts down the device. In shutdown, all functions are EN disabled drawing <1μA supply current. Do not leave EN floating. Power supply input pin. Must be closely decoupled to AGND with a 2.2uF or 2,3 IN 4,6 GND greater ceramic capacitor Analog ground pin. FB pin: adjustable version feedback input. Connect FB to the center point of 5 FB/OUT the external resistor divider. The feedback threshold voltage is 0.6V. OUT pin: Fixed version feedback input. Connect OUT to the output volgage, VOUT 7,8 LX Switching node pin. Connect the output inductor to this pin. 9,10 PGND Power ground pin. Power ground exposed pad. Must be connected to bare copper ground EP plane. BLOCK DIAGRAM AS1308A Rev.1.0 10/25/2008 www.anisem.com ANISEM Proprietary Information. Unauthorized Photocopy and Duplication Prohibited. © 2008 ANISEM All Rights Reserved. 5 AS1308A 1.2MHz, 2.0A Sync. Buck Converter OPERATION The AS1308A is a high output current monolithic switch - mode step-down converter. The device operates at a fixed 1.2MHz switching frequency, and uses a slope compensated current can supply up to 2A output current at Vin=3V and has an input voltage range from 2.5V to 6.0V. it minimizes external component size and optimizes efficiency at the heavy load range. The slope compensation allows the devices to remain stable over a wider range of inductor values so that smaller values(1uH to 4.7uH) with lower DCR can be used to achieve higher efficiency. Apart from the small bypass input capacitor, only a small L-C filter is required at the output. The fixed output version requires only three external power components (Cin, Cout, and L). the adjustable version can be programmed with external feedback to any voltage, ranging from 0.6V to near the input voltage. It uses internal MOSFETs to achieve high efficiency and can generate very low output voltages by using an internal reference of 0.6V. at dropout, the converter duty cycle increases to 100% and the output voltage tracks the input voltage minus the low RDS(ON) drop of the P-channel high-side MOSFET and the inductor DCR. The internal error amplifier and compensation provides excellent transient response, load and line regulation. Internal soft start eliminates any output voltage overshoot when the enable or the input voltage is applied. CURRENT MODE PWM CONTROL Slope compensated current mode PWM control provides stable switching and cycle-by-cycle current limit for excellent load and line response and protection of the internal main switch and synchronous rectifier. The AS1308A switches at a constant frequency (1.2MHz) and regulates the output voltage. During each cycle the PWM comparator modulates the power transferred to the load by changing the inductor peak current based on the feedback error voltage. During normal operation, the main switch is turned on for a certain time to ramp the inductor current at each rising edge of the internal oscillator, and switched off when the peak inductor current is above the error voltage. When the main switch is off, the synchronous rectifier will be turned on immediately and stay on until either the next cycle starts. CONTROL LOOP The AS1308A is a peak current mode step-down AS1308A Rev.1.0 10/25/2008 converter. The current through the P-channel MOSFET(high side) is sensed for current loop control, as well as short circuit and overload protection. A slop compensation signal is added to the sensed current to maintain stability for duty cycles greater than 50%. The peak current mode loop appears as a voltage-programmed current source in parallel with the output capacitor. The output of the voltage error amplifier programs the current mode loop for the necessary peak switch current to force a constant output voltage for all load and line conditions. Internal loop compensation terminates the transconductance voltage error amplifier output. For fixed voltage versions, the error amplifier reference voltage is internally set to program the converter output voltage. For the adjustable output, the error amplifier reference is fixed at 0.6V. SOFT START/ENABLE Soft start limits the current surge seen at the input and eliminates output voltage overshoot. The enable pin is active high. When pulled low, the enable input(EN) forces the AS1308A into a low-power, non-switching state. The total input current during shutdown is less than 1uA. CURRENT LIMIT and OVER-TEMPERATURE PROTECTION For overload conditions, the peak input current is limited to 3.5A. To minimize power dissipation and stresses under current limit and short-circuit conditions, switching is terminated after entering current limit for a series of pulses. The termination lasts for seven consecutive clock cycles after a current limit has been sensed during a series of four consecutive clock cycles. Thermal protection completely disables switching when internal dissipation becomes excessive the junction over temperature threshold is 170°C with 10°C of hysteresis. Once an over temperature or over current fault conditions is removed, the output voltage automatically recovers. DROPOUT OPERATION When the battery input voltage decreases near the value of the output voltage, the AS1308A allows the main switch to remain on for more than one switching cycle and increases the duty cycle until it reaches 100%. The duty cycle D of a step-down converter is defined as: D Ton Fosc 100% Vout Vin 100% www.anisem.com ANISEM Proprietary Information. Unauthorized Photocopy and Duplication Prohibited. © 2008 ANISEM All Rights Reserved. 6 AS1308A 1.2MHz, 2.0A Sync. Buck Converter Where Ton is the main switch on time and Fosc is the oscillator frequency. The output voltage then is the input voltage minus the voltage drop across the main switch and the inductor. At low input supply voltage, the RDS(ON) of the P-channel MOSFET increases, and the efficiency of the converter decreases. Caution must be exercised to ensure the heat dissipated does not exceed the maximum junction temperature of the IC. MAXIMUM LOAD CURRENT The AS1308A will operate with an input supply voltage as low as 2.5V, however, the maximum load current decreases at lower input voltages due to a large IR drop on the main switch and synchronous rectifier. The slope compensation signal reduces the peak inductor current as a function of the duty cycle to prevent sub-harmonic oscillations at duty cycles greater than 50%. Conversely the current limit increases as the duty cycle decreases. APPLICATION INFORMATION Figure 1: Application circuit for the adjustable output version Figure2: Application circuit for the fixed output version. SETTING THE OUTPUT VOLTAGE Figure 1 shows the basic application circuit with the AS1308A adjustable output version while figure 2 shows the application circuit with the AS1308A fixed output version. For applications requiring an adjustable output voltage, the AS1308A-adj can be externally programmed. Resistors R1 and R2 in figure1 program the output to regulate at a voltage higher than 0.6V. to limit the bias current required for the external feedback resistor string while AS1308A Rev.1.0 10/25/2008 maintaining good noise immunity, the minimum suggested value for R2 is 59K. Although a larger value will further reduce quiescent current, it will also increase the impedance of the feedback node, making it more sensitive to external noise and interference. Table1 summarizes the resistor values for various output voltages with R2 set to either 59K for good noise immunity or 316K for reduced no load input current. The adjustable version of the AS1308A, combined with an external feed forward capacitor(C3 in figure 1), delivers enhanced transient response for extreme pulsed load applications. The addition of the feed forward capacitor typically requires a larger output capacitor C2 for stability. The external resistor sets the output voltage according to the following equation: R1 Vout 0.6V 1 R2 Vout 1 R2 R1 0.6V Table1 shows the resistor selection for different output voltage settings. Vout R1 R2 1.2V 316K 316K 1.5V 470K 316K 1.8V 634K 316K 2.5V 1M 316K Note: standard 1% resistors INDUCTOR SELECTION For most designs, the AS1308A operates with inductor values of 1uH to 4.7uH. low inductance values are physically smaller but require faster switching, which results in some efficiency loss. The inductor value can be derived from the following equation: Vout Vin Vout L Vin IL fosc Where △IL is inductor ripple current. Large value inductors lower ripple current and small value inductors result in high ripple currents. Choose inductor ripple current approximately 30% of the maximum load current 2A or △IL=600mA For output voltages above 2.0V, when light load efficiency is important, the minimum recommended Inductor is 2.2uH. manufacturer’s specifications list both the inductor DC current rating, which is a thermal limitation, and the peak current rating, which is determined by the saturation characteristics. www.anisem.com ANISEM Proprietary Information. Unauthorized Photocopy and Duplication Prohibited. © 2008 ANISEM All Rights Reserved. 7 AS1308A 1.2MHz, 2.0A Sync. Buck Converter The inductor should not show any appreciable saturation under normal load conditions. Some inductors may meet the peak and average current ratings yet result in excessive losses due to a high DCR. Always consider the losses associated with the DCR and its effect on the total converter efficiency when selecting an inductor. For optimum voltage-positioning load transients, choose an inductor with DC series resistance in the 20mΩ to 100mΩ range. For higher efficiency at heavy loads(above 200mA), or minimal load regulation (but some transient overshoot), the resistance should be kept below 100mΩ. 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 (2A+600mA). Table2 lists some typical surface mount inductors that meet target applications for the AS1308A. For example, the 2.2uH CDRH5D16-2R2 inductor selected from sumida has a 28.7mΩ DCR and a 3.0A DC current rating. At full load, the inductor DC loss is 57mW which gives a 1.6% loss in efficiency for 1.8V/1.2A. SLOP COMPENSATION The AS1308A step-down converter uses peak current mode control with slope compensation for stability when duty cycles are greater than 50%. The slope compensation is set to maintain stability with lower value inductors which provide better overall efficiency. The output inductor value must be selected so the inductor current down slope meets the internal slope compensation requirements. As an example, the value of the slope compensation is set to 1A/us which is large enough to guarantee stability when using a 2.2uH inductor for all output voltage levels from 0.6V to 3.3V. the worst case external current slope(m) using the 2.2uH inductor is when Vout=3.3V and is: m Vout L 3.3 2.2 1.5A/us to keep the power supply stable when the duty cycle is above 50%, the internal slope compensation(m) should be: ma 1 m 2 0.75A/us Therefore, to guarantee current loop stability, the slope of the compensation ramp must be greater than one-half of the down slop of the current waveform. So the internal slope compensated value AS1308A Rev.1.0 10/25/2008 of 1A/us will guarantee stability using a 2.2uH inductor value for all output voltage from 0.6V to 3.3V. INPUT CAPACITOR SELECTION The input capacitor reduces the surge current drawn from the input and switching noise from the device. The input capacitor impedance at the switching frequency should be less than the input source impedance to prevent high frequency switching current passing to the input. The calculated value varies with input voltage and is a maximum when Vin is double the output voltage. Cin Vo Vin Vpp Io Cin min 1 Vo Vin ESR fs 1 Vpp Io ESR 4 fs A low ESR input capacitor sized for maximum RMS current must be used. Ceramic capacitors with X5R or X7R dielectrics are highly recommended because of their low ESR and small temperature coefficients. A 22uF ceramic capacitor for most applications is sufficient. A large value may be used for improved input voltage filtering. The maximum input capacitor RMS current is: IRMS IO VO 1 VIN VO VIN The input capacitor RMS ripple current varies with the input and output voltage and will always be less than or equal to half of the total DC load current. IRMS MAX 1 I 2 O To minimize stray inductance, the capacitor should be placed as closely as possible to the IC. This keeps the high frequency content of the input current localized, minimizing EMI and input voltage ripple. The proper placement of the input capacitor (C1) can be seen in the evaluation board layout in Figure3 and 4. A laboratory test set up typically consists of two long wires running from the bench power supply to the evaluation board input voltage pins. The inductance of these wires, along with the low ESR ceramic input capacitor, can create a high Q network that may affect converter performance. www.anisem.com ANISEM Proprietary Information. Unauthorized Photocopy and Duplication Prohibited. © 2008 ANISEM All Rights Reserved. 8 AS1308A 1.2MHz, 2.0A Sync. Buck Converter This problem often become apparent in the form of excessive ringing in the output voltage during load transients. Errors in the loop phase and gain measurements can also result. Since the inductance of a short PCB trace feeding the input voltage is significantly lower than the power leads from the bench power supply, most applications do not exhibit this problem. In applications where the input power source lead inductance cannot be reduced to a level that does not affect the converter performance, a high ESR tantalum or aluminum electrolytic should be placed in parallel with the low ESR, ESL bypass ceramic. This dampens the high Q network and stabilizes the system. OUTPUT CAPACITOR SELECTION The function of output capacitance is to store energy to attempt to maintain a constant voltage. The energy is stored in the capacitor’s electric field due to the voltage applied. The value of output capacitance is generally selected to limit output voltage ripple to the level required by the specification. Since the ripple current in the output inductor is usually determined by L, VOUT and VIN, the series impedance of the capacitor primarily determines the output voltage ripple. The three elements of the capacitor that contribute to its impedance (and output voltage ripple) are equivalent series resistance (ESR), equivalent series inductance (ESL), and capacitance ©, the output voltage droop due to a load transient is dominated by the capacitance of the ceramic output capacitor. During a step increase in load current, the ceramic output capacitor alone supplies the load current until the loop responds. Within three switching cycles, the loop responds and the inductor current increases to match the load current demand. The relationship of the output voltage droop during the switching cycles to the output capacitance can be estimated by: COUT 3 ILOAD VDROOP fs In many practical designs, to get the required ESR a capacitor with much more capacitance than is needed must be selected. For both continuous and discontinuous inductor current mode operation, the ESR of the COUT needed to limit the ripple to △Vo, V peak to peak is: ESR VO IL AS1308A Rev.1.0 10/25/2008 Ripple current flowing through a capacitor’s ESR Causes power dissipation in the capacitor. This power dissipation causes a temperature increase internal to the capacitor. Excessive temperature can seriously shorten the expected life of a capacitor. Capacitors have rippled current ratings that are dependent on ambient temperature and should not be exceeded. The output capacitor ripple current is the inductor current, IL, minus the output current IO. The RMS value of the ripple current flowing in the output capacitance (continuous inductor current mode operation) is given by: IRMS IL √3 6 IL 0.289 ESL can be a problem by causing ringing in the low megahertz region but can be controlled by choosing low ESL capacitors, limiting lead length (PCB and capacitor), and replacing one large device with several smaller ones connected in parallel. In conclusion, in order to meet the requirement of output voltage ripple small and regulation loop stability, ceramic capacitors with X5R or X7R dielectrics are recommended due to their low ESR and high ripple current ratings. The output ripple VOUT determined by: VOUT VOUT VIN VOUT VIN fOSC L A 22uF ceramic applications. ESR capacitor 1 8 fOSC COUT can satisfy most THERMAL CALCULATIONS There are three types of losses associated with the AS1308A step-down converter: switching losses, conduction losses, and quiescent current losses. Conduction losses are associated with the RDS(ON) characteristics of the power output switching devices. At full load, assuming continuous conduction mode (CCM), a simplified form of the losses is given by: PTOTAL IO R DSON HS VO R DSON LS VIN t SW F IO IQ VIN VO VIN IQ is the step-down converter quiescent current. The term tSW is used to estimate the full load step-down converter switching losses. For the condition where the step-down converter is in dropout at 100% duty cycle, the total device dissipation reduces to: www.anisem.com ANISEM Proprietary Information. Unauthorized Photocopy and Duplication Prohibited. © 2008 ANISEM All Rights Reserved. 9 AS1308A 1.2MHz, 2.0A Sync. Buck Converter PTOTAL IO R DSON HS IQ VIN Since RDS(ON), quiescent current, and switching losses all vary with input voltage, the total losses should be investigated over the complete input voltage range. Given the total losses, the maximum junction temperature can be derived from the ΘJA for the DFN-10L package which is 45°C/W. TJ MAX PTOTAL ΘJA AS1308A Rev.1.0 10/25/2008 TAMB www.anisem.com ANISEM Proprietary Information. Unauthorized Photocopy and Duplication Prohibited. © 2008 ANISEM All Rights Reserved. 10 AS1308A 1.2MHz, 2.0A Sync. Buck Converter PACKAGE DESCRIPTION Units: mm Package 10-Lead Plastic TDFN-10L AS1308A Rev.1.0 10/25/2008 www.anisem.com ANISEM Proprietary Information. Unauthorized Photocopy and Duplication Prohibited. © 2008 ANISEM All Rights Reserved. 11 AS1308A 1.2MHz, 2.0A Sync. Buck Converter PACKAGE DESCRIPTION Units: mm Package 10-Lead Plastic MSOP-10L AS1308A Rev.1.0 10/25/2008 www.anisem.com ANISEM Proprietary Information. Unauthorized Photocopy and Duplication Prohibited. © 2008 ANISEM All Rights Reserved. 12 AS1308A 1.2MHz, 2.0A Sync. Buck Converter © ANISEM Semiconductor Co., Ltd ANISEM assume responsibility for use of any circuitry other than circuitry entirely embodied in an ANISEM product. No circuit patent licenses, copyrights, mask work rights, or other intellectual property rights are implied. ANISEM reserves the right to make changes to their products or specifications or to discontinue any product or service without notice. Customers are advised to obtain the latest version of relevant information to verify, before placing orders, that information being relied on is current and complete. All products are sold subject to the terms and conditions of sale supplied at the time of order acknowledgement, including those pertaining to warranty, patent infringement, and limitation of liability. ANISEM warrants performance of its semiconductor products to the specifications applicable at the time of sale in accordance with ANISEM’s standard warranty. Testing and other quality control techniques are utilized to the extent ANISEM deems necessary to support this warranty. Specific testing of all parameters of each device is not necessarily performed. AS1308A Rev.1.0 10/25/2008 www.anisem.com ANISEM Proprietary Information. Unauthorized Photocopy and Duplication Prohibited. © 2008 ANISEM All Rights Reserved. 13 EV2300-1.0 1.2MHz, Sync. Boost Converter FEATURES GENERAL DESCRIPTION High Efficiency: Up to 92% The AS2300 is a 1.2MHz constant frequency, 1.2MHz Constant Switching Frequency current mode PWM step-up converter. It can supply 3.3V@100mA Output from 1 Single AA Cell; 3.3V output voltage at 100mA from a single AA Cell. 3.3V@400mA Output from 2 AA cells Low Start-up Voltage: 0.85V The device integrates a main switch and a Integrated main switch and sync. rectifier. synchronous rectifier for high efficiency without an 2.5V to 5V Output Voltage Range external Schottky diode. A switching frequency of Automatic Pulse Skipping Mode Operation 1.2MHz allows the use of tiny, low profile inductors Tiny External Components and ceramic capacitors. The current mode PWM <1 µA Shutdown Current operation with internal compensation provides Anti-ringing Control Reduces EMI excellent line and load transient characteristics. The Space Saving 6-Pin Thin SOT23 Package AS2300 features Pulse Skipping Mode operation at APPLICATIONS light loads to avoid unacceptable ripple voltage. Cellular and Smart Phones The AS2300 is offered in a low profile (1 mm) small Microprocessors and DSP Core Supplies 6-Pin SOT23 Package. Wireless and DSL Modems MP3 Player Digital Still and Video Cameras Portable Instruments EV2300-1.0 EVALUATION BOARD Figure1. High Performance Step-Up Converter EV2300 Rev.1.0 6/25/2008 www.anisem.com ANISEM Proprietary Information. Unauthorized Photocopy and Duplication Prohibited. © 2008 ANISEM All Rights Reserved. 1