Advanced Power Electronics Corp. APE1502 1.4MHz, 1A SYNCHRONOUS STEP-DOWN CONVERTER FEATURES DESCRIPTIOON 2.5V to 5.5V Input Voltage Range Output Voltage from 0.6V to VIN 1.4MHz Constant Frequency Operation Up to 1A Output Current High Efficiency : Up to 96% No Schottky Diode Required Quiescent Current: 250uA (Typical) Current Mode Operation for Excellent Line and Load Transient Response Current Limit, Enable Function Short Circuit Protect (SCP) Build in Soft Start Function < 1µA Shutdown Current SOT-23-5L and TDFN 2x2-6L Pb-Free APE1502 is a high efficiency monolithic synchronous buck regulator using a constant frequency, current mode architecture. The device is available in an adjustable version. Supply current with no load is 250uA and drops to <1uA in shutdown. The 2.5V to 5.5V input voltage range makes APE1502 ideally suited for single Li-Ion, two to three AA battery-powered applications. 100% duty cycle provides low dropout operation, extending battery life in portable systems. PWM operation provides very low output ripple voltage for noise sensitive applications. Switching frequency is internally set at 1.4MHz, allowing the use of small surface mount inductors and capacitors. The internal synchronous switch increases efficiency and decreases need of an external schottky diode. Low output voltages are easily supported with the 0.6V feedback reference voltage. APE1502 is available in small TSOT-23-5L and TDFN 2x2-6L packages. Packages Type Halogen Free Product TYPICAL APPLICATION V IN= 2.5V~5.5V U1 VIN C1 4.7u SW EN GND V OUT= 1.8V L1 2.2uH FB R1 600 K C3 15p C2 10u APE1502 V OUT = 0.6 x (1+R1/R2 ) R2 300 K R2= 100K~ 330K ORDERING INFORMATION APE1502X Package Type TY5 : TSOT-23-5L TGN2 : TDFN 2x2-6L Data and specifications subject to change without notice 1 20130823V7.2 Advanced Power Electronics Corp. APE1502 ABSOLUTE MAXIMUM RATINGS VIN PIN Voltage (VIN) -------------------------------------- VSS - 0.3V to VSS + 6.5V Feedback Pin Voltage (VFB) ------------------------------ VSS - 0.3V to VIN + 0.3V EN Pin Voltage (VEN) --------------------------------------- VSS - 0.3V to VIN + 0.3V Switch Pin Voltage (VSW ) --------------------------------- VSS - 0.3V to VIN + 0.3V Peak SW Sink & Source Current (IPSW ) --------------- 1.4A Power Dissipation (PD) ----------------------------------- ( TJ-TA ) / Rthja mW Storage Temperature Range (TST) --------------------- -40 to +150°C Operating Temperature Range (TOP) ------------------ -40 to +85°C Junction Temperature (TJ) -------------------------------- +125°C Thermal Resistance from Junction to case TSOT-23-5L 110°C/W TDFN 2x2-6L 25°C/W Thermal Resistance from Junction to ambient TSOT-23-5L 250°C/W TDFN 2x2-6L 120°C/W Note1 : Rthja is measured with the PCB copper area of approximately 1 in2(Multi-layer). That need connect to GND pin or exposed pad (APE1502TGN2). PACKAGE INFORMATION FB GND SW 6 5 4 FB VIN 5 4 (Top View) GND TSOT-23-5L 1 2 3 1 NC EN VIN TDFN 2x2-6L EN 2 3 GND SW ELECTRICAL SPECIFICATIONS (VIN = VEN=3.6V, TA =25oC, unless otherwise specified) Parameter Input Voltage Range SYM TEST CONDITION VIN Feedback Voltage VFB Feedback Bias Current IFB MIN TYP MAX UNITS V 2.5 - 6 TA = +25°C 0.588 0.6 0.612 -40°C < TA < 85°C 0.582 0.6 0.618 VFB=0.65V - - +30 nA V Quiescent Current ICCQ VFB=1V - 250 350 uA Shutdown Supply Current ISD VEN =0V - 0.1 1 uA 1.2 1.4 - A Switching Current Limit ILIMIT Line Regulation △VOUT/VOUT VIN = 2.5V to 5.5V - 0.04 0.4 %/V Load Regulation △VOUT/VOUT IOUT = 0.01 to 1A - 0.5 - % Oscillation Frequency FOSC SW pin 1.1 1.4 1.7 MHz RDS(ON) of P-CH MOSFET RDSON VFB = 0V, IOUT = 0.5A - 0.3 0.4 Ω RDS(ON) of N-CH MOSFET RDSON (Note 1) - 0.25 0.35 Ω 2 Advanced Power Electronics Corp. APE1502 ELECTRICAL SPECIFICATIONS Parameter SYM EN Pin Logic Input Threshold Voltage EN Pin Input Current TEST CONDITION MIN TYP MAX VENL - - 0.4 VENH 1.5 - - - +0.1 +1 uA - 94 - % IEN Efficiency VIN=5V, VOUT=3.3V, IOUT=0.5A EFFI UNITS V Thermal Shutdown TDS - 140 - °C Thermal Shutdown Hysteresis TSH - 30 - °C Note 1: Guaranteed by design. PIN DESCRIPTIONS PIN SYMBOL VIN PIN DESCRIPTION Power Supply Input Pin Enable Pin. EN H : Normal Operation L : Shutdown Switch output pin. Connect external inductor here. Minimize trace SW area at this pin to reduce EMI. GND Ground Pin NC No connect FB Output Feedback Pin BLOCK DIAGRAM VIN OSC SLOPE COMP + REF Isense AMP - 0.6V SET Soft-Star FB + - + Icomp Over-Temperature and Short-Circuit Protection RESET PWM LOGIC NON-OVERLAP CONTROL SW GND Enable Logic EN 3 Advanced Power Electronics Corp. APE1502 FUNCTION DESCRIPTIONS Operation APE1502 is a monolithic switching mode step-down DC-DC converter. It utilizes internal MOSFETs to achieve high efficiency and can generate very low output voltage by using internal reference at 0.6V. It operates at a fixed switching frequency, and uses the slope compensated current mode architecture. This step-down DC-DC Converter supplies minimum 1000mA output current at input voltage range from 2.5V to 5.5V. Current Mode PWM Control Slope compensated current mode PWM control provides stable switching and cycle-bycycle current limit for excellent load and line transient responses and protection of the internal main switch (P-Ch MOSFET) and synchronous rectifier (N-CH MOSFET). During normal operation, the internal P-Ch MOSFET 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. The current comparator, ICOMP, limits the peak inductor current. When the main switch is off, the synchronous rectifier will be turned on immediately and stay on until either the inductor current starts to reverse, as indicated by the current reversal comparator, IZERO, or the beginning of the next clock cycle. APPLICATION INFORMATION Setting the Output Voltage Application circuit item shows the basic application circuit with APE1502 adjustable output version. The external resistor sets the output voltage according to the following equation: V OUT ⎛ R1 ⎞ = 0.6V ×⎜1+ ⎟ ⎝ R2⎠ Table 1 Resistor select for output voltage setting VOUT R2 R1 1.2V 300K 300K 1.5V 300K 450K 1.8V 300K 600K 2.5V 150K 470K 3.3V 120K 540K Inductor Selection For most designs, the APE1502 operates with inductors of 2.2µH to 3.3µH. 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: L = V OUT V IN × (V IN − V OUT ) × ∆I L × f OSC Where is inductor Ripple Current. Large value inductors lower ripple current and small value inductors result in high ripple currents. Choose inductor ripple current approximately 20% of the maximum load current 1000mA, ΔIL=200mA. Table 2 Inductor select for output voltage setting (VIN =3.6V) VOUT Inductor Part Number WE-TPC 1.2V 1.5V 1.8V 2.5V 2.7uH 2.7uH 2.7uH 2.2uH 7440430027 7440430027 7440430027 7440430022 Note: Part type MH or M (www.we-online.com) 4 Advanced Power Electronics Corp. APE1502 For output voltages above 2.0V, when light-load efficiency is important, the minimum recommended inductor is 2.2 µ H. For optimum voltage-positioning load transients, choose an inductor with DC series resistance in the 50mΩ to 150mΩ 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 (1000mA+100mA). 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 shall be less than input source impedance to prevent high frequency switching current passing to the input. 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 4.7µF ceramic capacitor for most applications is sufficient. Output Capacitor Selection The output capacitor is required to be 10uF to keep the output voltage ripple small and to ensure regulation loop stability. The output capacitor must have low impedance at the switching frequency. Ceramic capacitors with X5R or X7R dielectrics are recommended due to their low ESR and high ripple current. Compensation Capacitor Selection The compensation capacitors for increasing phase margin provide additional stability. It is required 15pF, Please refer to Demo Board Schematic to design. Layout Guide TSOT-23-5L TDFN 2x2-6L C1's ground must be as closer to IC's GND pin as possible C1 C2, R1 and R2 must be as closer to IC's FB pin as possible C2 VIN GND R1 SW should be connected to Inductor by wide and short trace, keep sensitive components away from this trace FB VIN 5 4 C2, R1 and R2 must be as closer to IC's FB pin as possible and keep the switching trace away. R2 1 2 EN GND SW should be connected to Inductor by wide and short trace, keep sensitive components away from this trace 3 C2 VOUT R2 6 5 VOUT 4 C2 GND Expoed Pad SW GND C2's ground must be as closer to IC's GND pin as possible L1 FB GND SW APE1502TY5 VIN R1 C2 L1 1 NC 2 C1 and C2's ground must be as closer to IC's GND pin as possible 3 EN VIN C1 VIN GND 5 Advanced Power Electronics Corp. APE1502 TYPICAL PERFORMANCE CHARACTERISTICS 6 Advanced Power Electronics Corp. APE1502 TYPICAL PERFORMANCE CHARACTERISTICS 7 Advanced Power Electronics Corp. APE1502 TYPICAL PERFORMANCE CHARACTERISTICS VIN = 5V, VOUT = 1.2V, RLOAD = No Load VIN = 5V, VOUT = 1.2V, RLOAD = No Load VIN = 5V, VOUT = 1.2V, IOUT = 0.2A ←→ 1A VIN = 5V, VOUT = 1.2V, RLOAD = 1Ω VIN = 5V, VOUT = 1.2V VIN = 3.3V, VOUT = 1.2V, IOUT = 0.2A ←→ 1A 8 Advanced Power Electronics Corp. APE1502 MARKING INFORMATION TSOT-23-5L Part Number : G6 Week: A~Z : 01~26 a~z : 27~52 ID Code : Internal G6YWS Year : A = 2010 1 = 2011 ： ： TDFN 2x2-6L Part Number : GB GB YWS Week: A~Z : 01~26 a~z : 27~52 ID Code : Internal Year : A = 2010 1 = 2011 ： ： 9