[AP2403] AP2403 Current-Mode PWM Step-Down DC-DC Converter 1. Genaral Description The AP2403 is a Current-Mode Synchronous Step-Down DC-DC Converter with excellent transient response. The output voltage is selectable from the range of 0.8V to 5.0V by an external resistor. The input voltage ranges from 3.0V to 5.5V which is most suitable to generate a 1.0V, a 1.2V, and a 1.8V power supplies. Power MOSFETs are built in the AP2403; the maximum output current of the AP2403 is 2.5A. The switching frequency is selectable from 300 kHz to 4 MHz by the external resistor. For the protections, the AP2403 has Over-Current protection, Low-Input Voltage protection, Thermal protection and Power-Good function. 2. Features 1. Input Voltage Range: Vin = 3.0V to 5.5V 2. Output Voltage Range: Vout = 0.8V to 5.0V (by the external resistor) 3. Maximum Output Load Current: Iout(max) = 2.5A 4. Operation Temperature: Ta = -40C to 105C 5. Switching Frequency: http://akm.transim.com/ 300kHz to 4MHz (Selectable by an external resistor and External Synchronous Mode is available by an external clock) 6. Internal Reference Voltage: 0.6V 1.5% 7. Maximum Duty: 100% 8. Low Input Voltage Protection 9. Power-Good Function 10. Over-Current Protection (Automatic recovery type) 11. Thermal Protection 12. Soft Start Function 13. Package: 16-pin HTSSOP MS1528-E-02 2014/01 -1- [AP2403] 3. Table of Contents 1. Genaral Description ........................................................................................................................................... 1 2. Features .............................................................................................................................................................. 1 3. Table of Contents............................................................................................................................................... 2 4. Block Diagram and Functions ........................................................................................................................... 3 5. Pin Configurations and Functions...................................................................................................................... 4 ■ Ordering Guide ................................................................................................................................................ 4 ■ Pin Layout ....................................................................................................................................................... 4 ■ Pin Functions ................................................................................................................................................... 4 6. Absolute Maximum Ratings .............................................................................................................................. 6 7. Recommended Operating Conditions ................................................................................................................ 6 8. Electrical Characteristics ................................................................................................................................... 7 9. Functional Descriptions ..................................................................................................................................... 8 ■ Start-up Timing ............................................................................................................................................. 10 ■ Over Current Protection Timing .................................................................................................................... 11 ■ External Synchronization Timing .................................................................................................................. 12 10. Application Information .............................................................................................................................. 13 11. Recommended External Circuits ................................................................................................................. 15 12. PCB Layout Example .................................................................................................................................. 16 13. Package ........................................................................................................................................................ 17 ■ Outline Dimensions ....................................................................................................................................... 17 ■ Marking ......................................................................................................................................................... 18 14. Revision History .......................................................................................................................................... 19 IMPORTANT NOTICE .......................................................................................................................................... 20 MS1528-E-02 2014/01 -2- [AP2403] Block Diagram and Functions 4. RT AP2403 FSYN VIN VIN UVLO OSC BGR & VREF 20uA + - SS V1P0_BUFF CURR_ MONI VSEN V1P0_BUFF PWM_comp + - ERRAMP 1.4V OCL_comp + + - 1V DRIVER CC LOGIC IRAMP PGATE SW NGATE 0.78V OVP_comp + - BACK _OCL FB_ MONI FB PWGD PWON _LVS PWON SGND PGND Figure 1. Block Diagram MS1528-E-02 2014/01 -3- [AP2403] 5. Pin Configurations and Functions ■ Ordering Guide AP2403 -40C to 105C 16-pin HTSSOP ■ Pin Layout Figure 2. Pin Layout ■ Pin Functions No. Pin Name I/O 1 PWGD O 2 FSYN I 3 PWON I 4 RT 5 SGND O Power-Good Pin When the output voltage reaches the level that is ±20% of the setting voltage, this pin becomes “H”. External Synchronous Clock Input Pin An external clock within 20% of setting value which is set by the resistor at the RT pin is available. Power-ON Pin The AP2403 starts operation by inputting a 1.5V or more voltage to this pin. SS O 7 CC O GND Internal pull-up resistor to VIN pin is 300k. - HiZ (connect Operation Frequency Setting Pin an external The operation frequency is determined by a resistor connected resistor to this pin. between the GND) Signal Ground 6 Condition (Note 1) Function - Soft Start Pin Connect a capacitor of 0.047μF or more between the SS pin and the GND. The AP2403 charges this external capacitor when starts up, and a Soft Start operation is executed. When GND the over current protection is activated, the external capacitor is discharged and it generates a suspended time in a hiccup operation. Output pin of Output Voltage Feedback Amplifier (Error Amp.) Connect a resistor and a capacitor between the CC pin and the GND SS pin in parallel. These devices compensate the amplifier phase. MS1528-E-02 2014/01 -4- [AP2403] I Input pin of Output Voltage Feedback Amplifier (Error Amp.) It controls the output voltage so that the voltage at this pin becomes 0.6V. Connect two resistors for feedback between the output stage and the GND in series, and the FB pin must be connected to the middle point of these two resistors. Main Power Voltage Input Connect a capacitor of 4.7F or more between the VIN pin and the GND. Internal Switching MOSFET Output It is connected to the middle point of the internal output N-channel MOSFET and the P-channel MOSFET. Internal Switching MOSFET Output It is connected to the middle point of the internal output N-channel MOSFET and the P-channel MOSFET. HiZ (there is an external resistor between the GND) 8 FB 9 VIN 10 SW O 11 SW O 12 PGND Power Ground - 13 PGND Power Ground - - HiZ HiZ Internal Switching MOSFET Output It is connected to the middle point of the internal output HiZ N-channel MOSFET and the P-channel MOSFET. Internal Switching MOSFET Output 15 SW O It is connected to the middle point of the internal output HiZ N-channel MOSFET and the P-channel MOSFET. Main Power Voltage Input 16 VIN Connect a capacitor of 4.7F or more between the VIN pin and the GND. Note 1. Pin state when the PWON pin = “L” 14 SW O MS1528-E-02 2014/01 -5- [AP2403] 6. Absolute Maximum Ratings (GND=0V: Note 2) Parameters VIN pin SW pin All pins (Except SW pin, VIN pin) Junction Temperature (Note 4) Junction Temperature (Guaranteed Lifetime) Operating Ambient Temperature Symbol min max Unit Vin VSW VIND Tj1 Tj2 0.3 0.3 0.3 40 40 6.0 Vin + 0.3 Vin 150 135 V V V C C Ta 40 105 C Storage Ambient Temperature TSTG 40 150 Power Dissipation (Ta=25C) (Note 3) Pd 2750 Note 2. All voltages with respect to the GND pin Note 3. Thermal Resistance of the package (Rth): 40C/W (JEDEC51, four layers PCB) Note 4. Continuous operation above Tj=135C may impair device reliability. C mW WARNING: Operation at or beyond these limits may result in permanent damage to the device. Normal operation is not guaranteed at these extremes. 7. Recommended Operating Conditions Symbol min typ max (GND=0V) Unit VIN pin voltage Vin 3.0 5.5 V Output Current Iout 0 2.5 A Operating Ambient Temperature Top 40 105 C Parameter * AKM assumes no responsibility for the usage beyond the conditions in this datasheet. MS1528-E-02 2014/01 -6- [AP2403] 8. Electrical Characteristics (VIN=5.0V, Tj=40C to 135C, unless otherwise specified) Parameter Operating Input Voltage Range Feedback REF Voltage Operation Current Consumption (No Switching) Stand-by Current Load Regulation (Note 5) Output Pch MOSFET RDS(ON) Output Nch MOSFET RDS(ON) Over-Current Detection Oscillator Frequency FSYN Input Frequency Range Oscillator Accuracy Maximum ON Duty (Note 5) UVLO Detection Voltage UVLO Release Voltage UVLO Hysteresis Output Over Voltage Detection Charge Current (to Capacitor of Soft Start) Discharge Current (to Capacitor of Soft Start) Thermal Protection Detection (Note 6) Thermal Protection Hysteresis (Note 6) High side Power Good Detection High side Power Good Release Low side Power Good Detection Low side Power Good Release Power Good Hysteresis Power-OFF Threshold Power-ON Threshold Power-ON Hysteresis Gm (Error amplifier) Threshold voltage (of FSYN pin) Output voltage (of PWGD pin) Symbol Vin VFBref min 3.0 591 typ 600 max 5.5 609 Unit V mV ISUPPLY 0.48 0.8 1.12 mA Istandby - - 10 A VLOAD - 1 - % Rpmos Rnmos Ioclpeak Fosc Fext300 Fext2000 3.15 300 240 1600 65 65 4.5 - 100 100 4000 360 2400 mΩ mΩ A kHz kHz kHz Facu 20 0 20 % MAXDuty Vuvlo Vuvlorel Vuvhys Vovp 2.30 2.35 0.05 +26 2.50 2.70 0.20 +30 100 2.85 2.90 0.50 +34 % V V V % Iss+ 18.0 20.0 22.0 A Iss- 0.70 1.0 1.30 A Tsd 135 155 185 C Tsdhys 5 15 25 C Vpgonh Vpgoffh Vpgonl Vpgoffl Vpghys Vponl Vponh Vponhys Gm VEih VEil VPoh VPol +16 +21 16 21 3 1.5 50 360 0.7*VIN VIN0.4 - +20 +25 20 25 5 100 500 - +24 +29 24 29 7 0.4 150 730 0.3*VIN 0.4 % % % % % V V mV A/V V V V V Conditions Tj=25°C Tj=25°C Tj=25°C 0A to 2A, Ta=-40°C to 105°C Tj=25°C Tj=25°C Tj=25°C RT=702kΩ to 47kΩ RT=702kΩ (at 300kHz) RT=100kΩ (at 2MHz) RT=100kΩ (at 2MHz), Tj=25°C against VFBref Css=0V → 1.0V (at rise) Tj=25°C Css=1.0V→0.40V (at fall) Tj=25°C (in hiccup operation) by contrast with VFBref by contrast with VFBref by contrast with VFBref by contrast with VFBref Tj=25°C Tj=25°C Tj=25°C Ipoh=100A Ipol=100A Note 5. A reference value with the recommended circuit Note 6. Design assurance values MS1528-E-02 2014/01 -7- [AP2403] 9. Functional Descriptions 1. Shutdown The AP2403 is in shutdown condition when a Low signal is input to the PWON pin even if power supply was input to the VIN pin. When a High signal is input to the PWON pin, the AP2403 is powered up in soft-start mode. 2. Soft Start Mode: This function prevents an overshoot of the output voltage when the AP2403 is powered up. It controls the output voltage slowly. During the soft-start period a capacitor connected to the SS pin is charged from 0V to 1.0V by a 20A constant current. In soft start, an output voltage rising is controlled by changing the over-voltage limitation value linearly in accordance with the SS pin voltage. When this function starts, the over-current limitation value is fixed in 50% (2.25A typ.). It changes linearly during the period which the SS pin voltage increases to 1.0V from 0.5V. When a soft start operation is completed, the AP2403 shifts to a PWM control. 3. Constant Voltage Operation: The AP2403 operates by Current-mode PWM controls. It determines the target value of inductance current by amplifying the voltage difference between the FB pin and 0.6V which is feedback reference voltage. The internal P-channel MOSFET is powered on until the inductance current meets the target value. When the inductance current reaches the target value, the built-in P-channel MOSFET becomes OFF and the built-in N-channel MOSFET becomes ON. Then the AP2403 operates in synchronous rectification mode. 4. Prevention of Incorrect Operation in Low Voltage (UVLO: Under Voltage Lock Out): When the V5 pin voltage becomes less than 2.5V by a main power supply voltage decrease, all circuit blocks in the AP2403 are stopped and the AP2403 becomes UVLO state. The UVLO state has hysteresis, and the AP2403 keeps UVLO state until the main power supply voltage rises again and exceeds 2.5V. When the UVLO state is released, the AP2403 restarts by a soft start operation. 5. Output Over-Voltage Protection (OVP): When the output voltage becomes +30% or more of the setting value, the built-in P-channel MOSFET and the built-in N-channel MOSFET become OFF state and the AP2403 enters protection mode. This state is maintained until the built-in P-channel MOSFET is turned on by the FB amplifier. The AP2403 is in normal operation when recovering from the output over-voltage protection. It does not shift to soft-start mode. 6. Hiccup type Output Over-Current Limitation (OCL): This function reduces the output voltage and the output current by Hiccup operation in an over-current condition. When the over-current condition is detected, the built-in P-channel MOSFET and the built-in N-channel MOSFET become OFF and the SS pin voltage which is 1.0V discharged from 1.0V to 0.4V by a continuous current of 1.0uA. The AP2403 stops its operation without shifting to a soft start operation in this discharging period of the SS pin. When the SS pin voltage decreases to 0.4V, the AP2403 enters a soft start operation after the SS pin voltage is discharged further to the GND level by the internal switch. The AP2403 repeats this sequence until the over current condition is removed. MS1528-E-02 2014/01 -8- [AP2403] 7. Thermal Protection (TSD: Thermal Shutdown) The chip temperature is monitored, and the built-in P-channel MOSFET and the built-in N-channel MOSFET are stopped when the chip temperature becomes about 150C. The thermal protection function discharges electrical charge of the SS pin at this time, therefore a recovery sequence from the thermal protection is always in a soft start operation. This function has a hysteresis, and the AP2403 is restarted by soft start when the chip temperature decreases 15C from the thermal shutdown threshold. 8. Oscillation Frequency Setting: The oscillation frequency is determined by a resistor which is connected between the RT pin and the GND. Refer to the equation of this resistor value for frequency setting in the page of the application information. 9. External Synchronization External synchronization is available by inputting a clock to the FSYN pin. The external synchronization frequency is determined by a resistor which is connected between the RT pin and the GND, and the AP2403 accepts a frequency within 20% of this setting value. 10. Power Good The AP2403 has a power-good function which indicates output voltage condition. The PWGD pin becomes High level (VIN level), when the output voltage reaches a level that is within 25% of the setting value. The PWGD pin is always in Low level, during a power-off condition and a soft start operation. MS1528-E-02 2014/01 -9- [AP2403] ■ Start-up Timing Vin PWON Vref T1 100％ T1： 50％ Css [s] 20 10 -6 SS Vout 100％ 50％ OCL Level 0％ 130％ 100％ OVP Level 0％ OCL&OVP Control PWM Control SS_END Figure 3. Start Up Timing MS1528-E-02 2014/01 - 10 - [AP2403] ■ Over Current Protection Timing T1: Css [s] 20 10-6 T2: 512clock 0.6 Css T3 : [sec] 1 10 -6 T4 : 384clock 512clock When SS=0.1F, When Css=0.22F, T1: Soft Start Time is 5ms, T2: 256s (512 clocks/2MHz), T1: Soft Start Time is 11ms, T3: Rest Time is 60ms T4: 192s (384 clocks/2MHz) T3: Rest Time is 132ms Figure 4. Over Current Protection Timing MS1528-E-02 2014/01 - 11 - [AP2403] ■ External Synchronization Timing in 67% of the rest. 33% Fixed 33%固定It changes 残り67%で変化 1 : 2 Internal Clock 内部クロック (Setup by RT pin) （RT端子で設定） (1) FSYN pin Input FSYN端子入力 A fixed clock within 固定分33%以内 33% is ignored. のクロック無視 SW pin Output SW端子出力 (1) When the period of FSYN=”H” is longer than one cycle of an internal clock, the AP2403 operates according to the internal clock. (2) When the period of FSYN=”H” is shorter than one cycle of an internal clock, the AP2403 operates according to an external clock. (2) The AP2403 accepts an external clock within 20% of the setting frequency which is determined by the resistor of the RT pin for an external synchronization. VIN VIN 300k Ω 10k Ω FSYN Gate Input ゲート入力 AP2403 AL2010内部 External Synchronous 外部同期信号 Clock Figure 5. External Synchronous Timing MS1528-E-02 2014/01 - 12 - [AP2403] 10. Application Information 1. Inductance: An external inductor must be selected so that the maximum ripple current will be 30% of the rated current. The main power voltage (Vin) is the maximum value of input voltage range. The external inductor value is determined by following equation. L Vout （Vin - Vout ） [ H] 0.6 Vin Frequency 2. Phase Compensation: Resistors and a capacitor for phase compensation are connected between the CC pin and the Vref/SS pin. Recommended values of these are shown below but they are not fixed. These values can be changed according to the VIN and VOUT frequency settings to optimize the phase compensation. (values shown below is in the case of “11. Recommended External Circuits”) R4＝220[kΩ], R5＝4.7[kΩ], C5=2200[pF] 3. Soft Start Time: Soft-start time is determined by the C4 capacitor which is connected between the SS pin and the GND. The relation of the capacitance and the soft-start time is calculated by the following equation. Tss = C4／20×10-6 [s] 4. Suspended Time in Hiccup Operation: The suspended time in Hiccup operation is determined by the C4 capacitor which is connected between the SS pin and the GND. The relation of the capacitance and the suspended time is calculated by the following equation. THIC＝ 0.6 C4 [s] 1 10 -6 5. Output Voltage: The output voltage is determined by the feedback resistors, and those two resistors are placed in series between the output capacitor and the GND. Those resistor value of R2 (the output capacitor to FB pin) and R1 (FB pin to GND) are calculated by the following equation. 1 Vout ＝0.6 R2 [ V] R1 Please note that the operation may become unstable by an influence of the switching noise when the current which flows in the resistor becomes too small. 6. Oscillation Frequency: The oscillation frequency is determined by the R3 resistor which is connected between the RT pin and the GND. The relation of the resistor value and the oscillation frequency is calculated by the following equation. 0.6 （1/Frequency - 33 10-9 ) R3＝ [Ω] 1.2 2.35 10-12 MS1528-E-02 2014/01 - 13 - [AP2403] 7. Power Dissipation ディレーティング・カーブ 3000 2750 POWER DISSIPATION Pd (mW) 2500 2250 2000 1750 1500 1250 1000 750 500 250 0 -50- 40 0 25 50 75 100 105 100 125 135 150 OPERATING AMBIENT TEMPERATURE Ta (C ) Figure 6. HTSSOP-16 DERATING CURVE The derating curve of Package of HTSSOP-16 is above. The junction temperature (Tj) may become high temperature, even if the operating ambient temperature (Ta) is room temperature (25C). This IC must be operated within the power dissipation. MS1528-E-02 2014/01 - 14 - [AP2403] 11. Recommended External Circuits AP2403 C1 VIN PWGD 1 PWGD VIN 16 FSYN 2 FSYN SW 15 PWON 3 PWON SW 14 4 RT PGND 13 5 SGND PGND 12 R3 L1 C3 C4 C5 6 SS SW 11 7 CC SW 10 8 FB VIN 9 VOUT R1 R4 R5 R2 C2 Figure 7. Standard Recommended Circuit Example Parts List (VIN=5V, VOUT=1.8V, F=2MHz) Symbol Parts name C1 Input capacitor C2 Input capacitor C3 Output capacitor C4 SS capacitor C5 Phase compensation capacitor R1 FB resistor (High) R2 FB resistor (Low) R3 Frequency set-up resistor R4 Phase compensation resistor R5 Phase compensation resistor L1 Power Inductor Parts value Ceramic 10F Ceramic 10F Ceramic 10F Ceramic 0.1F 2200pF Ceramic 150kΩ 100kΩ 100kΩ 220kΩ 4.7kΩ 2.7H MS1528-E-02 Manufacturer TDK LTF5022-2R2N3R2-LC 2014/01 - 15 - [AP2403] 12. PCB Layout Example Figure 8. Recommended Layout Pattern MS1528-E-02 2014/01 - 16 - [AP2403] 13. Package ■ Outline Dimensions HTSSOP 16-pin (Unit: mm) MS1528-E-02 2014/01 - 17 - [AP2403] ■ Marking 1) 2) 3) Pin #1 indication Date Code : XXXXXX (6 digits: Date Code) Marketing Code : AP2403 MS1528-E-02 2014/01 - 18 - [AP2403] 14. Revision History Date (Y/M/D) Revision 13/04/23 00 13/07/02 01 Page 14/01/24 14 02 4, 9, 12, 13 Contents First edition The correction of the description of I/O in Pin Configuration and Functions The correction of the type error in TIMING CHART AT OVER CURRENT PROTECTION (the shifting of the equations of T3 and T4) Deletion of the diode of D1 in Figure 7 Deletion of the symbol of D1 in Figure 8 Addition of “Power Dissipation” MS1528-E-02 2014/01 - 19 - [AP2403] IMPORTANT NOTICE 0. Asahi Kasei Microdevices Corporation (“AKM”) reserves the right to make changes to the information contained in this document without notice. When you consider any use or application of AKM product stipulated in this document (“Product”), please make inquiries the sales office of AKM or authorized distributors as to current status of the Products. 1. All information included in this document are provided only to illustrate the operation and application examples of AKM Products. AKM neither makes warranties or representations with respect to the accuracy or completeness of the information contained in this document nor grants any license to any intellectual property rights or any other rights of AKM or any third party with respect to the information in this document. You are fully responsible for use of such information contained in this document in your product design or applications. AKM ASSUMES NO LIABILITY FOR ANY LOSSES INCURRED BY YOU OR THIRD PARTIES ARISING FROM THE USE OF SUCH INFORMATION IN YOUR PRODUCT DESIGN OR APPLICATIONS. 2. The Product is neither intended nor warranted for use in equipment or systems that require extraordinarily high levels of quality and/or reliability and/or a malfunction or failure of which may cause loss of human life, bodily injury, serious property damage or serious public impact, including but not limited to, equipment used in nuclear facilities, equipment used in the aerospace industry, medical equipment, equipment used for automobiles, trains, ships and other transportation, traffic signaling equipment, equipment used to control combustions or explosions, safety devices, elevators and escalators, devices related to electric power, and equipment used in finance-related fields. Do not use Product for the above use unless specifically agreed by AKM in writing. 3. Though AKM works continually to improve the Product’s quality and reliability, you are responsible for complying with safety standards and for providing adequate designs and safeguards for your hardware, software and systems which minimize risk and avoid situations in which a malfunction or failure of the Product could cause loss of human life, bodily injury or damage to property, including data loss or corruption. 4. Do not use or otherwise make available the Product or related technology or any information contained in this document for any military purposes, including without limitation, for the design, development, use, stockpiling or manufacturing of nuclear, chemical, or biological weapons or missile technology products (mass destruction weapons). When exporting the Products or related technology or any information contained in this document, you should comply with the applicable export control laws and regulations and follow the procedures required by such laws and regulations. The Products and related technology may not be used for or incorporated into any products or systems whose manufacture, use, or sale is prohibited under any applicable domestic or foreign laws or regulations. 5. Please contact AKM sales representative for details as to environmental matters such as the RoHS compatibility of the Product. Please use the Product in compliance with all applicable laws and regulations that regulate the inclusion or use of controlled substances, including without limitation, the EU RoHS Directive. AKM assumes no liability for damages or losses occurring as a result of noncompliance with applicable laws and regulations. 6. Resale of the Product with provisions different from the statement and/or technical features set forth in this document shall immediately void any warranty granted by AKM for the Product and shall not create or extend in any manner whatsoever, any liability of AKM. 7. This document may not be reproduced or duplicated, in any form, in whole or in part, without prior written consent of AKM. MS1528-E-02 2014/01 - 20 -