APW8825 3A 5V 1MHz Synchronous Buck Converter Features General Description • APW8825 is a 3A synchronous buck converter with integrated 110mΩ high side and 80mΩ low side power High Efficiency up to 95% - Automatic Skip/PWM Mode Operation • Adjustable Output Voltage from 0.6V to VIN • Integrated 110mΩ High side 80mΩ Low Side MOSFETs. The APW8825 design with a current-mode control scheme, can convert wide input voltage of 2.6V to 5.5V to the output voltage adjustable from 0.6V to 5.5V to provide excellent output voltage regulation. MOSFET • Low Dropout Operation : 100% Duty cycle • Stable with Low ESR Ceramic Capacitors • Power-On-Reset Detection on VIN • Integrate Soft Start and Soft-Stop • Over-Temperature Protection • Over Voltage Protection • Under Voltage Protection • High/ Low Side Current Limit • Power Good Indication • Enable/Shutdown Function • Small SOT-23-6 and TDFN2x2-8 packages • Lead Free and Green Devices Available (RoHS The APW8825 is equipped with an automatic Skip/PWM mode operation. At light load, the IC operates in the Skip mode to reduce the switching losses. At heavy load, the IC works in PWM mode. At PWM mode, the switching frequency is set by the external resistor. The APW8825 is also equipped with Power-on-reset, soft start, soft-stop, and whole protections (under-voltage, over-voltage, over-temperature and current-limit) into a single package. This device, available TDFN2X2-8 and SOT-23-6 provide a very compact system solution external components and PCB area. Applications compliant) • Notebook Computer & UMPC • LCD Minitor/TV • Set-Top Box • DSL, Switch HUB • Portable Instrument Simplified Application Circuit VIN VIN L1 APW8825 R3 NC C1 (option) ON R1 COUT FB R2 POK OFF VOUT LX CIN PGND EN AGND ANPEC reserves the right to make changes to improve reliability or manufacturability without notice, and advise customers to obtain the latest version of relevant information to verify before placing orders. Copyright ANPEC Electronics Corp. Rev. A.3 - Feb., 2016 1 www.anpec.com.tw APW8825 Pin Configurations APW8825 APW8825 EN 1 6 FB GND 2 FB POK VIN PGND 5 POK LX 3 4 VIN 1 8 AGND 2 7 EN 3 6 LX 4 5 NC TDFN2x2-8 (Top View) SOT23-6 (Top View) Ordering and Marking Information APW8825 Package Code QB : TDFN-2x2-8 Assembly Material C: SOT23-6 Operating Ambient Temperature Range I : -40 to 85oC Handling Code Temperature Range Handling Code TR : Tape & Reel Package Code Assembly Material G: Halogen and Lead Free Device APW8825QB : W25 X APW8825C : X - Date Code W25X X - Date Code Note : ANPEC lead-free products contain molding compounds/die attach materials and 100% matte tin plate termination finish; which are fully compliant with RoHS. ANPEC lead-free products meet or exceed the lead-free requirements of IPC/JEDEC J-STD-020D for MSL classification at lead-free peak reflow temperature. ANPEC defines “Green” to mean lead-free (RoHS compliant)and halogen free (Br or Cl does not exceed 900ppm by weight in homogeneous material and total of Br and Cl does not exceed 1500ppm by weight). Absolute Maximum Ratings (Note 1) Symbol Parameter Rating Unit -0.3 ~ 6.5 V < 30ns pulse width -3 ~ 8 V > 30ns pulse width -1 ~VIN+0.3 V POK, FB, EN to PGND Voltage -0.3 ~ 6.5 V AGND to PGND Voltage -0.3 ~ 0.3 VIN Input Supply Voltage to PGND VLX LX to GND Voltage V TJ Junction Temperature 150 o TSTG Storage Temperature -65 ~ 150 o 260 o TSDR Maximum Lead Soldering Temperature(10 Seconds) C C C Note1: Stresses beyond those listed under "absolute maximum ratings" may cause permanent damage to the device. These are stress ratings only and functional operation of the device at these or any other conditions beyond those indicated under "recommended operating conditions" is not implied. Exposure to absolute maximum rating conditions for extended periods may affect device reliability. Copyright ANPEC Electronics Corp. Rev. A.3 - Feb., 2016 2 www.anpec.com.tw APW8825 Thermal Characteristics Symbol Parameter Typical Value Junction-to-Ambient Resistance in free air (Note 2) θJA TDFN2x2-8 75 TSOT23-6 250 Unit o C/W Note 2: θJA is measured with the component mounted on a high effective thermal conductivity test board in free air. Recommended Operating Conditions Symbol VIN VOUT (Note 3) Parameter Range Unit Control and Driver Supply Voltage 2.6 ~ 5.5 V Converter Output Voltage 0.6 ~ VIN V 1 ~ 2.2 µH Inductance L IOUT Converter Output Current 0~3 Ambient Temperature TA Junction Temperature TJ A -40 ~ 85 o -40 ~ 125 o C C Note 3 : Refer to the typical application circuit Electrical Characteristics Unless otherwise specified, these specifications apply over VIN=3.7V and TA= -40 to 85 oC. Typical values are at TA=25oC. Pa ra mete r Symbol APW8 825 Test Conditions Unit Min Typ Max Supply Current I DD I SHDN VIN Supp ly Curre nt VFB=0.66 V - 65 - µA VIN Shutdown Su pply Cu rrent EN=GND - - 1 µA VIN Risi ng 2 .3 2.4 2 .5 V 0 .1 0.2 0 .3 V - 0 .6 - V -1 - +1 % -1.5 - +1.5 % 0.85 1 1.15 MHz - 70 - ns Power- On-Reset (POR) VIN POR Vo ltag e Thr eshold VIN POR Hyste resis Reference Volta ge VREF Referen ce Voltage o T A=25 C Ou tp ut Accu racy IOUT =1 0mA~3A, VIN=2.6~5.5V Os cillator F OSC Oscillator Frequ ency Minimum on Time Copyright ANPEC Electronics Corp. Rev. A.3 - Feb., 2016 3 www.anpec.com.tw APW8825 Electrical Characteristics Unless otherwise specified, these specifications apply over VIN=3.7V and TA= -40 to 85 oC. Typical values are at TA=25oC. Pa ra mete r APW8 825 Test Conditions Symbol Unit Min Typ Max Power MOSFET o High Si de P-MOS FET Resistance VIN=5V, I LX=0.5A, T A=25 C - 110 - mΩ Lo w Sid e N-MOSFET Resistance VIN=5V, I LX=0.5A, T A=25oC - 80 - mΩ - - 10 µA 4 5 6 A - 1 60 - °C High/Lo w Curre nt S ide MOSFET Leakage Protect ions I LIM High Si de MOSFET cur rent-limit T OTP Over- tem perature Trip Po int (Resoft start after OTP) Pea k Curre nt, VIN=2.6 ~5.5V o T A= -40 ~125 C - 50 - °C 12 0 1 25 13 0 %V REF 57 66 75 %V REF 20 25 30 µs - -1 - A So ft Sta rt time - 0.8 - ms EN Ena ble threshold - - 1 .4 V 0 .5 - - V - 0.5 2 µA 82.5 87.5 92.5 %VOUT - 5 - %VOUT 12 0 1 25 13 0 %VOUT - 5 - %VOUT - 1 00 - Ω - 20 - us Over- tem perature Hyster esis Over- Voltage Protectio n thre sh old VOUT Rising Unde r-Vol tag e Protecti on th reshold Over- Voltage Protectio n debo unce time Lo w Sid e Switch Curre nt-Limit From Dra in to S ource Soft-Sta rt, Enable a nd POK EN shutdown th reshold EN Pull L ow Curre nt PO K th reshold PO K i n from Lo wer (PO K Goes High) PO K L ow Hyster esis (PO K Goes Low) PO K i n from Highe r (PO K Goes High) PO K Hig h Hyste resis (PO K Goes Low) Po we r Good pu ll low re si stance Po we r Good Debo unce Copyright ANPEC Electronics Corp. Rev. A.3 - Feb., 2016 High to low 4 www.anpec.com.tw APW8825 Pin Description PIN Function TDFN2x2-8 TSOP23-6 Name 1 6 FB Output Feedback Input. The APW8825 senses the feedback voltage via FB and regulates the voltage at 0.6V. Connecting FB with a resistor-divider from the converter’s output sets the output voltage. 2 5 POK Power Good Output. This pin is open-drain logic output that is pulled to ground when the output voltage is not within 10% of regulation point. 3 4 VIN The control circuitry and converter supply input. Connecting a ceramic bypass capacitor from VIN to GND to eliminate switching noise and voltage ripple on the input to the IC. 4, Exposed pad - PGND 5 - NC No internal connection. 6 3 LX Power Switching Output. LX is the Junction of the high-side and low-side Power MOSFETs to supply power to the output LC filter. 7 1 EN Enable Input. EN is a digital input that turns the regulator on or off. Drive EN high to turn on the regulator, drive it low to turn it off. 8 - AGND - 2 GND Power ground. Connect this pin to AGND. Analog ground. Connect this pin to PGND. Power and signal ground. Block Diagram VIN Current Sense Amplifier LOC Over Temperature Protection PowerOnReset Current Limit Zero Crossing Comparator POR 125%VREF OTP OVP Fault Logics 66%VREF UVP Inhibit POK LX Gate Driver Current Compartor Error Amplifier 90%VREF FB Gate Control Gat e Gm Slope Compensation VREF 0.6V Shutdown Oscillator LOC Current Sense Amplifier GND ISS EN POK Copyright ANPEC Electronics Corp. Rev. A.3 - Feb., 2016 5 www.anpec.com.tw APW8825 Typical Application Circuit VIN L1 1uH VIN CIN 22uF APW8825 R3 100k NC C1 (option) ON R1 24K FB COUT 22uFx2 R2 12K POK OFF VOUT LX PGND EN Copyright ANPEC Electronics Corp. Rev. A.3 - Feb., 2016 AGND 6 www.anpec.com.tw APW8825 Function Description VCC and VIN Power-On-Reset (POR) The thermal sensor allows the converters to start a start- TThe APW8825 keeps monitoring the voltage on VIN pin to prevent wrong logic operations which may occur when up process and to regulate the output voltage again after the junction temperature cools by 50oC. The OTP is de- VIN voltage is not high enough for internal control circuitry to operate. The VIN POR rising threshold is 2.4V with signed with a 50 oC hysteresis to lower the average TJ during continuous thermal overload conditions, increas- 0.2V hysteresis. During startup, the VIN voltage must exceed the POR ing lifetime of the APW8825. Current-Limit Protection threshold. Then the IC starts a starts-up process and ramps up the output voltage to the voltage target. The APW8825 monitors the output current, flows through the high-side and low-side power MOSFETs, and limits the current peak at current-limit level to prevent the IC Output Under-Voltage Protection (UVP) from damaging during overload, short-circuit and overvoltage conditions. Typical high side power MOSFET cur- In the operational process, if a short-circuit occurs, the rent limit is 5A, and low side MOSFET current limit is 1A. output voltage will drop quickly. Before the current-limit circuit responds, the output voltage will fall out of the re- Soft-Start quired regulation range. The under-voltage continually monitors the FB voltage after soft-start is completed. If a The APW8825 has a built-in soft-start to control the rise rate of the output voltage and limit the input current surge during start-up. During soft-start, an internal voltage ramp load step is strong enough to pull the output voltage lower than the under-voltage threshold, the IC shuts down connected to one of the positive inputs of the error converter’s output. amplifier, rises up to replace the reference voltage until the voltage ramp reaches the reference voltage. During The under-voltage threshold is 66% of the nominal output voltage. The APW8825 will be latched after under- soft-start without output over-voltage, the APW8825 converter’s sinking capability is disabled until the output voltage protection. voltage reaches the voltage target. Soft-Stop At the moment of shutdown controlled by EN signal, under-voltage event or over-voltage event, the APW8825 ini- Over-Voltage Protection (OVP) The over-voltage function monitors the output voltage by tiates a soft-stop process to discharge the output voltage in the output capacitors. Certainly, the load current also FB pin. When the FB voltage increases over 125% of the reference voltage due to the high-side MOSFET failure or discharges the output voltage. During soft-stop, the internal voltage ramp (VRAMP) falls down to replace the refer- for other reasons, the over-voltage protection comparator will trigger soft-stop function and shutdown the converter output. ence voltage. The low side MOSFET turns on each cycle to discharge the output voltage. Therefore, the output volt- Over-Temperature Protection (OTP) age falls down slowly at the light load. After the soft-stop interval elapses, the soft-stop process ends and the IC The over-temperature circuit limits the junction temperature of the APW8825. When the junction temperature ex- turns off. Enable and Shutdown ceeds TJ =160 oC, a thermal sensor turns off the both power MOSFETs, allowing the devices to cool. Driving EN to ground places the APW8825 in shutdown. In shutdown mode, the internal power MOSFETs turns off, all internal circuitry shuts down and the quiescent supply current reduces to less than 1µA. Copyright ANPEC Electronics Corp. Rev. A.3 - Feb., 2016 7 www.anpec.com.tw APW8825 Function Description (Cont.) Power Good Indicator POK is actively held low in shutdown and soft-start status. In the soft-start process, the POK is an open-drain. When the soft-start is finished, the POK is high. In normal operation, the POK window is from 85% to 125% of the converter reference voltage. When the output voltage stays within this window, POK signal will become high after 0. 5ms internal delay. When the output voltage outruns 80% or 120% of the target voltage, POK signal will be pulled low immediately. In order to prevent false POK drop, capacitors need to parallel at the output to confine the voltage deviation with severe load step transient. The POK pin, if used, needs an axternal pull high resistor, the recommended resistor should be in the range of 30KΩ to 100KΩ. Copyright ANPEC Electronics Corp. Rev. A.3 - Feb., 2016 8 www.anpec.com.tw APW8825 Application Information Input Capacitor Selection shown in “Typical Application Circuits”. A suggestion of Because buck converters have a pulsating input current, a low ESR input capacitor is required. This results in the maximum value of R2 is 20kΩ to keep the minimum current that provides enough noise rejection ability through best input voltage filtering, minimizing the interference with other circuits caused by high input voltage spikes. the resistor divider. The output voltage can be calculated as below: R1 R1 VOUT = VREF ⋅ 1 + = 0.6 ⋅ 1 + R2 R2 Also, the input capacitor must be sufficiently large to stabilize the input voltage during heavy load transients. For good input voltage filtering, usually a 22µF input capacitor is sufficient. It can be increased without any limit for better VOUT input-voltage filtering. Ceramic capacitors show better performance because of the low ESR value, and they are R1≤80kΩ less sensitive against voltage transients and spikes compared to tantalum capacitors. Place the input capacitor as FB R2 ≤ 20kΩ APW8825 close as possible to the input and GND pin of the device for better performance. GND Inductor Selection Output Capacitor Selection For high efficiencies, the inductor should have a low DC The current-mode control scheme of the APW8825 allows the use of tiny ceramic capacitors. The higher ca- resistance to minimize conduction losses. Especially at high-switching frequencies, the core material has a pacitor value provides the good load transients response. higher impact on efficiency. When using small chip inductors, the efficiency is reduced mainly due to higher Ceramic capacitors with low ESR values have the lowest output voltage ripple and are recommended. If required, inductor core losses. This needs to be considered when selecting the appropriate inductor. The inductor value de- tantalum capacitors may be used as well. The output ripple is the sum of the voltages across the ESR and the termines the inductor ripple current. The larger the inductor value, the smaller the inductor ripple current and the ideal output capacitor. lower the conduction losses of the converter. Conversely, larger inductor values cause a slower load transient ∆VOUT response. A reasonable starting point for setting ripple current, ∆IL, is 40% of maximum output current. The rec- V VOUT ⋅ 1 − OUT VIN ≅ FSW ⋅ L 1 ⋅ ESR + 8 ⋅ FSW ⋅ COUT When choosing the input and output ceramic capacitors, ommended inductor value can be calculated as below: choose the X5R or X7R dielectric formulations. These dielectrics have the best temperature and voltage char- V VOUT 1 − OUT V IN L≥ FSW ⋅ ∆IL acteristics of all the ceramics for a given value and size. IL(MAX) = IOUT(MAX) + 1/2 x ∆IL VIN IIN To avoid the saturation of the inductor, the inductor should IP-FET be rated at least for the maximum output current of the converter plus the inductor ripple current. IL CIN IOUT P-FET VOUT SW Output Voltage Setting N-FET In the adjustable version, the output voltage is set by a resistive divider. The external resistive divider is con- ESR COUT nected to the output, allowing remote voltage sensing as Copyright ANPEC Electronics Corp. Rev. A.3 - Feb., 2016 9 www.anpec.com.tw APW8825 Application Information (Cont.) Output Capacitor Selection (Cont.) IL ILIM IPEAK ∆IL IOUT IP-FET Power Sequencing At start-up, it is necessary to ensure that the VIN (the voltage supplied to MOSFET drain) and VEN are sequenced correctly to avoid erroneous latch-off. To avoid UVP latch-off happened at start-up due to sequencing issues, the key method is the VIN should be larger than the output under-voltage threshold plus the drop through the pass MOSFET when that output is enabled. Figure 1 shows the VIN comes up before the VEN. Recommended power on sequence is shown in Figure1. VIN VEN VUV(TH) VEN(TH) VOUT VEN(TH) occurs after VUV(TH) is reached Figure 1. APW8825 power on sequence. Copyright ANPEC Electronics Corp. Rev. A.3 - Feb., 2016 10 www.anpec.com.tw APW8825 Package Information TDFN2x2-8 A b E D D2 A1 A3 NX aaa c E2 SEATING PLANE L K Pin 1 Corner e S Y M B O L TDFN2*2-8 MILLIMETERS INCHES MIN. MAX. MIN. MAX. A 0.70 0.80 0.028 0.031 A1 0.00 0.05 0.000 0.002 0.012 A3 0.20 REF 0.008 REF b 0.18 0.30 0.007 D 1.90 2.10 0.075 0.083 D2 1.00 1.60 0.039 0.063 E 1.90 2.10 0.075 0.083 E2 0.60 1.00 0.024 0.039 e 0.50 BSC 0.020 BSC L 0.30 0.45 0.012 0.018 K 0.20 0.30 0.008 0.012 aaa Copyright ANPEC Electronics Corp. Rev. A.3 - Feb., 2016 0.08 0.003 11 www.anpec.com.tw APW8825 Package Information SOT-23-6 D e E E1 SEE VIEW A b c 0.25 A L 0 GAUGE PLANE SEATING PLANE A1 A2 e1 VIEW A S Y M B O L SOT-23-6 INCHES MILLIMETERS MAX. MIN. A MIN. MAX. 1.45 0.057 A1 0.00 0.15 0.000 0.006 A2 0.90 1.30 0.035 0.051 b 0.30 0.50 0.012 0.020 c 0.08 0.22 0.003 0.009 D 2.70 3.10 0.106 0.122 E 2.60 3.00 0.102 0.118 E1 1.40 1.80 0.055 0.071 e 0.95 BSC e1 1.90 BSC 0.037 BSC 0.075 BSC L 0.30 0.60 0.012 0 0° 8° 0° 0.024 8° Note : 1. Follow JEDEC TO-178 AB. 2. Dimension D and E1 do not include mold flash, protrusions or gate burrs. Mold flash, protrusion or gate burrs shall not exceed 10 mil per side. Copyright ANPEC Electronics Corp. Rev. A.3 - Feb., 2016 12 www.anpec.com.tw APW8825 Carrier Tape & Reel Dimensions P0 P2 P1 A B0 W F E1 OD0 K0 A0 A OD1 B B T SECTION A-A SECTION B-B H A d T1 Application A H T1 C d D W E1 F 178.0±2.00 50 MIN. 8.4+2.00 -0.00 13.0+0.50 -0.20 1.5 MIN. 20.2 MIN. 8.0±0.20 1.75±0.10 3.5±0.05 P0 P1 P2 D0 D1 T A0 B0 K0 4.0±0.10 4.0±0.10 2.0±0.05 1.5+0.10 -0.00 1.5 MIN. 0.6+0.00 -0.40 2.35±0.20 2.35±0.20 1.00±0.20 A H T1 C d D W E1 F 178.0±2.00 50 MIN. 8.4+2.00 -0.00 13.0+0.50 -0.20 1.5 MIN. 20.2 MIN. 8.0±0.30 1.75±0.10 3.5±0.05 P0 P1 P2 D0 D1 T A0 B0 K0 2.0±0.05 1.5+0.10 -0.00 0.6+0.00 -0.40 3.20±0.20 3.10±0.20 1.50±0.20 TDFN2x2-8 Application SOT-23-6 4.0±0.10 4.0±0.10 1.0 MIN. (mm) Devices Per Unit Package Type Unit Quantity SOT-23-6 Tape & Reel 3000 TDFN2x2-8 Tape & Reel 3000 Copyright ANPEC Electronics Corp. Rev. A.3 - Feb., 2016 13 www.anpec.com.tw APW8825 Taping Direction Information TDFN2x2-8 USER DIRECTION OF FEED SOT-23-6 USER DIRECTION OF FEED AAAX AAAX Copyright ANPEC Electronics Corp. Rev. A.3 - Feb., 2016 AAAX AAAX 14 AAAX AAAX AAAX www.anpec.com.tw APW8825 Classification Profile Copyright ANPEC Electronics Corp. Rev. A.3 - Feb., 2016 15 www.anpec.com.tw APW8825 Classification Reflow Profiles Profile Feature Sn-Pb Eutectic Assembly Pb-Free Assembly 100 °C 150 °C 60-120 seconds 150 °C 200 °C 60-120 seconds 3 °C/second max. 3°C/second max. 183 °C 60-150 seconds 217 °C 60-150 seconds See Classification Temp in table 1 See Classification Temp in table 2 Time (tP)** within 5°C of the specified classification temperature (Tc) 20** seconds 30** seconds Average ramp-down rate (Tp to Tsmax) 6 °C/second max. 6 °C/second max. 6 minutes max. 8 minutes max. Preheat & Soak Temperature min (Tsmin) Temperature max (Tsmax) Time (Tsmin to Tsmax) (ts) Average ramp-up rate (Tsmax to TP) Liquidous temperature (TL) Time at liquidous (tL) Peak package body Temperature (Tp)* Time 25°C to peak temperature * Tolerance for peak profile Temperature (Tp) is defined as a supplier minimum and a user maximum. ** Tolerance for time at peak profile temperature (tp) is defined as a supplier minimum and a user maximum. Table 1. SnPb Eutectic Process – Classification Temperatures (Tc) Package Thickness <2.5 mm ≥2.5 mm Volume mm <350 235 °C 220 °C 3 Volume mm ≥350 220 °C 220 °C 3 Table 2. Pb-free Process – Classification Temperatures (Tc) Package Thickness <1.6 mm 1.6 mm – 2.5 mm ≥2.5 mm Volume mm <350 260 °C 260 °C 250 °C 3 Volume mm 350-2000 260 °C 250 °C 245 °C 3 Volume mm >2000 260 °C 245 °C 245 °C 3 Reliability Test Program Test item SOLDERABILITY HOLT PCT TCT HBM MM Latch-Up Method JESD-22, B102 JESD-22, A108 JESD-22, A102 JESD-22, A104 MIL-STD-883-3015.7 JESD-22, A115 JESD 78 Copyright ANPEC Electronics Corp. Rev. A.3 - Feb., 2016 16 Description 5 Sec, 245°C 1000 Hrs, Bias @ Tj=125°C 168 Hrs, 100%RH, 2atm, 121°C 500 Cycles, -65°C~150°C VHBM≧2KV VMM≧200V 10ms, 1tr≧100mA www.anpec.com.tw APW8825 Customer Service Anpec Electronics Corp. Head Office : No.6, Dusing 1st Road, SBIP, Hsin-Chu, Taiwan, R.O.C. Tel : 886-3-5642000 Fax : 886-3-5642050 Taipei Branch : 2F, No. 11, Lane 218, Sec 2 Jhongsing Rd., Sindian City, Taipei County 23146, Taiwan Tel : 886-2-2910-3838 Fax : 886-2-2917-3838 Copyright ANPEC Electronics Corp. Rev. A.3 - Feb., 2016 17 www.anpec.com.tw