Datasheet 6V to 20V, 1A 1ch PWM Buck Converter Integrated FET BD9227F Key Specifications General Description The BD9227F is a 20V, 1A non-synchronous PWM duty control buck converter with integrated internal high-side 20V Power MOSFET. Operating frequency is 1.0MHz fixed by inner circuit. Current mode control with internal slope compensation simplifies the external compensation calculation and reduces component count while allowing the use of ceramic output capacitors. Additional protection features are included such as Over Current Protection, Thermal Shutdown and Under Voltage Lockout. The under voltage lockout and hysteresis can be set by external resistor. The BD9227F is available in SOP8. Input Voltage Range: 6V to 20 V Ref. Precision: PWM=H: ±2.0 %(±1.0 %@Ta=25°C) Max Output Current: 1A (Max.) Switching Frequency: 1.0MHz (Typ.) Operating Temperature Range: -40℃ to +85°C Packages W(Typ) x D(Typ) x H(Max) 5.00mm x 6.20mm x 1.71mm SOP8 Features ■ ■ ■ ■ ■ ■ Wide Operating Input Range 6V to 20V 20V/200mΩ Internal Power MOSFET 1.0MHz Fixed Operating Frequency Current Mode Over Current Hiccup Period Protection Under Voltage Locked Out(UVLO), Over Voltage Protection(OVP), Thermal Shut Down(TSD) ■ Available in SOP8 Package. SOP8 Applications Home Appliance VM Motor Typical Application Circuits VB NON CNON: 1uF CVB: 0.1uF VCC VCC PWM PWM CVCC: 10uF L1:10uH VOUT FB LX COUT: 10uF D1 GND R1: 110k COMP BD9227F C2: 1.5nF R3: 33k R2: 10k Figure 1. Typical Application Circuit ○Product structure：Silicon monolithic integrated circuit .www.rohm.com © 2016 ROHM Co., Ltd. All rights reserved. TSZ22111・14・001 ○This product is not designed for protection against radioactive rays 1/25 TSZ02201-0252AAJ00010-1-2 8.Jun.2016 Rev.001 BD9227F Pin Configuration VB 1 8 NON VCC 2 7 PWM LX 3 6 FB GND 4 5 COMP BD9227F Figure 2. Pin Configuration (TOP VIEW) Pin Description Pin No. Pin Name Function 1 VB Inner voltage regulator output power supply 2 VCC Power supply 3 LX Switch pin of PWM buck 4 GND Ground 5 COMP Compensation node 6 FB Feedback signal 7 PWM PWM input signal 8 NON Inner DC ref voltage Block Diagram VCC VCC UVLO VB Current sense AMP TSD shutdown LVS VCC VB VCC-5V 1V max PWM FET 3V LX VOUT VREF Error Amp ICOMP Logic Σ 3V FB Oscillator 1MHz NON GND COMP Figure 3. Block Diagram www.rohm.com © 2016 ROHM Co., Ltd. All rights reserved. TSZ22111・15・001 2/25 TSZ02201-0252AAJ00010-1-2 8.Jun.2016 Rev.001 BD9227F Description of Blocks 1. VREF This block generates reference voltage and current. It starts operation when VCC rise up. It provides reference voltage and current to Error AMP, Oscillator, and etc. 2. VB This is a gate drive voltage generator and VCC-5.0V regulator for internal circuit voltage. 3. Oscillator This is a precise wave oscillation circuit with operation frequency fixed to 1.0MHz. 4. Error AMP This is an error amplifier which detects output signal, and outputs PWM control signal. Internal reference voltage is set by PWM input signal. Also, the BD9227F have current mode control with internal slope compensation simplifies the external compensation calculation and reduces component count while allowing the use of ceramic output capacitors. 5. ICOMP This is a comparator that outputs PWM signal from current feed-back signal and error-amp output for current-mode. 6. Pch FET SW This is a 20V/200mΩ Power Pch MOSFET SW that converts inductor current of DC/DC converter. 7. UVLO This is a low voltage error prevention circuit. This prevents internal circuit error during increase of power supply voltage and during decline of power supply voltage. It monitors VCC pin voltage and internal REG voltage, and when VCC voltage becomes 5.3V and below, it turns OFF all output FET and DC/DC converter’s output, and Soft Start circuit resets. Now this threshold has hysteresis of 200mV(Typ). 8. TSD The current of power MOSFET is limited by this function. When it detects an abnormal temperature exceeding Tj=175°C, it turns OFF DC/DC Converter Output. The threshold of TSD has Hysteresis (25°C). If temperature falls below 150°C, the IC automatically returns. 9. OVP Over Voltage Protection. Output voltage is monitored with FB terminal, and output FET is turned off when it becomes VNON+200mV. 10. OCP This is a circuit to protect the high-side FET from over-current. Every cycle the switch current and the reference voltage of over-current protection are compared; when the peak inductor current continuously intersects the reference voltage, the high-side switch is turned off. Once 2 times continuous over current is detected, the device will stop and COMP/ NON pin voltage will be reset( to GND) and after 8.191ms the device restart. (refer to Page.7 Figure 5) 11. PWM The PWM pin is the input pin to control active or inactive of the BD9227F and the PWM input pulse determines the OUTPUT voltage (refer to Page.15 (3) Output Voltage Setting). Once the pulse is input on the PWM pin, the internal enable signal turns on then the internal regulator turns on. After the each regulator operates, the BD9227F starts switching. When the low period of the PWM pulse is longer than 2.047msec (typ), the BD9227F stops operation (refer to Page.7 Figure 4). www.rohm.com © 2016 ROHM Co., Ltd. All rights reserved. TSZ22111・15・001 3/25 TSZ02201-0252AAJ00010-1-2 8.Jun.2016 Rev.001 BD9227F Absolute Maximum Ratings (Ta=25°C) Parameter Symbol Rating Unit VCC to GND VCC -0.3 to +22 V VB to GND VB -0.3 to +22 V LX to GND VLX -2.0 to +22 V VCC to LX ⊿VLX -0.3 to +22 V VCC to VB ⊿VB -0.3 to +7 V COMP to GND VCOMP -0.3 to +7 V NON to GND VNON -0.3 to +7 V VFB -0.3 to +7 V VPWM -0.3 to +7 V High-Side FET Drain Current IDH OCP A Power Dissipation Pd FB to GND PWM to GND 0.633 (Note 1) W Operating Temperature Topr -40 to +85 °C Storage Temperature Tstg -55 to +150 °C Junction Temperature Tjmax 150 °C (Note 1) During mounting of 114.3×76.2×1.57t mm 1layer board.Reduce by 5.07mW for every 1℃ increase. (Above 25℃) Caution: Operating the IC over the absolute maximum ratings may damage the IC. The damage can either be a short circuit between pins or an open circuit between pins and the internal circuitry. Therefore, it is important to consider circuit protection measures, such as adding a fuse, in case the IC is operated over the absolute maximum ratings. Thermal Resistance (Note 1) Parameter Symbol Thermal Resistance (Typ) 1s (Note 3) (Note 4) 2s2p Unit SOP8 Junction to Ambient Junction to Top Characterization Parameter (Note 2) θJA 197.4 109.8 °C/W ΨJT 21 19 °C/W (Note 1) Based on JESD51-2A(Still-Air) (Note 2) The thermal characterization parameter to report the difference between junction temperature and the temperature at the top center of the outside surface of the component package. (Note3) Using a PCB board based on JESD51-3 Layer Number of Measurement Board Single Material Board Size FR-4 114.3mm x 76.2mm x 1.57mmt Top Copper Pattern Thickness Footprints and Traces 70μm (Note 4) Using a PCB board based on JESD51-7 Layer Number of Measurement Board 4 Layers Thermal Via(Note 5) Material Board Size FR-4 114.3mm x 76.2mm x 1.6mmt Top 2 Internal Layers Pitch 1.20mm Diameter Φ0.30mm Bottom Copper Pattern Thickness Copper Pattern Thickness Copper Pattern Thickness Footprints and Traces 70μm 74.2mm x 74.2mm 35μm 74.2mm x 74.2mm 70μm (Note 5) This thermal via connects with the copper pattern of all layers www.rohm.com © 2016 ROHM Co., Ltd. All rights reserved. TSZ22111・15・001 4/25 TSZ02201-0252AAJ00010-1-2 8.Jun.2016 Rev.001 BD9227F Recommended Operating Conditions Parameter Symbol Min Typ Max Unit VCC 6 - 20 V VCC x 0.252 - VCC V Input Voltage Output Voltage VOUT (Note1) Output Current IOUT - - 1 A NON Input Voltage VNON - - 1 V PWM Input Voltage VPWM - - 5.5 V PWM Input Frequency FPWM 1 - 50 kHz (Note2) CVCC 4.7 10 - μF (Note3) CVB 0.047 0.1 0.22 μF 4.7 10 - μH 4.7 10 - μF - 1 - μF Input Capacitor Inner Regulator Capacitor Inductor L (Note4) (Note5) Output Capacitor COUT Ref Voltage Capacitor (Note6) CNON Please select each capacitor considering the effect of DC bias and temperature coefficient to satisfy the specification. (Note1) Refer to P.18(10) (Note2) Refer to P.15 (6) (Note3) Refer to P.15 (4) (Note4) Refer to P.14 (1) (Note5) Refer to P.15 (2) (Note6) Refer to P.16 (7) www.rohm.com © 2016 ROHM Co., Ltd. All rights reserved. TSZ22111・15・001 5/25 TSZ02201-0252AAJ00010-1-2 8.Jun.2016 Rev.001 BD9227F Electrical Characteristics (Unless otherwise specified Ta=25℃, VCC=16.0V, VOUT=12.0V, PWM=H) Parameter Symbol Min Typ Max Unit Conditions Operating Non-Switching Supply Current ICC - 0.4 1.0 mA PWM=H, FB=3V (Non-switching) Standby Quiescent Current IST - 0.05 0.2 mA PWM=L VUV 5.0 5.3 5.6 V VUVHY - 200 400 mV FSW 0.80 1.00 1.20 MHz VFBN 0.990 1.000 1.010 V PWM=H, Ta=25°C VFBA 0.980 1.000 1.020 V PWM=H, Ta=-40 to +85°C IFB -1.0 0 1.0 μA VFB = 0 V NON Inner R RNON 100 250 400 kΩ ICOMP Sink Current IVCSI 7.5 15 30 μA COMP=1V, NON=1V, FB=2V ICOMP Source Current IVCSO -30 -15 -7.5 μA COMP=1V, NON=1V, FB=0V Gm 50 115 180 μA/V ICOMP= ± 3μA, NON=1V, COMP=1V GCS - 2.2 5 A/V VCC=16V RONH - 200 - mΩ VB VCC-5.5 VCC-5 VCC-4.5 V IOCP 1.6 2.6 4.2 A PWM Logic High Level VPWMH 1.5 - 5.5 V PWM Logic Low Level VPWML - - 0.5 V PWM Internal Pull-Down Resistor RPWM 200 500 800 kΩ Circuit Current Under Voltage Lockout Detect Threshold Voltage Hysteresis Width VCC falling Oscillator Oscillating Frequency Error Amplifier FB Pin Reference Voltage FB Pin Bias Current Error Amplifier Transconductance Switch Current to COMP Transconductance High-Side MOSFET On Resistance VB Clamp Voltage Over Current Detect Current PWM www.rohm.com © 2016 ROHM Co., Ltd. All rights reserved. TSZ22111・15・001 6/25 TSZ02201-0252AAJ00010-1-2 8.Jun.2016 Rev.001 BD9227F Timing Chart VCC UVLO reset VCC PWM PWMON_IH(inner) REG UVLO reset REG(inner) REG UVLO REG UVLO_IL(inner) VCC VB VB UVLO VB UVLO reset VCC-5V VBUVLO_IL(inner) Shutdown delay 2.047 msec PWM_CNT_IH(inner) NON Tss COMP LX OVP OVP reset VOUT(FB) OVPOUT_IH(inner) Figure 4. Startup/Shutdown Timing Chart VOUT (FB) VOUT short to GND NON reset Short condition is reset restart restart COMP LX IL OCP th OCPOUT_IH(inner) OCP detect OCP latch is set OCP_latch(inner) Hiccup time:8.191 msec(typ) Figure 5. OCP Timing Chart www.rohm.com © 2016 ROHM Co., Ltd. All rights reserved. TSZ22111・15・001 7/25 TSZ02201-0252AAJ00010-1-2 8.Jun.2016 Rev.001 BD9227F 1.10 1.010 1.05 1.005 FB Threshold:VFB[V] Frequency:FSW [MHZ] Typical Performance Characteristics (Unless otherwise specified, Ta=25°C, VCC=16V, VOUT=12V, PWM=3V) 1.00 0.95 0.90 -40 -20 0 25 50 1.000 0.995 0.990 85 6 8 TEMPERATURE[℃] 12 14 16 18 20 Input Voltage:VCC [V] Figure 7. FB Threshold Voltage – Input Voltage Figure 6. Frequency - Temperature 1.50 PWM ON Threshold:VPWMH[V] 1.010 FB Threshold:VFB[V] 10 1.005 1.000 0.995 1.30 1.10 0.90 0.70 0.50 0.990 -40 -20 0 25 50 -40 85 0 25 50 85 TEMPERATURE[℃] TEMPERATURE[℃] Figure 8. FB Threshold Voltage - Temperature www.rohm.com © 2016 ROHM Co., Ltd. All rights reserved. TSZ22111・15・001 -20 Figure 9. PWM Pin Inner REG ON Threshold - Temperature 8/25 TSZ02201-0252AAJ00010-1-2 8.Jun.2016 Rev.001 1.100 0.28 1.050 0.24 PMOS Ron:RONH [Ω] Frequency:FSW [MHz] BD9227F 1.000 0.950 0.20 0.16 0.12 0.900 6 8 10 12 14 16 18 -40 20 -20 0 25 50 85 TEMPERATURE[℃] Input Voltage:VCC [V] Figure 10. Frequency – Input Voltage Figure 11. PMOS ON Resistance - Temperature 5 500 Input Current:ICC [μA] OCP:IOCP[A] 4 3 2 400 VCC=6V 300 VCC=16V 1 VCC=20V 0 200 -40 -20 0 25 50 85 -40 TEMPERATURE[℃] 0 25 50 85 TEMPERATURE[℃] Figure 13. Operating Current – Temperature Figure 12. OCP Detect Current - Temperature www.rohm.com © 2016 ROHM Co., Ltd. All rights reserved. TSZ22111・15・001 -20 9/25 TSZ02201-0252AAJ00010-1-2 8.Jun.2016 Rev.001 BD9227F Input Current:ICC [μA] 500 400 300 Ta=-40℃ Ta=25℃ Ta=85℃ 200 6 8 10 12 14 16 18 20 Input Voltage: VCC [V] Figure 14. Operating Current – Input Voltage www.rohm.com © 2016 ROHM Co., Ltd. All rights reserved. TSZ22111・15・001 10/25 TSZ02201-0252AAJ00010-1-2 8.Jun.2016 Rev.001 BD9227F Reference Characteristics of Typical Application Circuits (VOUT=12V) NON VB CNON: 1uF CVB: 0.1uF VCC PWM VCC PWM CVCC: 10uF L1:10uH VOUT FB LX COUT: 10uF D1 COMP GND R1: 110k C2: 1.5nF BD9227F R3: 33k C3: Open R2: 10k Figure 15. Typical Application Circuit (VOUT=12V) Parts L1 ： Coilcraft LPS5030-103ML 10μH CVCC/COUT ： Murata GRM31CR71E106MA12# 10μF/25V CVB ： Murata GRM155R71E104ME14# 0.1μF/25V D1 ： Rohm RB060MM-30 100 90 VCC=16V 80 Efficiency:η[%] 70 VCC=20V 60 50 40 30 20 10 0 1 10 100 1000 Output Current:IOUT[mA] Figure 16. Efficiency-Output Current (VOUT=12V) www.rohm.com © 2016 ROHM Co., Ltd. All rights reserved. TSZ22111・15・001 11/25 TSZ02201-0252AAJ00010-1-2 8.Jun.2016 Rev.001 BD9227F PWM: 10V/Div PWM: 10V/Div LX: 10V/Div LX: 10V/Div VOUT: 5V/Div VOUT: 5V/Div ILX: 1A/Div 200ms/Div ILX: 1A/Div Figure 17. Start-up Characteristics (VCC=16V, IOUT=0mA, VOUT=12V) Figure 18. Start-up Characteristics (VCC=16V, IOUT=1A, VOUT=12V) PWM: 10V/Div PWM: 10V/Div LX: 10V/Div LX: 10V/Div VOUT: 5V/Div VOUT: 5V/Div ILX: 1A/Div ILX: 1A/Div 1s/Div Figure 19. Shut-down Characteristics (VCC=16V, IOUT=0mA, VOUT=12V) www.rohm.com © 2016 ROHM Co., Ltd. All rights reserved. TSZ22111・15・001 200ms/Div 400us/Div Figure 20. Shut-down Characteristics (VCC=16V, IOUT=1A, VOUT=12V) 12/25 TSZ02201-0252AAJ00010-1-2 8.Jun.2016 Rev.001 BD9227F VOUT(AC): 20mV/Div VOUT(AC): 20mV/Div IOUT: 10mA/Div IOUT: 1A/Div 1μs/Div 1μs/Div Figure 22. VOUT Ripple (VCC=16V, IOUT=1A, VOUT=12V) Figure 21. VOUT Ripple (VCC=16V, IOUT=10mA; VOUT=12V) Phase Phase Gain Gain BW=33.11 kHz PM=81.64 deg BW=38.90 kHz PM=81.20 deg Figure 24. Frequency Response (VCC=16V, IOUT=1A, VOUT=12V) Figure 23. Frequency Response (VCC=16V, IOUT=100mA, VOUT=12V) www.rohm.com © 2016 ROHM Co., Ltd. All rights reserved. TSZ22111・15・001 13/25 TSZ02201-0252AAJ00010-1-2 8.Jun.2016 Rev.001 BD9227F IOUT: 0.5A/Div Overshoot: 0.83V VOUT: 0.5V/Div Undershoot: 0.79V 4ms/Div Figure 25. Load Response (VCC=16V, VOUT=12V, IOUT=100mA⇔1A) Selection of Components Externally Connected (1) Inductors Something of the shield type that fulfills the current rating (Current value Ipeak below), with low DCR is recommended. Value of Inductance influences Inductor Ripple Current and becomes the cause of Output Ripple. In the same way as the formula below, this Ripple Current can be made small for as big as the L value of Coil or as high as the Switching Frequency. Ipeak IOUT ΔIL IL 2 VCC VOUT VOUT 1 L1 VCC f ΔIL (1) (2) Figure 26. Inductor Current (ΔIL: Output Ripple Current, VCC: Input Voltage, VOUT: Output Voltage, f: Switching Frequency) For design value of Inductor Ripple Current, please carry out design tentatively with about 20%～50% of Maximum Input Current. In the BD9227F, it is recommended the inductance value more than 4.7uH. Recommended Inductor CoilCraft LPS5030 Series ※When current that exceeds Coil rating flows to the coil, the Coil causes a Magnetic Saturation, and there are cases wherein a decline in efficiency, oscillation of output happens. Please have sufficient margin and select so that Peak Current does not exceed Rating Current of Coil. www.rohm.com © 2016 ROHM Co., Ltd. All rights reserved. TSZ22111・15・001 14/25 TSZ02201-0252AAJ00010-1-2 8.Jun.2016 Rev.001 BD9227F (2) Output Capacitor In order for capacitor to be used in output to reduce output ripple, Low ceramic capacitor of ESR is recommended. Also, for capacitor rating, on top of putting into consideration DC Bias characteristics, please use something whose maximum rating has sufficient margin with respect to the Output Voltage. Output ripple voltage is looked for using the following formula. The actual value of the output capacitor is not critical, but some practical limits do exist. Consider the relationship between the crossover frequency of the design and LC corner frequency of the output filter. In general, it is desirable to keep the crossover frequency at less than 1/20 of the switching frequency. With high switching frequencies such as the 1.0MHz frequency of this design, internal circuit limitations of the BD9227F limit the practical maximum crossover frequency to about 50kHz. In general, the crossover frequency should be higher than the corner frequency determined by the load impedance and the output capacitor. This limits the minimum capacitor value for the output filter to: COUT_min 1 2 Rl fc_max (3) Where: Rl is the output load resistance and fc_max is the maximum crossover frequency. The output ripple voltage can be estimated by: Vpp ΔIL 1 2 π f COUT ΔIL RESR (4) Please design in a way that it is held within Capacity Ripple Voltage. In the BD9227F, it is recommended a ceramic capacitor more than 4.7μF. (3) Output Voltage Setting ERROR AMP internal Standard Voltage is 1V, VNON=1V x PWM Duty. Output Voltage is determined by VOUT ERROR AMP R1 FB VOUT R2 R1 R2 * PWM Duty R2 (5) VNON (1V*PWM Duty) Figure 27. Output Voltage Setting ( PWM Duty: the duty of the waveform inputted into PWM terminal) (4) VB Capacitor Please connect from 0.047µF~0.22uF (Laminate Ceramic Capacitor) between VCC Pin and VB Pin.(caution: Don’t connect Capacitor between VB pin to GND pin that cause destroy the chip) (5) Catch Diode The BD9227F is designed to operate using an external catch diode between LX and GND. The selected diode must meet the absolute maximum ratings for the application: Reverse voltage must be higher than the maximum voltage at the LX pin, which is VCCMAX + 0.5 V. Peak current must be greater than IOUTMAX+ΔIL plus on half the peak to peak inductor current. Forward voltage drop should be small for higher efficiencies. It is important to note that the catch diode conduction time is typically longer than the high-side FET on time, so attention paid to diode parameters can make a marked improvement in overall efficiency. Additionally, check that the device chosen is capable of dissipating the power losses. It’s recommanded to use schottky barrier diode with the BD9227F. (6) Input Capacitor The BD9227F requires an input capacitor for decoupling and depending on the application. Use low ESR capacitors for the best performance. Ceramic capacitors are preferred, but low-ESR electrolytic capacitors may also suffice. Please place this capacitor as possible as close to the VCC pin. In the BD9227F, it is recommended a ceramic capacitor more than 4.7μF. When using ceramic capacitors, make sure that they have enough capacitance to provide sufficient charge to prevent excessive voltage ripple at input. The input voltage ripple caused by capacitance can be estimated by: ΔVCC IOUT VOUT VOUT 1 f CVCC VCC VCC (6) Since the input capacitor (CVCC) absorbs the input switching current it requires an adequate ripple current rating. The RMS current in the input capacitor can be estimated by: I CVCC IOUT VOUT VOUT 1 VCC VCC (7) The worst case condition occurs at VCC = 2VOUT, where I CVCC_max IOUT 2 www.rohm.com © 2016 ROHM Co., Ltd. All rights reserved. TSZ22111・15・001 (8) 15/25 TSZ02201-0252AAJ00010-1-2 8.Jun.2016 Rev.001 BD9227F (7) Recommended CNON (vs PWM Frequency) setting The PWM signal control ON/OFF of BD9227F(PWM>1.5V ON, PWM<0.5V OFF) , and PWM duty determine the NON value, In order to get proper NON ripple value, according PWM frequency to select proper CNON capacitor. Below is the relationship of PWM frequency, CNON and NON ripple: NON ripple=D*(1-D)/(R*CNON*PWM Frequency). (9) When D=0.5, NON ripple=NON ripple(max) NON ripple(max)=0.25/(R*CNON*PWM Frequency) (10) D: PWM Duty; R: Inner 250kΩ resistor NON ripple=1mV condition NON value=1V*PWM Duty CNON[nF] 1000 100 10 1 10 100 PWM Frequency[kHz] Figure 28. Recommended PWM Frequency vs CNON (8) Recommended Tss selection vs CNON BD9227F Softstart time Tss is determined by NON rising speed, Tss have relation with CNON. Below is the relationship of Tss and CNON Tss=4.61*R*CNON (11) NON reach 99% of Target NON value R: Inner 250kΩ resistor 10000 Tss[ms] 1000 100 10 10 100 1000 CNON[nF] Figure 29. Recommended CNON vs Tss www.rohm.com © 2016 ROHM Co., Ltd. All rights reserved. TSZ22111・15・001 16/25 TSZ02201-0252AAJ00010-1-2 8.Jun.2016 Rev.001 BD9227F (9) About Adjustment of DC/DC Comparator Frequency Characteristics Role of Phase compensation element C2, C3, R3 (See P.11 Figure15. Example of Reference Application Circuit) Stability and Responsiveness of Loop are controlled through COMP Pin which is the output of Error Amp. The combination of zero and pole that determines Stability and Responsiveness is adjusted by the combination of resistor and capacitor that are connected in series to the COMP Pin. DC Gain of Voltage Return Loop can be calculated for using the following formula. Adc Rl Gcs AEA VFB VOUT (12) Here, VFB is Feedback Voltage (1.0V*PWM Duty).AEA is Voltage Gain of Error amplifier (typ : 66.8 dB), GCS is the Trans-conductance of Current Detect (typ : 2.2A/V), and Rl is the Output Load Resistance value. There are 2 important poles in the Control Loop of this DC/DC. The first occurs with/ through the output resistance of Phase compensation Capacitor (C3) and Error amplifier. The other one occurs with/through the Output Capacitor and Load Resistor. These poles appear in the frequency written below. GEA 2 C 2 AEA 1 fp 2 2 COUT Rl fp1 (13) (14) Here, GEA is the trans-conductance of Error amplifier (typ : 115uA/V). Here, in this Control Loop, one zero becomes important. With the zero which occurs because of Phase compensation Capacitor C2 and Phase compensation Resistor R3, the Frequency below appears. fz1 1 2 C 2 R3 (15) Also, if Output Capacitor is big, and that ESR (RESR) is big, in this Control Loop, there are cases when it has an important, separate zero (ESR zero). This ESR zero occurs due to ESR of Output Capacitor and Capacitance, and exists in the Frequency below. fz ESR 1 2 COUT RESR (16) rd (ESR zero) nd In this case, the 3 pole determined with the 2 Phase compensation Capacitor (C3) and Phase Correction Resistor (R3) is used in order to correct the ESR zero results in Loop Gain. This pole exists in the frequency shown below. fp 3 1 2 C 3 R3 (17) (pole that corrects ESR zero) The target of Phase compensation design is to create a communication function in order to acquire necessary bandwidth and Phase margin. Cross-over Frequency (bandwidth) at which Loop gain of Return Loop becomes “0” is important. When Cross-over Frequency becomes low, Power supply Fluctuation Response, Load Response, etc worsens. On the other hand, when Cross-over Frequency is too high, instability of the Loop can occur. Tentatively, Cross-over Frequency is targeted to be made 1/20 or below of Switching Frequency. Selection method of Phase Compensation constant is shown below. 1. Phase Compensation Resistor (R3) is selected in order to set to the desired Cross-over Frequency. Calculation of RC is done using the formula below. R3 2 COUT fc VOUT GEA GCS VFB (18) Here, fc is the desired Cross-over Frequency. It is made about 1/20 and below of the Switching Frequency (FSW). 2. Phase compensation Capacitor (C2) is selected in order to achieve the desired phase margin. In an application that has a representative Inductance value (more than 4.7uH), by matching zero of compensation to 1/4 and below of the Cross-over Frequency, sufficient Phase margin can be acquired.C2 can be calculated using the following formula. C2 4 2 R3 fc www.rohm.com © 2016 ROHM Co., Ltd. All rights reserved. TSZ22111・15・001 (19) 17/25 TSZ02201-0252AAJ00010-1-2 8.Jun.2016 Rev.001 BD9227F 3. Examination whether the second Phase compensation Capacitor C3 is necessary or not is done. If the ESR zero of Output Capacitor exists in a place that is smaller than half of the Switching Frequency, a second Phase compensation Capacitor is necessary. In other words, it is the case wherein the formula below happens. F 1 SW 2 COUT RESR 2 (20) In this case, add the second phase compensation Capacitor C3, and match the frequency of the third pole to the Frequency fp3 of ESR zero. C3 is looked for using the following formula: C3 (10) COUT RESR R3 (21) About PWM Duty adjustable range of BD9227F BD9227F VOUT voltage is determined by LX duty, but BD9227F Ton-min limited Duty range. The Ton-min(max)=210ns, Tperiod(min)=833ns, then the Duty worst=210/833=25.2%, then the 25.2%<VOUT/VCC<100%. 20 18 16 VOUT:VOUT[V] 14 12 10 8 Available Area 6 4 2 Unavailable Area 0 6 8 10 12 14 16 18 20 Input Voltage:VCC [V] Figure 30. VOUT vs VCC available range www.rohm.com © 2016 ROHM Co., Ltd. All rights reserved. TSZ22111・15・001 18/25 TSZ02201-0252AAJ00010-1-2 8.Jun.2016 Rev.001 BD9227F Cautions on PCB board layout Power GND VCC sense GND CNON VB NON VCC PWM CVB CVCC L1 R1 R2 GND VOUT FB LX D1 COMP BD9227F C2 R3 C3 sense GND COUT Power GND Figure 31. Reference PCB layout Layout is a critical portion of good power supply design. There are several signals paths that conduct fast changing currents or voltages that can interact with stray inductance or parasitic capacitance to generate noise or degrade the power supplies performance. To help eliminate these problems, the VCC pin should be bypassed to ground with a low ESR ceramic bypass capacitor with B dielectric. Care should be taken to minimize the loop area formed by the bypass capacitor connections, the VCC pin, and the anode of the catch diode. See Figure31 for a PCB layout example. In the BD9227F, since the LX connection is the switching node, the catch diode and output inductor should be located close to the LX pins, and the area of the PCB conductor minimized to prevent excessive capacitive coupling. And GND area should be connected directly to power GND for avoiding the external connect which causes the different GND voltage. The additional external components can be placed approximately as shown. www.rohm.com © 2016 ROHM Co., Ltd. All rights reserved. TSZ22111・15・001 19/25 TSZ02201-0252AAJ00010-1-2 8.Jun.2016 Rev.001 BD9227F Power Dissipation t It is shown below reducing characteristics of power dissipation to mount 114.3mm×76.2mm×1.57mm (1 layer) and t 114.3mm×76.2mm×1.6mm (4layer) PCB. Junction temperature must be designed not to exceed 150℃. Power Dissipation: Pd[W] 1.500 1.138W 1.200 4 Layer 0.900 0.633W 0.600 1 Layer 0.300 0.000 0 25 50 75 100 125 150 Ambient Temperature:Ta[℃] Figure 32. Power Dissipation t t ( 114.3mm×76.2mm×1.57mm 1layer / 114.3mm×76.2mm×1.6mm 4layer PCB ) Power Dissipation Estimate The following formulas show how to estimate the device power dissipation under continuous mode operations. They should not be used if the device is working in the discontinuous conduction mode. The device power dissipation includes: 2 1) Conduction loss： Pcon = IOUT × Ron × VOUT / VCC + Vf × IOUT × (VCC-VOUT) / VCC -9 2) Switching loss: Psw = 6 × 10 × VCC × IOUT × Fsw -9 -12 3) Gate charge loss： Pgc =(5.78 × 10 + 197.67×10 × VCC × VCC) × Fsw -3 4) Quiescent current loss： Pq =0.4 ×10 × VCC Where: IOUT is the output current (A), Ron is the on-resistance of the Power MOSFET(Ω), VOUT is the output voltage (V). VCC is the input voltage (V), Fsw is the switching frequency (Hz). Therefore Power dissipation of IC is the sum of above dissipation. Pd = Pcon + Psw + Pgc + Pq For given Tj, Tj =Ta + θja × Pd Where: Pd is the total device power dissipation (W), Ta is the ambient temperature (°C) Tj is the junction temperature (°C), θja is the thermal resistance of the package (°C) www.rohm.com © 2016 ROHM Co., Ltd. All rights reserved. TSZ22111・15・001 20/25 TSZ02201-0252AAJ00010-1-2 8.Jun.2016 Rev.001 BD9227F I/O Equivalent Circuit Pin. No Pin Name 1 VB 2 VCC 3 LX 4 GND Pin Equivalent Circuit Pin. No Pin Name 5 COMP Pin Equivalent Circuit VCC VB COMP LX GND GND FB 6 FB 7 PWM GND 8 PWM GND NON NON GND Figure 33. I/O Equivalent Circuit www.rohm.com © 2016 ROHM Co., Ltd. All rights reserved. TSZ22111・15・001 21/25 TSZ02201-0252AAJ00010-1-2 8.Jun.2016 Rev.001 BD9227F Operational Notes 1) About Absolute Maximum Rating When the absolute maximum ratings of application voltage, operating temperature range, etc. was exceeded, there is possibility of deterioration and destruction. Also, the short Mode or open mode, etc. destruction condition cannot be assumed. When the special mode where absolute maximum rating is exceeded is assumed, please give consideration to the physical safety countermeasure for the fuse, etc. 2) About GND Electric Potential In every state, please make the electric potential of GND Pin into the minimum electrical potential. Also, include the actual excessive effect, and please do it such that the pins, excluding the GND Pin do not become the voltage below GND. 3) About Heat Design Consider the Power Dissipation (Pd) in actual state of use, and please make Heat Design with sufficient margin. 4) About short circuit between pins and erroneous mounting When installing to set board, please be mindful of the direction of the IC, phase difference, etc. If it is not installed correctly, there is a chance that the IC will be destroyed. Also, if a foreign object enters the middle of output, the middle of output and power supply GND, etc., even for the case where it is shorted, there is a change of destruction. 5) About the operation inside a strong electro-magnetic field When using inside a strong electro-magnetic field, there is a possibility of error, so please be careful. 6) About checking with Set boards When doing examination with the set board, during connection of capacitor to the pin that has low impedance, there is a possibility of stress in the IC, so for every 1 process, please make sure to do electric discharge. As a countermeasure for static electricity, in the process of assembly, do grounding, and when transporting or storing please be careful. Also, when doing connection to the jig in the examination process, please make sure to turn off the power supply, then connect. After that, turn off the power supply then take it off. 7) About common impedance For the power supply and the wire of GND, lower the common impedance, then, as much as possible, make the ripple smaller (as much as possible make the wire thick and short, and lower the ripple from L・C), etc., then and please consider it sufficiently. 8) In the application, when the mode where the VCC and each pin electrical potential becomes reversed exists, there is a possibility that the internal circuit will become damaged. For example, during cases wherein the condition when charge was given in the external capacitor, and the VCC was shorted to GND, it is recommended to insert the bypass diode to the diode of the back current prevention in the VCC series or the middle of each Pin-VCC. 9) About IC Pin Input + This IC is a Monolithic IC, and between each element, it has P isolation for element separation and P board. With the N layer of each element and this, the P-N junction is formed, and the parasitic element of each type is composed. For example, like the diagram below, when resistor and transistor is connected to Pin, ○When GND＞(PinA) in Resistor, when GND＞(PinA), when GND＞(PinB) in Transistor (NPN), the P-N junction will operate as a parasitic diode. ○Also, during GND＞(Pin B) in the Transistor (NPN), through the N layer of the other elements connected to the above-mentioned parasitic diode , the parasitic NPN Transistor will operation. On the composition of IC, depending on the electrical potential, the parasitic element will become necessary. Through the operation of the parasitic element interference of circuit operation will arouse, and error, therefore destruction can be caused. Therefore please be careful about the applying of voltage lower than the GND (P board) in I/O Pin, and the way of using when parasitic element operating. B (Pin B) (Pin A) C ～ ～ Transistor (NPN) Resistor E GND N P P+ N N N N GND N N Parasitic Element P Substrate P Substrate Parasitic Element (Pin A) P P+ + ～ ～ P P + GND Parasitic Element GND Figure 34. Example of simple structure of Bipolar IC www.rohm.com © 2016 ROHM Co., Ltd. All rights reserved. TSZ22111・15・001 22/25 TSZ02201-0252AAJ00010-1-2 8.Jun.2016 Rev.001 BD9227F Ordering Information B D 9 2 2 7 Part Number F - E2 Package Packaging and forming specification F: SOP8 E2: Embossed tape and reel Marking Diagram SOP8(TOP VIEW) Part Number Marking D 9 2 2 7 LOT Number 1PIN MARK Figure 35. Marking Diagram www.rohm.com © 2016 ROHM Co., Ltd. All rights reserved. TSZ22111・15・001 23/25 TSZ02201-0252AAJ00010-1-2 8.Jun.2016 Rev.001 BD9227F Physical Dimension, Tape and Reel Information Package Name SOP8 (Max 5.35 (include.BURR)) (UNIT : mm) PKG : SOP8 Drawing No. : EX112-5001-1 www.rohm.com © 2016 ROHM Co., Ltd. All rights reserved. TSZ22111・15・001 24/25 TSZ02201-0252AAJ00010-1-2 8.Jun.2016 Rev.001 BD9227F Revision History Data Modification point Content 8.Jun.2016 - New Release www.rohm.com © 2016 ROHM Co., Ltd. All rights reserved. TSZ22111・15・001 25/25 TSZ02201-0252AAJ00010-1-2 8.Jun.2016 Rev.001 Notice Precaution on using ROHM Products 1. Our Products are designed and manufactured for application in ordinary electronic equipments (such as AV equipment, OA equipment, telecommunication equipment, home electronic appliances, amusement equipment, etc.). If you (Note 1) intend to use our Products in devices requiring extremely high reliability (such as medical equipment , transport equipment, traffic equipment, aircraft/spacecraft, nuclear power controllers, fuel controllers, car equipment including car accessories, safety devices, etc.) and whose malfunction or failure may cause loss of human life, bodily injury or serious damage to property (“Specific Applications”), please consult with the ROHM sales representative in advance. Unless otherwise agreed in writing by ROHM in advance, ROHM shall not be in any way responsible or liable for any damages, expenses or losses incurred by you or third parties arising from the use of any ROHM’s Products for Specific Applications. (Note1) Medical Equipment Classification of the Specific Applications JAPAN USA EU CHINA CLASSⅢ CLASSⅡb CLASSⅢ CLASSⅢ CLASSⅣ CLASSⅢ 2. ROHM designs and manufactures its Products subject to strict quality control system. However, semiconductor products can fail or malfunction at a certain rate. Please be sure to implement, at your own responsibilities, adequate safety measures including but not limited to fail-safe design against the physical injury, damage to any property, which a failure or malfunction of our Products may cause. The following are examples of safety measures: [a] Installation of protection circuits or other protective devices to improve system safety [b] Installation of redundant circuits to reduce the impact of single or multiple circuit failure 3. Our Products are designed and manufactured for use under standard conditions and not under any special or extraordinary environments or conditions, as exemplified below. Accordingly, ROHM shall not be in any way responsible or liable for any damages, expenses or losses arising from the use of any ROHM’s Products under any special or extraordinary environments or conditions. If you intend to use our Products under any special or extraordinary environments or conditions (as exemplified below), your independent verification and confirmation of product performance, reliability, etc, prior to use, must be necessary: [a] Use of our Products in any types of liquid, including water, oils, chemicals, and organic solvents [b] Use of our Products outdoors or in places where the Products are exposed to direct sunlight or dust [c] Use of our Products in places where the Products are exposed to sea wind or corrosive gases, including Cl2, H2S, NH3, SO2, and NO2 [d] Use of our Products in places where the Products are exposed to static electricity or electromagnetic waves [e] Use of our Products in proximity to heat-producing components, plastic cords, or other flammable items [f] Sealing or coating our Products with resin or other coating materials [g] Use of our Products without cleaning residue of flux (even if you use no-clean type fluxes, cleaning residue of flux is recommended); or Washing our Products by using water or water-soluble cleaning agents for cleaning residue after soldering [h] Use of the Products in places subject to dew condensation 4. The Products are not subject to radiation-proof design. 5. Please verify and confirm characteristics of the final or mounted products in using the Products. 6. In particular, if a transient load (a large amount of load applied in a short period of time, such as pulse. is applied, confirmation of performance characteristics after on-board mounting is strongly recommended. Avoid applying power exceeding normal rated power; exceeding the power rating under steady-state loading condition may negatively affect product performance and reliability. 7. De-rate Power Dissipation depending on ambient temperature. When used in sealed area, confirm that it is the use in the range that does not exceed the maximum junction temperature. 8. Confirm that operation temperature is within the specified range described in the product specification. 9. ROHM shall not be in any way responsible or liable for failure induced under deviant condition from what is defined in this document. Precaution for Mounting / Circuit board design 1. When a highly active halogenous (chlorine, bromine, etc.) flux is used, the residue of flux may negatively affect product performance and reliability. 2. In principle, the reflow soldering method must be used on a surface-mount products, the flow soldering method must be used on a through hole mount products. If the flow soldering method is preferred on a surface-mount products, please consult with the ROHM representative in advance. For details, please refer to ROHM Mounting specification Notice-PGA-E © 2015 ROHM Co., Ltd. All rights reserved. Rev.003 Precautions Regarding Application Examples and External Circuits 1. If change is made to the constant of an external circuit, please allow a sufficient margin considering variations of the characteristics of the Products and external components, including transient characteristics, as well as static characteristics. 2. You agree that application notes, reference designs, and associated data and information contained in this document are presented only as guidance for Products use. Therefore, in case you use such information, you are solely responsible for it and you must exercise your own independent verification and judgment in the use of such information contained in this document. ROHM shall not be in any way responsible or liable for any damages, expenses or losses incurred by you or third parties arising from the use of such information. Precaution for Electrostatic This Product is electrostatic sensitive product, which may be damaged due to electrostatic discharge. Please take proper caution in your manufacturing process and storage so that voltage exceeding the Products maximum rating will not be applied to Products. Please take special care under dry condition (e.g. Grounding of human body / equipment / solder iron, isolation from charged objects, setting of Ionizer, friction prevention and temperature / humidity control). Precaution for Storage / Transportation 1. Product performance and soldered connections may deteriorate if the Products are stored in the places where: [a] the Products are exposed to sea winds or corrosive gases, including Cl2, H2S, NH3, SO2, and NO2 [b] the temperature or humidity exceeds those recommended by ROHM [c] the Products are exposed to direct sunshine or condensation [d] the Products are exposed to high Electrostatic 2. Even under ROHM recommended storage condition, solderability of products out of recommended storage time period may be degraded. It is strongly recommended to confirm solderability before using Products of which storage time is exceeding the recommended storage time period. 3. Store / transport cartons in the correct direction, which is indicated on a carton with a symbol. Otherwise bent leads may occur due to excessive stress applied when dropping of a carton. 4. Use Products within the specified time after opening a humidity barrier bag. Baking is required before using Products of which storage time is exceeding the recommended storage time period. Precaution for Product Label A two-dimensional barcode printed on ROHM Products label is for ROHM’s internal use only. Precaution for Disposition When disposing Products please dispose them properly using an authorized industry waste company. Precaution for Foreign Exchange and Foreign Trade act Since concerned goods might be fallen under listed items of export control prescribed by Foreign exchange and Foreign trade act, please consult with ROHM in case of export. Precaution Regarding Intellectual Property Rights 1. All information and data including but not limited to application example contained in this document is for reference only. ROHM does not warrant that foregoing information or data will not infringe any intellectual property rights or any other rights of any third party regarding such information or data. 2. ROHM shall not have any obligations where the claims, actions or demands arising from the combination of the Products with other articles such as components, circuits, systems or external equipment (including software). 3. No license, expressly or implied, is granted hereby under any intellectual property rights or other rights of ROHM or any third parties with respect to the Products or the information contained in this document. Provided, however, that ROHM will not assert its intellectual property rights or other rights against you or your customers to the extent necessary to manufacture or sell products containing the Products, subject to the terms and conditions herein. Other Precaution 1. This document may not be reprinted or reproduced, in whole or in part, without prior written consent of ROHM. 2. The Products may not be disassembled, converted, modified, reproduced or otherwise changed without prior written consent of ROHM. 3. In no event shall you use in any way whatsoever the Products and the related technical information contained in the Products or this document for any military purposes, including but not limited to, the development of mass-destruction weapons. 4. The proper names of companies or products described in this document are trademarks or registered trademarks of ROHM, its affiliated companies or third parties. Notice-PGA-E © 2015 ROHM Co., Ltd. All rights reserved. Rev.003 Datasheet General Precaution 1. Before you use our Pro ducts, you are requested to care fully read this document and fully understand its contents. ROHM shall n ot be in an y way responsible or liabl e for fa ilure, malfunction or acci dent arising from the use of a ny ROHM’s Products against warning, caution or note contained in this document. 2. All information contained in this docume nt is current as of the issuing date and subj ect to change without any prior notice. Before purchasing or using ROHM’s Products, please confirm the la test information with a ROHM sale s representative. 3. The information contained in this doc ument is provi ded on an “as is” basis and ROHM does not warrant that all information contained in this document is accurate an d/or error-free. ROHM shall not be in an y way responsible or liable for an y damages, expenses or losses incurred b y you or third parties resulting from inaccur acy or errors of or concerning such information. Notice – WE © 2015 ROHM Co., Ltd. All rights reserved. Rev.001 Datasheet BD9227F - Web Page Part Number Package Unit Quantity Minimum Package Quantity Packing Type Constitution Materials List RoHS BD9227F SOP8 2500 2500 Taping inquiry Yes