Datasheet 2.7V to 5.5V, 1.2A 1ch Synchronous Buck Converter with Integrated FET BD9123MUV General Description Key Specifications BD9123MUV is ROHM's high efficiency step-down switching regulator designed to produce voltage as low as 0.85V to 1.2V from a supply voltage of 5V/3.3V. It offers high efficiency by using pulse skip control technology and synchronous switches, and provides fast transient response to sudden load changes by implementing current mode control. Features Input Voltage Range: Output Voltage Range: Output Current: Switching Frequency: Pch FET ON-Resistance: Nch FET ON-Resistance: Standby Current: Operating Temperature Range: Package Fast Transient Response with Current Mode PWM Control System. High Efficiency for All Load Range with Synchronous Rectifier (Nch/Pch FET) and SLLMTM (Simple Light Load Mode) Output Voltage Selector (3 bit) PGOOD Function Soft-Start Function Thermal Shutdown and UVLO Functions. Short-Circuit Protection Circuit with Time Delay Function. Shutdown Function 2.7V to 5.5V 0.85V to 1.2V 1.2A (Max) 1MHz(Typ) 0.35(Typ) 0.25(Typ) 0A (Typ) -40C to +95C W(Typ) x D(Typ) x H(Max) VQFN016V3030 3.00mm x 3.00mm x 1.00mm Applications Power Supply for LSI including DSP, Microcomputer and ASIC Typical Application Circuit VCC VIN RPG CIN VCC,PVCC EN VOUT VID<2:0> PGOOD VOUT L VID<2:0) ITH VOUT SW GND,PGND RITH CO CITH Figure 1. Typical Application Circuit Product structureSilicon monolithic integrated circuit www.rohm.com (c)2012 ROHM Co., Ltd. All rights reserved. TSZ2211114001 This product has no designed protection against radioactive rays 1/24 TSZ02201-0J3J0AJ00120-1-2 02.Oct.2014 Rev.002 BD9123MUV Datasheet Pin Configuration (TOP VIEW) VID<0> VID<1> VID<2> VOUT > 10 12 11 9 8 ITH 7 PGOOD 15 6 GND 16 5 PGND EN 13 VCC 14 PVCC PVCC (TOP VIEW) 1 2 3 4 SW SW SW PGND Figure 2. Pin Configuration Pin Description Pin No. 1 2 3 4 5 6 7 Pin name Function 8 ITH 9 10 11 12 13 14 15 16 VOUT VID<2> VID<1> VID<0> EN VCC Ground Power good pin Gm Amp output pin/connected phase compensation capacitor Output voltage pin Output voltage control pin<2> Output voltage control pin<1> Output voltage control pin<0> Enable pin(High Active VCC power supply input pin PVCC Pch FET source pin Pch/Nch FET drain output pin SW Nch FET source pin PGND GND PGOOD Block Diagram VCC EN 0.1F 13 VCC 14 VREF VID<0> 12 VID<1> 11 VID<2> 10 R Q S SELECTOR SLOPE CLK Gm Amp OSC VOUT 9 Current Sense/ Protect 16 Driver Logic Input SW 1 + 100 10F 4.7H Output 2 3 22F VCC VCC PGND Soft Start UVLO 7 PGOOD PVCC 15 Current Comp 4 5 TSD PGOOD 6 8 GND ITH RITH CITH www.rohm.com (c)2012 ROHM Co., Ltd. All rights reserved. TSZ2211115001 Figure 3. Block Diagram 2/24 TSZ02201-0J3J0AJ00120-1-2 02.Oct.2014 Rev.002 BD9123MUV Datasheet Absolute Maximum Ratings (Ta=25C) Parameter Symbol Rating Unit (Note 1) V PVCC -0.3 to +7 (Note 1) V EN,SW,ITH Voltage VEN, VSW, VITH -0.3 to +7 V Logic Input Voltage VVID<2:0> -0.3 to +7 V Power Dissipation 1 Pd1 0.27 (Note 2) W Power Dissipation 2 Pd2 0.62 (Note 3) W Power Dissipation 3 Pd3 1.77 (Note 4) W Power Dissipation 4 Pd4 (Note 5) W Operating Temperature Range Topr -40 to +95 C Storage Temperature Range Tstg -55 to +150 C Tjmax +150 C VCC Voltage VCC PVCC Voltage Maximum Junction Temperature -0.3 to +7 2.66 (Note 1) Pd should not be exceeded. (Note 2) IC only (Note 3) Mounted on a 1-layer 74.2mmx74.2mmx1.6mm glass-epoxy board, occupied area by copper foil : 6.28mm2 (Note 4) Mounted on a 4-layer 74.2mmx74.2mmx1.6mm glass-epoxy board, 1st and 4th copper foil area : 6.28mm2 , 2nd and 3rd copper foil area : 5505mm2 (Note 5) Mounted on a 4-layer 74.2mmx74.2mmx1.6mm glass-epoxy board, occupied area by copper foil : 5505mm2, in each layers 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. Recommended Operating Conditions (Ta=-40C to +95C) Parameter Power Supply Voltage EN Voltage Logic Input Voltage Output Voltage Setting Range SW Average Output Current Symbol Rating Min Typ Max Unit VCC 2.7 3.3 5.5 V PVCC 2.7 3.3 5.5 V VEN 0 - VCC V VVID<2:0> 0 - 5.5 V VOUT 0.85 - 1.2 V - 1.2(Note 6) A ISW - (Note 6) Pd should not be exceeded. www.rohm.com (c)2012 ROHM Co., Ltd. All rights reserved. TSZ2211115001 3/24 TSZ02201-0J3J0AJ00120-1-2 02.Oct.2014 Rev.002 BD9123MUV Datasheet Electrical Characteristics (Ta=25C VCC=PVCC=5V, VEN=VCC, VVID<2>= VVID <1>= VVID <0>= 0V, unless otherwise specified.) Parameter Symbol Standby Current Active Current EN Low Voltage EN High Voltage EN Input Current VID Low Voltage VID High Voltage VID Input Current Oscillation Frequency Pch FET ON-Resistance Nch FET ON-Resistance Output Voltage ITH SInk Current ITH Source Current UVLO Threshold Voltage UVLO Release Voltage Power Good Threshold Power Good Release Power Good Delay PGOOD ON-Resistance Soft-Start Time Timer Latch Time Output Short Circuit Threshold Voltage ISTB ICC VENL VENH IEN VVIDL VVIDH IVID fOSC RONP RONN VOUT ITHSI ITHSO VUVLO1 VUVLO2 VPGOOD1 VPGOOD2 tPG RONPG tSS tLATCH VSCP www.rohm.com (c)2012 ROHM Co., Ltd. All rights reserved. TSZ2211115001 Limit Min Typ Max 2.0 2.0 0.8 0.98 25 25 2.4 2.425 70 85 2.5 0.4 1 - 0 300 GND VCC 5 GND VCC 5 1 0.35 0.25 1.0 50 50 2.5 2.55 75 90 5 140 0.8 2 VOUTx0.5 10 500 0.8 10 0.8 10 1.2 0.60 0.50 1.02 2.6 2.7 80 95 10 280 1.6 4 VOUTx0.7 4/24 Unit A A V V A V V A MHz V A A V V % % ms ms ms V Conditions EN=GND Standby mode Active mode VEN=5V VVID=5V PVCC=5V PVCC=5V VVID<2:0>=(0,0,0) VOUT =1.2V VOUT =0.8V VCC=5V to 0V VCC=0V to 5V VOUT to 0V 0V to VOUT VOUT to 0V TSZ02201-0J3J0AJ00120-1-2 02.Oct.2014 Rev.002 BD9123MUV Datasheet Typical Performance Curves [VOUT=1.0V] IO=1.2A Ta=25C Output Voltage: VOUT[V] Output Voltage: VOUT[V] [VOUT=1.0V] Input Voltage: VCC[V] EN Voltage:VEN[V] Figure 5. Output Voltage vs EN Voltage Figure 4. Output Voltage vs Input Voltage [ VOUT = 1.0V] Output Voltage: VOUT[V] Output Voltage: VOUT[V] [ VOUT = 1.0V] VCC=5V Ta=25C EN Voltage: [V] EN[V] Voltage:VVEN VCC=5V IO=0A Input Voltage: VCC[V] Figure 6. Output Voltage vs EN Volatge www.rohm.com (c)2012 ROHM Co., Ltd. All rights reserved. TSZ2211115001 VCC=5V IO=0A Ta=25C Figure 7. Output Voltage vs Input Voltage 5/24 TSZ02201-0J3J0AJ00120-1-2 02.Oct.2014 Rev.002 BD9123MUV Datasheet Typical Performance Curves - continued Efficiency: [%] Frequency: fOSC [MHz] [V = 1.0] OUT [V =1.0V] OUT VCC=5.0V Ta=25C Ta=25C Output Current:IO [A] Input Voltage:VCC[V] VCC=5V Figure 9. Frequency vs Input Voltage ON-Resistance : RON [] Frequency: fOSC [MHz] Figure 8. Efficiency vs Output Current VCC=5.0V Temperature:Ta[C] Temperature:Ta[C] Figure 10. Frequency vs Temperature Figure 11. On-Resistance vs Temperature www.rohm.com (c)2012 ROHM Co., Ltd. All rights reserved. TSZ2211115001 6/24 TSZ02201-0J3J0AJ00120-1-2 02.Oct.2014 Rev.002 BD9123MUV Datasheet EN Voltage: VEN[V] ON-Resistamce:RON[] Typical Performance Curves - continued VCC=5V Temperature:Ta[C] Temperature:Ta[C] Figure 12. EN Voltage vs Temperature www.rohm.com (c)2012 ROHM Co., Ltd. All rights reserved. TSZ2211115001 VCC=5V Figure 13. ON-Resistance vs Temperature 7/24 TSZ02201-0J3J0AJ00120-1-2 02.Oct.2014 Rev.002 BD9123MUV Datasheet Typical Waveforms [ SLLM control [VOUT=1.0V] VOUT=1.0V] VCC=5V SW IO=0A Ta=25C SW VOUT VOUT VCC=5V IO=1.2A Ta=25 C Figure 14. Soft-Start Waveform Figure 15. SW Waveform (IO=0mA) SW VOUT VOUT IOUT VCC=5V IO=1.2A Ta=25C Ta=25C Figure 16. SW Waveform (IO=1.2A) www.rohm.com (c)2012 ROHM Co., Ltd. All rights reserved. TSZ2211115001 Figure 17. Transient Response (IO=125mA to 850mA, 2A) 8/24 TSZ02201-0J3J0AJ00120-1-2 02.Oct.2014 Rev.002 BD9123MUV Datasheet Typical Waveforms - continued VOUT VID VOUT IOUT a 25C Figure 19. Bit Chance Response Figure 18. Transient Response (IO=850mA125mA, 2A) VID VPGOOD VOUT VOUT VCC=5V VO=1V Ta=25C Figure 21. PGOOD Delay Figure 20. Bit Chance Response www.rohm.com (c)2012 ROHM Co., Ltd. All rights reserved. TSZ2211115001 9/24 TSZ02201-0J3J0AJ00120-1-2 02.Oct.2014 Rev.002 BD9123MUV Datasheet Application Information 1. Operation BD9123MUV is a synchronous rectifying step-down switching regulator that achieves faster transient response by employing current mode PWM control system. Its switching operation utilizes PWM (Pulse Width Modulation) mode for heavier load, while SLLMTM (Simple Light Load Mode) operation for lighter load to improve efficiency. (1) Synchronous Rectifier Integrated synchronous rectification using two MOSFETS reduces power dissipation and increases efficiency when compared to converters using external diodes. Internal shoot-through current limiting circuit further reduces power dissipation. (2) Current Mode PWM Control The PWM control signal of this IC depends on two feedback loops, the voltage feedback and the inductor current feedback. (a) PWM (Pulse Width Modulation) Control The clock signal coming from OSC has a frequency of 1MHz. When OSC sets the RS latch, the P-Channel MOSFET is turned ON and the N-Channel MOSFET is turned OFF, causing an inductor current IL to increase. The opposite happens when the current comparator (Current Comp) resets the RS latch i.e. the P-Channel MOSFET is turned OFF and the N-Channel MOSFET is turned ON. Current Comp's output is a comparison of two signals, the current feedback control signal "SENSE" which is a voltage proportional to the current IL and the voltage feedback control signal, FB. (b) SLLMTM (Simple Light Load Mode) Control When the control mode is shifted by PWM from heavier load to the one for lighter load or vice versa, the switching pulse is designed to turn OFF with the device held operating in normal PWM control loop. This allows linear operation without voltage drop or deterioration in transient response during sudden load changes. . Although the PWM control loop continues to operate with a SET signal from OSC and a RESET signal from Current Comp, it is designed such that the RESET signal is kept constant when shifted to the light load mode where the switching is tuned OFF and the switching pulses disappear. Activating the switching discontinuously reduces the switching dissipation and improves the efficiency. SENSE Current Comp RESET VOUT Level Shift R Q FB SET S Gm Amp IL Driver Logic VOUT SW Load RITH OSC Figure 22. Diagram of Current Mode PWM Control PVCC Current Comp SENSE PVCC SENSE Current Comp FB FB SET GND SET GND RESET GND RESET GND SW GND SW IL GND IL(AVE) IL 0A VOUT VOUT(AVE) VOUT VOUT(AVE) Not switching Figure 23. PWM Switching Timing Chart www.rohm.com (c)2012 ROHM Co., Ltd. All rights reserved. TSZ2211115001 Figure 24. SLLMTM Switching Timing Chart 10/24 TSZ02201-0J3J0AJ00120-1-2 02.Oct.2014 Rev.002 BD9123MUV Datasheet 2. Description of Functions (1) Soft-Start Function When EN terminal is shifted to "High" activates a soft-starter to gradually establish the output voltage with the current being limited during startup. It prevents an overshoot of output voltage and an inrush current. The slope of input signal is different and the soft start time is different depending on the value offset output voltage. When set to 1V ,tSS=1msec(Typ) VCC,EN 1.2V 0.85V VOUT tSS [ms] tSS' Figure 25. Soft-Start Action (2) Shutdown Function When EN terminal is shifted to "Low", the device turns to Standby Mode, and all the functional blocks including reference voltage circuit, internal oscillator and drivers are turned to OFF. Circuit current during standby is 0A(Typ). (3) UVLO Function It detects whether the input voltage supplied is sufficient to secure the output voltage of this IC. A hysteresis of 50mV (Typ) is designed to prevent output chattering. Hysteresis 50mV Vcc EN VOUT tss Soft start Standby Mode tss tss Operating Mode UVLO Standby Mode Operating Mode UVLO Standby Mode EN Standby Mode Operating Mode UVLO Figure 26. Soft-Start, Shutdown, UVLO Timing Chart (4) PGOOD Function When the output voltage falls below 75% (Typ) of a set value, the output of an Open-Drain PGOOD pin is turned OFF. A hysteresis width of 15% (Typ) is designed to prevent output chattering. VOUT 90% The hysteresis width 75% tGP PGOOD Figure 27. PGOOD Timing Chart www.rohm.com (c)2012 ROHM Co., Ltd. All rights reserved. TSZ2211115001 11/24 TSZ02201-0J3J0AJ00120-1-2 02.Oct.2014 Rev.002 BD9123MUV Datasheet 3. About Setting the Output Voltage Output voltage shifts step by step as often as bit setting to control the overshoot/undershoot that occurs when changing the of output voltage value. 8 steps (max) delay will occur from the bit switching until output voltage reach to setting value. (0,0,1) VID<2:0> (1,1,1) 1.2V 0.85V VOUT tVID (max)=0.06ms (a) Switching 3 bit synchronously (b) Switching 3 bit with the time lag V2D2 VID<2> 1 VID<1> 0 VID<0> Count STOP Count STOP VOUT VOUT About 10s from bit switching 5s(max) About 10s from bit switching (c) Switching 3 bit with the time lag VID<2> VID<1> VID<0> Count STOP VOUT About 10s from switching the last bit Figure 28. Timing Chart of Setting the Output voltage It is possible to set output voltage, shown in diagram 1 below, by setting VID<0> to <2> 0 or 1. VID<2:0> terminal is set to VID<2:0>=(0,0,0) originally by the pull down resistor while in high impedance inside IC. By pulling up/ pulling down about 10k, the original value can be changed optionally. Table of output voltage setting VID<2> VID<1> VID<0> VOUT 0 0 0 1.0V 0 0 1 0.85V 0 1 0 0.9V 0 1 1 0.95V 1 0 0 1.05V 1 0 1 1.1V 1 1 0 1.15V 1 1 1 1.2V (Note) After 10s(max) from the bit change, VOUT change starts. Requiring time for one step (50 mV shift) of VOUT is 5s(max). From the bit switching until output voltage reach to setting value, tVID(max)=0.06ms delay will occur. www.rohm.com (c)2012 ROHM Co., Ltd. All rights reserved. TSZ2211115001 12/24 TSZ02201-0J3J0AJ00120-1-2 02.Oct.2014 Rev.002 BD9123MUV Datasheet (1) Short-Current protection circuit with time delay function It turns OFF the output to protect the IC from breakdown when the incorporated current limiter is activated continuously for the fixed time (tLATCH) or more. The output may be recovered from OFF state by restarting EN or by re-unlocking UVLO. VCC Output voltage OFF Latch Output Short circuit Threshold Voltage VOUT IL Limit IL t1<tLATCH Output voltage OFF t2=tLATCH Operated mode Output voltage OFF Timer Latch UVLO Operated mode UVLO Figure 29. Short-current protection circuit with time delay timing chart 4. Information on Advantages Advantage 1: Offers fast transient response with current mode control system. Conventional product (Load response IO=0.1A to 0.6A) BD9123MUV (Load response IO=0.6A to 0.1A) VOUT VOUT 37mV 27mV IOUT IOUT Figure 30. Comparison of Transient Response Advantage 2: Offers High Efficiency for all Load Range. (a) For lighter load: Utilizes the current mode control called SLLMTM for lighter load, which reduces various dissipations such as switching dissipation (PSW), gate charge/discharge dissipation (PGATE), ESR dissipation of output capacitor (PESR) and ON-Resistance dissipation (PRON) that may otherwise cause degradation in efficiency for lighter load. Achieves Efficiency Improvement for Lighter Load. (b) For heavier load: Utilizes the synchronous rectifying mode and the low ON-Resistance MOS FETs incorporated as power transistor. Achieves Efficiency Improvement for Heavier Load. Offers high efficiency for all load range with the improvements mentioned above. 100 SLLM Efficiency [%] ON-Resistance of Pch side MOS FET : 0.35m(Typ) ON-Resistance of Nch side MOS FET : 0.25m(Typ) 50 PWM improvement by SLLM system improvement by synchronous rectifier 0 0.001 0.01 0.1 Output current IOUT[A] 1 Figure 31. Efficiency www.rohm.com (c)2012 ROHM Co., Ltd. All rights reserved. TSZ2211115001 13/24 TSZ02201-0J3J0AJ00120-1-2 02.Oct.2014 Rev.002 BD9123MUV Datasheet Advantage 3: (a) Supplied in smaller package due to small-sized power MOS FET incorporated. Output capacitor Co required for current mode control: 10F ceramic capacitor Inductor L required for the operating frequency of 1 MHz: 4.7H inductor Reduces a Mounting Area Requirement. VCC VCC 20mm RPGOOD Rf L CIN Co DC/DC Convertor L VOUT RITH Cf CIN RPGOOD 15mm CO RITH CITH CITH Figure 32. Example of Application 5. Switching Regulator Efficiency Efficiency may be expressed by the equation shown below: VOUT IOUT P POUT 100 OUT 100 100 VIN LIN PIN POUT Pd % Efficiency may be improved by reducing the switching regulator power dissipation factors Pd as follows: Dissipation factors: (1) ON-Resistance Dissipation of Inductor and FET: Pd(I2R) Pd( I 2 R) I OUT 2 ( RCOIL RON ) Where: RCOIL is the DC resistance of inductor. RON is the ON-Resistance of FET. IOUT is the output current. (2) Gate Charge/Discharge Dissipation: Pd(Gate) Pd (Gate) C gs f V 2 Where: Cgs is the gate capacitance of FET. f is the switching frequency. V is the gate driving voltage of FET. (3) Switching Dissipation: Pd(SW) Pd ( SW ) VIN 2 CRSS IOUT f I DRIVE Where: CRSS is the reverse transfer capacitance of FET. IDRIVE is the peak current of gate. (4) ESR Dissipation of Capacitor: Pd(ESR) Pd( ESR) I RMS 2 ESR Where: IRMS is the ripple current of capacitor. ESR is the equivalent series resistance. (5) Operating Current Dissipation of IC: Pd(IC) Pd( IC) VIN ICC Where: ICC is the circuit current. www.rohm.com (c)2012 ROHM Co., Ltd. All rights reserved. TSZ2211115001 14/24 TSZ02201-0J3J0AJ00120-1-2 02.Oct.2014 Rev.002 BD9123MUV Datasheet 6. Consideration on Permissible Dissipation and Heat Generation As this IC functions with high efficiency without significant heat generation in most applications, no special consideration is needed on permissible dissipation or heat generation. In case of extreme conditions, however, including lower input voltage, higher output voltage, heavier load, and/or higher temperature, the allowable dissipation and/or heat generation must be carefully considered. For dissipation, only conduction losses due to DC resistance of inductor and ON-Resistance of FET are considered. The reason is that the conduction losses are considered to play the leading role among other dissipation mentioned above including gate charge/discharge dissipation and switching dissipation. 4 layers (Copper foil area : 5505mm2) copper foil in each layers. j-a=47.0C/W 4 layers (1st and 4th copper foil area : 6.28m2) (2nd and 3rd copper foil area: 5505m2) (copper foil in each layers) j-a=70.62C/W 1 layer (Copper foil area : 6.28m2) j-a=201.6C/W IC only. j-a=462.9C/W Power dissipation: Pd [W] 4.0 3.0 2.66W 2.0 1.0 1.77W P I OUT 2 RON RON D RONH 1 D RONL 0.62W 0.27W 0 0 25 50 75 100 105 125 150 Ambient temperature:Ta [C] Where: D is the ON duty (=VOUT/VCC). RONH is the ON-Resistance of Highside MOSFET. RONL is the ON-Resistance of Lowside MOSFET. IOUT is the Output current. Figure 33. Thermal Derating Curve (VQFN016V3030) If VCC=5V, VOUT=1.2V, RONP=0.35m, RONN=0.25m IOUT=1.2A, for example, D=VOUT/VCC=1.2/5=0.24 RON=0.24x0.35+(1-0.24)x0.25 =0.084+0.19 =0.274[] P=1.22x0.274=0.394[W] As RONP is greater than RONN in this IC, the dissipation increases as the ON time becomes greater. With the consideration on the dissipation as mentioned above, thermal design must be carried out with sufficient margin allowed. www.rohm.com (c)2012 ROHM Co., Ltd. All rights reserved. TSZ2211115001 15/24 TSZ02201-0J3J0AJ00120-1-2 02.Oct.2014 Rev.002 BD9123MUV Datasheet 7. Selection of Components Externally Connected (1) Selection of Inductor (L) The inductance significantly depends on output ripple current. As seen in equation (1), the ripple current decreases as the inductor and/or switching frequency increases. IL IL I L VCC VOUT VOUT A L VCC f VCC (1) Appropriate ripple current at output should be 30% more or less of the maximum output current. IL I L 0.3 I OUTMax VOUT L L Co [ A] VCC VOUT VOUT (2) H I L VCC f (3) Where: IL is the Output ripple current, and f is the Switching frequency. Figure 34. Output ripple current Note: Current exceeding the current rating of the inductor results in magnetic saturation of the inductor, which decreases efficiency. The inductor must be selected allowing sufficient margin with which the peak current may not exceed its current rating. If VCC=5.0V, VOUT=1.2V, f=1MHz, IL=0.3x1.2A=0.36A, for example, L 5 1.21.2 2.53 4.7 0.6 5 1M H Note: Select the inductor with low resistance component (such as DCR and ACR) to minimize dissipation in the inductor for better efficiency. (2) Selection of Output Capacitor (CO) Output capacitor should be selected in consideration with the stability region and the equivalent series resistance required to smoothen the ripple voltage. VCC Output ripple voltage is determined by the equation (4): VOUT I L ESR V (4) Where: IL is the Output ripple current, and ESR is the Equivalent series resistance of output capacitor. VOUT L ESR CO Note:Rating of the capacitor should be determined allowing sufficient margin against output voltage. A 10F to 100F ceramic capacitor is recommended. Figure 35. Output Capacitor Less ESR allows reduction in output ripple voltage. (3) Selection of Input Capacitor (CIN) The input capacitor to be selected must have sufficiently low ESR to cope with high ripple current to prevent high transient voltage. The ripple current IRMS is given by the equation (5): VCC CIN IRMS IOUT VOUT L VOUT VCC VOUT < Worst case > IRMSMax Co When VCC=2xVOUT, VCC IRMS [ A ] (5) IOUT 2 If VCC=5V, VOUT=1.2V, and IOUTMax=1.2A, IRMS= 1.25 1.2 ARMS 0.51 5 A low ESR 10F/10V ceramic capacitor is recommended to reduce ESR dissipation of input capacitor for better efficiency. Figure 36. Input Capacitor www.rohm.com (c)2012 ROHM Co., Ltd. All rights reserved. TSZ2211115001 I RMS 1.2 16/24 TSZ02201-0J3J0AJ00120-1-2 02.Oct.2014 Rev.002 BD9123MUV Datasheet (4) Determination of RITH, CITH that works as a phase compensator As the Current Mode Control is designed to limit the inductor current, a pole (phase lag) appears in the low frequency area due to a CR filter consists of an output capacitor and a load resistance, while a zero (phase lead) appears in the high frequency area due to the output capacitor and its ESR. So, the phases are easily compensated by adding a zero to the power amplifier output with C and R as described below to cancel a pole at the power amplifier. fp(Min) 1 fp A 2 RO CO fp(Max) Gain [dB] f Z ESR 0 fZ(ESR) IOUTMin Phase [deg] IOUTMax Pole at power amplifier When the output current decreases, the load resistance Ro increases and the pole frequency lowers. 0 -90 fpMin Figure 37. Open Loop Gain Characteristics fpMax A 1 2 ESR CO 1 2 ROMax CO 1 2 ROMin CO Hz with lighterload Hz with heavier load Zero at Power Amplifier Increasing capacitance of the output capacitor lowers the pole frequency while the zero frequency does not change. (This is because when the capacitance is doubled, the capacitor ESR is reduced to half.) fZ(Amp) Gain [dB] 0 1 f Z Amp 0 Phase [deg] -90 2 RITH CITH Figure 38. Error Amp Phase Compensation Characteristics VCC VCC RPG CIN VCC,PVCC EN VOUT VID<2:0> VOUT PGOOD L VID<2:0) ITH GND,PGND VOUT SW RITH CO CITH Figure 39. Typical Application Stable feedback loop may be achieved by canceling the pole fp (Min) produced by the output capacitor and the load resistance with CR zero correction by the error amplifier. f Z Amp fpMin 1 1 2 R ITH C ITH 2 RO Max CO www.rohm.com (c)2012 ROHM Co., Ltd. All rights reserved. TSZ2211115001 17/24 TSZ02201-0J3J0AJ00120-1-2 02.Oct.2014 Rev.002 BD9123MUV Datasheet 8. Cautions on PC Board Layout Figure 40. Layout Diagram (1) Lay out the input ceramic capacitor CIN close to the pins PVCC and PGND, and the output capacitor Co close to pin PGND. (2) Lay out CITH and RITH between the pins ITH and GND as near as possible with least necessary wiring. Note: VQFN016V3030 has thermal PAD on the reverse of the package. The package thermal performance may be enhanced by bonding the PAD to GND plane which take a large area of PCB. 9. Recommended Components Lists on Above Application Symbol Value Manufacturer Coil 4.7H TDK VLF5014S-4R7M1R7 CIN Ceramic Capacitor 10F KYOCERA CM316X5R106M10A CO Ceramic Capacitor 22F KYOCERA CM316B226M06A CITH Ceramic Capacitor 1500pF Murata GRM18 Series RITH Resistance 9.1k ROHM MCR03 Series Cf Ceramic Capacitor 0.1F Murata GRM18 Series Rf Resistance 100 ROHM MCR03 Series L Part Series Note: The parts list presented above is an example of recommended parts. Although the parts are standard, actual circuit characteristics should be checked carefully on your application before use. Be sure to allow sufficient margins to accommodate variations between external devices and this IC when employing the depicted circuit with other circuit constants modified. Both static and transient characteristics should be considered in establishing these margins. When switching noise is substantial and may impact the system, a low pass filter should be inserted between the VCC and PVCC pins, and a Schottky Barrier diode or snubber connected between the SW and PGND pins. www.rohm.com (c)2012 ROHM Co., Ltd. All rights reserved. TSZ2211115001 18/24 TSZ02201-0J3J0AJ00120-1-2 02.Oct.2014 Rev.002 BD9123MUV Datasheet I/O Equivalent Circuit BD9123MUV EN pin SW pin PVCC EN PVCC PVCC SW VOUT pin ITH pin VCC VOUT ITH PGOOD VID2:0 pin PGOOD VID2:0 Figure 41. I/O Equivalent Circuit www.rohm.com (c)2012 ROHM Co., Ltd. All rights reserved. TSZ2211115001 19/24 TSZ02201-0J3J0AJ00120-1-2 02.Oct.2014 Rev.002 BD9123MUV Datasheet Operational Notes 1. Reverse Connection of Power Supply Connecting the power supply in reverse polarity can damage the IC. Take precautions against reverse polarity when connecting the power supply, such as mounting an external diode between the power supply and the IC's power supply pins. 2. Power Supply Lines Design the PCB layout pattern to provide low impedance supply lines. Separate the ground and supply lines of the digital and analog blocks to prevent noise in the ground and supply lines of the digital block from affecting the analog block. Furthermore, connect a capacitor to ground at all power supply pins. Consider the effect of temperature and aging on the capacitance value when using electrolytic capacitors. 3. Ground Voltage Ensure that no pins are at a voltage below that of the ground pin at any time, even during transient condition. 4. Ground Wiring Pattern When using both small-signal and large-current ground traces, the two ground traces should be routed separately but connected to a single ground at the reference point of the application board to avoid fluctuations in the small-signal ground caused by large currents. Also ensure that the ground traces of external components do not cause variations on the ground voltage. The ground lines must be as short and thick as possible to reduce line impedance. 5. Thermal Consideration Should by any chance the power dissipation rating be exceeded the rise in temperature of the chip may result in deterioration of the properties of the chip. In case of exceeding this absolute maximum rating, increase the board size and copper area to prevent exceeding the Pd rating. 6. Recommended Operating Conditions These conditions represent a range within which the expected characteristics of the IC can be approximately obtained. The electrical characteristics are guaranteed under the conditions of each parameter. 7. Inrush Current When power is first supplied to the IC, it is possible that the internal logic may be unstable and inrush current may flow instantaneously due to the internal powering sequence and delays, especially if the IC has more than one power supply. Therefore, give special consideration to power coupling capacitance, power wiring, width of ground wiring, and routing of connections. 8. Operation Under Strong Electromagnetic Field Operating the IC in the presence of a strong electromagnetic field may cause the IC to malfunction. 9. Testing on Application Boards When testing the IC on an application board, connecting a capacitor directly to a low-impedance output pin may subject the IC to stress. Always discharge capacitors completely after each process or step. The IC's power supply should always be turned off completely before connecting or removing it from the test setup during the inspection process. To prevent damage from static discharge, ground the IC during assembly and use similar precautions during transport and storage. 10. Inter-pin Short and Mounting Errors Ensure that the direction and position are correct when mounting the IC on the PCB. Incorrect mounting may result in damaging the IC. Avoid nearby pins being shorted to each other especially to ground, power supply and output pin. Inter-pin shorts could be due to many reasons such as metal particles, water droplets (in very humid environment) and unintentional solder bridge deposited in between pins during assembly to name a few. www.rohm.com (c)2012 ROHM Co., Ltd. All rights reserved. TSZ2211115001 20/24 TSZ02201-0J3J0AJ00120-1-2 02.Oct.2014 Rev.002 BD9123MUV Datasheet Operational Notes - continued 11. Unused Input Pins Input pins of an IC are often connected to the gate of a MOS transistor. The gate has extremely high impedance and extremely low capacitance. If left unconnected, the electric field from the outside can easily charge it. The small charge acquired in this way is enough to produce a significant effect on the conduction through the transistor and cause unexpected operation of the IC. So unless otherwise specified, unused input pins should be connected to the power supply or ground line. 12. Regarding the Input Pin of the IC This monolithic IC contains P+ isolation and P substrate layers between adjacent elements in order to keep them isolated. P-N junctions are formed at the intersection of the P layers with the N layers of other elements, creating a parasitic diode or transistor. For example (refer to figure below): When GND > Pin A and GND > Pin B, the P-N junction operates as a parasitic diode. When GND > Pin B, the P-N junction operates as a parasitic transistor. Parasitic diodes inevitably occur in the structure of the IC. The operation of parasitic diodes can result in mutual interference among circuits, operational faults, or physical damage. Therefore, conditions that cause these diodes to operate, such as applying a voltage lower than the GND voltage to an input pin (and thus to the P substrate) should be avoided. Resistor Transistor (NPN) Pin A Pin B C E Pin A N P+ P N N P+ N Pin B B N Parasitic Elements P+ N P N P+ B N C E Parasitic Elements P Substrate P Substrate GND GND Parasitic Elements GND Parasitic Elements GND N Region close-by Figure 42. Example of monolithic IC structure 13. Thermal Shutdown Circuit(TSD) This IC has a built-in thermal shutdown circuit that prevents heat damage to the IC. Normal operation should always be within the IC's power dissipation rating. If however the rating is exceeded for a continued period, the junction temperature (Tj) will rise which will activate the TSD circuit that will turn OFF all output pins. When the Tj falls below the TSD threshold, the circuits are automatically restored to normal operation. Note that the TSD circuit operates in a situation that exceeds the absolute maximum ratings and therefore, under no circumstances, should the TSD circuit be used in a set design or for any purpose other than protecting the IC from heat damage. 14. Selection of Inductor It is recommended to use an inductor with a series resistance element (DCR) 0.1 or less. Especially, note that use of a high DCR inductor will cause an inductor loss, resulting in decreased output voltage. Should this condition continue for a specified period (soft start time + timer latch time), output short circuit protection will be activated and output will be latched OFF. When using an inductor over 0.1, be careful to ensure adequate margins for variation between external devices and this IC, including transient as well as static characteristics. Furthermore, in any case, it is recommended to start up the output with EN after supply voltage is within. www.rohm.com (c)2012 ROHM Co., Ltd. All rights reserved. TSZ2211115001 21/24 TSZ02201-0J3J0AJ00120-1-2 02.Oct.2014 Rev.002 BD9123MUV Datasheet Ordering Information B D 9 1 2 Part Number 3 M U V Package MUV : VQFN016V3030 E2 Packaging and forming specification E2: Embossed tape and reel Marking Diagram VQFN016V3030 (TOP VIEW) Part Number Marking D 9 1 2 LOT Number 3 1PIN MARK www.rohm.com (c)2012 ROHM Co., Ltd. All rights reserved. TSZ2211115001 22/24 TSZ02201-0J3J0AJ00120-1-2 02.Oct.2014 Rev.002 BD9123MUV Datasheet Physical Dimension, Tape and Reel Information Package Name www.rohm.com (c)2012 ROHM Co., Ltd. All rights reserved. TSZ2211115001 VQFN016V3030 23/24 TSZ02201-0J3J0AJ00120-1-2 02.Oct.2014 Rev.002 BD9123MUV Datasheet Revision History Date Revision 02.Mar.2012 02.Oct.2014 001 002 Changes New Release Applied the ROHM Standard Style and improved understandability. www.rohm.com (c)2012 ROHM Co., Ltd. All rights reserved. TSZ2211115001 24/24 TSZ02201-0J3J0AJ00120-1-2 02.Oct.2014 Rev.002 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 CLASS CLASSb CLASS CLASS CLASS CLASS 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 (Pd) depending on Ambient temperature (Ta). When used in sealed area, confirm the actual ambient 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 - GE (c) 2014 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 QR code 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 our Products might fall under controlled goods prescribed by the applicable foreign exchange and foreign trade act, please consult with ROHM representative 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. ROHM shall not be in any way responsible or liable for infringement of any intellectual property rights or other damages arising from use of such information or data.: 2. 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 information contained in this document. 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 - GE (c) 2014 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 (c) 2014 ROHM Co., Ltd. All rights reserved. Rev.001 Mouser Electronics Authorized Distributor Click to View Pricing, Inventory, Delivery & Lifecycle Information: ROHM Semiconductor: BD9123MUV-E2