Single-chip Type with Built-in FET Switching Regulator Series Output 1.0A High-efficiency Step-down Switching regulators with Built-in Power MOSFET BU90002GWZ, BU90003GWZ, BU90004GWZ, BU90005GWZ, BU90006GWZ, No.11xxxEATxx ●Description The BU9000XGWZ are a high efficiency 6MHz synchronous step-down switching regulator with ultra low current PFM mode. It provides up to 1.0A load current and an input voltage range from 3.0V to 5.5V, optimized for battery powered portable applications. BU9000XGWZ has a mode control pin that allows the user to select Forced PWM(Pulse Width Modulation)mode or PFM(Pulse Frequency Modulation) and PWM auto change mode utilized power save operation at light load current. ●Features 1) 93% peak efficiency 2) 4 to 6 MHz switching frequency 3) Input voltage VIN=2.3V to 5.5V(BU90003～BU90006), VIN=4.0V to 5.5V (BU90002) 4) 45uA typical quiescent current 5) Fast transient response 6) Automatic PFM/PWM operation 7) Forced PWM operation 8) Internal Soft Start 9) Under voltage lockout 10) Over current protection 11) Thermal shutdown 12) Ultra small and low profile WLCSP (1.3mm×0.9mm t=0.40mm MAX) (UCSP35L1 ) ●Applications Cell phones, Smart phones, Portable applications and Micro DC/DC modules, USB accessories ●Operating range Part No. Output voltage Input voltage BU90002GWZ 3.30V 4.0V to 5.5V BU90003GWZ 1.20V 2.3V to 5.5V BU90004GWZ 1.80V 2.3V to 5.5V BU90005GWZ 2.50V 2.3V to 5.5V BU90006GWZ 3.00V 2.3V to 5.5V www.rohm.com © 2011 ROHM Co., Ltd. All rights reserved. 1/14 Target spec. ver.1.7 BU90002GWZ, BU90003GWZ, BU90004GWZ, BU90005GWZ, BU90006GWZ Technical Note ●Absolute maximum ratings Parameter Maximum input power supply voltage Symbol Rating Unit VIN 7 V VEN, VFB, VLX, VMODE 7 V Pd 0.39(*1) W Operating temperature range Topr -40 ～ +85 ℃ Storage temperature range Tstg -55 ～ +125 ℃ Tjmax +125 ℃ Maximum voltage at EN, FB, LX, MODE Power dissipation Junction temperature (*1) When mounted on the specified PCB (55mm x 63mm), Deducted by 3.9m W/c when used over Ta=25c ●Operating conditions Ta=25c, VIN=3.6V(BU90003GWZ～ ～BU90006GWZ),VIN=5.0V(BU90002GWZ) Rating Item Symbol Unit Condition Min. Typ. Max. 【Switching regulator】 MODE:H(PWM Operation) -2 +2 VOUTA % MODE:L(PWM/PFM Operation) -2 +3 Output voltage accuracy 3.0V≦VIN＜5.5V IoutMax1 1.0 A IoutMax2 IoutMax3 - - 0.8 0.6 A A Tss 65 120 240 usec 5.4 6.0 6.6 MHz 4.8 5.4 6.0 MHz 3.6 4.0 4.4 MHz - 250 300 220 250 400 450 350 380 mOhm mOhm mOhm mOhm 2.7V≦VIN＜3.0V 2.3V≦VIN＜2.7V 【Soft start】 Soft start time 【Frequency control】 Switching frequency fosc No load BU90002GWZ,BU90005GWZ BU90006GWZ No load BU90004GWZ No load BU90003GWZ 【Driver】 RonP1 RonP2 RonN1 RonN2 PchFET on resistance NchFET on resistance 【Control】 EN pin control voltage - VIN=5.0V VIN=3.6V VIN=5.0V VIN=3.6V Operation VENH 1.4 - VIN V Non Operation VENL 0 - 0.4 V Operation VMODEH 1.4 - VIN V Forced PWM Non Operation VMODEL 0 - 0.4 V Automatic PFM/PWM Protect threshold voltage Hysteresis 【Current limit】 Uvth Uvhy 1.95 50 2.05 100 2.15 150 V mV Current limit threshold ILIMIT 1.5 1.7 1.9 A 【Output discharge】 Output discharge resistance 【Circuit current】 DRES 55 110 220 Ohm Operating quiescent current IINS - 45 65 uA Shutdown current SHD - 0 1 uA MODE pin control voltage 【UVLO】 PMOS current detect, Open loop EN=0V EN:H, MODE:L, VOUT=3.6V forced Not switching EN=0V ○No design for durability against radiation www.rohm.com © 2011 ROHM Co., Ltd. All rights reserved. 2/14 Target spec. ver.1.7 BU90002GWZ, BU90003GWZ, BU90004GWZ, BU90005GWZ, BU90006GWZ Technical Note ●Electrical characteristic curves (Reference data) L:LQM21MPN1R0NG0 (2.0mm×1.6mm×1.0mm Murata) COUT:GRM155R60J475M(1.0mm×0.5mm×0.5mm Murata) BU90002GWZ（ （3.3V OUTPUT） ） EN 2V/div EN 2V/div VOUT 2V/div VOUT 1V/div 20us IL 500mA/div 100us Fig.1 Start up Fig.2 Shut down Vout 50mV/div ac coupled Vout 50mV/div ac coupled 10us 4us IOUT 200mA/div IOUT 50mA/div Fig.3 Load transient response 5mA to 50mA tr=tf=100ns, Mode :Low Fig.4 Load transient response 50mA to 350mA tr=tf=100ns, Mode :Low Vout 20mV/div ac coupled Vout 50mV/div ac coupled 400ns 4us LX 5V/div IOUT 200mA/div IL 500mA/div Fig.5 Load transient response 150mA to 500mA tr=tf=100ns, Mode :High www.rohm.com © 2011 ROHM Co., Ltd. All rights reserved. 3/14 Fig.6 PFM mode Operation Iout=40mA Target spec. ver.1.7 BU90002GWZ, BU90003GWZ, BU90004GWZ, BU90005GWZ, BU90006GWZ Technical Note ●Electrical characteristic curves (Reference data) – Continued BU90002GWZ（ （3.3V OUTPUT） ） MODE 1V/div Vout 20mV/div ac coupled 4us 80ns LX 5V/div Vout 20mV/div ac coupled IL 500mA/div LX 500mA/div Fig.7 PFM mode Operation Iout=100mA Fig.8 Mode Change Response MODE High to Low 100 4us 95 MODE 2V/div Efficiency[%] 90 Vout 20mV/div ac coupled 85 80 75 70 65 LX 500mA/div 60 1 10 100 1000 Load current[mA] Fig.10 Efficiency vs Load current VIN=5V PWM/PFM Auto Mode 3.38 30 3.37 25 Vout Ripple Voltage[mV] Voltage[V] Fig.9 Mode Change Response MODE Low to High 3.36 3.35 Output 3.34 3.33 3.32 3.31 20 15 10 5 0 0 200 400 600 800 1000 0 Load current[mA] 400 600 800 1000 Load current[mA] Fig.11 Load regulation VIN=5V PWM/PFM Auto mode www.rohm.com © 2011 ROHM Co., Ltd. All rights reserved. 200 Fig.12 Vout Ripple Voltage VIN=5V PWM/PFM Auto Mode 4/14 Target spec. ver.1.7 BU90002GWZ, BU90003GWZ, BU90004GWZ, BU90005GWZ, BU90006GWZ Technical Note ●Electrical characteristic curves (Reference data) BU90003GWZ(1.2V OUTPUT) EN 2V/div EN 2V/div VOUT 500mV/div VOUT 1V/div 40us 100us IL 200mA/div Fig.13 Start up Fig.14 Shut down Vout 50mV/div 1.2V offset Vout 50mV/div 1.2V offset 10us 4us IOUT 200mA/div IOUT 200mA/div Fig.15 Load transient response 5mA to 200mA tr=tf=100ns, Mode :Low Fig.16 Load transient response 50mA to 350mA tr=tf=100ns, Mode :Low Vout 20mV/div ac coupled 4us Vout 50mV/div ac coupled 400ns LX 2V/div IOUT 500mA/div IL 500mA/div Fig.17 Load transient response 400mA to 1000mA tr=tf=100ns, Mode :Low www.rohm.com © 2011 ROHM Co., Ltd. All rights reserved. 5/14 Fig.18 PFM mode Operation Iout=50mA Target spec. ver.1.7 BU90002GWZ, BU90003GWZ, BU90004GWZ, BU90005GWZ, BU90006GWZ Technical Note ●Electrical characteristic curves (Reference data) – Continued BU90003GWZ(1.2V OUTPUT) MODE 2V/div Vout 50mV/div ac coupled 2us 80ns Vout 50mV/div ac coupled LX 2V/div LX 200mA/div IL 500mA/div Fig.19 PWM mode Operation Iout=100mA Fig.20 Mode Change Response MODE High to Low 100 90 2us 80 MODE 2V/div Efficiency[%] 70 Vout 50mV/div ac coupled 60 50 40 VIN=2.7V 30 VIN=3.6V 20 LX 200mA/div VIN=4.2V 10 0 0.1 1 10 100 1000 Load current[mA] Fig.22 Efficiency vs Load current VIN=3.6V PWM/PFM Auto Mode Fig.21 Mode Change Response MODE Low to High 1.224 VIN=2.7V VIN=3.6V 1.212 Vout[V] VIN=4.2V 1.2 1.188 1.176 1 10 100 1000 Iout[mA] Fig.23 Load regulation PWM/PFM Auto mode www.rohm.com © 2011 ROHM Co., Ltd. All rights reserved. 6/14 Target spec. ver.1.7 BU90002GWZ, BU90003GWZ, BU90004GWZ, BU90005GWZ, BU90006GWZ Technical Note ●Electrical characteristic curves (Reference data) BU90004GWZ(1.80V OUTPUT) EN 5V/div EN 5V/div VOUT 1V/div VOUT 1V/div 40us 100us IL 200mA/div Fig.25 Shut down Fig.24 Start up Vout 50mV/div ac coupled Vout 50mV/div ac coupled 4us 4us IOUT 200mA/div IOUT 200mA/div Fig. 26 Load transient response 5mA to 200mA tr=tf=100ns, Mode :Low Vout 50mV/div ac coupled Fig.27 Load transient response 50mA to 350mA tr=tf=100ns, Mode :Low 4us Vout 50mV/div ac coupled 400ns LX 2V/div IOUT 200mA/div Fig.28 Load transient response 200mA to 600mA tr=tf=100ns, Mode :Low www.rohm.com © 2011 ROHM Co., Ltd. All rights reserved. 7/14 Fig.29 PFM mode Operation Iout=50mA Target spec. ver.1.7 BU90002GWZ, BU90003GWZ, BU90004GWZ, BU90005GWZ, BU90006GWZ Technical Note ●Electrical characteristic curves (Reference data) – Continued BU90004GWZ(1.80V OUTPUT) Vout 20mV/div ac coupled MODE 5V/div 80ns 4us Vout 50mV/div ac coupled LX 2V/div LX 200mA/div Fig.30 PWM mode Operation Iout=100mA MODE 5V/div Fig.31 Mode Change Response MODE High to Low Efficiency[%] 2us Vout 50mV/div ac coupled LX 200mA/div 100 90 80 70 60 50 40 30 20 10 0 VIN=2.7V VIN=3.6V VIN=4.2V 0.1 1 10 100 1000 Load current[mA] Fig.32 Mode Change Response MODE Low to High Fig.33 Efficiency vs Load current VIN=3.6V PWM/PFM Auto Mode 1.836 Vout[V] 1.818 1.8 VIN=3.6V VIN=2.7V 1.782 VIN=4.2V 1.764 0.1 1 10 100 1000 Load Current[mA] Fig.34 Load regulation PWM/PFM Auto mode www.rohm.com © 2011 ROHM Co., Ltd. All rights reserved. 8/14 Target spec. ver.1.7 BU90002GWZ, BU90003GWZ, BU90004GWZ, BU90005GWZ, BU90006GWZ Technical Note ●Block diagram /Application circuit L ： PWM/PFM MODE H ： PWM MODE MODE B1 TSD UVLO FB VIN A1 PWM/PFM control 2.3～5.5V B3 VOUT EN + ERROR COMP Switching Control Logic and Gate Driver 1.5～0.47uH B2 VOUT 4.7uF LX VREF EN H ： ON L ： OFF A2 SHUTDOWN Frequency control A3 GND ●External dimensions ●Pin layout (BOTTOM VIEW) B1 MODE B2 LX B3 FB A1 VIN A2 EN A3 GND ●Pin number/Name/Functions Pin No. www.rohm.com © 2011 ROHM Co., Ltd. All rights reserved. 9/14 Name Function A1 VIN Power supply input pin A2 EN Enable pin A3 GND B1 MODE Forced PWM mode pin GND pin B2 LX Inductor connection pin B3 FB Feedback voltage input pin Target spec. ver.1.7 BU90002GWZ, BU90003GWZ, BU90004GWZ, BU90005GWZ, BU90006GWZ Technical Note ●Functional descriptions The BU9000XGWZ are a synchronous step-down DC/DC converter that achieves fast transient response from light load to heavy load by hysteretic PWM control system and current constant PFM control system. ○PWM control BU9000XGWZ operates by hysteretic PWM control. This scheme ensures fast switching, high efficiency, and fast transient response. When the output voltage is below the VREF voltage, the error comparator output is low to high and turning on P-channel MOSFET until above the VREF voltage and minimum on time. ○PFM control At light load the regulator and MODE=low, the regulator operates with reduced switching frequency and improves the efficiency. During PFM operation, the output voltage slightly higher than typical output voltage. output PWM mode voltage PFM (constant current)Threshold. turn off Pch FET PFM Threshold. turn on PFET PFM Mode at Light Load PWM Mode at Moderate to Heavy Loads Fig. Operation of PFM mode and PWM mode www.rohm.com © 2011 ROHM Co., Ltd. All rights reserved. 10/14 Target spec. ver.1.7 BU90002GWZ, BU90003GWZ, BU90004GWZ, BU90005GWZ, BU90006GWZ Technical Note ●Description of operations 1) Shutdown If the EN input pin set to low (<0.4V), all circuit are shut down and the regulator is standby mode. Do not leave the EN pin floating. 2) Soft start function The regulator has a soft start circuit that reduces in-rush current at start-up. Typical start up times with a 4.7uF output capacitor is 120usec. 3) Current limit The BU9000XGWZ has a current limit circuit that protects itself and external components during overload condition. 4) UVLO The BU9000XGWZ has a Under Voltage Lock Out circuit that turn off device when VIN>2.05V(typ.) 5) FORCED PWM MODE Setting MODE pin high (>1.4V) places the regulator in forced PWM. 6) TSD The BU9000XGWZ has a thermal shutdown feature to protect the device if the junction temperature exceeds 150℃.In thermal shutdown, the DRIVER is disabled. www.rohm.com © 2011 ROHM Co., Ltd. All rights reserved. 11/14 Target spec. ver.1.7 BU90002GWZ, BU90003GWZ, BU90004GWZ, BU90005GWZ, BU90006GWZ Technical Note ●PC Board layout The suggested PCB layout for the BU9000XGWZ are shown in Figure. The following guidelines should be used to ensure a proper layout. 1) The input capacitor CIN should be connect as closely possible to VIN pin and GND pin. 2) From the output voltage to the FB pin line should be as separate as possible. 3) COUT and L should be connected as closely as possible. The connection of L to the LX pin should be as short as possible. Fig. PCB layout ●External parts selection 1) Inductor selection The inductance significantly depends on output ripple current. As shown by following equation, the ripple current decreases as the inductor and/or switching frequency increase. ⊿IL= (VIN-VOUT)×VOUT L×VIN×f f: switching frequency L: inductance ⊿IL: inductor current ripple As a minimum requirement, the DC current rating of the inductor should be equal to the maximum load current plus half of the inductor current ripple as shown by the following equation. ILPEAK= IOUTMAX + ⊿IL 2 Recommended inductor selection LQM21MPN1R0NG0 (2.0mm×1.6mm×1.0mm Murata) Iout≦1A LQM21PN1R0NGC (2.0mm×1.2mm×1.0mm Murata) Iout≦0.6A 2)Recommended input capacitor(CIN) selection GRM155R60J225M(1.0mm×0.5mm×0.5mm Murata) GRM188R60J475ME84(1.6mm×0.8mm×0.8mm Murtata) 3)Recommended output capacitor(COUT) selection GRM155R60J475M(1.0mm×0.5mm×0.5mm Murata) GRM155R60G106ME44(1.0mm×0.5mm×0.5mm Murata) GRM188R60J475ME84(1.6mm×0.8mm×0.8mm Murtata) www.rohm.com © 2011 ROHM Co., Ltd. All rights reserved. 12/14 Target spec. ver.1.7 BU90002GWZ, BU90003GWZ, BU90004GWZ, BU90005GWZ, BU90006GWZ Technical Note ●Caution of use 1) Absolute maximum ratings An excess in the absolute maximum rating, such as supply voltage, temperature range of operating conditions, etc., can break down the devices, thus making impossible to identify breaking mode, such as a short circuit or an open circuit. If any over rated values will expect to exceed the absolute maximum ratings, consider adding circuit protection devices, such as fuses. 2) GND voltage The potential of GND pin must be minimum potential in all condition. As an exception, the circuit design allows voltages up to -0.3 V to be applied to the IC pin. 3) Thermal design Use a thermal design that allows for a sufficient margin in light of the power dissipation (Pd) in actual operating conditions. 4) Inter-pin shorts and mounting errors Use caution when positioning the IC for mounting on printed circuit boards. The IC may be damaged if there is any connection error or if pins are shorted together. 5) Actions in strong electromagnetic field Use caution when using the IC in the presence of a strong electromagnetic field as doing so may cause the IC to malfunction. 6) Mutual impedance Power supply and ground wiring should reflect consideration of the need to lower mutual impedance and minimize ripple as much as possible (by making wiring as short and thick as possible or rejecting ripple by incorporating inductance and capacitance). 7) Thermal shutdown Circuit (TSD Circuit) This model IC has a built-in TSD circuit. This circuit is only to cut off the IC from thermal runaway, and has not been design to protect or guarantee the IC. Therefore, the user should not plan to activate this circuit with continued operation in mind. 8) Regarding 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 these P layers with the N layers of other elements, creating a parasitic diode or transistor. For example, as shown in the figures below, the relation between each potential is as follows: 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 can occur inevitable in the structure of the IC. The operation of parasitic diodes can result in mutual interference among circuits, operational faults, or physical damage. Accordingly, methods by which parasitic diodes operate, such as applying a voltage that is lower than the GND (P substrate) voltage to an input pin, should not be used. www.rohm.com © 2011 ROHM Co., Ltd. All rights reserved. 13/14 Target spec. ver.1.7 BU90002GWZ, BU90003GWZ, BU90004GWZ, BU90005GWZ, BU90006GWZ Technical Note ●Ordering part number TBD www.rohm.com © 2011 ROHM Co., Ltd. All rights reserved. 14/14 Target spec. ver.1.7