High Performance Regulators for PCs Switching Regulator with MOSFET for DDR-SDRAM Cores BD95500MUV No.10030ECT21 ●Description BD95500MUV is a switching regulator with high output current (up to 6A) which can achieve low output voltage (0.7V to 5.0V) from a wide input voltage range (3V to 20V). High efficiency for the switching regulator can be realized by 3 TM utilizing an internal N-MOSFET power transistor. A new technology called H Reg is a Rohm proprietary control method to realize ultra high transient response against load change. SLLM (Simple Light Load Mode) technology is also integrated to improve efficiency in light load mode, providing high efficiency over a wide load range. For protection and ease of use, the soft start function, variable frequency function, short circuit protection function with timer latch, over voltage protection function, and power good function are all built in. This switching regulator is specially designed for sets of various kinds. ●Features 1) Integrated low ON resistance N-MOSFET (TYP. 50mΩ) 3 TM 2) H Reg DC/DC converter controller 3) Adjustable Simple Light Load Mode (SLLM), and forced continuous mode 4) Thermal Shut Down (TSD), Under Voltage LockOut (UVLO), Adjustable Over Current Protection (OCP), Over Voltage Protection (OVP), Short Circuit Protection(SCP) built-in 5) Soft start function to minimize rush current during startup 6) Adjustable switching frequency (f=200KHz～1000KHz) 7) Built-in output discharge function 8) VQFN040V6060 Package 9) Tracking Function 10) Integrated boot strap diode 11) Power Good function ●Applications Mobile PC, Desktop PC, LCD-TV, Digital Components, etc www.rohm.com © 2010 ROHM Co., Ltd. All rights reserved. 1/20 2010.05 - Rev.C Technical Note BD95500MUV ●Maximum Absolute Ratings (Ta=25℃) Parameter Symbol Ratings Unit VCC 7 *1 V Input Voltage 2 VDD 7 *1 V Input Voltage 3 VIN 24 *1 Input Voltage 1 BOOT Voltage BOOT-SW Voltage LG Voltage REF Voltage Output Voltage ILIM/SS/FS/MODE Voltage VREG Voltage EN Input Voltage V BOOT 30 V BOOT-SW 7 V LG VDD V REF VCC V VOUT/Is+/Is- VCC V ILIM/SS/FS/MODE VCC V VREG VCC V EN 7 V Output Current (Average) Isw 6 A Power Dissipation 1 Pd1 0.54 *2 W Power Dissipation 2 Pd2 1.00 *3 W Power Dissipation 3 Pd3 3.77 *4 W Power Dissipation 4 Pd4 *5 W Operating Temperature Range Topr -10～+100 ℃ Storage Temperature Range Tstg -55～+150 ℃ Tjmax +150 ℃ Junction Temperature 4.66 *1 Not to exceed Pd, ASO, and Tjmax=150℃. *2 Reduced by 4.3mW for each increase in Ta of 1℃ over 25℃ (when don’t mounted on a heat radiation board ) *3 Reduced by 8.0mW for increase in Ta of 1℃ over 25℃. (when mounted on a board 70.0mm×70mm×1.6mm Glass-epoxy PCB which has 1 layer. (Copper foil area : 0mm2)) *4 Reduced by 30.1mW for increase in Ta of 1℃ over 25℃. (when mounted on a board 70.0mm×70mm×1.6mm Glass-epoxy PCB which has 4 layers. (1st and 4th copper foil area : 20.2mm2, 2nd and 3rd copper foil area : 5505mm2)) *5 Reduced by 37.3mW for increase in Ta of 1℃ over 25℃. (when mounted on a board 70.0mm×70mm×1.6mm Glass-epoxy PCB which has 4 layers. (All copper foil area : 5505mm2)) ●Operating Conditions (Ta=25℃) Parameter Ratings Symbol MIN MAX Unit Input Voltage 1 VCC 4.5 5.5 V Input Voltage 2 VDD 4.5 5.5 V Input Voltage 3 VIN 3.0 20 V BOOT Voltage BOOT 4.5 25 V SW -0.7 20 V BOOT-SW 4.5 5.5 V MODE 0 5.5 V EN 0 5.5 V SW Voltage BOOT-SW Voltage MODE Input Voltage EN Input Voltage Output Adjustable Voltage REF 0.7 2.0 V Is Input Voltage Is+/Is- 0.7 2.7 V MIN ON Time Tonmin - 200 nsec *This product should not be used in a radioactive environment. www.rohm.com © 2010 ROHM Co., Ltd. All rights reserved. 2/20 2010.05 - Rev.C Technical Note BD95500MUV ●Electrical characteristics (Unless otherwise noted, Ta=25℃, VCC=5V, VDD=5V, EN / MODE=5V, VIN=12V, REF=1.8V, RFS=68kΩ） Limit Parameter Symbol Unit Condition Min. Typ. Max. [Whole Device] VCC Bias Current Icc 1200 2000 μA VIN Bias Current Iin 100 200 μA VCC Standby Current Iccstb 0 10 μA EN＝0V VIN Standby Current Iinstb 0 10 μA EN＝0V EN Low Voltage Enlow GND 0.8 V EN High Voltage Enhigh 2.3 5.5 V EN Bias Current Ien 7 10 μA Ireg=0 to 500uA, VREG Voltage Vreg 2.475 2.500 2.525 V Ta=-10℃ to 100℃* [Under Voltage Locked Out ] VCC Threshold Voltage Vcc_UVLO 4.1 4.3 4.5 V VCC:Sweep up VCC Hysteresis Voltage dVcc_UVLO 100 160 220 mV VCC:Sweep down VIN Threshold Voltage Vin_UVLO 2.4 2.6 2.8 V VIN:Sweep up VIN Hysteresis dVin_UVLO 100 160 220 mV VIN:Sweep down VREG Threshold Voltage Vreg_UVLO 2.0 2.2 2.4 V VREG:Sweep up VREG Hysteresis Voltage dVreg_UVLO 100 160 220 mV VREG:Sweep down 3 TM [H REG Control Block] ON Time Ton 400 500 600 nsec MAX ON Time Tonmax 3 6.0 μsec MIN OFF Time Toffmin 450 550 nsec [FET Block] High Side ON Resistance HGhon 50 80 mΩ Low Side ON Resistance HGlon 50 80 mΩ [SCP Block] SCP Start up Voltage Vscp REF×0.60 REF×0.70 REF×0.80 V Delay Time Tscp 1.0 2.0 ms [OVP Block] OVP Detect Voltage Vovp REF×1.16 REF×1.2 REF×1.24 V [Soft Start Block] Charge Current Iss 2 4 6 μA Discharge Current Idis 0.5 1.0 2.0 μA Standby Voltage Vss_stb 50 mV [Over Current Protection Block] ILIM=0.5V , Current Limit Threshold 1 Ilim1 40 50 60 mV Ta=-10℃ to 100℃ Current Limit Threshold2 Ilim2 160 200 240 mV ILIM=2.0V [Vout Setting] VOUT Offset Voltage 1 Voutoff1 REF-10m REF REF+10m V Ta=-10℃ to 100℃ VOUT Bias Current Ivout -100 0 100 nA REF Bias Current Iref -100 0 100 nA Is+ Input Current IIs+ -1 0 1 μA Is+=1.8V Is- Input Current IIs-1 0 1 μA Is-=1.8V [MODE Block] SLLM Threshold VthSLLM VCC-0.5 VCC V Forced Continuous Mode VthCONT GND 0.5 V Input Impedance RMODE 400 kΩ [Power Good Block] VOUT Power Good Low Voltage VoutPL REF×0.85 REF×0.90 REF×0.95 V VOUT Power Good High Voltage VoutPH REF×1.05 REF×1.10 REF×1.15 V www.rohm.com © 2010 ROHM Co., Ltd. All rights reserved. 3/20 2010.05 - Rev.C Technical Note BD95500MUV ●Reference Data 4.30 2.500 2.70 2.65 4.25 2.498 Sweep up Sweep up 2.60 2.494 VIN[V] 2.496 VCC[V] 4.15 2.492 Sweep down 2.40 4.00 -10 10 30 50 Ta( ℃) 70 -10 90 Fig.1 Ta vs VREG 10 30 50 Ta( ℃) 70 -10 90 2.15 Sweep up 2.15 VREG[V] 2.05 Sweep down Sweep down 2.00 1.95 1.95 -10 10 30 50 Ta( ℃) 70 Fig.4 Ta vs UVLO (VREG) Left: 100℃ Middle: 25℃ Right: -10℃ 0.0 10 30 50 Ta( ℃) 70 0 90 Fig.5 Ta vs EN Threshold 360 52 frequency[kHz] 1 ⊿Is [mV] 3 4.5 Vcc(V) 6 400 2 0 1.5 Fig.6 Vcc vs VREG 54 3 VOUT-REF [mV] 1.2 0.4 -10 90 90 1.6 0.8 1.90 1.90 70 2.0 2.05 2.00 50 Ta( ℃) 2.4 2.10 2.10 30 2.8 2.20 Sweep up 10 Fig.3 Ta vs UVLO (VIN) Fig.2 Ta vs UVLO (VCC) 2.20 VREG[V] Sweep down 2.45 4.05 2.490 2.55 2.50 4.10 VREG(V) VREG[V] 4.20 50 -1 48 Io=2A 320 Io=0A 280 240 -2 ILIM=0.5V 10 30 50 70 46 -10 90 200 10 30 Ta (℃) Fig.7 Ta vs VOUT Offset SLLM 80 0 Forced Continuous 40 20 0.1 Io(mA) 1 10 SLLM Fig.10 Io vs Efficiency (VIN=7V, VOUT=1.5V) www.rohm.com © 2010 ROHM Co., Ltd. All rights reserved. 20 25 80 SLLM 60 Forced Continuous 40 0 0.001 10 15 VIN(V) 100 Forced Continuous 40 20 20 0.01 5 Fig.9 VIN vs f 60 η[%] η[%] 90 100 60 0 0.001 70 Fig.8 Ta vs Current Limit Threshold 100 80 50 Ta ( ℃) η[%] -3 -10 0.01 0.1 Io(mA) 1 Fig.11 Io vs Efficiency (VIN=12V, VOUT=1.5V) 4/20 10 0 0.001 0.01 0.1 Io(mA) 1 10 Fig.12 Io vs Efficiency (VIN=19V, VOUT=1.5V) 2010.05 - Rev.C Technical Note BD95500MUV ●Reference Data VOUT VOUT HG/LG HG/LG IOUT IOUT IOUT Fig.13 Transient Response (VIN=7V) Fig.14 Transient Response (VIN=12V) Fig.15 Transient Response (VIN=19V) VOUT HG/LG VOUT VOUT HG/LG HG/LG IOUT IOUT IOUT Fig.16 Transient Response (VIN=7V) Fig.17 Transient Response (VIN=12V) VOUT HG/LG Fig.18 Transient Response (VIN=19V) VOUT VOUT VOUT IL IL IL HG/LG HG/LG HG/LG Fig.19 SLLM Mode (IOUT=0A) Fig.21 SLLM Mode (IOUT=1A) Fig.20 SLLM Mode (IOUT=0.4A) IL IL IL HG/LG/SW HG/LG/SW HG/LG/SW Fig.22 Continuous Mode (Io=0A) www.rohm.com © 2010 ROHM Co., Ltd. All rights reserved. Fig.23 Continuous Mode (Io=4A) 5/20 Fig.24 OCP Status (Io=5A) 2010.05 - Rev.C Technical Note BD95500MUV ●Reference Data VIN VIN EN SS VOUT HG/LG HG/LG VOUT PGOOD VOUT Fig.27 EN wake up Fig.26 VIN change (19→5V) Fig.25 VIN change (5→19V) 500 1.52 60 Continuous 400 SLLM 1.50 1.49 50 Continuous 300 40 Continuous SLLM SLLM 200 ΔTc [℃] Frequency [kHz Output Voltage [V 1.51 20 100 1.48 0.001 0.01 0.1 1 10 0 0.001 10 30 0 0.01 0.1 Iout [A] 1 10 0 1 2 3 Iout [A] Fig.28 IOUT vs VOUT 4 5 6 Io [A] Fig.29 IOUT vs f Fig.30 IOUT vs ΔTc ●Block Diagram VIN VDD VINS Vcc 5 VREG 37 SS 9 7 VDD EN 39 UVLO VREG VIN Reference Block BOOT 2.5V SS 38 2.5VReg Soft Start REF × 1.2 SCP REF × 0.85 SS × 0.85 V OUT Vcc H 3 Reg TM Controller Block 10 1 PGOOD VIN C IN R Q SLLM/ Driver S Circuit Power Good 22 | 29 V OUT SW C OUT 14 VDD 5V MODE SS V OUT 3.3V ～ 20V V OUT Delay REF 31 | 36 OVP 11 EN/UVLO UVLO ILIM SCP TSD 15 | 21 Current Limit ILIM 30 TSD Thermal Protection PGND 3 × 0.1 6 8 GND www.rohm.com © 2010 ROHM Co., Ltd. All rights reserved. PGND 40 FS 2 MODE 4 N.C. CE 13 ILIM 6/20 Is+ 12 Is - 2010.05 - Rev.C Technical Note BD95500MUV ●Pin Configuration PGND SW 30 29 SW SW SW SW SW SW SW PGND 28 27 26 25 24 23 22 21 VIN 31 20 PGND VIN 32 19 PGND VIN 33 18 PGND VIN 34 17 PGND VIN 35 16 PGND VIN 36 15 PGND 14 VDD VINS 37 BOOT 38 EN 39 13 Is+ 12 Is- 11 VOUT MODE 40 1 2 PGOOD N.C. 3 4 CE ILIM 5 6 7 VCC GND VREG 8 FS 9 10 SS/ REF TRACK *Connect the bottom side (FIN) to the ground terminal ●Pin Function Table PIN No. PIN name PIN function Power Good Output Pin(+/-10% Window) 1 PGOOD 2 N.C. 3 CE Ceramic Capacitor Reactive Pin 4 ILIM Current Limit Setting Pin 5 VCC Power Supply Input pin (Control Block) 6 GND Sense GND 7 VREG 8 FS 9 SS/TRACK 10 REF - IC Reference Voltage (2.5V/500uA) Switching Frequency Adjustable Pin (30k～100kΩ) Soft Start Setting Pin (w/ Capacitor)/Tracking Voltage Input Pin Vo Setting Pin Output Voltage Sense Pin 11 VOUT 12 Is- Current Sense Pin - 13 Is+ Current Sense Pin + 14 VDD 15-21 PGND FET Driver Power Supply Pin (5V Input) Power GND Pin High Side FET Source Pin 22-29 SW 30 PGND 31-36 VIN 37 VINS Battery Voltage Sense pin 38 BOOT HG Driver Power Supply Pin 39 EN 40 MODE bottom FIN www.rohm.com © 2010 ROHM Co., Ltd. All rights reserved. Power GND Pin Battery Voltage Input pin (3.3~20V Input) Enable Input pin (IC ON when High) Control Mode Adjustment Pin Low: Continuous High: SLLM Substrate connection 7/20 2010.05 - Rev.C Technical Note BD95500MUV ●Pin Descriptions ・VCC (5 Pin) This is the power supply pin for IC internal circuits, except the FET driver. The input supply voltage range is 4.5V to 5.5V. It is recommended that a 10Ω/0.1uF C-R filter be put in this pin from VDD rail. ・EN (39 Pin) When EN pin voltage is at least 2.3V, the status of this switching regulator becomes active. Conversely, the status switches off when EN pin voltage goes lower than 0.8V and circuit current becomes 0µA. ・VDD (14 Pin) This is the power supply pin to drive the LOW side FET and for Boot-strap diode. It is recommended that a 1~10µF bypass capacitor be established to compensate for rush current during the FET ON/OFF transition. ・VREG (7 Pin) This is the reference voltage output pin. The voltage is 2.5V, with 500uA current ability. It is recommended that a 0.22~1µF capacitor (X5R or X7R) be established between VREG and GND (6 Pin). When REF is not adjusted from the external voltage supply, the REF voltage can be adjusted using the external resistor divider of VREG. ・REF (10 Pin) This is the output voltage adjustment pin by resistor divider network from VREG pin (0.7~2.0V). It is also very convenient for synchronizing external voltage supply. The IC controls the output voltage (REF≒VOUT). ・ILIM (4 Pin) BD95500MUV detects the voltage between Is+ pin and Is- pin and limits the output current (OCP). Voltage equivalent to 1/10 of the ILIM voltage is the voltage drop of external current sense resistor. A very low current sense resistor or inductor DCR can also be used for this platform. ・SS/TRACK (9 Pin) This is the adjustment pin to set the soft start time. SS voltage is low during standby status. When EN is ON, the soft start time can be determined by the SS charge current and capacitor between SS-GND. Until SS reaches REF voltage, the output voltage is equivalent to SS voltage. And also this pin enables to operate tracking function. The output voltage keeps track of a power supply rail by connecting 10kΩ resistance between the power supply rail and SS/TRACK pin. ・VINS (37 Pin) The duty cycle is determined by input voltage and controls output voltage. In other words, the output voltage is affected by input voltage. Therefore, when VINS voltage fluctuates, the output voltage becomes also unstable. Since the VINS line is also the input voltage of the switching regulator, stability depends on the impedance of the voltage supply. It is recommended to establish a bypass capacitor or CR filter suitable for the actual application. ・FS (8 Pin) This is the pin to adjust the switching frequency with the resistor. It is recommended that a resistor be established to GND (6 pin).The frequency range is from 200kHz to 1000kHz. ・Is+ (13 pin), Is- (12 pin) These pins are connected to both sides of the current sense resistor to detect output current. The voltage drop between Is+ and Is- is compared with the voltage equivalent to 1/10 of ILIM voltage. When this voltage drop hits the specified voltage level, the output voltage is OFF. Since the maximum input voltage is 2.7V, set the output voltage by the resistance division value in case the output voltage is 2.7V or more. ・BOOT (38 pin) This is the voltage supply to drive the high side FET and a Diode for BOOT strap function is built in. The maximum absolute ratings are 30V (from GND) and 7V (from SW). BOOT voltage swings between (VIN+Vcc) and Vcc during active operation. ・PGOOD (1 pin) This pin is output pin for Power Good. It is open drain pin and recommended to connect to other power supply through the pull-up resistance (about 100kΩ). ・CE (3 pin) This pin is for the ceramic capacitor. It is useful to utilize low ESR capacitor for output capacitor. ・MODE (40 pin) TM This is the control mode changeable pin. The status is Low : continuous mode, the status is High : SLLM . ・VOUT (11 pin) This is the monitor pin for output voltage. This IC controls the voltage in the status of REF≒VOUT. When output voltage is required 2V or more, set the output voltage by the resistance division value. ・SW (22-29 pin) This is connected pin for coil. SW voltage swings between VIN and GND. It is recommended to connect by heavy and short pattern to coil. ・VIN (31-36 pin) This is input power supply pin. Recommend input voltage is 3.3V to 20V. Connect the input capacitor against PGND directly. ・PGND (15-21, 30 pin) This is power ground pin. It is recommended to connect by heavy and short pattern. Connect in reverse side of IC when connecting to GND (6 pin). www.rohm.com © 2010 ROHM Co., Ltd. All rights reserved. 8/20 2010.05 - Rev.C Technical Note BD95500MUV ●Explanation of Operation 3 TM The BD95500MUV is a switching regulator controller incorporating ROHM’s proprietary H Reg CONTROLLA control system. When VOUT drops due to a rapid load change, the system quickly restores VOUT by extending the tON time interval. Thus, it serves to improve the regulator’s transient response. Activating the Light Load Mode will also exercise Simple Light Load Mode (SLLM) control when the load is light, to further increase efficiency. H3RegTM control (Normal operation) VOUT When VOUT falls to a threshold voltage (REF), the drop is detected, activating the H3RegTM CONTROLLA system. REF HG TON= LG REF VIN × 1 f [sec]・・・(1) HG output is determined by the formula above. (VOUT drops due to a rapid load change) VOUT When VOUT drops due to a rapid load change, and the voltage remains below VREF after the programmed tON time interval has elapsed, the system quickly restores VOUT by extending the tON time, improving the transient response. REF Io tON+α HG LG VIN VIN REF HG 3 TM H Reg CONTROLLA R Q SLLM S SLLM Driver Circuit VOUT LG SW VOUT PGND www.rohm.com © 2010 ROHM Co., Ltd. All rights reserved. 9/20 2010.05 - Rev.C Technical Note BD95500MUV ●Timing Chart ・Soft Start Function EN Soft start is exercised with the EN pin set high. Current control takes effect at startup, enabling a moderate output voltage “ramping start.” Soft start timing and incoming current are calculated with formulas (2) and (3) below. TSS SS Soft start time Tss= VOUT REF×Css 4μA(typ) [sec] ・・・(2) Rush current IIN Co×VOUT Tss IIN (ON)= [A] ・・・(3) (Css: Soft start capacitor; Co: Output capacitor) ・Soft Stop Function Soft stop is exercised with the EN pin set low. Current control takes effect at startup, enabling a moderate output voltage. Soft start timing and incoming current are calculated with formulas (4) below. EN TSS(OFF) Soft stop time 1.2V TSS (OFF) = SS (REF+2VBE)×Css 1μA (typ) 0.1V Spontaneous Discharge (It is determined by load and output capacitor) VOUT [sec] ・・・(4) ΔVSS= 1.2[V] (typ) Tdelay = CSS 1μA(typ) [sec] ・・・(5) Tdelay ・Timer Latch Type Short Circuit Protection REF×0.70 When output voltage (Is-) falls to REF×0.7 or less, SCP comparator inside IC is exercised. If the status of High is continued 1ms or more (programmed time inside IC), the IC goes OFF. It can be restored either by reconnecting the EN pin or disabling UVLO. VOUT 1ms SCP EN/UVLO www.rohm.com © 2010 ROHM Co., Ltd. All rights reserved. 10/20 2010.05 - Rev.C Technical Note BD95500MUV ・Output Over Voltage Protection REF×1.2 VOUT When output rise to or above REF×1.2, output over voltage protection is exercised, and low side FET goes up maximum for reducing output. （LG=High, HG=Low）. When output falls, it returns to the standard mode. HG LG Switching ・Over current protection circuit tON tON tMAX tON During the normal operation, when VOUT becomes less than REF Voltage, HG becomes High during the time tON (P9). However, when inductor current exceeds ILIMIT threshold, HG becomes OFF. After MAX ON TIME, HG becomes ON again if the output voltage is lower than the specific voltage level and IL is lower than ILIMIT level. HG LG ILIMIT IL ・Synchronous operation with external power supply These power supply sequences are realized to connect SS pin to other power supply output through the resistance (10kΩ). 3.3V (External Power Supply) 1.5 V (BD95500 Output 1) www.rohm.com © 2010 ROHM Co., Ltd. All rights reserved. 11/20 2010.05 - Rev.C Technical Note BD95500MUV ●External Component Selection 1. Inductor (L) selection The inductor value is a major influence on the output ripple current. As formula (5) below indicates, the greater the inductor or the switching frequency, the lower the ripple current. (VIN-VOUT)×VOUT [A]・・・(4) ΔIL= L×VIN×f ΔIL VIN The proper output ripple current setting is about 30% of maximum output current. IL HG SW VOUT ΔIL=0.3×IOUTmax. [A]・・・(5) L Co LG L= (VIN-VOUT)×VOUT PGND L×VIN×f [H]・・・(6) (ΔIL: output ripple current; f: switch frequency) Output Ripple Current ※Passing a current larger than the inductor’s rated current will cause magnetic saturation in the inductor and decrease system efficiency. In selecting the inductor, be sure to allow enough margin to assure that peak current does not exceed the inductor rated current value. ※To minimize possible inductor damage and maximize efficiency, choose a inductor with a low (DCR, ACR) resistance. 2. Output Capacitor (CO) Selection VIN HG SW VOUT L ΔVOUT=ΔIL×ESR + ESL×ΔIL / TON・・・(7) ESR LG ESL (ΔIL: Output ripple current; ESR: CO equivalent series resistance, ESL: equivalent series inductance) Co PGND When determining the proper output capacitor, be sure to factor in the equivalent series resistance and equivalent series inductance required to set the output ripple voltage 20mV or more. In selecting the limit of inductor, be sure to allow enough margin for output voltage. Output ripple voltage is determined as in formula (7) below. Output Capacitor Please give due consideration to the conditions in formula (8) below for output capacity, bear in mind that output rise time must be established within the soft start time frame. Co≦ TSS×(Limit-IOUT) ・・・(8) VOUT Tss: Soft start time (See formula (2) in P10) Limit: Over current detection (See formula (10)(11) in P13) Note: Improper capacitor may cause startup malfunctions 3. Input Capacitor (Cin) Selection The input capacitor selected must have low enough ESR resistance to fully support large ripple output, in order to prevent extreme over current. The formula for ripple current IRMS is given in (9) below. VIN Cin HG SW VOUT L IRMS=IOUT× √VIN (VIN-VOUT) Co LG Where VIN=2×VOUT, IRMS= PGND [A]・・・(9) VIN IOUT 2 Input Capacitor A low ESR capacitor is recommended to reduce ESR loss and maximize efficiency. www.rohm.com © 2010 ROHM Co., Ltd. All rights reserved. 12/20 2010.05 - Rev.C Technical Note BD95500MUV 4. Setting Detection Resistance The over current protection function detects the output ripple current peak value. This parameter (setting value) is determined as in formula (10) below. VIN HG L SW R VOUT IL PGND VILIM×0.1 [A]・・・(10) R (VILIM: ILIM voltage, R: Detection resistance) Co LG ILMIT= Is+ IsCurrent limit VIN When the over current protection is detected by DCR of coil L, this parameter (setting value) is determined as in formula (11) below. IL HG L SW RL r LG PGND VOUT ILMIT=VILIM×0.1× Co C r×C L [A]・・・(11) L ) r×C (VILIM:ILIM voltage, RL: the DCR value of coil) (RL= Is+ IsCurrent limit IL detect point As soon as the voltage drop between Is+ and Is- generated by the inductor current becomes specific threshold, the gate voltage of the high side MOSFET becomes low. Since the peak voltage of the inductor ripple current is detected, this operation can sense high current ripple operation caused by inductance saturated rated current and lead to high reliable systems. ILIMIT 0 t VIN HG L SW R IL Co LG PGND Is+ R1 R1 Current limit ILMIT= R1+R2 R1 × VLIMIT×0.1 R [A]・・・(12) (VILIM: ILIM voltage R: Detection resistance) Is- VOUT VOUT When the output voltage is 2.7V or more, use the resistance for setting output voltage like left figure, for Is+ and Is-. According to the setting value above, ILIMIT setting current is in proportion to the divided ratio. R2 R2 www.rohm.com © 2010 ROHM Co., Ltd. All rights reserved. 13/20 2010.05 - Rev.C Technical Note BD95500MUV 5.Setting frequency The On Time (tON) at steady state is determined by resistance value connected to FS pin. But actually SW rising time and falling time come up due to influence of the external MOSFET gate capacity or switching speed and tON is increased. The frequency is determined by the following formula after tON, input current and the REF voltage are fixed. REF F= VIN×tON ・・・(13) 3000 VIN=5V 7V 12V 16V 19V 2500 TON [nsec] 2000 1500 1000 500 REF=1.8V 0 0 50 100 RFS [kΩ] 150 200 Consequently, total frequency becomes lower than the formula above. TON is also influenced by Dead Time around the output current 0A area in continuous mode. This frequency becomes lower than setting frequency. It is recommended to check the steady frequency in large current area (at the point where the coil current doesn’t back up). 1200 VIN=5V 7V 12V 16V 19V Frequency [kHz 1000 800 600 400 200 0 0 50 100 150 200 Resistance [kΩ] 6. Setting standard voltage (REF) VIN REF H3RegTM CONTROLLA R Q It is available to synchronize setting the reference voltage (REF) with outside supply voltage [V] by using outside power supply voltage. Q It is available to set the reference voltage (REF) by the resistance division value from VREG in case it is not set REF from an external power supply. S Outside voltage VOUT VREG VIN R1 REF H3RegTM CONTROLLA R S R2 R2 REF= R1+R2 ×VREG [V]・・・(14) VOUT www.rohm.com © 2010 ROHM Co., Ltd. All rights reserved. 14/20 2010.05 - Rev.C Technical Note BD95500MUV 7. Setting output voltage This IC is operated that output voltage is REF≒VOUT. And it is operated that output voltage is feed back to FB pin in case the output voltage is 0.7V to 2.0V. VIN REF VIN H3RegTM CONTROLLA R Q SLLM S Output voltage Driver Circuit SLLM VOUT In case the output voltage range is 0.7V to 2.0V. It is operated that the resistance division value of the output voltage is feed back to VOUT pin in case the output voltage is more than 2.0V. R1+R2 output voltage≒ ×REF [V]・・・(15) R2 And then the frequency is also in proportion to the divided ratio. F= R2 R1+R2 × REF VIN×tON ・・・(16) VIN VIN REF H3RegTM CONTROLLA R Q SLLM S Output voltage Driver Circuit SLLM VOUT R1 In case the output voltage is more than 2.0V. www.rohm.com © 2010 ROHM Co., Ltd. All rights reserved. 15/20 R2 2010.05 - Rev.C Technical Note BD95500MUV ●I/O Equivalent Circuit 1pin (PGOOD) 3pin (CE) 4pin (ILIM) VCC 7pin (VREG) 8pin (FS) 9pin (SS/TRACK) VCC VCC VCC 10pin (REF) 11pin (VOUT) VCC 13pin (Is+) VCC VCC 12pin (Is-) VCC VCC 22-29pin (SW) 31-36pin (VIN) VIN VCC SW PGND 37pin (VINS) 38pin (BOOT) 39pin (EN) VDD 40pin (MODE) SW VCC www.rohm.com © 2010 ROHM Co., Ltd. All rights reserved. 16/20 2010.05 - Rev.C Technical Note BD95500MUV ●Evaluation Board Circuit (Frequency=300kHz Continuous/SLLM Circuit Example) SW ILIM 18 R12 IPULSE C7 Q1 R11 C14 C8 C14 R20 R20 21 VOUT 16 15 C6 14 GND_VDD R19 13 12 11 R19 REF SS VDD(5V) R7 VREG C5 C4 R18 R10 SS R5 C3 C1 C2 R2 R3 5 20 19 10 1 MODE 9 MOD E SW2 1 3 6 PGND 22 23 SW SW 24 25 SW SW 26 27 SW 28 SW 29 SW Is- FS VDD Is+ 8 40 BOOT EN VREG 39 VDD VIN_S 7 C13 38 PGND GND VDD C12 VIN 6 EN PGND VQFN040V6060 VCC 37 VIN GND_VOUT PGND 17 BD95500MUV ILIM 36 VIN 5 R15 PGND 4 35 VIN CE 34 C16 PGND NC 33 C11 PGND VIN 3 GND_VIN SW 30 C15 VIN 2 32 PGND 31 PGOOD VIN (5V) VOUT (3.3V/6A) R13 + R14 C10 C9 D1 L1 REF R6 R4 R8 R9 PGOOD ●Evaluation Board Parts List Value Company Part No Part name Part No Value Company Part name U1 - ROHM BD95500MUV R17 100kΩ ROHM MCR03 Series D1 - ROHM RB051L-40 R18 1kΩ ROHM MCR03 Series L1 4.3uH Sumida CDEP105NP-4R3MC-88 R19 10kΩ ROHM MCR03 Series Q1 - - - R20 12kΩ ROHM MCR03 Series R1 0Ω ROHM MCR03 Series C1 0.1uF MURATA GRM18 Series R2 0Ω ROHM MCR03 Series C2 100pF MURATA GRM18 Series R3 100kΩ ROHM MCR03 Series C3 0.47uF MURATA GRM18 Series R4 150kΩ ROHM MCR03 Series C4 1000pF MURATA GRM18 Series R5 68kΩ ROHM MCR03 Series C5 1000pF MURATA GRM18 Series R6 100kΩ ROHM MCR03 Series C6 10uF MURATA GRM21 Series R7 150kΩ ROHM MCR03 Series C7 - MURATA GRM18 Series functional high polymer R8 - ROHM MCR03 Series C8 220uF SANYO or something R9 100kΩ ROHM MCR03 Series C9 10uF MURATA GRM21 Series R10 10Ω ROHM MCR03 Series C10 0.1uF MURATA GRM18 Series CM316B106M25A R11 - ROHM MCR03 Series C11 10uF KYOSERA or something R12 10Ω ROHM MCR03 Series C12 0.1uF MURATA GRM18 Series ROHM MCR03 Series C13 0.1uF MURATA GRM18 Series R13 R14 1kΩ ROHM MCR03 Series C14 100pF MURATA GRM18 Series R15 1kΩ ROHM MCR03 Series C15 10uF KYOSERA or something CM316B106M25A R16 100kΩ ROHM MCR03 Series C16 0.1uF MURATA GRM18 Series www.rohm.com © 2010 ROHM Co., Ltd. All rights reserved. 17/20 2010.05 - Rev.C Technical Note BD95500MUV ●Operation Notes (1) Absolute maximum ratings An excess in the absolute maximum ratings, 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) Connecting the power supply connector backward Connecting of the power supply in reverse polarity can damage IC. Take precautions when connecting the power supply lines. An external direction diode can be added. (3) Power supply lines Design PCB layout pattern to provide low impedance GND and supply lines. To obtain a low noise ground and supply line, separate the ground section and supply lines of the digital and analog blocks. Furthermore, for all power supply terminals to ICs, connect a capacitor between the power supply and the GND terminal. When applying electrolytic capacitors in the circuit, not that capacitance characteristic values are reduced at low temperatures. (4) GND voltage The potential of GND pin must be minimum potential in all operating conditions. (5) Thermal design Use a thermal design that allows for a sufficient margin in light of the power dissipation (Pd) in actual operating conditions. (6) 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. (7) 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. (8) ASO When using the IC, set the output transistor so that it does not exceed absolute maximum ratings or ASO. (9) Thermal shutdown circuit The IC incorporates a built-in thermal shutdown circuit (TSD circuit). The thermal shutdown circuit (TSD circuit) is designed only to shut the IC off to prevent thermal runaway. It is not designed to protect the IC or guarantee its operation. Do not continue to use the IC after operating this circuit or use the IC in an environment where the operation of this circuit is assumed. TSD ON Temp. [℃] BD95500MUV 175 (typ.) Hysteresis Temp. [℃] (typ.) 15 (10) Testing on application boards When testing the IC on an application board, connecting a capacitor to a pin with low impedance subjects the IC to stress. Always discharge capacitors after each process or step. Always turn the IC's power supply off before connecting it to or removing it from a jig or fixture during the inspection process. Ground the IC during assembly steps as an antistatic measure. Use similar precaution when transporting or storing the IC. www.rohm.com © 2010 ROHM Co., Ltd. All rights reserved. 18/20 2010.05 - Rev.C Technical Note BD95500MUV (11) 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, 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. Resistor Transistor (NPN) Pin A Pin B Pin B B C E Pin A N P+ N P+ P N N N GND P+ P Parasitic element P substrate Parasitic element P+ B C N E P substrate Parasitic element GND GND Parasitic element Other adjacent elements GND Example of IC structure (12) Ground Wiring Pattern When using both small signal and large current GND patterns, it is recommended to isolate the two ground patterns, placing a single ground point at the ground potential of application so that the pattern wiring resistance and voltage variations caused by large currents do not cause variations in the small signal ground voltage. Be careful not to change the GND wiring pattern of any external components, either. ●Power Dissipation VQFN040V6060 5.0 ④4.66W 4.5 4.0 ③3.77W Power Dissipation: Pd [W] 3.5 3.0 2.5 2.0 1.5 ②1.00W 1.0 ①0.54W 0.5 0 0 25 50 75 100 125 150 Ambient Temperature :Ta [℃] ①IC unit time θj-a=231.5℃/W 2 ②1 layer (Substrate surface copper foil area : 0mm ) θj-a=125.0℃/W ③4ndlayer (Substrate surface and bottom copper foil area : 20.2mm2 2 and 3rd copper foil area : 5505mm2) θj-a=33.2℃/W ④4 layer (all layers copper foil area : 5505mm2) θj-a=26.8℃/W www.rohm.com © 2010 ROHM Co., Ltd. All rights reserved. 19/20 2010.05 - Rev.C Technical Note BD95500MUV ●Ordering part number B D 9 Part No. 5 5 0 0 M Part No. U V - Package MUV : VQFN040V6060 E 2 Packaging and forming specification E2: Embossed tape and reel VQFN040V6060 <Tape and Reel information> 6.0±0.1 6.0±0.1 The direction is the 1pin of product is at the upper left when you hold ( reel on the left hand and you pull out the tape on the right hand ) 11 3.7±0.1 0.4±0.1 E2 10 40 31 0.75 2000pcs (0.22) 3.7±0.1 +0.03 0.02 -0.02 1.0MAX S 1 Embossed carrier tape Quantity Direction of feed 1PIN MARK 0.08 S C0.2 Tape 20 30 21 0.5 +0.05 0.25 -0.04 1pin (Unit : mm) www.rohm.com © 2010 ROHM Co., Ltd. All rights reserved. Reel 20/20 Direction of feed ∗ Order quantity needs to be multiple of the minimum quantity. 2010.05 - Rev.C Notice Notes No copying or reproduction of this document, in part or in whole, is permitted without the consent of ROHM Co.,Ltd. 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If a Product is intended to be used for any such special purpose, please contact a ROHM sales representative before purchasing. If you intend to export or ship overseas any Product or technology specified herein that may be controlled under the Foreign Exchange and the Foreign Trade Law, you will be required to obtain a license or permit under the Law. Thank you for your accessing to ROHM product informations. More detail product informations and catalogs are available, please contact us. ROHM Customer Support System http://www.rohm.com/contact/ www.rohm.com © 2010 ROHM Co., Ltd. All rights reserved. R1010A