BD8649EFV

Single-chip Type with Built-in FET type Switching Regulators Flexible Step-down Switching Regulator with Built-in Power MOSFET BD8649EFV No.10027EAT45 ●Description The BD8649EFV is a synchronous step-down switching regulator that integrates 2 low resistances N-channel MOSFETs. It achieves 3A continuous output current over a wide input supply range. Current mode operation provides fast transient response and easy phase compensation. ●Feature 1) Synchronous rectification with built-in FET type DC/DC converter 2) 3.0A output current 3) Range of operation power-supply voltage 4.5V～18V 4) Reference voltage FB 0.8V±1% 5) Programmable frequency 100kHz～600kHz 6) Over current protection function 7) Thermal shutdown function 8) Under voltage protection 9) Soft start time out function / Soft start delay circuit 10) Programmable OFFLATCH time ●Applications FPD,DVD,HDD Recorder,STB,Amusement,Other ●Absolute maximum rating (Ta=25℃) Parameter Input supply voltage BOOT terminal voltage EN terminal voltage Input terminal voltage SW terminal voltage Output current Power dissipation Operating temperature Storage temperature Symbol VIN VBOOT VEN VINP *1 Ratings 20 28 GND-0.3 ～ VIN+0.3 GND-0.3 ～ 7 GND-0.3 ～ VIN+0.3 3.5*2 3.2 *2 Unit V V V V V A W ℃ ℃ VSW IOUT Pd Topr Tstg -20 ～ 85 -55 ～ 150 *1 VINP Application terminal: SS/DELAY, FB, FC, RT, PSET *2 (70mm×70mm, thickness 1.6mm, and four layer glass epoxy substrates)When mounting substrate and the package back exposure part are connected with solder Operating at higher than Ta=25℃, 25.6mW shall be reduced per 1 ●Operation condition Parameter Input supply voltage Output current * Symbol VIN IOUT Ratings Min. 4.5 Typ. Max. 18.0 3.0 Unit V A This product is not designed for protection against radioactive rays. www.rohm.com © 2010 ROHM Co., Ltd. All rights reserved. 1/13 2010.09 - Rev.A BD8649EFV ●Electrical characteristic (Unless otherwise noted Ta=25℃, VIN=12V, VEN = 3V) Parameter VIN supply current (operating) VIN supply current (standby) Reference voltage (VREF) Oscillation frequency High side FET ON resistance Low side FET ON resistance UVLO voltage SW leak current EN terminal H threshold voltage EN terminal L threshold voltage SS/DELAY terminal source current SS/DELAY – FB Offset voltage PSET terminal source current PSET terminal threshold voltage ● ● Technical Note Symbol IQ_active IQ_stby VFB fOSC RHFET RLFET VUVLO ILSW VENH VENL ISSSO VSSFBOST IPSET VPSET Limits Min. 0.792 270 3.8 1.6 2.8 450 3.0 0.8 Typ. 1.5 0.8 0.800 300 110 110 4.0 0 4.0 600 5.0 1.0 Max. 2.5 1.2 0.808 330 160 160 4.2 5 0.4 5.2 750 7.0 1.2 UNIT mA mA V kHz mΩ mΩ V μA V V μA mV μA V Condition VFB = 0.75V VEN = 0V FB-FC Short RRT= 56kΩ ISW = -1A ISW = 1A VIN Sweep VEN= 0V VSS= 1V VSS= 1V VPSET= 2V VFB :FB terminal voltage,VEN :EN terminal voltage,VSS :SS/DELAY terminal voltage, VPSET :PSET terminal voltage, RRT :RT resistor Current capability should not exceed Pd. ●Package outline dimension Product number BD8649 1 PIN Lot No. HTSSOP-B20 (Unit: mm) www.rohm.com © 2010 ROHM Co., Ltd. All rights reserved. 2/13 2010.09 - Rev.A BD8649EFV ●Reference data 0.820 0.815 0.810 Technical Note 0.810 VIN=12V 0.805 Ta=25℃ VFB and FC [V] VFBとFC[V] 0.800 0.795 0.790 0.785 0.780 -20 -5 10 25 40 55 70 85 VFB and FC [V] VFBとFC[V] 0.805 0.800 0.795 0 .790 4 6 8 10 12 14 16 18 Ta [℃] VIN[V] Fig.1 Reference voltage – temperature characteristic 340 330 320 Fig.2 Reference voltage – VIN characteristic 340 330 VIN=12V fsw[kHz] 320 310 300 290 280 270 2 60 Ta=25℃ fsw[kHz] 310 300 290 280 270 260 -20 -5 10 25 40 55 70 85 4 6 8 10 12 14 16 18 Ta [℃] Fig.3 Frequency – temperature characteristic 5.0 4.8 4.6 4.4 4.2 4.0 3.8 3.6 3.4 3.2 3.0 2.8 2.6 2.4 2.2 2 .0 -20 Fig.4 Frequency – VIN characteristic 5.0 4.5 VIN[V] VIN=12V 4.0 3.5 Ta=25℃ ISS[μA] ICC[mA] -5 10 25 40 55 70 85 3.0 2.5 2.0 1.5 1.0 0.5 0 .0 4 6 8 10 12 14 16 18 Ta [℃] VIN[V] Fig.5 SS/DELAY charge current - temperature characteristic 320 280 240 320 280 Fig.6 Circuit Current – VIN characteristic VIN=12V SW_PGND[mΩ] 240 200 160 120 80 40 0 VIN=12V VIN_SW[mΩ] 200 160 120 80 40 0 -20 -5 10 25 40 55 70 85 -20 -5 10 25 40 55 70 85 Ta [℃] Ta [℃] Fig.7 Hi side FET ON_R - temperature characteristic 320 280 240 Fig.8 Low side FET ON_R - temperature characteristic 320 280 Ta=25℃ SW_PGND[mΩ] 240 200 160 120 80 40 0 Ta=25℃ VIN_SW[mΩ] 200 160 120 80 40 0 4 6 8 10 12 14 16 18 4 6 8 10 12 14 16 18 VIN[V] VIN[V] Fig.9 Hi side FET ON_R - VIN characteristic www.rohm.com © 2010 ROHM Co., Ltd. All rights reserved. Fig.10 Low side FET ON_R – VIN characteristic 3/13 2010.09 - Rev.A BD8649EFV ●Block Diagram Technical Note FB 1 FC 2 RT 3 PSET 4 EN 5 NC 6 NC 7 VIN 8 VIN 9 VIN 10 EN PWM CONTROL Protect time OSC CURRENT DET 5V Softstart/Delay GND 20 SS/DELAY 19 NC 18 BOOT 17 SW 16 SW 15 SW 14 PGND 13 PGND 12 PGND 11 VOUT Fig.11 Block diagram ●Pin Assignment No. 1 2 3 4 5 6 7 8 9 10 Symbol FB FC RT PSET EN NC NC VIN VIN VIN Description Feedback terminal Phase amends terminal Frequency adjustment resistance connection terminal Adjust OFF LATCH time terminal Enable input Power supply input terminal Power supply input terminal Power supply input terminal No. 11 12 13 14 15 16 17 18 19 20 Symbol PGND PGND PGND SW SW SW BOOT NC SS/DELAY GND Description Power GND terminal Power GND terminal Power GND terminal Switching output terminal Switching output terminal Switching output terminal Boot strap terminal Soft start adjustment capacity connection terminal Signal GND terminal www.rohm.com © 2010 ROHM Co., Ltd. All rights reserved. 4/13 2010.09 - Rev.A BD8649EFV ●Operation description Technical Note 1 Enable control The device can be controlled ON/OFF by EN terminal (5 pin) voltage. An internal circuit starts when VEN reaches 1.6V. When standing up of VIN is too steep (1msec or less), a defective start might be caused according to the state of Pascon between GND substrate pattern and power supply-when the terminal EN is short-circuited to the terminal VIN and it is used. VEN EN terminal VENH VENL 0 VSSCLM SS terminal VSSTH VSS 0 VO Output setting voltage 0 tSS Fig.12 ON/OFF transition wave form in EN controlling 2 Soft start time set function As for BD8649EFV, output can do soft start without overshoot by charging soft start capacity (CSS) connected between SS/DELAY (19 pin) and GND (20 pin) terminal. Also, soft start time (tss) can be set by setting soft start capacity (CSS) arbitrarily. (Refer to 5-2 soft start time setting method) 3 OSC oscillation frequency setting function The output oscillation frequency can be set by connecting resistance between terminal RT (3 pin) and GND (range = 100kHz – 600kHz) The relation between RT terminal resistance and the oscillation frequency follows Fig.13. 10000 1000 SW[kHz] 100 10 1 10 100 1000 RT[kΩ] Fig.13 Oscillation frequency setting by RT resistance www.rohm.com © 2010 ROHM Co., Ltd. All rights reserved. 5/13 2010.09 - Rev.A BD8649EFV ●Protection function Technical Note Protection circuit is effective for destruction prevention due to accident so that avoid using under continuous protection operation. 1 Low voltage protection function (LVP) The voltage of the terminal FB (1pin) is compared with internal reference voltage VREF. If FB terminal voltage falls below VLVP (= VREF -120mV) and the state continues, output changes to low voltage and the state is fixed. Table 1 output low voltage protection function EN terminal SS terminal >1.4V(typ) 1.4V(typ)