Noise High Efficiency Step-down Switching Regulator with Built-in Powe
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Single-chip Type with Built-in Switching Regulator Series
Noise High Efficiency Step-down Switching Regulator with Built-in Power MOSFET
BD8966FVM
No.09027EAT24
Description ROHM's high efficiency step-down switching regulator BD8966FVM power supply designed produce voltage including volts from 5/3.3 volts power supply line. Offers high efficiency with synchronous rectifier. Employs current mode control system provide faster transient response sudden change load. Features Offers fast transient response with current mode control system. Offers highly efficiency load range with synchronous rectifier (Nch/Pch FET) Incorporates soft-start function. Incorporates thermal protection ULVO functions. Incorporates short-current protection circuit with time delay function. Incorporates shutdown function Employs small surface mount package MSOP8 Power supply including DSP, Micro computer ASIC Line Parameter Voltage PVCC Voltage Voltage SW,ITH Voltage Power Dissipation Power Dissipation Operating temperature range Storage temperature range Maximum junction temperature
Symbol PVCC VSW,VITH Topr Tstg Tjmax
Limits -0.3+7 -0.3+7 -0.3+7 -0.3+7 387.52 587.43 -25+85 -55+150 +150
Unit
should exceeded. Derating done 3.1mW/ temperatures above Ta=25. Derating done 4.7mW/ temperatures above Ta=25, Mounted Glass Epoxy PCB.
Operating Conditions (Ta=25) Parameter Voltage PVCC Voltage Voltage Output voltage Setting Range average output current
Symbol PVCC VOUT
Min.
BD8966FVM Typ.
Unit Max.
should exceeded.
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2009.05 Rev.A
BD8966FVM
Electrical Characteristics (Ta=25, VCC=5V, EN=VCC, R1=20k, R2=10k unless otherwise specified.) Parameter Symbol Min. Typ. Max. Standby current ISTB Bias current voltage VENL High voltage VENH input current Oscillation frequency FOSC resistance RONP resistance RONN voltage VADJ 0.78 0.80 0.82 SInk current ITHSI Source Current ITHSO UVLO threshold voltage VUVLO1 3.20 3.40 UVLO release voltage VUVLO2 3.25 3.50 3.80 Soft start time Timer latch time TLATCH
Technical Note
Unit
Conditions EN=GND Standby mode Active mode VEN=5V PVCC=5V PVCC=5V VADJ=H VADJ=L VCC=40V VCC=04V VADJ=H SCP/TSD operated
Block Diagram, Application Circuit
2.9±0.1
Max3.25(include.BURR)
VREF
Input PVCC
0.29±0.15 0.6±0.2
Current Comp. Amp. SLOPE
4.0±0.2
2.8±0.1
Current Sense/ Protect Driver Logic Output
0.475
0.9Max. 0.75±0.05 0.08±0.05
1PIN MARK
+0.05 0.145 -0.03
+0.05 0.22 -0.04
Soft Start
UVLO
PGND
0.65
0.08
Fig.1 BD8966FVM View
Fig.2 BD8966FVM Block Diagram
function table
name PGND PVCC Output voltage detect
function GmAmp output pin/Connected phase compensation capacitor Enable pin(Active High) Ground source Pch/Nch drain output source power supply input
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2/14
2009.05 Rev.A
BD8966FVM
Characteristics data (Reference data)
Technical Note
OUTPUT VOLTAGE:VOUT[V]
OUTPUT VOLTAGE:VOUT[V]
OUTPUT VOLTAGE:VOUT[V]
VOUT=1.8V Ta=25 Io=0A
VOUT=1.8V
VOUT=1.8V
VCC=5V Ta=25 Io=0A
VCC=5V Ta=25
INPUT VOLTAGE:VCC[V]
VOLTAGE:VEN[V]
OUTPUT CURRENT:IOUT
Fig.3 Vcc-Vout
Fig.4 Ven-Vout
Fig.5 Iout-Vout
1.85 1.84
OUTPUT VOLTAGE:VOUT[V]
1.20
FREQUENCY:FOSC[MHz]
1.83 1.82 1.81 1.80 1.79 1.78 1.77 1.76 1.75
EFFICIENCY:[%]
VOUT=1.8V VCC=5V Io=0A
VOUT=1.8V
1.15 1.10 1.05 1.00 0.95 0.90 0.85 0.80
VCC=5V
VCC=5V Ta=25
OUTPUT CURRENT:IOUT[mA] 1000
TEMPERATURE:Ta[]
TEMPERATURE:Ta[]
Fig.6 Ta-VOUT
Fig.7 Efficiency
Fig.8 Ta-FOSC
0.40 0.35
VOLTAGE:VEN[V]
VCC=5V
CIRCUIT CURRENT:I
VCC=5V
0.30 0.25 0.20 0.15 0.10 0.05 0.00
PMOS
RESISTANCE:R
NMOS
VCC=5V
TEMPERATURE:Ta[]
TEMPERATURE:Ta[]
TEMPERATURE:Ta[]
Fig.9 Ta-RONN, RONP
Fig.10 Ta-VEN
Fig.11 Ta-ICC
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3/14
2009.05 Rev.A
BD8966FVM
Technical Note
VOUT=1.8V
FREQUENCY:FOSC[MHz]
SLLMSW
VOUT=1.8V
VCC=PVCC
VOUT
VOUT VCC=5V Ta=25 Io=0A
INPUT VOLTAGE:VCC
VCC=5V Ta=25
Fig.12 Vcc-Fosc
Fig.13 Soft start waveform
Fig.14 waveform
VOUT=1.8V VOUT VOUT
VOUT=1.8V
98mV 90mV IOUT IOUT VCC=5V Ta=25 VCC=5V Ta=25
Fig. Transient response Io=100600mA(10µs)
Fig.16 Transient response Io=600100mA(10µs)
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4/14
2009.05 Rev.A
BD8966FVM
Information advantages Advantage 1Offers fast transient response with current mode control system. Conventional product (Load response IO=0.1A0.6A)
Technical Note
BD8966FVM (Load response IO=0.1A0.6A)
VOUT
110mV
VOUT
90mV
IOUT
IOUT
Voltage drop sudden change load reduced Fig.17 Comparison transient response
Advantage Offers high efficiency with synchronous rectifier
EFFICIENCY:[%]
heavier load: Utilizes synchronous rectifying mode on-resistance FETs incorporated power transistor. resistance P-channel 350m(Typ.) resistance N-channel 250m(Typ.)
VOUT=1.5V 1000 OUTPUT CURRENT:IOUT[mA] 10000
VCC=5V Ta=25
Fig.18 Advantage 3Supplied smaller package small-sized power incorporated. Output capacitor required current mode control:10F ceramic capacitor Inductance required operating frequency MHz: 4.7H inductor Reduces mounting area required.
15mm DC/DC Convertor Controller RITH VOUT 10mm CITH
RITH CITH
Fig.19 Example application
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5/14
2009.05 Rev.A
BD8966FVM
Technical Note
Operation BD8966FVM synchronous rectifying step-down switching regulator that achieves faster transient response employing current mode control system. Synchronous rectifier does require power dissipated rectifier externally connected conventional DC/DC converter junction shoot-through protection circuit limits shoot-through current during operation, which power dissipation reduced. Current mode control Synthesizes control signal with inductor current feedback loop added voltage feedback. (Pulse Width Modulation) control oscillation frequency MHz. signal form turns P-channel (while N-channel turned OFF), inductor current increases. current comparator (Current Comp) receives signals, current feedback control signal (SENSE: Voltage converted from voltage feedback control signal (FB), issues RESET signal both input signals identical each other, turns P-channel (while N-channel turned rest fixed period. control repeat this operation.
SENSE Current Comp RESET Level Shift Amp. Driver Logic Load VOUT
VOUT
Fig.20 Diagram current mode control
Current Comp
PVCC SENSE IL(AVE)
RESET
VOUT
VOUT(AVE)
Fig.21 switching timing chart
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6/14
2009.05 Rev.A
BD8966FVM
Technical Note
Description operations Soft-start function terminal shifted "High" activates soft-starter gradually establish output voltage with current limited during startup, which possible prevent overshoot output voltage inrush current. Shutdown function With terminal shifted "Low", device turns Standby Mode, function blocks including reference voltage circuit, internal oscillator drivers turned OFF. Circuit current during standby (Typ.).
UVLO function Detects whether input voltage sufficient secure output voltage this supplied. hysteresis width 300mV (Typ.) provided prevent output chattering.
Hysteresis 100mV
VOUT
Soft start Standby mode Operating mode Standby mode UVLO
Operating mode
Standby mode
Operating mode
Standby mode
UVLO
UVLO
Fig.22 Soft start, Shutdown, UVLO timing chart Short-current protection circuit with time delay function Turns output protect from breakdown when incorporated current limiter activated continuously least output thus held tuned recovered restarting re-unlocking UVLO.
Output latch VOUT Limit 1msec Standby mode Standby mode Timer latch
Operating mode
Operating mode
Fig.23 Short-current protection circuit with time delay timing chart
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7/14
2009.05 Rev.A
BD8966FVM
Switching regulator efficiency Efficiency expressed equation shown below: POUT POUT POUT+PD
Technical Note
Efficiency improved reducing switching regulator power dissipation factors follows: Dissipation factors: resistance dissipation inductor FETPD(I Gate charge/discharge dissipationPD(Gate) Switching dissipationPD(SW) dissipation capacitorPD(ESR) Operating current dissipation ICPD(IC)
1)PD(I R)=IOUT (RCOIL[]DC resistance inductor, RON[]ON resistance FET, IOUT[A]Output current.) (Cgs[F]Gate capacitance FET, f[Hz]Switching frequency, V[V]Gate driving voltage FET) 3)PD(SW)= (CRSS[F]Reverse transfer capacitance FET, IDRIVE[A]Peak current gate.) IDRIVE 4)PD(ESR)=IRMS (IRMS[A]Ripple current capacitorESR[]Equivalent series resistance.) (ICC[A]Circuit current.)
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8/14
2009.05 Rev.A
BD8966FVM
Technical Note
Consideration permissible dissipation heat generation this functions with high efficiency without significant heat generation most applications, special consideration needed permissible dissipation heat generation. case extreme conditions, however, including lower input voltage, higher output voltage, heavier load, and/or higher temperature, permissible dissipation and/or heat generation must carefully considered. dissipation, only conduction losses resistance inductor resistance considered. Because conduction losses considered play leading role among other dissipation mentioned above including gate charge/discharge dissipation switching dissipation.
P=IOUT
1000
using alone
Power dissipation:Pd [mW]
duty (=VOUT/VCC) RCOILDC resistance coil RONPON resistance P-channel RONNON resistance N-channel IOUTOutput current VCC=5V, VOUT=1.5V, RCOIL=0.15, RONP=0.35, RONN=0.25 IOUT=0.8A, example, D=VOUT/VCC=1.5/5=0.3 =0.105+0.175 =0.28[] 275.2[mW]
587.4mW
j-a=322.6/W mounted glass epoxy j-a=212.8/W
387.5mW
Fig.
RONP greater than RONN this dissipation increases duty becomes greater. With consideration dissipation above, thermal design must carried with sufficient margin allowed. Selection components externally connected Selection inductor
inductance significantly depends output ripple current. seen equation (1), ripple current decreases inductor and/or switching frequency increases. [A](1) Appropriate ripple current output should more less maximum output current. [A](2) [H](3)
VOUT
Fig.25 Output ripple current
(IL: Output ripple current, Switching frequency)
*Current exceeding current rating inductor results magnetic saturation inductor, which decreases efficiency. inductor must selected allowing sufficient margin with which peak current exceed current rating. VCC=5V, VOUT=1.5V, f=1MHz, example, =4.375 4.7[H] *Select inductor resistance component (such ACR) minimize dissipation inductor better efficiency.
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9/14
2009.05 Rev.A
BD8966FVM
Selection output capacitor (CO)
Technical Note
Output capacitor should selected with consideration stability region equivalent series resistance required smooth ripple voltage. Output ripple voltage determined equation
VOUT
[V](4) (IL: Output ripple current, ESR: Equivalent series resistance output capacitor) *Rating capacitor should determined allowing sufficient margin against output voltage. Less allows reduction output ripple voltage.
Fig.26 Output capacitor
output rise time must designed fall within soft-start time, capacitance output capacitor should determined with consideration requirements equation (5): VOUT Tss: Soft-start time Ilimit: Over current detection level, 2A(Typ)
case BD8966FVM, instance, VOUT=1.5V, IOUT=0.8A, TSS=1ms, 800[F]
Inappropriate capacitance cause problem startup. ceramic capacitor recommended.
Selection input capacitor (Cin)
Input capacitor select must capacitor capacitance sufficient cope with high ripple current prevent high transient voltage. ripple current IRMS given equation (5):
VOUT
OUT(VCC-VOUT)
[A](5) IOUT
Worst case IRMS(max.) VCC=5.0V, VOUT=1.5V, IOUTmax.=0.8A 5(5-1.5) =0.67[ARMS] When twice VOUT, IRMS=
Fig.27 Input capacitor
10F/10V ceramic capacitor recommended reduce dissipation input capacitor better efficiency.
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10/14
2009.05 Rev.A
BD8966FVM
Technical Note
Determination RITH, CITH that works phase compensator Current Mode Control designed limit inductor current, pole (phase lag) appears frequency area filter consisting output capacitor load resistance, while zero (phase lead) appears high frequency area output capacitor ESR. phases easily compensated adding zero power amplifier output with described below cancel pole power amplifier.
fp(Min.) Gain [dB] fp(Max.) IOUTMin. IOUTMax. fz(ESR)
fz(ESR)= Pole power amplifier When output current decreases, load resistance increases pole frequency lowers. fp(Min.)= [Hz]with lighter load [Hz] with heavier load
Phase [deg]
Fig.28 Open loop gain characteristics fp(Max.)=
Gain [dB] fz(Amp.)
Zero power amplifier Increasing capacitance output capacitor lowers pole frequency while zero frequency does change. (This because when capacitance doubled, capacitor reduces half.) fz(Amp.)=
Phase [deg]
Fig.29 Error phase compensation characteristics
VOUT VOUT RITH CITH
VCC,PVCC
VOUT
GND,PGND
Fig.30 Typical application Stable feedback loop achieved canceling pole (Min.) produced output capacitor load resistance with zero correction error amplifier. fz(Amp.)= fp(Min.)
Determination output voltage output voltage VOUT determined equation (7): VADJ: Voltage terminal (0.8V Typ.) With adjusted, output voltage determined required. (Adjustable output voltage range 1.0V1.8V) k100 resistor resistor resistance higher than used, check assembled carefully ripple voltage etc.
4.7µH 10µF Output
Fig.31 Determination output voltage
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11/14
2009.05 Rev.A
BD8966FVM
BD8966FVM Cautions Board layout RITH CITH
Technical Note
PVCC PGND
VOUT
Fig.32 Layout diagram
sections drawn with heavy line, thick conductor pattern short possible. input ceramic capacitor closer pins PVCC PGND, output capacitor closer PGND. CITH RITH between pins near possible with least necessary wiring. Recommended components Lists above application Symbol Part Value CITH Coil Ceramic capacitor Ceramic capacitor Ceramic capacitor 4.7µH 10µF 10µF 750pF VOUT=1.0V VOUT=1.2V VOUT=1.5V VOUT=1.8V VOUT=2.5V
RITH
Resistance
Manufacturer Sumida Kyocera Kyocera murata ROHM ROHM ROHM ROHM ROHM
Series CMD6D11B VLF5014AT-4R7M1R1 CM316X5R106K10A CM316X5R106K10A GRM18series MCR10 1802 MCR10 2202 MCR10 2202 MCR10 2702 MCR10 3602
parts list presented above example recommended parts. Although parts sound, actual circuit characteristics should checked your application carefully before use. sure allow sufficient margins accommodate variations between external devices this when employing depicted circuit with other circuit constants modified. Both static transient characteristics should considered establishing these margins. When switching noise substantial impact system, pass filter should inserted between PVCC pins, schottky barrier diode established between PGND pins.
equivalence circuit
PVCC PVCC PVCC
Fig.33 equivalence circuit
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12/14
2009.05 Rev.A
BD8966FVM
Technical Note
Notes Absolute Maximum Ratings While utmost care taken quality control this product, application that exceed some absolute maximum ratings including voltage applied operating temperature range result breakage. broken, short-mode open-mode identified. expected encounter with special mode that exceed absolute maximum ratings, requested take necessary safety measures physically including insertion fuses. Electrical potential must designed have lowest electrical potential operating conditions. Short-circuiting between terminals, mismounting When mounting board, care must taken avoid mistake orientation alignment. Failure result breakdown. Short-circuiting foreign matters entered between output terminals, between output power supply also cause breakdown. 4.Operation Strong electromagnetic field noted that using strong electromagnetic radiation cause operation failures. Thermal shutdown protection circuit Thermal shutdown protection circuit circuit designed isolate from thermal runaway, intended protect guarantee thermal shutdown protection circuit which once activated should used thereafter operation originally intended. Inspection with board capacitor must connected lower impedance during inspection with board, capacitor must discharged after each process avoid stress electrostatic protection, provide proper grounding assembling processes with special care taken handling storage. When connecting jigs inspection process, sure turn power supply before connected removed. Input terminals This monolithic with isolation between P-substrate each element illustrated below. This P-layer N-layer each element form junction, various parasitic element formed. resistor joined transistor terminal shown junction works parasitic diode following relationship satisfied; GND>Terminal resistor side), GND>Terminal transistor side); GND>Terminal transistor side), parasitic transistor activated N-layer other element adjacent above-mentioned parasitic diode. structure inevitably forms parasitic elements, activation which cause interference among circuits, and/or malfunctions contributing breakdown. therefore requested take care device such manner that voltage lower than P-substrate) applied input terminal, which result activation parasitic elements.
Resistor
Transistor (NPN)
Parasitic element
substrate Parasitic element
substrate Parasitic element
Parasitic element
Other adjacent elements
Fig.34 Simplified structure monorisic Ground wiring pattern small-signal large-current provided, will recommended separate large-current pattern from small-signal pattern establish single ground reference point that resistance wiring pattern voltage fluctuations large current will cause fluctuations voltages small-signal GND. attention cause fluctuations wiring pattern external parts well. Selection inductor recommended inductor with series resistance element (DCR) less. Note that high inductor will cause inductor loss, resulting decreased output voltage. Should this condition continue specified period (soft start time timer latch time), output short circuit protection will activated output will latched OFF. When using inductor over 0.1, careful ensure adequate margins variation between external devices this including transient well static characteristics. Furthermore, case, recommended start output with after supply voltage within operation range.
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13/14
2009.05 Rev.A
BD8966FVM
Ordering part number
Technical Note
Part
Part
Package FVM:MSOP8
Packaging forming specification Embossed tape reel (MSOP8)
MSOP8
<Tape Reel information>
2.9±0.1 (MAX 3.25 include BURR)
Tape
0.29±0.15 0.6±0.2
Embossed carrier tape 3000pcs
direction 1pin product upper right when hold
Quantity Direction feed
4.0±0.2
2.8±0.1
reel left hand pull tape right hand
1pin
1PIN MARK 0.475 +0.05 0.22 -0.04 0.08 0.65
+0.05 0.145 -0.03
0.9MAX 0.75±0.05
0.08±0.05
Direction feed
(Unit
Reel
Order quantity needs multiple minimum quantity.
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14/14
2009.05 Rev.A
Notice
Notes
copying reproduction this document, part whole, permitted without consent ROHM Co.,Ltd. content specified herein subject change improvement without notice. content specified herein purpose introducing ROHM's products (hereinafter "Products"). wish such Product, please sure refer specifications, which obtained from ROHM upon request. Examples application circuits, circuit constants other information contained herein illustrate standard usage operations Products. peripheral conditions must taken into account when designing circuits mass production. Great care taken ensuring accuracy information specified this document. However, should incur damage arising from inaccuracy misprint such information, ROHM shall bear responsibility such damage. technical information specified herein intended only show typical functions examples application circuits Products. ROHM does grant you, explicitly implicitly, license exercise intellectual property other rights held ROHM other parties. ROHM shall bear responsibility whatsoever dispute arising from such technical information. Products specified this document intended used with general-use electronic equipment devices (such audio visual equipment, office-automation equipment, communication devices, electronic appliances amusement devices). Products specified this document designed radiation tolerant. While ROHM always makes efforts enhance quality reliability Products, Product fail malfunction variety reasons. Please sure implement your equipment using Products safety measures guard against possibility physical injury, fire other damage caused event failure Product, such derating, redundancy, fire control fail-safe designs. ROHM shall bear responsibility whatsoever your Product outside prescribed scope accordance with instruction manual. Products designed manufactured used with equipment, device system which requires extremely high level reliability failure malfunction which result direct threat human life create risk human injury (such medical instrument, transportation equipment, aerospace machinery, nuclear-reactor controller, fuel-controller other safety device). ROHM shall bear responsibility Products above special purposes. Product intended used such special purpose, please contact ROHM sales representative before purchasing. intend export ship overseas Product technology specified herein that controlled under Foreign Exchange Foreign Trade Law, will required obtain license permit under Law.
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