Noise High Efficiency Step-down Switching Regulator with Built-in Powe

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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
BD8961NV
No.09027EAT22
Description ROHM's high efficiency step-down switching regulator BD8961NV power supply designed produce voltage including volts from 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 SON008V5060 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
Unit
-0.3+7 -0.3+7 9002 3900
-25+105 -55+150 +150
should exceeded. Derating done 7.2mW/ temperatures above Ta=25, Mounted Glass Epoxy (the density copper:3%) Derating done 31.2mW/ temperatures above Ta=25, Mounted JESD51-7.
Operating Conditions (Ta=25) Parameter Voltage PVCC Voltage Voltage average output current
Symbol PVCC
Limits Min. Typ. Max.
Unit
should exceeded.
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1/13
2009.05 Rev.A
BD8961NV
Electrical Characteristics (Ta=25, VCC=PVCC=3.3V, EN=VCC.) Parameter Standby current Bias current voltage High voltage input current Oscillation frequency resistance resistance Output voltage SInk current Source Current UVLO threshold voltage UVLO release voltage Soft start time Timer latch time Output Short circuit Threshold Voltage Block Diagram, Application Circuit
Technical Note
Symbol ISTB VENL VENH FOSC RONP RONN VOUT ITHSI ITHSO VUVLO1 VUVLO2 TLATCH VSCP
Min. 3.250 3.65
Limits Typ. 3.300 3.90 1.65
Max. 3.350 2.31
Unit VOUT
Conditions EN=GND Standby mode Active mode VEN=5V PVCC=5V PVCC=5V VOUT=3.6V VOUT=3.0V VCC=50V VCC=05V SCP/TSD operated VOUT=3.30V
D8961
VREF
Input
Current Comp Amp. SLOPE Soft Start UVLO VOUT
Current Sense/ Protect Driver Logic
PVCC
Output
PGND
CITH
RITH
Fig.1 BD8961NV View
Fig.2 BD8961NV Block Diagram
function table
name VOUT PGND PVCC
function Output voltage power supply input GmAmp output pin/Connected phase compensation capacitor Ground source Pch/Nch drain output source Enable (Active High)
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2/13
2009.05 Rev.A
BD8961NV
Characteristics data (Reference data)
OUTPUT VOLTAGE:VOUT[V]
Technical Note
OUTPUT VOLTAGE:VOUT[V]
INPUT VOLTAGE:VCC[V]
OUTPUT VOLTAGE:VOUT[V]
Ta=25 Io=2A
VCC=5V Ta=25 Io=0A
VOLTAGE:VEN[V]
VCC=5V Ta=25
OUTPUT CURRENT:IOUT
Fig.3 Vcc-Vout
Fig.4 Ven-Vout
Fig.5 Iout-Vout
3.35 3.34
OUTPUT VOLTAGE:VOUT[V]
1.20 1.15 FREQUENCY:FOSC[MHz] 1.10 1.05 1.00 0.95 0.90 0.85 0.80
1000 OUTPUT CURRENT:IOUT[mA] 10000
3.33 3.32 3.31 3.30 3.29 3.28 3.27 3.26 3.25
VCC=5V Io=0A
EFFICIENCY:[%]
VCC=5V
VCC=5V Ta=25
TEMPERATURE:Ta[]
TEMPERATURE:Ta[]
Fig. Ta-VOUT
Fig.7 Efficiency
Fig.8 Ta-FOSC
0.40 0.35
VCC=5V
VOLTAGE:VEN[V]
VCC=5V
CIRCUIT CURRENT:I
VCC=5V
0.30 0.25 0.20 0.15 0.10 0.05 0.00 TEMPERATURE:Ta[]
RESISTANCE:R
PMOS
NMOS
TEMPERATURE:Ta[]
TEMPERATURE:Ta[]
Fig.9 Ta-RONN, RONP
Fig.10 Ta-VEN
Fig.11 Ta-ICC
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3/13
2009.05 Rev.A
BD8961NV
Technical Note
Ta=25
FREQUENCY:FOSC[MHz]
VCC=PVCC 1msec
VOUT
VOUT VCC=5V Ta=25 Io=0A VCC=5V Ta=25
INPUT VOLTAGE:VCC
Fig.12 Vcc-Fosc
Fig.13 Soft start waveform
Fig.14 waveform Io=10mA
VOUT
100mV
VOUT
110mV
IOUT VCC=5V Ta=25
IOUT VCC=5V Ta=25
Fig. Transient response Io=1A2A(10s)
Fig.17 Transient response Io=2A1A(10s)
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4/13
2009.05 Rev.A
BD8961NV
Information advantages Advantage 1Offers fast transient response with current mode control system. Conventional product (Load response IO=0.1A0.6A)
Technical Note
BD8961NV (Load response IO=1A2A)
VOUT 160mV
VOUT 100mV
IOUT
IOUT
Voltage drop sudden change load reduced about 50%. Fig.18 Comparison transient response
Advantage Offers high efficiency with synchronous rectifier
heavier load: Utilizes synchronous rectifying mode on-resistance FETs incorporated power transistor.
EFFICIENCY:[%]
1000 10000 OUTPUT CURRENT:IOUT[mA]
resistance P-channel 200m(Typ.) resistance N-channel 160m(Typ.)
VCC=5V
Fig.19 Efficiency
Advantage 3Supplied smaller package small-sized power incorporated. Output capacitor required current mode control: ceramic capacitor Inductance required operating frequency MHz: 2.2H inductor Reduces mounting area required.
15mm DC/DC Convertor Controller RITH VOUT 10mm CITH
RITH CITH
Fig.20 Example application
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5/13
2009.05 Rev.A
BD8961NV
Technical Note
Operation BD8961NV 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.21 Diagram current mode control
Current Comp
PVCC SENSE IL(AVE)
RESET
VOUT
VOUT(AVE)
Fig.22 switching timing chart
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6/13
2009.05 Rev.A
BD8961NV
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 100mV (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.23 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 fixed time(TLATCH) more. output thus held tuned recovered restarting re-unlocking UVLO.
Output latch
Output Short circuit Threshold Voltage VOUT Limit
Standby mode
t1<TLATCH Operating mode
t2=TLATCH
Standby mode
Operating mode
Timer latch
Fig.24 Short-current protection circuit with time delay timing chart
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7/13
2009.05 Rev.A
BD8961NV
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) (CRSS[F]Reverse transfer capacitance FET, IDRIVE[A]Peak current gate.) 3)PD(SW)= IDRIVE 4)PD(ESR)=IRMS (IRMS[A]Ripple current capacitor, ESR[]Equivalent series resistance.) (ICC[A]Circuit current.)
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.
3.9W
SON008V5060 JEDEC layer board j-a=32.1/W SON008V5060 ROHM standard layer board j-a=138.9/W only j-a=195.3/W
Power dissipation:Pd
duty (=VOUT/VCC) RCOILDC resistance coil RONPON resistance P-channel RONNON resistance N-channel IOUTOutput current
0.90W 0.64W
100105
Ambient temperature:Ta
Fig.25 Thermal derating curve (SON008V5060) VCC=5V, VOUT=3.3V, RONP=0.2, RONN=0.16 IOUT=2A, example, D=VOUT/VCC=3.3/5.0=0.66 =0.132+0.0544 =0.1864[] RONP greater than RONN this dissipation increases duty becomes greater. With consideration dissipation above, thermal design must carried with sufficient margin allowed.
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8/13
2009.05 Rev.A
BD8961NV
Selection components externally connected Selection inductor
Technical Note
inductance significantly depends output ripple current. seen equation (1), ripple current decreases inductor and/or switching frequency increases. [A](1)
VOUT
Appropriate ripple current output should more less maximum output current. [A](2) [H](3)
Fig.26 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=3.3V, f=1MHz, example,(BD8961NV) =1.87 2.2[H]
*Select inductor resistance component (such ACR) minimize dissipation inductor better efficiency. Selection output capacitor (CO)
Output capacitor should selected with consideration stability region equivalent series resistance required smooth ripple voltage.
VOUT
Output ripple voltage determined equation [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. 22µF 100µF ceramic capacitor recommended.
Fig.27 Output capacitor 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=3.3V, IOUTmax.=2A, (BD8961NV) 3.3(5.0-3.3) =0.947[ARMS] When twice VOUT, IRMS=
Fig.28 Input capacitor
22F/10V ceramic capacitor recommended reduce dissipation input capacitor better efficiency.
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9/13
2009.05 Rev.A
BD8961NV
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.) fz(ESR) IOUTMin. IOUTMax.
fz(ESR)= Pole power amplifier When output current decreases, load resistance increases pole frequency lowers. fp(Min.)= [Hz]with lighter load
Phase [deg]
Fig.29 Open loop gain characteristics fp(Max.)= [Hz] with heavier load
Gain [dB] Phase [deg]
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.)= Fig.30 Error phase compensation characteristics
VOUT VOUT RITH CITH
VCC,PVCC
VOUT
GND,PGND
Fig.31 Typical application
Stable feedback loop achieved canceling pole (Min.) produced output capacitor load resistance with zero correction error amplifier.
fz(Amp.)= fp(Min.)
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10/13
2009.05 Rev.A
BD8961NV
BD8961NV Cautions Board layout RITH CITH
Technical Note
VOUT
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.
SON008V5060 (BD8961NV) thermal reverse package. package thermal performance enhanced bonding plane which take large area PCB.
Recommended components Lists above application Symbol CITH RITH Part Coil Ceramic capacitor Ceramic capacitor Ceramic capacitor Resistance Value 2.2uH 22uF 22uF 680pF Manufacturer Kyocera Kyocera murata Rohm Series LTF5022-2R2N3R2 CM32X5R226M10A CM316B226M06A MCH03Serise
*The 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
VOUT
VOUT
Fig.33 equivalence circuit
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11/13
2009.05 Rev.A
BD8961NV
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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12/13
2009.05 Rev.A
BD8961NV
Ordering part number
Technical Note
Part
Part
Package
SON008V5060
Packaging forming specification
Embossed tape reel
SON008V5060
5.0±0.15
0.15
<Tape Reel information>
Tape Quantity Direction feed Embossed carrier tape 2000pcs
direction 1pin product upper left when hold
1.0MAX
1PIN MARK
+0.03 0.02 -0.02 (0.22)
reel left hand pull tape right hand
0.08 C0.25
4.2±0.1 1.27
0.59
+0.05 -0.04
1pin
Direction feed
(Unit
Reel
Order quantity needs multiple minimum quantity.
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13/13
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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Noise High Efficiency Step-down Switching Regulator with Built-in Powe

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