BD8966FVM_10_技术文档

Single-chip Type with Built-in FET Switching Regulators

Low Noise High Efficiency

Step-down Switching Regulator

with Built-in Power MOSFET

BD8966FVM

No.10027EBT24

●Description

ROHM’s high efficiency step-down switching regulator BD8966FVM is a power supply designed to produce a low voltage

including 1 volts from 5/3.3 volts power supply line. Offers high efficiency with synchronous rectifier. Employs a current mode

control system to provide faster transient response to sudden change in load.

●Features

1) Offers fast transient response with current mode PWM control system.

2) Offers highly efficiency for all load range with synchronous rectifier (Nch/Pch FET)

3) Incorporates soft-start function.

4) Incorporates thermal protection and ULVO functions.

5) Incorporates short-current protection circuit with time delay function.

6) Incorporates shutdown function

7) Employs small surface mount package : MSOP8

●Applications

Power supply for LSI including DSP, Micro computer and ASIC

●Absolute maximum ratings

Parameter

Symbol

VCC

Ratings

-0.3～+7 ^*1

-0.3～+7

387.5^*2

Unit

V

VCC Voltage

PVCC Voltage

EN Voltage

PVCC

VEN

V

SW,ITH Voltage

VSW,VITH

Pd1

V

Power Dissipation 1

mW

℃

Power Dissipation 2

Pd2

587.4^*3

Operating temperature range

Storage temperature range

Maximum junction temperature

Topr

-25～+85

-55～+150

+150

Tstg

℃

Tjmax

℃

*1

Pd should not be exceeded.

Derating in done 3.1mW/℃ for temperatures above Ta=25℃.

Derating in done 4.7mW/℃ for temperatures above Ta=25℃, Mounted on 70mm×70mm×1.6mm Glass Epoxy PCB.

*2

*3

●Operating Conditions (Ta=25℃)

Limits

Typ.

5.0

-

Parameter

Symbol

Unit

Min.

4.0

0

Max.

5.5

*4

VCC

V

A

V

VCC Voltage

*4

PVCC

5.5

PVCC Voltage

VEN

Isw ^*4

VOUT

VCC

0.8

EN Voltage

-

SW average output current

1.0

-

2.5

Output voltage Setting Range

*4

Pd should not be exceeded.

www.rohm.com

2010.04 - Rev.B

1/14

Technical Note

BD8966FVM

●Electrical characteristics

◎(Ta=25℃, VCC=5V, EN=VCC, R1=20kΩ, R2=10kΩ unless otherwise specified.)

Limits

Parameter

Symbol

Unit

Conditions

Min.

-

Typ.

0

Max.

10

450

0.8

-

Standby current

ISTB

ICC

µA

V

EN=GND

Bias current

-

250

GND

VCC

1

EN Low voltage

VENL

VENH

IEN

-

Standby mode

Active mode

VEN=5V

EN High voltage

2.0

-

V

EN input current

Oscillation frequency

Pch FET ON resistance

Nch FET ON resistance

ADJ voltage

10

1.2

600

500

0.82

-

µA

MHz

mΩ

V

FOSC

RONP

RONN

VADJ

ITHSI

0.8

-

1

350

250

0.80

20

PVCC=5V

-

0.78

10

3.20

3.25

1.5

0.5

ITH SInk current

µA

V

VADJ=H

ITH Source Current

UVLO threshold voltage

UVLO release voltage

Soft start time

ITHSO

VUVLO1

VUVLO2

TSS

20

-

VADJ=L

3.40

3.50

3

3.6

3.80

6

VCC=4→0V

VCC=0→4V

VADJ=H

V

ms

Timer latch time

TLATCH

2

3

SCP/TSD operated

●Block diagram, Application circuit

VCC

EN

3

V^CC

8

VREF

2.9 0.1

Input

7

+6

-4

4

PV^CC

Max3.25(include.BURR)

Current

Comp.

8

5

Current

Sense/

Protect

Q

R

D

6

8

9

6

Gm Amp.

S

Output

+

SLOPE

CLK

6

OSC

UVLO

TSD

V^CC

SW

Lot No.

Driver

Logic

1

4

+0.05

0.145

-0.03

0.475

1PIN MARK

Soft

Start

5

4

S

PGND

GND

+0.05

0.22

-0.04

1

2

0.08 S

0.65

ADJ

ITH

Fig.2 BD8966FVM Block Diagram

PIN function

Fig.1 BD8966FVM View

●Pin No. & function table

Pin No.

Pin name

1

2

3

4

5

6

7

8

ADJ

ITH

Output voltage detect pin

GmAmp output pin/Connected phase compensation capacitor

Enable pin(Active High)

EN

GND

PGND

SW

Ground

Nch FET source pin

Pch/Nch FET drain output pin

Pch FET source pin

PVCC

VCC

VCC power supply input pin

www.rohm.com

2010.04 - Rev.B

2/14

Technical Note

BD8966FVM

●Characteristics data (Reference data)

2.0

1.5

1.0

0.5

0.0

2.0

1.5

1.0

0.5

0.0

2.0

【VOUT=1.8V】

Ta=25℃

Io=0A

1.5

1.0

0.5

0.0

V_CC=5V

Ta=25℃

Io=0A

V_CC=5V

Ta=25℃

0

1

2

3

0

1

2

3

4

5

0

1

2

3

4

5

INPUT VOLTAGE:V [V]

CC

OUTPUT CURRENT:I

[A]

EN VOLTAGE:VEN[V]

OUT

Fig.3 Vcc-Vout

Fig.5 Iout-Vout

Fig.4 Ven-Vout

1.85

1.84

1.83

1.82

1.81

1.80

1.79

1.78

1.77

1.76

1.75

100

90

80

70

60

50

40

30

20

10

0

1.20

1.15

1.10

1.05

1.00

0.95

0.90

0.85

0.80

【VOUT=1.8V】

VCC=5V

V_CC=5V

Io=0A

V_CC=5V

Ta=25℃

-25 -15 -5

5

15 25 35 45 55 65 75 85

1

10

100

1000

-25 -15 -5

5

15 25 35 45 55 65 75 85

TEMPERATURE:Ta[

]

OUTPUT CURRENT:I_OUT[mA]

℃

TEMPERATURE:Ta[

]

℃

Fig.6 Ta-VOUT

Fig.7 Efficiency

Fig.8 Ta-FOSC

2.0

1.8

1.6

1.4

1.2

1.0

0.8

0.6

0.4

0.2

0.0

350

300

250

200

150

100

50

0.40

0.35

0.30

0.25

0.20

0.15

0.10

0.05

0.00

V_CC=5V

PMOS

NMOS

V_CC=5V

0

-25 -15 -5

5

15 25 35 45 55 65 75 85

-25 -15 -5

5

15 25 35 45 55 65 75 85

-25 -15 -5

5

15 25 35 45 55 65 75 85

TEMPERATURE:Ta[

]

℃

TEMPERATURE:Ta[

]

TEMPERATURE:Ta[

]

℃

Fig.9 Ta-RONN, RONP

Fig.10 Ta-VEN

Fig.11 Ta-ICC

www.rohm.com

2010.04 - Rev.B

3/14

Technical Note

BD8966FVM

1.2

1.1

1

【V^OUT=1.8V】

【PWM

SW

VOUT=1.8V】

VCC=PVCC

=EN

VOUT

V^OUT

0.9

0.8

V

_CC=5V

Ta=25℃

Io=0A

V_CC=5V

Ta=25℃

4

4.5

5

5.5

INPUT VOLTAGE:V^CC[V]

Fig.13 Soft start waveform

Fig.12 Vcc-Fosc

Fig.14 SW waveform

【V^OUT=1.8V】

VOUT

98mV

90mV

IOUT

I^OUT

V_CC=5V

Ta=25℃

V^CC=5V

Ta=25℃

Fig.16 Transient response

Io=600→100mA(10µs)

Fig. 15 Transient response

Io=100→600mA(10µs)

www.rohm.com

2010.04 - Rev.B

4/14

Technical Note

BD8966FVM

●Information on advantages

Advantage 1:Offers fast transient response with current mode control system.

BD8966FVM (Load response IO=0.1A→0.6A)

Conventional product (Load response IO=0.1A→0.6A)

V^OUT

VOUT

110mV

90mV

I^OUT

IOUT

Voltage drop due to sudden change in load was reduced .

Fig.17 Comparison of transient response

Advantage 2: Offers high efficiency with synchronous rectifier

100

90

80

70

60

50

40

30

20

10

0

【VOUT=1.5V】

・For heavier load:

Utilizes the synchronous rectifying mode and the low on-resistance MOS FETs

incorporated as power transistor.

ON resistance of P-channel MOS FET : 350mΩ(Typ.)

ON resistance of N-channel MOS FET : 250mΩ(Typ.)

V_CC=5V

Ta=25℃

1

10

100

1000

10000

OUTPUT CURRENT:I^OUT[mA]

Fig.18

Advantage 3:・Supplied in smaller package due to small-sized power MOS FET incorporated.

・Output capacitor Co required for current mode control:10μF ceramic capacitor

・Inductance L required for the operating frequency of 1 MHz: 4.7μH inductor

Reduces a mounting area required.

V^CC

15mm

CIN

Cin

R^ITH

L

DC/DC

Convertor

Controller

L

V^OUT

10mm

CITH

RITH

CITH

Co

C^O

Fig.19 Example application

www.rohm.com

2010.04 - Rev.B

5/14

Technical Note

BD8966FVM

●Operation

BD8966FVM is a synchronous rectifying step-down switching regulator that achieves faster transient response by employing

current mode PWM control system.

○Synchronous rectifier

It does not require the power to be dissipated by a rectifier externally connected to a conventional DC/DC converter IC,

and its P.N junction shoot-through protection circuit limits the shoot-through current during operation, by which the power

dissipation of the set is reduced.

○Current mode PWM control

Synthesizes a PWM control signal with a inductor current feedback loop added to the voltage feedback.

・PWM (Pulse Width Modulation) control

The oscillation frequency for PWM is 1 MHz. SET signal form OSC turns ON a P-channel MOS FET (while a

N-channel MOS FET is turned OFF), and an inductor current I_Lincreases. The current comparator (Current Comp)

receives two signals, a current feedback control signal (SENSE: Voltage converted from I_L) and a voltage feedback

control signal (FB), and issues a RESET signal if both input signals are identical to each other, and turns OFF the

P-channel MOS FET (while a N-channel MOS FET is turned ON) for the rest of the fixed period. The PWM control

repeats this operation.

SENSE

Current

Comp

V^OUT

RESET

R

S

Q

IL

Level

Shift

FB

SET

Driver

Logic

V^OUT

Gm Amp.

SW

Load

OSC

ITH

Fig.20 Diagram of current mode PWM control

PVCC

Current

Comp

SENSE

FB

SET

GND

RESET

SW

I^L

I^L(AVE)

V^OUT

V^OUT(AVE)

Fig.21 PWM switching timing chart

www.rohm.com

2010.04 - Rev.B

6/14

Technical Note

BD8966FVM

●Description of operations

・Soft-start function

EN terminal shifted to “High” activates a soft-starter to gradually establish the output voltage with the current limited during

startup, by which it is possible to prevent an overshoot of output voltage and an inrush current.

・Shutdown function

With EN terminal shifted to “Low”, the device turns to Standby Mode, and all the function blocks including reference

voltage circuit, internal oscillator and drivers are turned to OFF. Circuit current during standby is 0μF (Typ.).

・UVLO function

Detects whether the input voltage sufficient to secure the output voltage of this IC is supplied. And the hysteresis width of

300mV (Typ.) is provided to prevent output chattering.

Hysteresis 100mV

VCC

EN

V^OUT

Tss

Soft start

Standby

mode

Standby

mode

Standby mode

Operating mode

Standby mode

UVLO

EN

UVLO

Fig.22 Soft start, Shutdown, UVLO timing chart

・Short-current protection circuit with time delay function

Turns OFF the output to protect the IC from breakdown when the incorporated current limiter is activated continuously for

at least 1 ms. The output thus held tuned OFF may be recovered by restarting EN or by re-unlocking UVLO.

EN

Output OFF

latch

V^OUT

Limit

IL

1msec

Standby

mode

Standby

mode

Operating mode

EN

Timer latch

EN

Fig.23 Short-current protection circuit with time delay timing chart

www.rohm.com

2010.04 - Rev.B

7/14

Technical Note

BD8966FVM

●Switching regulator efficiency

Efficiency ŋ may be expressed by the equation shown below:

VOUT×IOUT

Vin×Iin

POUT

η=

×100[%]=

×100[%]

POUT+PDα

Efficiency may be improved by reducing the switching regulator power dissipation factors P_Dα as follows:

Dissipation factors:

1) ON resistance dissipation of inductor and FET:PD(I²R)

2) Gate charge/discharge dissipation:PD(Gate)

3) Switching dissipation:PD(SW)

4) ESR dissipation of capacitor:PD(ESR)

5) Operating current dissipation of IC:PD(IC)

2

1)PD(I²R)=IOUT ×(RCOIL+RON) (RCOIL[Ω]:DC resistance of inductor, RON[Ω]:ON resistance of FET, IOUT[A]:Output current.)

2)PD(Gate)=Cgs×f×V (Cgs[F]:Gate capacitance of FET, f[Hz]:Switching frequency, V[V]:Gate driving voltage of FET)

Vin²×CRSS×IOUT×f

3)PD(SW)=

(CRSS[F]:Reverse transfer capacitance of FET, IDRIVE[A]:Peak current of gate.)

IDRIVE

2

4)PD(ESR)=IRMS ×ESR (IRMS[A]:Ripple current of capacitor、ESR[Ω]:Equivalent series resistance.)

5)PD(IC)=Vin×ICC (ICC[A]:Circuit current.)

www.rohm.com

2010.04 - Rev.B

8/14

Technical Note

BD8966FVM

●Consideration on permissible dissipation and heat generation

As this IC functions with high efficiency without significant heat generation in most applications, no special consideration is

needed on permissible dissipation or heat generation. In case of extreme conditions, however, including lower input

voltage, higher output voltage, heavier load, and/or higher temperature, the permissible dissipation and/or heat generation

must be carefully considered.

For dissipation, only conduction losses due to DC resistance of inductor and ON resistance of FET are considered.

Because the conduction losses are considered to play the leading role among other dissipation mentioned above including

gate charge/discharge dissipation and switching dissipation.

2

P=IOUT ×(RCOIL+RON)

RON=D×RONP+(1-D)RONN

1000

①using an IC alone

D:ON duty (=VOUT/VCC)

RCOIL:DC resistance of coil

RONP:ON resistance of P-channel MOS FET

θj-a=322.6℃/W

②mounted on glass epoxy PCB

800

θj-a=212.8℃/W

①587.4mW

RONN:ON resistance of N-channel MOS FET

IOUT:Output current

600

②387.5mW

If VCC=5V, VOUT=1.5V, RCOIL=0.15Ω, RONP=0.35Ω, RONN=0.25Ω

400

200

0

IOUT=0.8A, for example,

D=VOUT/VCC=1.5/5=0.3

RON=0.3×0.35+(1-0.3)×0.25

=0.105+0.175

=0.28[Ω]

0

25

50

75 85 100

125

150

P =0.8²×(0.15+0.28)

≒275.2[mW]

Fig. 24

As RONP is greater than RONN in this IC, the dissipation increases as the ON duty becomes greater. With the consideration

on the dissipation as above, thermal design must be carried out with sufficient margin allowed.

●Selection of components externally connected

1. Selection of inductor (L)

IL

The inductance significantly depends on output ripple current.

As seen in the equation (1), the ripple current decreases as the

ΔIL

inductor and/or switching frequency increases.

VCC

(VCC-VOUT)×VOUT

ΔIL=

[A]・・・(1)

L×VCC×f

IL

L

Appropriate ripple current at output should be 30% more or less of

the maximum output current.

VOUT

ΔIL=0.3×IOUTmax. [A]・・・(2)

Co

(VCC-VOUT)×VOUT

L=

[H]・・・(3)

ΔIL×VCC×f

(ΔIL: Output ripple current, and f: Switching frequency)

Fig.25 Output ripple current

* Current exceeding the current rating of the inductor results in magnetic saturation of the inductor, which decreases

efficiency.

The inductor must be selected allowing sufficient margin with which the peak current may not exceed its current rating.

If VCC=5V, VOUT=1.5V, f=1MHz, ΔIL=0.3×0.8A=0.24A, for example,

(5-1.5)×1.5

L=

=4.375μ → 4.7[μH]

0.24×5×1M

* Select the inductor of low resistance component (such as DCR and ACR) to minimize dissipation in the inductor for

better efficiency.

www.rohm.com

2010.04 - Rev.B

9/14

Technical Note

BD8966FVM

2. Selection of output capacitor (CO)

VCC

Output capacitor should be selected with the consideration on the stability region

and the equivalent series resistance required to smooth ripple voltage.

Output ripple voltage is determined by the equation (4)：

V^OUT

L

ΔVOUT=ΔIL×ESR [V]・・・(4)

ESR

(ΔIL: Output ripple current, ESR: Equivalent series resistance of output capacitor)

Co

*Rating of the capacitor should be determined allowing sufficient margin

against output voltage. Less ESR allows reduction in output ripple voltage.

Fig.26 Output capacitor

As the output rise time must be designed to fall within the soft-start time, the capacitance of output capacitor should be

determined with consideration on the requirements of equation (5):

TSS×(Ilimit-IOUT)

VOUT

Tss: Soft-start time

Ilimit: Over current detection level, 2A(Typ)

Co≦

・・・(5)

In case of BD8966FVM, for instance, and if VOUT=1.5V, IOUT=0.8A, and TSS=1ms,

1m×(2-0.8)

Co≦

≒800[μF]

1.5

Inappropriate capacitance may cause problem in startup. A 10 μF to 100 μF ceramic capacitor is recommended.

3. Selection of input capacitor (Cin)

Input capacitor to select must be a low ESR capacitor of the capacitance

sufficient to cope with high ripple current to prevent high transient voltage.

The ripple current IRMS is given by the equation (5):

VCC

Cin

√

V^OUT

VOUT(VCC-VOUT)

IRMS=IOUT×

[A]・・・(5)

L

VCC

Co

< Worst case > IRMS(max.)

IOUT

2

When Vcc is twice the V_OUT, IRMS=

If VCC=5.0V, VOUT=1.5V, and IOUTmax.=0.8A

Fig.27 Input capacitor

√

5(5-1.5)

IRMS=0.8×

=0.67[ARMS]

5

A low ESR 10µF/10V ceramic capacitor is recommended to reduce ESR dissipation of input capacitor for better efficiency.

www.rohm.com

2010.04 - Rev.B

10/14

Technical Note

BD8966FVM

4. Determination of RITH, CITH that works as a phase compensator

As the Current Mode Control is designed to limit a inductor current, a pole (phase lag) appears in the low frequency area

due to a CR filter consisting of a output capacitor and a load resistance, while a zero (phase lead) appears in the high

frequency area due to the output capacitor and its ESR. So, the phases are easily compensated by adding a zero to the

power amplifier output with C and R as described below to cancel a pole at the power amplifier.

fp(Min.)

1

A

0

fp=

fp(Max.)

2π×RO×CO

Gain

[dB]

1

fz(ESR)=

fz(ESR)

2π×ESR×CO

IOUTMin.

I^OUTMax.

Pole at power amplifier

When the output current decreases, the load resistance Ro

increases and the pole frequency lowers.

0

Phase

[deg]

-90

1

fp(Min.)=

[Hz]←with lighter load

2π×ROMax.×CO

Fig.28 Open loop gain characteristics

1

fp(Max.)=

[Hz] ←with heavier load

2π×ROMin.×CO

A

fz(Amp.)

Zero at power amplifier

Gain

[dB]

Increasing capacitance of the output capacitor lowers the pole

frequency while the zero frequency does not change.

(This is because when the capacitance is doubled, the capacitor

ESR reduces to half.)

0

Phase

[deg]

1

fz(Amp.)=

-90

2π×RITH×CITH

Fig.29 Error amp phase compensation characteristics

Cin

L

V^CC

V^CC,PVCC

EN

SW

VOUT

V^OUT

ITH

ESR

C^O

RO

GND,PGND

R^ITH

C^ITH

Fig.30 Typical application

Stable feedback loop may be achieved by canceling the pole fp (Min.) produced by the output capacitor and the load

resistance with CR zero correction by the error amplifier.

fz(Amp.)= fp(Min.)

1

=

2π×RITH×CITH

2π×ROMax.×CO

5. Determination of output voltage

The output voltage VOUT is determined by the equation (7):

4.7µH

VOUT=(R2/R1+1)×VADJ・・・(7) VADJ: Voltage at ADJ terminal (0.8V Typ.)

With R1 and R2 adjusted, the output voltage may be determined as required.

(Adjustable output voltage range: 1.0V～2.5V)

Use 1 kΩ～100 kΩ resistor for R1. If a resistor of the resistance higher than

100 kΩ is used, check the assembled set carefully for ripple voltage etc.

6

1

Output

SW

10µF

R2

R1

ADJ

Fig.31 Determination of output voltage

www.rohm.com

2010.04 - Rev.B

11/14

Technical Note

BD8966FVM

●BD8966FVM Cautions on PC Board layout

VCC

EN

1

2

8

7

ADJ

VCC

ITH

EN

PVCC

SW

L

①

3

6

5

VOUT

GND

RITH

4

CIN

Co

③

GND

PGND

②

CITH

Fig.32 Layout diagram

For the sections drawn with heavy line, use thick conductor pattern as short as possible.

①

②

Lay out the input ceramic capacitor CIN closer to the pins PVCC and PGND, and the output capacitor Co closer to the

pin PGND.

③

Lay out CITH and RITH between the pins ITH and GND as near as possible with least necessary wiring.

●Recommended Components Lists on Above Application

Symbol

Part

Value

Manufacturer

Sumida

TDK

Kyocera

murata

ROHM

Series

CMD6D11B

VLF5014AT-4R7M1R1

CM316X5R106K10A

GRM18series

MCR10 1802

MCR10 2202

MCR10 2702

L

Coil

4.7µH

Ceramic capacitor

CIN

CO

10µF

750pF

CITH

VOUT=1.0V

18kꢀ

22kꢀ

27kꢀ

36kꢀ

VOUT=1.2V

VOUT=1.5V

VOUT=1.8V

VOUT=2.5V

ROHM

RITH

Resistance

MCR10 3602

*

The parts list presented above is an example of recommended parts. Although the parts are sound, actual circuit characteristics should be checked on

your application carefully before use. Be sure to allow sufficient margins to accommodate variations between external devices and this IC when

employing the depicted circuit with other circuit constants modified. Both static and transient characteristics should be considered in establishing these

margins. When switching noise is substantial and may impact the system, a low pass filter should be inserted between the VCC and PVCC pins, and a

schottky barrier diode established between the SW and PGND pins.

●I/O equivalence circuit

・EN pin

PVCC

・SW pin

EN

SW

・ADJ pin

・ITH pin

VCC

10kΩ

ITH

ADJ

Fig.33 I/O equivalence circuit

12/14

www.rohm.com

2010.04 - Rev.B

Technical Note

BD8966FVM

●Notes for use

1. Absolute Maximum Ratings

While utmost care is taken to quality control of this product, any application that may exceed some of the absolute

maximum ratings including the voltage applied and the operating temperature range may result in breakage. If broken,

short-mode or open-mode may not be identified. So if it is expected to encounter with special mode that may exceed the

absolute maximum ratings, it is requested to take necessary safety measures physically including insertion of fuses.

2. Electrical potential at GND

GND must be designed to have the lowest electrical potential In any operating conditions.

3. Short-circuiting between terminals, and mismounting

When mounting to pc board, care must be taken to avoid mistake in its orientation and alignment. Failure to do so may

result in IC breakdown. Short-circuiting due to foreign matters entered between output terminals, or between output and

power supply or GND may also cause breakdown.

4.Operation in Strong electromagnetic field

Be noted that using the IC in the strong electromagnetic radiation can cause operation failures.

5. Thermal shutdown protection circuit

Thermal shutdown protection circuit is the circuit designed to isolate the IC from thermal runaway, and not intended to

protect and guarantee the IC. So, the IC the thermal shutdown protection circuit of which is once activated should not be

used thereafter for any operation originally intended.

6. Inspection with the IC set to a pc board

If a capacitor must be connected to the pin of lower impedance during inspection with the IC set to a pc board, the

capacitor must be discharged after each process to avoid stress to the IC. For electrostatic protection, provide proper

grounding to assembling processes with special care taken in handling and storage. When connecting to jigs in the

inspection process, be sure to turn OFF the power supply before it is connected and removed.

7. Input to IC terminals

This is a monolithic IC with P⁺isolation between P-substrate and each element as illustrated below. This P-layer and the

N-layer of each element form a P-N junction, and various parasitic element are formed.

If a resistor is joined to a transistor terminal as shown in Fig 34.

○P-N junction works as a parasitic diode if the following relationship is satisfied; GND>Terminal A (at resistor side), or

GND>Terminal B (at transistor side); and

○if GND>Terminal B (at NPN transistor side),

a parasitic NPN transistor is activated by N-layer of other element adjacent to the above-mentioned parasitic diode.

The structure of the IC inevitably forms parasitic elements, the activation of which may cause interference among circuits, and/or

malfunctions contributing to breakdown. It is therefore requested to take care not to use the device in such manner that the voltage

lower than GND (at P-substrate) may be applied to the input terminal, which may result in activation of parasitic elements.

Resistor

Transistor (NPN)

B

Pin A

Pin B

C

E

Pin A

B

C

E

N

P⁺

N

P

Parasitic

element

N

Parasitic

element

P substrate

GND

Parasitic element

Other adjacent elements

Fig.34 Simplified structure of monorisic IC

8. Ground wiring pattern

If small-signal GND and large-current GND are provided, It will be recommended to separate the large-current GND

pattern from the small-signal GND pattern and establish a single ground at the reference point of the set PCB so that

resistance to the wiring pattern and voltage fluctuations due to a large current will cause no fluctuations in voltages of the

small-signal GND. Pay attention not to cause fluctuations in the GND wiring pattern of external parts as well.

9 . Selection of inductor

It is recommended to use an inductor with a series resistance element (DCR) 0.1ꢀ or less. Note that use of a high DCR

inductor will cause an inductor loss, resulting in decreased output voltage. Should this condition continue for a specified

period (soft start time + timer latch time), output short circuit protection will be activated and output will be latched OFF.

When using an inductor over 0.1ꢀ, be careful to ensure adequate margins for variation between external devices and this

IC, including transient as well as static characteristics. Furthermore, in any case, it is recommended to start up the output

with EN after supply voltage is within operation range.

www.rohm.com

2010.04 - Rev.B

13/14

Technical Note

BD8966FVM

●Ordering part number

B

D

8

9

6

F

V

M - T

R

Part No.

Package

FVM : MSOP8

Packaging and forming specification

TR: Embossed tape and reel

(MSOP8)

MSOP8

2.9 0.1

(MAX 3.25 include BURR)

Tape

Embossed carrier tape

3000pcs

+

6°

4°

Quantity

−4°

8

7

6

5

TR

Direction

of feed

The direction is the 1pin of product is at the upper right when you hold

reel on the left hand and you pull out the tape on the right hand

(

)

1

2

3

4

1PIN MARK

+0.05

1pin

+0.05

−0.03

0.145

0.475

S

0.22

−0.04

0.08

S

Direction of feed

Order quantity needs to be multiple of the minimum quantity.

0.65

Reel

(Unit : mm)

∗

www.rohm.com

2010.04 - Rev.B

14/14

Notice

N o t e s

No copying or reproduction of this document, in part or in whole, is permitted without the

consent of ROHM Co.,Ltd.

The content speciﬁed herein is subject to change for improvement without notice.

The content speciﬁed herein is for the purpose of introducing ROHM's products (hereinafter

"Products"). If you wish to use any such Product, please be sure to refer to the speciﬁcations,

which can be obtained from ROHM upon request.

Examples of application circuits, circuit constants and any other information contained herein

illustrate the standard usage and operations of the Products. The peripheral conditions must

be taken into account when designing circuits for mass production.

Great care was taken in ensuring the accuracy of the information speciﬁed in this document.

However, should you incur any damage arising from any inaccuracy or misprint of such

information, ROHM shall bear no responsibility for such damage.

The technical information speciﬁed herein is intended only to show the typical functions of and

examples of application circuits for the Products. ROHM does not grant you, explicitly or

implicitly, any license to use or exercise intellectual property or other rights held by ROHM and

other parties. ROHM shall bear no responsibility whatsoever for any dispute arising from the

use of such technical information.

The Products speciﬁed in this document are intended to be used with general-use electronic

equipment or devices (such as audio visual equipment, ofﬁce-automation equipment, commu-

nication devices, electronic appliances and amusement devices).

The Products speciﬁed in this document are not designed to be radiation tolerant.

While ROHM always makes efforts to enhance the quality and reliability of its Products, a

Product may fail or malfunction for a variety of reasons.

Please be sure to implement in your equipment using the Products safety measures to guard

against the possibility of physical injury, ﬁre or any other damage caused in the event of the

failure of any Product, such as derating, redundancy, ﬁre control and fail-safe designs. ROHM

shall bear no responsibility whatsoever for your use of any Product outside of the prescribed

scope or not in accordance with the instruction manual.

The Products are not designed or manufactured to be used with any equipment, device or

system which requires an extremely high level of reliability the failure or malfunction of which

may result in a direct threat to human life or create a risk of human injury (such as a medical

instrument, transportation equipment, aerospace machinery, nuclear-reactor controller, fuel-

controller or other safety device). ROHM shall bear no responsibility in any way for use of any

of the Products for the above special purposes. 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

R1010

A


型号：	BD8966FVM_10
厂家：	ROHM
描述：	Low Noise High Efficiency Step-down Switching Regulator with Built-in Power MOSFET 低噪音高效率降压开关稳压器具有内置功率MOSFET 稳压器开关
文件：	总15页 (文件大小：390K)
中文：	中文翻译
下载：	下载PDF数据表文档文件

BD8966FVM_10 [ROHM]

相关型号：

BD8966FVM_12

BD8967FVM

BD8967FVM-TR

BD8967FVM_12

BD896A

BD896A

BD896A

BD897

BD897

BD897

BD897

BD897