ROHM BD8641EFV

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STRUCTURE :
PRODUCT NAME
:
BD8641EFV
MODEL NAME:
FEATURES
:
Silicon Monolithic Integrated Circuit
Synchronous rectification with built-in FET type DC/DC converter IC
・Synchronous rectification with built-in FET type DC/DC converter
・Reference voltage accuracy FB 0.8V±1%
・Switching frequency 250kHz~2.3MHz(Synchronizable with external clock.)
・Over current protection circuit
・Thermal shutdown
・Output voltage watch (VDET) function
・Input low voltage detection (UVLO) function
・Soft start / Start delay circuit
◎ABSOLUTE MAXIMUM RATING (Ta=25℃)
Parameter
Input supply voltage
Input terminal voltage
Output terminal voltage
Output current
Power dissipation
Operating temperature
Storage temperature
Symbol
PVIN, SVIN
VINP*1
*2
VOUT
IOUT
Pd
Topr
Tstg
Limits
7
VIN
VIN
4
*3
3.2
-40 ~ 85
-55 ~ 150
Unit
V
V
V
A
W
℃
℃
*1 VINP Application terminal: SYNCLK, EN, SS/DELAY, FB
*2 VOUT Application terminal:SW, VDET, FC, RT
*3 (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
MIN
3.0
-
TYP
-
This product is not designed for protection against radioactive rays.
Status of this document
The Japanese version of this document is the formal specification.
A customer may use this translation version only for a reference to help reading the formal version.
If there are any differences in translation version of this document, formal version takes priority.
Be careful to handle because the content of the description of this material might correspond to the labor
(technology in the design, manufacturing, and use) in foreign country exchange and Foreign Trade Control Law.
REV. C
MAX
5.5
3
Unit
V
A
2/4
◎Electrical characteristic
(Unless otherwise noted Ta=25℃, PVIN, SVIN=3.3V, GND=0V)
Specification value
Parameter
Symbol
MIN
TYP
MAX
VIN supply current (operating)
IQ_active
380
570
VIN supply current (standby)
IQ_stby
0
10
VREF
0.792
0.8
0.808
Reference voltage (VREF)
Output rise detection voltage
VOVP
30
60
90
Output decrease detection voltage
VLVP
-90
-60
-30
Terminal VDET output current
IVDET
0.4
Oscillation frequency
fOSC
2.0
2.3
2.6
Pch FET ON resistance
RPFET
75
110
Nch FET ON resistance
RNFET
55
90
UVLO voltage
VUVLO
2.35
2.50
2.65
SW leak current
ILSW
0
10
EN terminal H threshold voltage
VENH
1.1
EN terminal L threshold voltage
VENL
0.4
FC sink current
IFCSI
5
10
FC source current
IFCSO
-10
-5
SS/DELAY terminal source current
ISSSO
2
4
6
UNIT
μA
μA
V
mV
mV
mA
MHz
mΩ
mΩ
V
μA
V
V
μA
μA
μA
Condition
VFB = 0.83V, VFC = 1V
VEN = 0V
Monitoring FB terminal
Monitoring FB terminal
VVDET < 0.3V
RRT = 43kΩ
ISW = 1A
ISW = -1A
VEN= 0V, VIN = 5.5V
●VFB :FB terminal voltage、VEN :EN terminal voltage、VFC :FC terminal voltage、VVDET: VDET terminal voltage
●Current capability should not exceed Pd.
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10
Detect Abnormal
Voltage
and Start error
PWM
CONTROL
◎BLOCK DIAGRAM
◎PIN ASSIGNMENT
No.
Symbol
Description
No.
Symbol
1
2
3
4
5
6
7
8
9
10
SGND
RT
VDET
SW
SW
PGND
PGND
PGND
SW
SW
Signal GND terminal
Frequency adjustment resistance connection terminal
Output abnormality detection terminal
Switching output terminal
Switching output terminal
Power GND terminal
Power GND terminal
Power GND terminal
Switching output terminal
Switching output terminal
11
12
13
14
15
16
17
18
19
20
PVIN
PVIN
PVIN
SVIN
SYNCLK
EN
NC
SS/DELAY
FC
FB
Description
Power supply input terminal
Power supply input terminal
Power supply input terminal
Signal system power supply input terminal
Input terminal for external clock synchronization
Enable input terminal
Soft start adjustment capacity connection terminal
Phase amends terminal
Feedback terminal
◎PACKAGE OUTLINE
Product number
BD8641
1PIN MARK
Lot No.
HTSSOP-B20 (UNIT:mm)
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◎NOTE ON USE
1.About the absolute maximum rating
Attention is brushed off enough to the quality control, it is likely to destroy when the absolute maximum rating such as impressed voltages
(VCC_IN,DCIN) and ranges (Topr) of the operating temperature as it is exceeded, the mode of breakings of the short or the opening, etc. cannot
be specified, and examine it in this IC to give physical measures for safety such as fuses when a special mode that exceeds the absolute
maximum rating is assumed.
2.About the reverse-connection of the power supply connector
IC might destroy it by reversely connecting the power supply connector. Give measures such as putting the diode between power supply
terminals of power supply and IC outside for the reverse-touching destruction protection.
3.Power supply line
Please do measures such as putting the bypass capacitor in power supply-GND nearest pin of this IC as the route of the resurrection current to
cause the return of the current in which it resurrected it by the counter electromotive force of the coil.
Please confirm the characteristic of the electrolytic capacitor enough as the capacity omission etc. at the low temperature never happen, and
decide it.
4.About grand potential
Any state of operation must become the lowest potential about the potential of the terminal GND. Moreover, confirm whether there is terminal that
is actually the voltage of GND or less including transients.
5.About the heat design
Think about permissible loss (Pd) in an actual state of use, and do the heat design with the margin enough.
6.About the short and the miss-installation between terminals
Note the direction and the miss-registration of IC enough when you install it in the set substrate. IC might destroy it as well as reversely connecting
the power supply connector when installing it by mistake. Moreover, there is fear of destruction when the foreign body enters between terminals,
the terminal, the power supply, and grandeur and it is short-circuited.
7.About operation in strong electromagnetic field
In use in strong electromagnetic field, note that there is a possibility of malfunctioning.
8.About the capacitor during output-GND
The current charged the capacitor with when VCC is 0V or is GND and is short-circuited when a big capacitor is connected between GND output
by some factors flows into the output and it is likely to destroy it. Give the capacitor between GND output to 0.1μF or less.
9.About the inspection by the set substrate
It is likely to suffer stress to IC and discharge electricity every one process when you connect the capacitor with the pin with low impedance when
inspecting it in the set substrate. Moreover, detach it after connecting after the power supply is turned off without fail when detaching it to G in the
inspection process, inspecting, and turning off the power supply. n addition, be give the earth to the assembly process as a static electricity
measures, and careful enough when it transports and you preserve it.
10.About each input terminal
+
This IC is a monolithic IC which has a P isolations and P substrate to isolate elements each other.
This P layer and an N layer in each element form a PN junction to construct various parasitic elements.
For instance, the potential difference operates in resistance as shown in the figure below when resistance and the transistor connect it with the
terminal and the playground (GND) >(terminal B) joint of PN operates as a parasitic diode in playground (GND) >(terminal A) transistor (NPN). In
addition, the NPN transistor of parasitism works with N layer of the element of the above-mentioned parasitic diode and the neighborhood and
others in transistor (NPN). A parasitic element in IC composition is inevitably formed because of the potential relation.
A parasitic element can operate, the interference with the circuit operation be caused, it malfunction, and, consequently, it cause destruction.
Therefore, do not do the usage that a parasitic element operates as a voltage that is lower than the playground (GND;P substrate) is impressed to
the input terminal enough. Moreover, do not impress the voltage to the input terminal when you do not impress the power-supply voltage to IC.
Give each input terminal to me the voltage below the power-supply voltage or in the guarantee value of an electric characteristic when you
similarly impress the power-supply voltage.
Example of IC of simple structure
11.Earth wiring pattern
If small signal GND and large current GND exist, disperse their pattern. In addition, for voltage change by pattern wiring impedance and large
current not to change voltage of small signal GND, each ground terminal of IC must be connected at the one point on the set circuit board. As for
GND of external parts, it is similar to the above-mentioned.
12.Thermal Shut-Down
When a thermal shutdown operates, the DC/DC converter controller of all Ch is turned off. When a thermal shutdown is released, the DC/DC
converter controller of all Ch becomes an operation beginning from turning off.
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Appendix
Notes
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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
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Appendix-Rev4.0