ROHM BD8118FM

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STRUCTURE
PRODUCT NAME
TYPE
FEATURES
Silicon Monolithic Integrated Circuit
White LED driver for car navigation back light
BD8118FM
・Step-up DC/DC converter
・Built in UVLO
Built in OSC
・Built in OVP
・4 parallel current output (output current is set with external resister)
・LED open detection circuit
・Built in TSD
・PWM adjustment
・Built in OCP
・FAIL output (self diagnosis)
●ABSOLUTE MAXIMUM RATINGS (Ta=25℃)
PARAMETER
Power supply voltage(Pin : 1)
Load switch output voltage(Pin : 2)
SYMBOL
LIMITS
UNIT
VCC
36
V
VLOADSW
36
V
LED output voltage(Pin : 12, 14, 15, 17)
VLED
36
V
FAIL output voltage(Pin : 3, 20)
VOL
7
V
VIN
-0.3~7 < VCC
V
VDAC
-0.3~7 < VCC
V
Input voltage(Pin : 5, 6, 10, 11, 24)
VDAC input voltage(Pin : 8)
Power dissipation
※1
Pd
2.20
Junction Temperature
Tjmax
150
℃
W
Operating temperature range
Topr
-40~+95
℃
Strage temperature range
Tstg
-55~+150
℃
LED drive current(Pin : 12, 14, 15, 17)
ILED
150 ※2※3
mA
※1 70mm×70mm×1.6mm glass epoxy mounting. Decline by 17.6mw/℃
※2 It is correlate LED drive current with VF dispersion each of current outputs. Refer to the technical note.
※3 Current maximum for 1ch. Do not however exceed Pd.
●Operating range(Ta=25℃)
SYMBOL
LIMITS
Power Supply Voltage(Pin : 1)
PARAMETER
VCC
4.5~30
V
Oscillation frequency(Pin : 26)
FOSC
50~550
kHz
FSYNC
fosc~550
kHz
External synchronous frequency(Pin : 6)
※4 ※5
UNIT
External synchronous pulse(Pin : 6)
FSDUTY
40~60
%
※4 SYNC have to be connected to GND when external synchronizing frequency is not needed.
※5 Don’t change external synchronous frequency to internal oscillation frequency when external synchronous frequency is inputted.
* This product is not designed for protection against radioactive rays.
REV. A
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●ELECTRICAL CHARACTERISTICS(Unless otherwise specified Ta=25℃, VCC=12V)
LIMIT
PARAMETER
SYMBOL
Min
Typ
Max
UNIT
CONDITIONS
EN=2V, SYNC=VREG, RT=OPEN
PWM=OPEN, ISET=OPEN, CIN=1μF
EN=Low
Circuit current
ICC
2.5
6
10
mA
Standby current
[VREG] (Pin : 4)
VREG output voltage
[SW] (Pin : 22, 23)
SWOUT upper ON resistance
SWOUT lower ON resistance
Over current protection limited voltage
[error amp] (Pin : 12, 14, 15, 17, 27, 28)
LED control voltage
COMP shink current
COMP source current
SS charge current
SS maximum voltage
SS standby current
[frequency] (Pin : 23, 26)
Oscillation frequency
[OVP] (Pin : 25)
Over voltage detection voltage
OVP hysteresis range
[UVLO] (Pin : 4)
UVLO detection voltage
UVLO Hysteresis range
[Load SW] (Pin : 2)
Load sw low voltage
IST
-
0
2
μA
VREG
4.5
5
5.5
V
IREG=-10mA, CREG=1μF
RONH
RONL
VDCS
0.05
0.05
0.3
3
2
0.4
7
5
0.5
Ω
Ω
V
ION=-10mA
ION=10mA
VCS=sweep up
VLED
ISKCP
ISCCP
ISS
VMXSS
ISTSS
0.7
40
-200
-14
2
-
0.8
100
-100
-10
2.5
0
0.9
200
-40
-6
3
2
V
μA
μA
μA
V
μA
VLED=2V, Vcomp=1V
VLED=0V, Vcomp=1V
VSS=1.0V
EN=High
EN=Low
FOSC
250
300
350
KHz
RT=100kΩ
VDOVP
VDOHS
1.86
0.35
2.0
0.45
2.14
0.55
V
V
VOVP=Sweep up
VOVP=Sweep down
VDUVLO
VDUHS
2.5
50
2.8
100
3.1
200
V
mV
VREG=Sweep down
VREG=Sweep up
VLDL
0.05
0.15
0.3
V
[LED output] (Pin : 5, 9, 12, 14, 15, 17, 25)
LED current relative dispersion width
LED current absolute dispersion width
ISET voltage
PWM frequency
PWM adjustment
ΔILED1
ΔILED2
VISET
Duty
FPWM
-6
0
1.96
0.38
0
0
3
2.00
-
6
6
2.04
99.5
20
%
%
V
%
KHz
Open detection voltage1
VDOP1
0.05
0.15
0.3
V
Open detection voltage2
VDOP2
1.56
1.7
1.84
V
VINH
VINL
IIN
IEN
2.6
GND
18
13
35
25
5.5
0.8
53
38
V
V
μA
μA
VFLL
0.05
0.1
0.2
[Logic input] (Pin : 5, 6, 10, 11, 24)
Input high voltage
Input low voltage
Input current
Input current
[FAIL output] (Pin : 3, 20)
FAIL low voltage
◎ This product is not designed for protection against radioactive rays.
● PHYSICAL DIMENSIONS・MARKING
Product
series
Max 18.85 (include BURR)
BD8118FM
Lot No.
HSOP-M28 (UNIT:mm)
REV. A
V
ILOAD=10mA
ILED=50mA
ILED=50mA
ILED=50mA
FPWM=150Hz, ILED=50mA ※1, 2, 3
Duty=50%,ILED=50mA ※2, 3
VLED= Sweep down, VOVP>VDOP2,
VSS≧VMXSS
VOVP= Sweep up, VLED > VDOP1,
VSS≧VMXSS
VIN=5V (Pin : 5, 6, 10, 11)
VEN=5V (Pin : 24)
IOL=1mA
※1 0%, 100% input possible
※2 ILED=VDAC÷RISET×3300
※3 ILED=VISET÷RISET×3300, VDAC>VISET
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●BLOCK DIAGRAM
VREG
LOADSW
VCC
OVP
VREG
UVLO
TSD
OVP
FAIL1
EN
Driver
PW M Comp
SWOUT
SYNC
OSC
RT
-
+
+
Control
Log ic
CS
-
+
OCP
ERR Amp
-
-
-
-
+
COMP
GND
LED1
Soft
SS
Start
LED2
LED3
Current driver
PWM
LED4
ISET
VDAC
PGND
ISET
Open
Detect
FAIL2
LEDEN1
●Pin No, Pin Name, Function
Pin
Pin
No
Name
Function
Power supply
LEDEN2
Pin
No
Pin
Name
Function
15
LED3
LED output (Open Drain)
1
VCC
2
LOADSW
FET pin for load sw (Open Drain)
16
-
3
FAIL1
Fail signal output (Open Drain)
17
LED4
4
VREG
Internal voltage regulator
18
-
N.C
LED output (Open Drain)
N.C.
5
PWM
PWM adjustment input
19
-
6
SYNC
External synchronizing input
20
FAIL2
Fail signal output (Open det : Open Drain)
N.C.
LED output GND pin
7
GND
Ground pin
21
PGND
8
VDAC
DC flexible input
22
CS
9
ISET
LED output current set resistor
23
SWOUT
10
LEDEN1
LED output enable pin1
24
EN
11
LEDEN2
LED output enable pin2
25
OVP
12
LED1
LED output (Open Drain)
26
RT
Frequency set resistor
N.C.
27
SS
Softstart pin
LED output (Open Drain)
28
COMP
13
-
14
LED2
REV. A
DC/DC output current detection pin
DC/DC SW output pin
Enable pin
OVP pin over voltage detection pin
Error amp output
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● Operation Notes
(1) Absolute maximum ratings
Use of the IC in excess of absolute maximum ratings such as the applied voltage or operating temperature range may result in IC damage.
Assumptions should not be made regarding the state of the IC (short mode or open mode) when such damage is suffered.
A physical safety measure such as a fuse should be implemented when use of the IC in a special mode where the absolute maximum
ratings may be exceeded is anticipated.
(2) Reverse connection of a power supply connector
If the connector of power is wrong connected, it may result in IC breakage. In order to prevent the breakage from the wrong
connection, the diode should be connected between external power and the power terminal of IC as protection solution.
(3) Power supply and ground lines.
Fluctuating voltage on the power supply and ground lines may damage the device. Be sure to connect a bypass filter capacitor as close
as possible to the IC between the power supply and ground pins. Check that the selected capacitance will not have an adverse influence
on any characteristics, such as a drop in the electrolytic capacitor value that can occur at low temperatures.
(4) GND potential
Ensure a minimum GND pin potential in all operating conditions.
(5) Setting of heat
Use a setting of heat that allows for a sufficient margin in light of the power dissipation (Pd) in actual operating conditions.
(6) Pin short and mistake fitting
Use caution when orienting and positioning the IC for mounting on printed circuit boards.Improper mounting may result in damage to the
IC. Use of the IC in excess of absolute maximum ratings such as the applied voltage or operating temperature range may
result in IC damage.
(7) Actions in strong magnetic field
Use caution when using the IC in the presence of a strong electromagnetic field as doing so may cause the IC to malfunction.
(8) Thermal shutdown circuit(TSD)
This IC built-in a Thermal shutdown circuit (TSD circuit). If Chip temperature becomes 175℃(TYP.), make the output an Open
state. Eventually, warmly clearing the circuit is decided by the condition of whether the heat excesses over the assigned limit, resulting
the cutoff of the circuit of IC, and not by the purpose of preventing and ensuring the IC. Therefore, the warm switch-off should not be
applied in the premise of continuous employing and operation after the circuit is switched on.
(9) Testing on application boards
When testing the IC on an application board, connecting a capacitor to a pin with low impedance subjects the IC to stress.
Always discharge capacitors after each process or step. Ground the IC during assembly steps as an antistatic measure, and use similar
caution when transporting or storing the IC. Always turn the IC's power supply off before connecting it to or removing it from a jig or
fixture during the inspection process
(10) IC terminal input
This monolithic IC contains P+ isolation and P substrate layers between adjacent elements in order to keep them isolated. P/N junctions are formed
at the intersection of these P layers with the N layers of other elements to create a variety of parasitic elements.
For example, when a resistor and transistor are connected to pins. (See the chart below.)
 the P/N junction functions as a parasitic diode when GND > (Pin A) for the resistor or GND > (Pin B) for the transistor (NPN).
 Similarly, when GND > (Pin B) for the transistor (NPN), the parasitic diode described above combines with the N layer of other adjacent
elements to operate as a parasitic NPN transistor.
The formation of parasitic elements as a result of the relationships of the potentials of different pins is an inevitable result of the IC's architecture. The
operation of parasitic elements can cause interference with circuit operation as well as IC malfunction and damage. For these reasons, it is necessary
to use caution so that the IC is not used in a way that will trigger the operation of parasitic elements, such as by the application of voltages lower than
the GND (PCB) voltage to input pins.
(Pin A)
B
(Pin B)
C
(Pin B)
E
GND
B
+
P
P
+
P
N
+
P
N
N
N
P Substrate
Parasitic diode
GND
N
P
C
E
+
P
GND
near by other element
N
N
parasitic diode
P Substrate
Parasitic diode
GND
Fig of chart of Parasitic diode
(11) Ground wiring patterns
When using both small signal and large current GND patterns,it is recommended to isolate the two ground patterns,placing a single ground
point at the application's reference point so that the pattern wiring resistance and voltage variations caused by large currents do not
cause variations in the small signal ground voltage. Be careful not to change the GND wiring patterns of any external components.
(12) LED output terminal
Don’t connect Capacitor to LED output terminal (Pin : 12,14,15,17), as doing so may cause LED short detection to malfunction.
REV. A
Notice
Notes
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