ROHM BD6077GUT-E2

BD6077GUT
LED Drivers for LCD Backlights
White Backlight LED Drivers
for Small to Medium LCD Panels
(Switching Regulator Type)
BD6077GUT
No.11040EAT41
●Description
The BD6077GUT is a white LED driver IC with synchronous rectification that can drive up to 3LEDs.
With synchronous rectification (no external schottky diode required) and small package, they can save mount space.
And the brightness of LED can be adjusted by using PWM pulse on EN pin.
●Features
1) Synchronous rectification Boost DC/DC converter
2) No external schottky diode required
3) Driving 3 series white LEDs
4) Over voltage protection
5) Protect open and short output
6) Thermal shut down
7) Brightness adjustment by external PWM pulse
8) Small and Thin CSP package in 8pins
●Applications
White LED Backlight
Torchlight and easy flash for camera of mobile phone
●Absolute maximum ratings (Ta=25°C)
Parameter
Symbol
Ratings
Unit
Maximum applied voltage 1
VMAX1
7 *1
V
Vin, EN, VFB, TEST
Maximum applied voltage 2
VMAX2
20 *1
V
SW, Vout
Pd
750 *2
mW
Operating temperature range
Topr
-30~+85
℃
Storage temperature range
Tstg
-55~+150
℃
Power dissipation
Condition
*1 These value are based on GND and GNDA pins.
*2 50mm×58mm×1.75mm At glass epoxy board mounting. When it’s used by more than Ta=25 ℃, it’s reduced by 6.0mW/℃.
●Operating conditions (Ta=25°C)
Parameter
Power supply voltage
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Symbol
Vin
Ratings
Min.
Typ.
Max.
2.7
3.6
5.5
1/16
Unit
Condition
V
2011.12 - Rev.A
Technical Note
BD6077GUT
●Electrical characteristics
Unless otherwise specified Ta =-30℃~+85℃, Vin=3.1~5.5V
Limits
Parameter
Symbol
Min.
Typ.
Max.
Unit
Condition
[ EN terminal ]
EN threshold voltage (Low)
VthL
-
-
0.4
V
EN threshold voltage (High)
VthH
1.4
-
-
V
Iin
-
18.3
30.0
µA
EN=5.5V
Iout
-2.0
-0.1
-
µA
EN=0
Quiescent Current
Iq
-
0.1
2.0
µA
EN=TEST=VFB=0V,SW=open
Current Consumption
Idd
-
1.0
1.5
mA
EN=1.4V,TEST=0V,VFB=1.0V,
SW=open
Feedback voltage
Vfb
0.47
0.50
0.53
V
Inductor current limit
Icoil
210
310
410
mA
SW saturation voltage
Vsat
-
0.245
0.345
V
Isw=200mA, Vin=3.6V
SW on resistance P
Ronp
-
5.4
7.2
Ω
Isw=200mA, Vout=10V
Switching frequency
fSW
0.8
1.0
1.2
MHz
Duty cycle limit
Duty
82.7
95.0
-
%
Over voltage limit
Ovl
14.0
14.5
15.0
V
EN terminal input current
EN terminal output current
[ Switching regulator ]
1
EN=1.4V,TEST=0V
EN=1.2V, TEST=2.9V,
Vin=3.6V,VOUT=9V (*1)
EN=1.4V,TEST=0V,VFB=0V,
VOUT=10V,SW=open
EN=1.4V,TEST=0V,VFB=0V,
VOUT=10V,SW=open
EN=1.4V,TEST=0V,VFB=0V,
SW=open
This parameter is tested with DC measurement.
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2/16
2011.12 - Rev.A
Technical Note
BD6077GUT
●Test circuit
*Test circuit A (for Inductor current limit, Feedback voltage.)
Procedure
~Inducton current limit~
1. Start to increase Iout from 0mA gradually.
2. You will find that Vout will start to go down and the duty will be decreased.
3. Then, you can measure the coil current as “inductor current limit”
~VFB voltage~
1. Supply 0mA to Iout
2. Then, you can measure the VFB voltage as “Feedback voltage”.
Icoil
3.1~5.5V
VIN
22µH
monitor
A
1µF
Tall
Ton
SW
VIN
VOUT
Duty=
Ton
Tall
1µF
EN
Iout
TEST
GNDA
VFB
GND
RFB
24Ω
V
Fig.1 Test Circuit A
*Test circuit B (for Over voltage limit,Duty cycle limit, Switching frequency)
Procedure
~Over voltage limit~
1. Start to increase VOUT from 12V to 16V
2. You will find frequency change from around 1MHz to 0Hz
3. Then,you can measur the VOUT voltage as “Over Voltage limit”
~Duty cycle limit, Switching frequency ~
1. Supply 9V to VOUT terminal
2. Then,you can measure the duty as “Duty cycle limit” and the frequency and “Switching frequency”.
monitor
3.1~5.5V
VIN
Ton
SW
VIN
VOUT
1µF
1µF
EN
TEST
GNDA
Tall
Duty=
Ton
Tall
12V to 16V
VFB
GND
Fig.2 Test Circuit B
*TEST circuit C
(for Quiescent current, current comsumption, EN Terminal input/output current, EN threshold voltage(Low/High))
ICC
3.1~5.5V
1uF
A
VIN
SW
A
EN
VOUT
IEN
0.0~5.5V
TEST
TEST
GNDA
GND VFB
1.0V(current comsumption)
Fig.3 Test Circuit C
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3/16
2011.12 - Rev.A
Technical Note
BD6077GUT
1.0
4
0.8
3
Ta=85℃
2
Ta=25℃
1.2
1.1
Frequency [MHz]
5
IIN[uA]
IIN[mA]
●Electrical characteristic curves (Reference data)
0.6
0.4
Ta=85℃
0.2
1
1
2
3
0.9
Ta=25℃
0.0
4
VIN[V]
5
6
0.8
1
7
Fig.4 Current consumption
vs.
Power supply voltage
2
3
4
5
VIN[V]
6
7
2.5
450
525
400
3
500
475
Ta=-30℃
VIN=3.6V
VIN=5.5V
5
5.5
Murata : LQH32CN53L
80
350
300
VIN=3.1V
75
70
TOKO : DB3015CK
65
60
250
55
450
2.7 3.1 3.5 3.9 4.3 4.7 5.1 5.5
200
Ta[℃]
-30
Fig.7 Feedback voltage
vs.
Power supply voltage
-10
10
30
50
Ta [deg]
Output Power[mW]
VIN=3.6V
VIN=4.2V
70
35
40
85
Ta=-30℃
Ta=25℃
1000
800
Ta=85℃
600
Ta=25℃
65
60
25
30
Iout [mA]
35
40
Fig.10 Efficiency vs. LED current
(3LED=VOUT10.5V)
coil : TOKO DB3015CK
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80
Ta=85℃
75
Ta=25℃
70
65
400
20
25
30
Iout[mA]
90
1200
15
20
Ta=-30℃
80
10
15
Fig.9 Efficiency vs. LED current
(4LED=VOUT14V)
1400
85
VIN=3.1V
10
Fig.8 Inductor current limit
vs.
Temperature
VIN=5.5V
75
50
85
70
Efficiency[%]
90
Efficiency [%]
4.5
90
Efficiency[%]
Inductor current [mA]
VFB[mV]
Ta=85℃
4
Fig.6 Oscillation frequency
vs.
Power supply voltage
85
Ta=25℃
3.5
VIN[V]
Fig.5 Quiescent current
vs.
Power supply voltage
550
Ta=85℃
Ta=25℃
Ta=-30℃
Ta=-30℃
0
Ta=-30℃
1.0
60
3.0
3.2
3.4
3.6 3.8
VIN[V]
4.0
4.2
Fig.11 Output power
vs.
Power supply voltage
coil : TOKO DB3015CK
4/16
2.7
3.1
3.5
3.9 4.3
VIN[V]
4.7
5.1
5.5
Fig.12 Efficiency
vs.
Power supply voltage
(Load=34mA)
coil : TOKO DB3015CK
2011.12 - Rev.A
Technical Note
BD6077GUT
●Electrical characteristic curves (Reference data) – Continued
VOUT
EN
VOUT
EN
VOUT
VFB
Peak=208mA
delta=1.68V
VFB
Peak=160m
Iin
Iin
Vin=3.6V, Ta=25 oC
3LED, 34mA Load
Fig.13 LED Open output voltage
Fig.14 LED brightness adjustment
Fig.15 Soft Start
50
500
20%
40
15%
VIN=4.2V
VIN=4.2V
VFB[mV]
VIN=3.9V
200
VIN=5.2V
VFB[mV]
30
300
VIN=3.9V
20
VIN=5.2V
VIN=3.1V
VIN=3.1V
10
VIN=3.6V
100
10%
VIN=3.6V
20
40
60
Duty[%]
80
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2
4
100
Fig.16 LED brightness adjustment
for PWM control
VIN=3.6V
0%
-5%
VIN=3.1V
VIN=4.2V
-15%
0
0
VIN=5.2V
5%
-10%
0
0
VFB voltage variation
400
Duty[%]
6
8
10
-20%
0
Fig.17 LED brightness adjustment
for PWM control (Expansion)
5/16
20
40
60
Duty[%]
80
100
Fig.18 LED brightness variation
for PWM control
(comparison of VFB at VIN=3.9V)
2011.12 - Rev.A
Technical Note
BD6077GUT
●Block diagram and pin configuration
L
22µH
CIN
1µF
VIN
SW
VOUT
over voltage
protect
Q2
short protect
TSD
Q1
Q
S
Q
R
PWMcomp
Current
Sence
COUT
1µF
+
+
VFB
+
RFB
24Ω
OSC
GND
GNDA
EN
white LED
ERRAMP
+
Control
+
-
TEST
Fig.19 Block diagram and recommended circuit diagram
C1
C2
B3
B1
A1
C3
A2
A3
Fig.20 Pin location diagram VCSP60N1( 8 pin )
●Pin assignment table
PIN Name
In/Out
Ball number
Function
GNDA
-
A1
Analog GND
EN
In
A2
Enable control (pull down by inner resistor)
TEST
In
A3
TEST input (pull down by inner resistor)
VIN
In
B1
Power supply input
VFB
In
B3
Feedback voltage input
VOUT
Out
C1
Boost output
SW
In
C2
Switching terminal
GND
-
C3
Power GND
●Operation
BD6077GUT is PWM current mode DC/DC converter with fixed frequency. It adopts synchronous rectification architecture.
The feature of the PWM current mode is that input is the combination of error components from the error amplifier, and a
current sense signal that controls the inductor current into Slope waveform for sub harmonic oscillation prevention.
This output controls Q1 and Q2 via the RS latch. Timing of Q1 and Q2 is precisely adjusted so that they will not turn ON at
the same time, thus putting them into non-overlapped relation. In the period when Q1 is ON, energy is accumulated in the
external inductor, and in the period when Q1 is OFF, energy is transferred to the capacitor of VOUT via Q2. Further more,
BD6077GUT has many safety functions, and their detection signals stop switching operation at once.
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6/16
2011.12 - Rev.A
Technical Note
BD6077GUT
●Functional descriptions
1) Soft start and off status
BD6077GUT has soft start function and off status function.
The soft start function and the off status function prevent large current from flowing to the IC via coil.
The soft start function prevents rush current when turning on and the off status function prevents invalid current when
turning off.
・Soft start
When VOUT is smaller than Vshort, to decrease charge current PMOS is set to off by PMOS Startup Control (in Term
“I”). Vshort means “VOUT short detect voltage”. After VOUT is bigger than Vshort, PMOS is turned on and start
switching. In term “II” (Vshort < VOUT < VIN), status of Current Limiter is “soft mode”. So “A” voltage is restricted and
“D” duty is kept low. Therefore VOUT voltage goes up slowly and coil current is restricted. In term III (VOUT > VIN),
status of Current Limiter is “normal mode”. So “A” voltage goes up suitable voltage, and “D” duty goes up slowly. And
then VOUT voltage goes up to required voltage.
Operation
Current at start
Current at PWM
Max current
380mA
270mA
LED [email protected],
COUT : 1µ[email protected] X5R
Vout
LED current
L
ERRAMP
PWM comp
SW
A
Soft
Current
limit
B
R
Q
S
Q
D
C
PMOS
Startup
Control
Off Status
Soft Reference
Charge
current
OSC
FB
24ohm
Fig. 21 lock diagram of soft start and off status
EN
I
II
III
VIN
Vshort
VOUT
Normal
mode
Current
Limit
Soft
mode
D
Fig. 22 timing chart
・Off status
The gate voltage of the switching Tr either "H" or "L" at power off depends on the operation conditions at that time. When
it is fixed to "H", the switching Tr remains to be ON, and invalid current from the battery is consumed. In order to prevent
this, at power off, D is always fixed to L level. So that, it is possible to prevent invalid current at power off.
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7/16
2011.12 - Rev.A
Technical Note
BD6077GUT
2) Isolation control
BD6077GUT has isolation control to prevent LED wrong lighting at power off.
The cause of the LED wrong lighting is leak current from VIN to the white LED.
Therefore, when BD6077GUT powered off (EN = L), the isolation control cuts the DC path between SW and Vout, so that,
it prevents from leak current from VIN to LED.
VIN
SW
White LED
Vout
VFB
Fig.23 Isolation control
3) Short-circuit protection and over voltage protection
BD6077GUT has short-circuit protection and over voltage protection. These detect the voltage of VOUT, and at error, they
stop the output Tr. Details are as shown below.
・Short-circuit protection
In the case of short-circuit of the DC/DC output (VOUT) to GND, the coil or the IC may be destroyed.
Therefore, in a case of error as VOUT becomes 0.7V or lower, the Under Detector shown in the figure works, and turns
off the output Tr, and prevents the coil and the IC from being destroyed.
And the IC turns into non operation condition from operation condition, and current does not flow to the coil (0mA).
・Over voltage protection
In a case of error as the IC and the LED being cut off, over voltage causes the SW terminal and the VOUT terminal
exceed the absolute maximum ratings, and may destroy the IC. Therefore, when VOUT becomes 14.5V or higher, the
over voltage limits works, and turns off the output Tr, and prevents the SW terminal and the VOUT terminal from
exceeding the absolute maximum ratings.
At this moment, turns into non operation condition from operation condition, and the output voltage goes down slowly.
And, when the output voltage becomes the hysteresis of the over voltage limit or below, the output voltage goes on up
to 14.5V once again.
This protection action is shown in Fig.24.
Cout
SW
Vout
OVER Detector
OVER VOLTAGE REF
driver
UNDER Detector
UNDER VOLTAGE REF
Control
Fig.24 Block diagram of short-circuit protection and over voltage
4) Thermal shut down
BD6077GUT has thermal shut down function.
The thermal shut down works at 175°C or higher, and while holding the setting of EN control from the outside, turns into
non operation condition from operation condition. And at 175°C or below, the IC gets back to its normal operation.
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8/16
2011.12 - Rev.A
Technical Note
BD6077GUT
●Start control and brightness control
BD6077GUT can control the start conditions by its EN terminal, and power off at 0.4V or below, and power on at 1.4V or
higher. And by changing the duty of power on and off by PWM control, the LED brightness can be adjusted.
Two techniques are available for the brightness adjustment. One is PWM adjustment, and the other is analog adjustment.
(1) PWM brightness adjustment is done by giving PWM signal to EN as shown in Fig.25.
The BD6077GUT is powered on/off by the PWM signal. By this method, LED current is controlled from 0 to the maximum
current. The average LED current increases with proportion to the duty cycle of PWM signal. While in PWM off-cycle mode,
the IC and LED both consume no currents, thus providing a high-efficiency operation. The recommended PWM frequency
is 100Hz ~ 300Hz.
22µH
VIN
SW
VIN
VOUT
PWM
1µF
EN
TEST
GNDA
GND
VFB
24Ω
Fig.25 The brightness adjustment example of EN terminal by PWM (fPWM = 100 ~ 300Hz)
High Pulse
Minimum High Pulse = 26µs
(Duty = 1/128)
Range of Period = 3.3 ~ 10 ms
EN
Period
Low Pulse
Minimum Low Pulse = 26µs
(Duty = 127/128)
Range of Period = 3.3 ~ 10 ms
EN
Period
Fig.26 The Rule of PWM signal of EN
●FB characteristic on PWM function
BD6077GUT constantly controls the rising time to decrease the tolerance of the FB voltage at PWM function.
EN
PWM1 Pulse = 26µs
(Duty = 1/128)
(300Hz)
400 μ s typ
VFB
EN
Fig.27 VFB signal at PWM
Compare the value of VFB average voltage
at VBAT=4.2V and at VBAT=3.9V in PWM1.
(PWM1 = 1/128 Duty)
Difference between VBAT=3.9V and 4.2V
VFB voltage is less than 3%.
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VFB
Average of This period
time
(VFB)
Fig.28 VFB Line Regulation (PWM1)
9/16
2011.12 - Rev.A
Technical Note
BD6077GUT
●VBAT characteristic in Battery charge
Transient during Battery charger is normally +300mV, 1Hz(duty 50%) from a baseline Battery Voltage 3.1 to 2.8V. In this
term, it is necessary that VOUT Voltage noise is less than 200mVp-p.
VBAT [V]
20µs
VBAT [V]
20µs
4ms
3.1V
3.1V
2.8V
300mVp- p
2.8V
600µs
time
time
VOUT [V]
less than 200mVp -p
time
VFB[V]
less than 100mVp -p
time
Fig.29 Battery Voltage transient during charger
●Setting range of LED current
LED current is determined by the voltage of VFB
and the resistor connected to VFB terminal.
ILED is given as shown below.
ILED=VFB/RFB
The current in the standard application is as shown below.
VFB=0.5V, RFB=24Ω
ILED=20.8mA
22µH
VIN
1µF
SW
VIN
VOUT
PWM
EN
1µF
ILED
TEST
GNDA
GND
VFB
RFB
24Ω
Fig.30 standard application
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10/16
2011.12 - Rev.A
Technical Note
BD6077GUT
●Load Regulation Test
The load current from VOUT is set as 15mA(LED)+10mA(key) and +10mA is set to ON/OFF and tested. At that time, VOUT
and Ripple of VFB are measured. (VOUT : less than 700mV,VFB : less than 150mV) The difference of VFB voltage in case
load is ON and the voltage at the time of being OFF is measured. (≤ ±1%)
22µH
VIN
1µF
SW
VIN
VOUT
PWM
EN
less than 700mVp-p
I load
VOUT
1µF
ILED
TEST
GNDA
Less than 150mVp-p
1kΩ
GND
VFB
VFB
Aver.A
RFB
33Ω
24Ω
ON/OFF
Aver.B
I load
1 - A/B = less than 1%
Fig.31 Load Regulation Test circuit
Fig.32 Transient Load Regulation test
The shaded portion in the figure below is the setting range of LED current to become the standard. Depending on coils and
white LEDs to be used, however, some ICs may not be used at desired currents. Consequently, for the proper setting of
LED current, thoroughly check it for the suitability under use conditions including applicable power supply voltage and
temperature.
80
Po=310mW Line
70
ILED [mA]
60
50
40
30
20
10
0
7
8
9
10
11
12
13
14
VOUT [V]
Fig.33 Setting range of LED current
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11/16
2011.12 - Rev.A
Technical Note
BD6077GUT
●Selection of external parts
Recommended external parts are listed as below.
When to use other parts than these, select the following equivalent components.
・Coil
Value
Tolerance
Manufacturer
Product number
Vertical
size
Size
Horizontal
size
22µH
±10%
MURATA
LQH32CN220K53
2.5
22µH
±20%
MURATA
LQH3NPN220MGOL
22µH
±20%
Panasonic
22µH
±20%
Taiyo Yuden
Height
DCR
(Ω)
3.2
1.55
0.710
3.0
3.0
0.9
1.100
ELLVEG220NN
3.0
3.0
0.9
1.440
NR3010T220M
3.0
3.0
1.0
1.236
22µH
±20%
TDK
VLS3010T-220MR46
3.0
3.0
Please refer to the reference data of p.4 for the change in the efficiency when the coil is changed.
1.0
・Capacitor
Value
Manufacturer
Product number
Vertical
size
Size
Horizontal
size
MURATA
GRM188B11A105K
1.6
MURATA
GRM188R61C105K
Height
Temperature
range
0.8
0.8
-25℃~+85℃
1.6
0.8
0.8
-55℃~+85℃
[ CIN ]
1µF
[ COUT ]
1µF
・Resistor
Value
Tolerance
Manufacturer
Product number
Vertical
size
Size
Horizontal
size
±1%
ROHM
MCR006YZPF□□□□
0.6
0.3
Height
[ RFB ]
24Ω
0.23
Value □□□□
15Ω 15R0
24Ω 24R0
33Ω 33R0
The coil is the component that is most influential to efficiency. Select the coil which direct current resistor (DCR) and current
- inductance characteristic are excellent. The BD6077GUT are designed for the inductance value of 22µH. Please do not
use other inductance value. Select a capacitor of ceramic type with excellent frequency and temperature characteristics.
Further, select Capacitor to be used for CIN/COUT with small direct current resistance, and pay much attention to the PCB
layout shown in the next page.
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12/16
2011.12 - Rev.A
Technical Note
BD6077GUT
●PCB layout
In order to make the most of the performance of this IC, PCB layout is very important.
Please note that characteristics such as efficiency and ripple will likely to change greatly depending on PCB layout.
To battery power source
CIN
GNDA
EN
TEST
VIN
VFB
VOUT
SW
RLED
GND
To battery GND
COUT
L1
Fig.34 PCB layout
Connect the input bypath capacitor CIN between VIN and GNDA pin closely, as shown in the upper diagram. Thereby, the
input voltage ripple of the IC can be reduced. And, connect the output capacitor COUT between VOUT and GND pin closely.
Thereby, the output voltage ripple of the IC can be reduced. Connect the current setting RLED FB pin closely. Connect the
GND closely connection side of RLED directly to GND pin. Connect the GNDA pin directly to GND pin. When those pins are
not connected directly near the chip, the performance of BD6077GUT shall be influenced and may limit the current drive
performance. As for the wire to the inductor, make its resistance component small to reduce electric power consumption
and increase the entire efficiency. Please keep away which are subject to be influenced like FB pin in wire connection with
SW. The layout pattern in consideration of these is shown in the next page.
VOUT
83mV
(VBAT=3.6V, Ta=25 oC, VOUT=10V. 34mA Load)
Fig.35 Output noise
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13/16
2011.12 - Rev.A
Technical Note
BD6077GUT
●Recommended PCB layout
FB
EN
GNDA
GND
LED
Cin
RFB
1 1V
1 1V
1 2G
LED
Cout
SW
SW
L1
VOUT
LED
VBAT
1 2G
VOUT
GND
VOUT
Fig.36 Front surface (TOP VIEW)
VOUT
Fig.37 Rear surface (TOP VIEW)
●Attention point for PCB layout
For PCB layout design, the wire of power supply line should be low Impedance, and put bypass capacitor if necessary.
Especially the wiring impedance must be low around DC/DC converter.
●About heat loss
For heat design, operate DC/DC converter in the following condition.
(The following temperature is a guaranteed temperature, margin will be needed.)
1. Periphery temperature Ta must be less than 85℃.
2. The loss of IC must be less than dissipation Pd.
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14/16
2011.12 - Rev.A
Technical Note
BD6077GUT
●Notes for use
1) Absolute Maximum Ratings
An excess in the absolute maximum ratings, such as supply voltage, temperature range of operating conditions, etc.,
can break down devices, thus making impossible to identify breaking mode such as a short circuit or an open circuit. If
any special mode exceeding the absolute maximum ratings is assumed, consideration should be given to take physical
safety measures including the use of fuses, etc.
2) Operating conditions
These conditions represent a range within which characteristics can be provided approximately as expected. The
electrical characteristics are guaranteed under the conditions of each parameter.
3) Reverse connection of power supply connector
The reverse connection of power supply connector can break down ICs. Take protective measures against the
breakdown due to the reverse connection, such as mounting an external diode between the power supply and the IC’s
power supply terminal.
4) Power supply line
Design PCB pattern to provide low impedance for the wiring between the power supply and the GND lines. In this
regard, for the digital block power supply and the analog block power supply, even though these power supplies has
the same level of potential, separate the power supply pattern for the digital block from that for the analog block, thus
suppressing the diffraction of digital noises to the analog block power supply resulting from impedance common to the
wiring patterns. For the GND line, give consideration to design the patterns in a similar manner.
Furthermore, for all power supply terminals to ICs, mount a capacitor between the power supply and the GND terminal.
At the same time, in order to use an electrolytic capacitor, thoroughly check to be sure the characteristics of the
capacitor to be used present no problem including the occurrence of capacity dropout at a low temperature, thus
determining the constant.
5) GND voltage
Make setting of the potential of the GND terminal so that it will be maintained at the minimum in any operating state.
Furthermore, check to be sure no terminals are at a potential lower than the GND voltage including an actual electric
transient.
6) Short circuit between terminals and erroneous mounting
In order to mount ICs on a set PCB, pay thorough attention to the direction and offset of the ICs. Erroneous mounting
can break down the ICs. Furthermore, if a short circuit occurs due to foreign matters entering between terminals or
between the terminal and the power supply or the GND terminal, the ICs can break down.
7) Operation in strong electromagnetic field
Be noted that using ICs in the strong electromagnetic field can malfunction them.
8) Inspection with set PCB
On the inspection with the set PCB, if a capacitor is connected to a low-impedance IC terminal, the IC can suffer stress.
Therefore, be sure to discharge from the set PCB by each process. Furthermore, in order to mount or dismount the set
PCB to/from the jig for the inspection process, be sure to turn OFF the power supply and then mount the set PCB to
the jig. After the completion of the inspection, be sure to turn OFF the power supply and then dismount it from the jig. In
addition, for protection against static electricity, establish a ground for the assembly process and pay thorough attention
to the transportation and the storage of the set PCB.
9) Input terminals
In terms of the construction of IC, parasitic elements are inevitably formed in relation to potential. The operation of the
parasitic element can cause interference with circuit operation, thus resulting in a malfunction and then breakdown of
the input terminal. Therefore, pay thorough attention not to handle the input terminals, such as to apply to the input
terminals a voltage lower than the GND respectively, so that any parasitic element will operate. Furthermore, do not
apply a voltage to the input terminals when no power supply voltage is applied to the IC. In addition, even if the power
supply voltage is applied, apply to the input terminals a voltage lower than the power supply voltage or within the
guaranteed value of electrical characteristics.
10) 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.
11) External capacitor
In order to use a ceramic capacitor as the external capacitor, determine the constant with consideration given to a
degradation in the nominal capacitance due to DC bias and changes in the capacitance due to temperature, etc.
12) Thermal shutdown circuit (TSD)
When junction temperatures become 175°C (typ) or higher, the thermal shutdown circuit operates and turns a switch
OFF. The thermal shutdown circuit, which is aimed at isolating the LSI from thermal runaway as much as possible, is
not aimed at the protection or guarantee of the LSI. Therefore, do not continuously use the LSI with this circuit
operating or use the LSI assuming its operation.
13) Thermal design
Perform thermal design in which there are adequate margins by taking into account the permissible dissipation (Pd) in
actual states of use.
14) Selection of coil
Select the low DCR inductors to decrease power loss for DC/DC converter.
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15/16
2011.12 - Rev.A
Technical Note
BD6077GUT
●Ordering part number
B
D
ROHM
type name
6
0
7
Part No.
6077
7
G
U
T
-
Package
GUT: VCSP60N1
E
2
Packaging and forming specification
E2: Embossed tape and reel
VCSP60N1 (BD6077GUT)
<Tape and Reel information>
Tape
Embossed carrier tape
Quantity
3000pcs
Direction
of feed
(Unit:mm)
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© 2011 ROHM Co., Ltd. All rights reserved.
E2
The direction is the 1pin of product is at the upper left when you hold
( reel on the left hand and you pull out the tape on the right hand
1pin
Reel
16/16
)
Direction of feed
∗ Order quantity needs to be multiple of the minimum quantity.
2011.12 - Rev.A
Notice
Notes
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, communication 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
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of the Products for the above special purposes. If a Product is intended to be used for any
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R1120A