TOSHIBA TB62732FUG

TB62732FUG
TOSHIBA BiCD Digital Integrated Circuit Silicon Monolithic
TB62732FUG
Step-up DC/DC Converter for White LED Driver
The TB62732FUG is a high-efficiency step-up DC/DC converter
designed and optimized for the constant-current lighting of white
LEDs.
This IC is particularly suitable for illuminating two to four
serial white LEDs with a Li-ion battery.
The IC incorporates an N-ch MOS transistor, which is
necessary for switching of the coil.
Also, the LED current IF can be easily set through the use of
an external resistor.
The TB62732FUG is best suited for use as a driver for white
LED source backlighting in color LCDs used on PDAs, cellular
phones and handy terminal devices.
The suffix (G) appended to the part number represents a Lead
(Pb) -Free product.
Weight: 0.016 g (typ.)
Features
•
LED current values can set through the use of an external resistor
15 mA (typ.) @R_sens = 3.3 Ω
18.5 mA (typ.) @R_sens = 2.7 Ω
•
Efficiency of 80% realized (serial LEDs 2 to 3, IF = 20 mA)
•
Maximum output voltage: Vo = 17 V
•
Output power: Up to 320 mW supported
•
Compact package: 6-pin SOT23 (SSOP6-P-0.95B)
•
Built-in N-channel MOS with low ON-resistance (Ron)
Ron = 2.0 Ω (typ.) @VCC = VIN = 3.6 V
•
Switching frequency: 1.1 MHz (typ.)
•
Output capacitor
•
Inductance: 2.2 µH to 10 µH
Small capacity of 0.47 µF
Pin assignment (top view)
K
<
A
GND
GND
SHDN
VCC
Note 1: This product contains pins that are vulnerable to electrostatic discharge. Handle with care.
This IC may break if mounted 180 degrees in the reverse direction. Be sure to orientate the IC in the
correct direction.
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TB62732FUG
Block Diagram
A
VCC
S R Q
1.1 MHz
Iref
SHDN
K
GND
Pin Functions
No
Symbol
1
K
Function
Pin connecting LED cathode to resistor used to set current.
Feedback pin for voltage waveforms for controlling the LED constant current.
2, 5
GND
Ground pin for the logic
3
SHDN
IC enable pin.If Low, Standby Mode takes effect and pin A is turned off.
4
VCC
Input pin for power supply for operating the IC.
Operating voltage range: 3.0 to 5.5 V
6
A
DC-DC converter switch pin.
The switch is an N-channel MOSFET transistor.
Note 2: Connect both GND pins to ground.
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TB62732FUG
Absolute Maximum Ratings
Characteristics
Symbol
Rating
Unit
Supply voltage
VCC
−0.3 to +6.0
V
Input voltage
VIN
−0.3 to +VCC + 0.3
V
Switching pin current
Io (A)
380
mA
Switching pin voltage
Vo (A)
−0.3 to 17
V
0.41 (IC only)
Power dissipation
PD
0.47 (IC mounted on PCB)
(Note 3)
W
Saturation thermal resistance
Rth (j-a)
300 (IC only)
260 (IC mounted on PCB)
°C/W
Operating temperature range
Topr
−40 to +85
°C
Storage temperature range
Tstg
−40 to +150
°C
Tj
125
°C
Maximum junction temperature
Note 3: The power dissipation is derated by 3.8 mW/°C from the absolute maximum rating for every 1°C exceeding
the ambient temperature of 25°C (when the IC is mounted on a PCB).
Recommended Operating Conditions
(unless otherwise specified, Ta = 25°C and VCC = 3.6 V)
Symbol
Test
circuit
Test condition
Min
Typ.
Max
Unit
Supply voltage
VCC
⎯
⎯
3.0
⎯
4.3
V
SHDN pin high-level input voltage
VIH
⎯
VCC = 3 to 4.3 V
2.6
⎯
VCC
V
SHDN pin low-level input voltage
VIL
⎯
VCC = 3 to 4.3 V
0
⎯
0.5
V
tpw SHDN
⎯
SHDN = High and Low level
50
⎯
⎯
µs
Io
⎯
VCC = 3 V,
illuminating series LEDs 2 to 4
5
⎯
20
mA
Characteristics
SHDN pin input pulse width
Set LED current
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TB62732FUG
Electrical Characteristics
(unless otherwise specified, Ta = 25°C, VCC = 3.6 V, VSHDN = 3.6 V)
Symbol
Test
circuit
Test condition
Min
Typ.
Max
Unit
VCC
⎯
⎯
3.0
⎯
5.5
V
Current consumption at operation
ICC (on)
⎯
SHDN = VCC
⎯
0.52
0.8
mA
Current consumption at standby
ICC (off)
⎯
SHDN = 0 V
⎯
0.5
1.0
µA
SHDN pin current
I_SHDN
⎯
SHDN = VCC,
Built-in pull-down resistor
⎯
4.2
7
µA
Ron
⎯
Io = 300 mA,
detection resistance value is
contained
⎯
2.0
2.5
Ω
Characteristics
Supply voltage
MOS transistor on-resistance
fOSC
⎯
⎯
0.77
1.1
1.43
MHz
Pin A voltage
Vo (A)
⎯
⎯
17
⎯
⎯
V
Pin A current
Io (A)
⎯
⎯
⎯
350
380
mA
Pin A leakage current
Ioz (A)
⎯
⎯
⎯
0.5
1
µA
⎯
18.5
⎯
mA
⎯
±8
±12
%
MOS transistor switching frequency
Set LED current IF
Io
⎯
LED current VCC dependence
dIo
⎯
R_sens = 2.7 Ω,
L = 6.8 µH
(Note 4)
Note 4: Fluctuation in R_sens resistors is not included in the specified value.
The absolute value of Io may vary and therefore differ from the value specified due to the relation between
the inductor value and the load.
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TB62732FUG
IL, ILpeak
10 µH
A
VCC
S R Q
ZD
C2
Ic2
1.1 MHz
C1
Iref
Io= If LED
K
GND
Figure 1
C3
R_sens
Amp
Application Circuit
Basic Operation
The basic TB62732FUG circuit uses a step-up DC/DC converter, and features peak control of the current
pulse.
The inductance is turned on and off with the fixed frequency fOSC (1.1 MHz (typ.)), and the inductor is charged
with energy.
When the inductance is turned on, the inductor current IL increases from IL = 0; and when IL = ILpeak is
reached, the inductance is turned off.
At this point, the Schottky diode is turned on and IL = Ic2 flows so that the coil may retain IL = ILpeak.
After that, Ic2 is decreased, and IL = 0 is reached.
This operation is repeated; and as soon as Ic2 has fully charged C2, Io flows to the LED.
The details of the basic pulse used for the current control are shown in Figure 2.
IL = ILpeak
ILpeak = 350 mA (typ.)
VIN
SHDN
0 (mA)
min
Maximum duty 85%
Waveform of recommend
inductance 1
Recommended inductor
waveform 1
Recommended inductor
waveform (max.)
T = 1/fOSC, fOSC = 1.1 MHz (typ.)
Figure 2 Switching Waveform of Inductance
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TB62732FUG
Switching frequency
fOSC = 1.1 MHz
Maximum On pulse
width = 85%
LED VF
Pin A voltage
I A (peak)
As I A (peak) is lowered, it is stabilized at the set value
Io..
Pin A current (external
inductance current)
As I A (peak) is lowered, it is stabilized at the set value
Io .
Pin K voltage (current
charged on capacitor)
Figure 3 Burst Control Waveforms
State of Peak Current Control
“Peak current control” is control that can vary the peak current pulse shown in Figure 2 on the previous page.
The current pulse in Figure 2 is a charging current on the output side capacitor C2. This is supplied to the LED
as a C2 discharge current and flows through the R_sens resistor to GND.
The charging voltage wave form of C2 is fed back to the IC from pin K.
In the internal circuit to which it is assumed pin K is input, the mean value of the AC voltage waveform
obtained decreases the peak current to an assumed value of approximately 48 to 54 mV.
As a result, a constant current is controlled as an average current in the LED.
Therefore, if R_sens = 2.7 Ω is connected, an IF current of 19.6 mA can be obtained.
The TB62732FUG is designed to be able to supply a load power of 320 mW (min.). With an inductance of 4.7
to 10 µH, the boost inductor has been optimally designed for this load power of 320 mW.
Also, make the inductance small when the load power is low.
A condition applying to the LED load between pins A and K is that
VIN (VCC) < LED VF total
should be strictly maintained.
The LED will be illuminated always regardless of the IC control. Care should be taken in this regard.
Standby Operation
Pin A
voltage
The SHDN pin is used to set normal or standby
operation. When SHDN is set to Low, operation is in
standby; when the pin is High, the LED is turned on.
Current consumption in Standby Mode is 1 µA (max).
5 V/DIV
Pin K
tvoltage
Drive Waveform
0.5 V/DIV
The figure on the left is an actual drive waveform.
From the top, the switching voltage waveform of
the coil of the generator terminal (pin A), the
feedback voltage wave form of pin K, and the LED
IF .
IF current
20 mA/DIV
C2 = 0.1 µF
t
200 ns/DIV
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2006-06-14
TB62732FUG
Output-side capacitor setting
To reduce the effect of ripple current, we recommend C2 = 0.47 (µF) or above.
Capacitor C2
(µF)
Ripple Current
0.01
15 to 25
0.1
5 to 8
0.47
2 to 4
1
1 to 3
(mA)
Note
Recommend
External inductance setting
The minimum external inductance is calculated as follows:
L (µH) = ((K × Po) − VIN min × IO) × (1/fOSC min) × 2 × (1/Ip min × Ip min) . . . formula 2
The above parameters are described below:
Po: output power (power required by LED load)
Po (W) = VF LED × IF LED + Vf schottky × IF LED + R_sens × IF LED × IF LED
LED forward current: IF LED (mA) = Set current: IO (mA), LED forward voltage: VF LED (V),
Schottky diode forward voltage: Vf schottky (V),
Setting resistance: R_sens (Ω)
VIN min (V): Minimum input voltage (battery voltage)
IO (A): The average current value established with R_sens.
fOSC (Hz): The switching frequency of the internal MOS transistor
fOSC
Min
Typ.
Max
Unit
0.77
1.1
1.43
MHz
Ip (A): Peak current value for supply to the inductance
Ip
Min
Typ.
Max
Unit
320
350
380
MHz
For example, the following condition is substituted for the formula:
Input voltage VIN: VIN = 3 to 4.3 V,
VF LED = 16 V, Schottky diode Vf: Schottky = 0.3 (V),
Setup resistance R_sens: R_sens = 2.7 (Ω),
Setup current IO: IO = 18.5 mA,
L (µH) = 5.6 (µH, VIN = 3.0 V) and 6.3 (µH, VIN = 4.3 V).
In this case, Toshiba recommend selection of L = 5.6 (µH) when VCC = 3 V. .
This value does not allow for inductor variation and temperature characteristics; therefore we strongly
recommend that these factors be taken into account when selecting products.
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TB62732FUG
Selection of R_sens
The resistance R_sens (Ω) between pin K and GND is used for setting the output current IO. The mean output
current IO can be set using this resistance.
The mean current IO (mA) to be set is roughly calculated as follows:
Io (mA) = V (K): pin K feedback voltage (mV) ÷ R_sens Ω)
Number of LEDs
Pin K voltage
V (K)
2
48
3
50
4
52
Note
For example, if R_sens = 2.7 (Ω), then IO = 18.5 (mA) with a current error of ±12%.
The IC has a minimum output Po = 320 (mW).
In this case, if the product Po of the set current IF LED and the output voltage VF LED exceeds Po = 320 (mW), it
is possible that the current IF LED will not exceed a given value.
If the IC is not connected to the smoothing capacitor, then IF LED is obtained as the mean current.
In this instance, because the current which flows to the LED is a triangular waveform current with a maximum
peak value of 380 mA, make sure that the inrush current IFP (mA) does not flow to the LED.
Toshiba recommend use of components with low reactance (parasitic inductance) and minimized PCB wiring.
Protection for when the LED is open
The zener diode in the example application circuit in Figure 1 is necessary for over-voltage protection when the
LED is open.
It is strongly recommended that a zener diode be connected since this driver lacks a voltage protection circuit.
The zener voltage should satisfy the following conditions:
≤ maximum output voltage of the TB62732FUG
i)
ii) ≥ LED aggregate Vf
iii) ≤ maximum output capacitance C2.
Moreover, it is possible to control the output current IZD for when the LED is open by connecting the R_ZD as in
Figure 4, and to use a zener diode with lower power dissipation.
Standard for Control of Output Current IZD through R_ZD Connection
(R_sens = 2.7 Ω)
S-Di
R_DZ (Ω)
IZD (mA)
18
3
100
A
IZD
0.47 µF
C2
IF
R_ZD
GND
0.1
K
R_sens
2.7 Ω
Since driver characteristics may be adversely affected,
Toshiba recommend 100 Ω or less.
Figure 4
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Application Circuit
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TB62732FUG
Current consumption at normal operation ICC (ON)
ICC (On)
(µA)
800
VCC
4
600
3
1 TB62732FUG 6
400
2
5
200
0
3
3.5
4
4.5
5
5.5
VCC (V)
Current consumption at shutdown
ICC (SHDN)
900
ICC (SHDN)
(µA)
VCC
600
VCC = 3.6 V
4
3
1 TB62732FUG 6
300
0
2.4
2.6
2.8
VSHDN
3
3.2
2
5
4
3
3.4
(V)
Output switching frequency
1.4
fOSC
(MHz)
1.2
VCC
1
0.8
1 TB62732FUG 6
2
0.6
fOSC
5
0.4
3
3.5
4
4.5
5
5.5
VCC (V)
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TB62732FUG
Application Evaluation Circuit Example 1
(Example of evaluation result using a small coil: Coil LDR304612T-6R8)
6.8 µH is optimum for illuminating serial LEDs 3 to 4 LEDs using IF = 20 mA.
4.7 µH is recommended for steady illumination of serial LED 2 in the range VIN > 4.5 V.
L1 = 6.8 µH
A
SHDN
OFF
K
GND
IF
C3 =
0.015 µF
VCC
3 to 4
LEDs
C2 = 0.47 µF
ON
S-Di
R_sens =
2.61 Ω
C1 = 2.2 µF
VIN =
3.0 to 4.3 V
L1 : TDK LDR304612T-6R8
S-Di : TOSHIBA CUS02 30 V/1 A
LED : NICHIA NSCW215T
Note 5: Connection of C3 is not necessary in every case.
The IF is expected to stabilize on decrease of voltage.
VIN – Efficiency/IF
VIN – Efficiency/IF
85
75
85
(mA)
80
IF
LED Current
20
Efficiency (%)
(mA)
80
IF
LED Current
25
70
20
75
70
4 LEDs efficiency
4 LEDs IF
15
3
3 LEDs efficiency
3 LEDs IF
65
3.2
3.4
3.6
VIN
3.8
4
15
3
4.2
(V)
85
20
75
Efficiency (%)
LED Current
IF
(mA)
80
2 LEDs efficiency
2 LEDs IF
65
3.6
VIN
3.8
3.6
3.8
4
4.2
(V)
4
Number
of LED
Efficiency (%)
Average Efficiency
(%)
2
79.0 to 83.8
81.6
3
75.1 to 80.9
78.3
4
72.0 to 78.3
75.7
IF in the range VIN = 3.0 to 4.3 V
70
3.4
3.4
<Measurement>
Efficiency in the range VIN = 3.0 to 4.3 V
25
3.2
65
3.2
VIN
VIN – Efficiency/IF
15
3
Efficiency (%)
25
Number
of LED
IF (mA)
VCC Dependence (%)
2
19.5 to 21.1
7.8
3
19.5 to 20.5
4.9
4
19.6 to 20.7
5.3
4.2
Note 6: The above values have been obtained
through Toshiba’s own measurements.
However, results may vary according to the
measurement environment.
(V)
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TB62732FUG
Application Evaluation Circuit Example 2
(Example of evaluation result using a small coil: Coil CXML321610-7R0)
6.8 µH is optimum for illumination of serial LEDs 4 to 3 using IF = 20 mA.
4.7 µH is recommended for steady illumination of serial LED 2 in the range VIN > 4.5 V.
L1 = 7.0 µH
3 to 4
LEDs
A
SHDN
OFF
R_sens =
2.61 Ω
K
GND
IF
C3 =
0.015 µF
VCC
ON
S-Di
C2 = 0.47 µF
C1 = 2.2 µF
VIN =
3.0 to 4.3 V
L1 : SUMITOMO CXML321610-7R0
S-Di : TOSHIBA CUS02 30 V/1 A
LED : NICHIA NSCW215T
Note 7: Connection of C3 is not necessary in every case. .
The IF is expected to stabilize on decrease of voltage. .
VIN – Efficiency/IF
VIN – Efficiency/IF
85
75
85
(mA)
80
IF
LED Current
20
Efficiency (%)
(mA)
80
IF
LED Current
25
70
20
75
70
4 LEDs efficiency
4 LEDs IF
15
3
3 LEDs efficiency
3 LEDs IF
65
3.2
3.4
3.6
VIN
3.8
4
15
3
4.2
(V)
85
20
75
Efficiency (%)
LED Current
IF
(mA)
80
2 LEDs efficiency
2 LEDs IF
65
3.4
3.6
VIN
3.8
3.6
4
3.8
4
4.2
(V)
Number
of LED
Efficiency (%)
Average Efficiency
(%)
2
78.2 to 84.1
81.3
3
72.0 to 79.1
75.8
4
66.9 to 71.1
74.6
IF in the range VIN = 3.0 to 4.3 V
70
3.2
3.4
<Measurement>
Efficiency in the range VIN = 3.0 to 4.3 V
VIN – Efficiency/IF
15
3
65
3.2
VIN
25
Efficiency (%)
25
4.2
Number
of LED
IF (mA)
VCC Dependence (%)
2
19.8 to 21.6
8.1
3
20.0 to 21.0
4.8
4
20.4 to 21.5
4.9
Note 8: The above values have been obtained
through Toshiba’s own measurements.
However, results may vary according to the
measurement environment.
(V)
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2006-06-14
TB62732FUG
Application Evaluation Circuit Example 3
(Example of evaluation result using a small coil: Coil 976AS-6R8)
6.8 µH is optimum for illumination of serial LEDs 4 to 3 using IF = 20 mA.
4.7 µH is recommended for steady illumination of serial LED 2 in the range VIN > 4.5 V.
L1 = 6.8 µH
3 to 4
LEDs
A
SHDN
OFF
R_sens =
2.61 Ω
K
GND
IF
C3 =
0.015 µF
VCC
ON
S-Di
C2 = 0.47 µF
C1 = 2.2 µF
VIN =
3.0 to 4.3 V
L1 : TOKO 976AS-6R8
S-Di : TOSHIBA CUS02 30 V/1 A
LED : NICHIA NSCW215T
Connection of C3 is not necessary in every case. .
The IF is expected to stabilize on decrease of voltage. .
VIN – Efficiency/IF
VIN – Efficiency/IF
25
85
75
85
(mA)
80
IF
LED Current
20
Efficiency (%)
(mA)
80
IF
LED Current
25
70
20
75
70
4 LEDs efficiency
4 LEDs IF
15
3
3 LEDs efficiency
3 LEDs IF
65
3.2
3.4
3.6
VIN
3.8
4
15
3
4.2
(V)
85
20
75
Efficiency (%)
LED Current
IF
(mA)
80
2 LEDs efficiency
2 LEDs IF
65
3.4
3.6
VIN
3.8
3.6
4
3.8
4
4.2
(V)
Number
of LED
Efficiency (%)
Average Efficiency
(%)
2
79.7 to 84.4
82.3
3
76.7 to 82.1
79.5
4
73.1 to 79.7
74.0
IF in the range VIN = 3.0 to 4.3 V
70
3.2
3.4
<Measurement>
Efficiency in the range VIN = 3.0 to 4.3 V
VIN – Efficiency/IF
15
3
65
3.2
VIN
25
Efficiency (%)
Note 9:
4.2
(V)
Number
of LED
IF (mA)
VCC Dependence (%)
2
19.4 to 21.1
8.1
3
19.5 to 20.5
5.1
4
19.6 to 20.7
5.3
Note 10: The above values have been obtained
through Toshiba’s own measurements.
However, results may vary according to the
measurement environment.
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TB62732FUG
Application Evaluation Circuit Example 4
(Example of evaluation result using a small coil: Coil CXLD140-6R8)
6.8 µH is optimum for illumination of serial LEDs 4 to 3 using IF = 20 mA.
4.7 µH is recommended for steady illumination of serial LED 2 in the range VIN > 4.5 V.
L1 = 6.8 µH
3 to 4
LEDs
A
SHDN
OFF
R_sens =
2.61 Ω
K
GND
IF
C3 =
0.015 µF
VCC
ON
S-Di
C2 = 0.47 µF
C1 = 2.2 µF
VIN =
3.0 to 4.3 V
L1 : SUMITOMO CXLD140-6R8
S-Di : TOSHIBA CUS02 30 A/1 V
LED : NICHIA NSCW215T
Note11: Connection of C3 is not necessary in every case. .
The IF is expected to stabilize on decrease of voltage. .
VIN – Efficiency/IF
VIN – Efficiency/IF
85
75
85
(mA)
80
IF
LED Current
20
Efficiency (%)
(mA)
80
IF
LED Current
25
70
20
75
70
4 LEDs efficiency
4 LEDs IF
15
3
3 LEDs efficiency
3 LEDs IF
65
3.2
3.4
3.6
VIN
3.8
4
15
3
4.2
(V)
85
20
75
Efficiency (%)
LED Current
IF
(mA)
80
2 LEDs efficiency
2 LEDs IF
65
3.4
3.6
VIN
3.8
3.6
4
3.8
4
4.2
(V)
Number
of LED
Efficiency (%)
Average Efficiency
(%)
2
80.3 to 84.9
82.9
3
77.2 to 82.8
80.2
4
74.1 to 80.4
77.6
IF in the range VIN = 3.0 to 4.3 V
70
3.2
3.4
<Measurement>
Efficiency in the range VIN = 3.0 to 4.3 V
VIN – Efficiency/IF
15
3
65
3.2
VIN
25
Efficiency (%)
25
4.2
Number
of LED
IF (mA)
VCC Dependence (%)
2
19.4 to 21.0
7.6
3
19.5 to 20.5
5.1
4
19.6 to 20.7
5.3
Note 12: The above values have been obtained
through Toshiba’s own measurements.
However, results may vary according to the
measurement environment.
(V)
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TB62732FUG
Package Dimensions
Weight: 0.016 g (typ.)
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TB62732FUG
Notes on Contents
1. Block Diagrams
Some of the functional blocks, circuits, or constants in the block diagram may be omitted or simplified for
explanatory purposes.
2. Equivalent Circuits
The equivalent circuit diagrams may be simplified or some parts of them may be omitted for explanatory
purposes.
3. Timing Charts
Timing charts may be simplified for explanatory purposes.
4. Application Circuits
The application circuits shown in this document are provided for reference purposes only.
Thorough evaluation is required, especially at the mass production design stage.
Toshiba does not grant any license to any industrial property rights by providing these examples of
application circuits.
5. Test Circuits
Components in the test circuits are used only to obtain and confirm the device characteristics. These
components and circuits are not guaranteed to prevent malfunction or failure from occurring in the
application equipment.
IC Usage Considerations
Notes on Handling of ICs
(1)
The absolute maximum ratings of a semiconductor device are a set of ratings that must not be
exceeded, even for a moment. Do not exceed any of these ratings.
Exceeding the rating(s) may cause the device breakdown, damage or deterioration, and may result
injury by explosion or combustion.
(2)
Use an appropriate power supply fuse to ensure that a large current does not continuously flow in
case of over current and/or IC failure. The IC will fully break down when used under conditions that
exceed its absolute maximum ratings, when the wiring is routed improperly or when an abnormal
pulse noise occurs from the wiring or load, causing a large current to continuously flow and the
breakdown can lead smoke or ignition. To minimize the effects of the flow of a large current in case of
breakdown, appropriate settings, such as fuse capacity, fusing time and insertion circuit location, are
required.
(3)
If your design includes an inductive load such as a motor coil, incorporate a protection circuit into the
design to prevent device malfunction or breakdown caused by the current resulting from the inrush
current at power ON or the negative current resulting from the back electromotive force at power OFF.
IC breakdown may cause injury, smoke or ignition.
Use a stable power supply with ICs with built-in protection functions. If the power supply is unstable,
the protection function may not operate, causing IC breakdown. IC breakdown may cause injury,
smoke or ignition.
(4)
Do not insert devices in the wrong orientation or incorrectly.
Make sure that the positive and negative terminals of power supplies are connected properly.
Otherwise, the current or power consumption may exceed the absolute maximum rating, and
exceeding the rating(s) may cause the device breakdown, damage or deterioration, and may result
injury by explosion or combustion.
In addition, do not use any device that is applied the current with inserting in the wrong orientation
or incorrectly even just one time.
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(5)
Carefully select external components (such as inputs and negative feedback capacitors) and load
components (such as speakers), for example, power amp and regulator.
If there is a large amount of leakage current such as input or negative feedback condenser, the IC
output DC voltage will increase. If this output voltage is connected to a speaker with low input
withstand voltage, overcurrent or IC failure can cause smoke or ignition. (The over current can cause
smoke or ignition from the IC itself.) In particular, please pay attention when using a Bridge Tied
Load (BTL) connection type IC that inputs output DC voltage to a speaker directly.
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Points to Remember on Handling of ICs
(1)
Heat Radiation Design
In using an IC with large current flow such as power amp, regulator or driver, please design the
device so that heat is appropriately radiated, not to exceed the specified junction temperature (Tj) at
any time and condition. These ICs generate heat even during normal use. An inadequate IC heat
radiation design can lead to decrease in IC life, deterioration of IC characteristics or IC breakdown. In
addition, please design the device taking into considerate the effect of IC heat radiation with
peripheral components.
(2)
Back-EMF
When a motor rotates in the reverse direction, stops or slows down abruptly, a current flow back to
the motor’s power supply due to the effect of back-EMF. If the current sink capability of the power
supply is small, the device’s motor power supply and output pins might be exposed to conditions
beyond absolute maximum ratings. To avoid this problem, take the effect of back-EMF into
consideration in system design.
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About solderability, following conditions were confirmed
• Solderability
(1) Use of Sn-37Pb solder Bath
· solder bath temperature = 230°C
· dipping time = 5 seconds
· the number of times = once
· use of R-type flux
(2) Use of Sn-3.0Ag-0.5Cu solder Bath
· solder bath temperature = 245°C
· dipping time = 5 seconds
· the number of times = once
· use of R-type flux
RESTRICTIONS ON PRODUCT USE
060116EBA
• The information contained herein is subject to change without notice. 021023_D
• TOSHIBA is continually working to improve the quality and reliability of its products. Nevertheless, semiconductor
devices in general can malfunction or fail due to their inherent electrical sensitivity and vulnerability to physical
stress. It is the responsibility of the buyer, when utilizing TOSHIBA products, to comply with the standards of
safety in making a safe design for the entire system, and to avoid situations in which a malfunction or failure of
such TOSHIBA products could cause loss of human life, bodily injury or damage to property.
In developing your designs, please ensure that TOSHIBA products are used within specified operating ranges as
set forth in the most recent TOSHIBA products specifications. Also, please keep in mind the precautions and
conditions set forth in the “Handling Guide for Semiconductor Devices,” or “TOSHIBA Semiconductor Reliability
Handbook” etc. 021023_A
• The TOSHIBA products listed in this document are intended for usage in general electronics applications
(computer, personal equipment, office equipment, measuring equipment, industrial robotics, domestic appliances,
etc.). These TOSHIBA products are neither intended nor warranted for usage in equipment that requires
extraordinarily high quality and/or reliability or a malfunction or failure of which may cause loss of human life or
bodily injury (“Unintended Usage”). Unintended Usage include atomic energy control instruments, airplane or
spaceship instruments, transportation instruments, traffic signal instruments, combustion control instruments,
medical instruments, all types of safety devices, etc. Unintended Usage of TOSHIBA products listed in this
document shall be made at the customer’s own risk. 021023_B
• The products described in this document shall not be used or embedded to any downstream products of which
manufacture, use and/or sale are prohibited under any applicable laws and regulations. 060106_Q
• The information contained herein is presented only as a guide for the applications of our products. No
responsibility is assumed by TOSHIBA for any infringements of patents or other rights of the third parties which
may result from its use. No license is granted by implication or otherwise under any patent or patent rights of
TOSHIBA or others. 021023_C
• The products described in this document are subject to the foreign exchange and foreign trade laws. 021023_E
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