TECHNICAL NOTE
Power Management LSI Series for Automotive Body Control
High temperature
operating
LDO Regulator
BD3940FP, BD3941FP/HFP/T
Now available
Description
BD394□FP Series regulators feature a high 36 V breakdown voltage and are compatible with onboard vehicle microcontrollers. They offer
an output current of 500 mA while limiting dark current to 30
µA
(TYP). The series supports the use of ceramic capacitors as output phase
compensation capacitors. Since the ICs use P-channel DMOS output transistors, increased loads do not result in increased total supply
current. BD394□FP Series is ideal for lowering current consumption and costs in battery direct-coupled systems.
Features
1) Super-low dark current: 30
µA
(Typ.)
2) Low-saturation voltage type P-channel DMOS output transistors
Output on resistance: 1.6
Ω
(Typ.)
3) High precision output voltage: 5 V
±2%
(Ta = 25°C) / Iomax = 500 mA
4) Low-ESR ceramic capacitors can be used as output capacitors
5) Vcc power supply voltage = 36 V / Peak power supply voltage = 50 V (tr
≥
1 ms, tH
≤
200 ms)
6) Built-in over current protection circuit and thermal shutdown circuit
7) TO252-3/HRP-5/TO220FP-3 package
Applications
Vehicle equipment, car stereos, satellite navigation systems, etc.
Product line
Model
Output voltage
BD3940FP
3.3 V
BD3941FP/HFP/T
5.0 V
Absolute maximum ratings
(Ta = 25°C)
Parameter
Power supply voltage
Output current
Power dissipation
Symbol
Vcc
Io
Pd
Limit
36
*1
500
1.2
*2
1.6
*3
2.0
*4
Operating temperature range
Storage temperature range
Peak power supply voltage
Maximum junction temperature
Topr
Tstg
Vcc Peak
Tjmax
−40
to +125
−55
to +150
50
*5
150
°C
°C
V
°C
W
Unit
V
mA
* 1Not to exceed Pd.
*2 For TO252-3, reduced by 9.6 mW/°C over 25°C, when mounted on a glass epoxy board (70 mm
×
70 mm
×
1.6 mm).
*3 Reduced by 12.8 mW/°C over 25°C, when mounted on a glass epoxy board (70 mm
×
70 mm
×
1.6 mm).
*4 For TO220FP-3, reduced by 16.0 mW/°C over 25°C.
*5 Application time 200 ms or shorter. (tr
≥
1 ms)
Ver.B Oct2005
Recommended operating conditions
(Ta = 25°C)
Parameter
Input voltage
Output current
BD3940FP/HFP
BD3941FP/HFP/T
Symbol
Vcc
Vcc
Io
Min.
4.5
6.2
—
Max.
25.0
25.0
500
Unit
V
V
mA
Electrical characteristics
(Unless otherwise specified, Ta = 25°C; Vcc = 13.2 V; Io = 200 mA)
Parameter
Bias current 1
Bias current 2
Output voltage
Output current
Minimum I/O voltage
difference
Ripple rejection
Input stability
Load stability
BD3940FP
BD3941FP/HFP/T
BD3940FP
BD3941FP/HFP/T
BD3940FP
BD3941FP/HFP/T
Symbol
Ib1
Ib2
Vo
Vo
Io
∆Vd
R.R.
Reg.I
Reg.L
Limit
Min.
—
—
3.234
4.900
500
—
45
—
—
Typ.
30
30
3.300
5.000
—
0.45
55
10
20
Max.
40
—
3.366
5.100
—
0.65
—
30
60
Unit
µA
µA
V
V
mA
V
dB
mV
mV
Vcc = 3.135 V, Io = 100
½A
Vcc = 4.75 V, Io = 200
½A
f = 120 Hz, ein = 1 Vrms,
Io = 100 mA
Vcc = 4.5 V
→
25 V
Vcc = 6.2 V
→
25 V
Io = 0 mA
→
200 mA
Io = 0 mA
Io = 200 mA
Conditions
Electrical characteristics
(Unless otherwise specified, Ta =
−40°C
to +125°C; Vcc = 13.2 V; Io = 200 mA)
Parameter
Bias current 1
Bias current 2
Output voltage
Output current
Minimum I/O voltage
difference
Ripple rejection
Input stability
Load stability
BD3940FP
BD3941FP/HFP/T
BD3940FP
BD3941FP/HFP/T
BD3940FP
BD3941FP/HFP/T
Symbol
Ib1
Ib2
Vo
Vo
Io
∆Vd
R.R.
Reg.½
Reg.L
Limit
Min.
—
—
3.168
4.800
500
—
45
—
—
Typ.
30
30
3.300
5.000
—
—
55
10
20
Max.
40
—
3.366
5.100
—
0.9
—
45
60
Unit
µA
µA
V
V
mA
V
dB
mV
mV
Vcc = 3.135 V, Io = 100
½A
Vcc = 4.75 V, Io = 200
½A
f = 120 Hz, ein = 1 Vrms,
Io = 100 mA
Vcc = 4.5 V
→
25 V
Vcc = 6.2 V
→
25 V
Io = 0 mA
→
200 mA
Io = 0 mA
Io = 200 mA
Conditions
Note: This IC is not designed to be radiation-resistant.
Note: All characteristics are measured with 0.33
µF
and 0.1
µF
capacitors connected to input and output pins, respectively.
Because measurements (pulse measurements) were taken when Ta
≈
Tj, data other than the output voltage/temperature coefficient
does not include fluctuations due to temperature variations.
2/8
Reference data
(Unless otherwise specified, Ta = 25°C)
50
6
6
Ta =
−40°C
CIRCUIT CURRENT: Icc [µA]
OUTPUT VOLTAGE: Vo [V]
OUTPUT VOLTAGE: Vo [V]
40
5
4
3
2
1
0
5
4
3
2
1
0
Ta = 125°C
Ta = 25°C
30
Ta =
−40°C
Ta = 25°C
Ta = 125°C
20
10
0
0
5
10
15
20
25
0
5
10
15
20
25
0
500
1000
1500
2000
SUPPLY VOLTAGE: V½½ [V]
SUPPLY VOLTAGE: V½½ [V]
OUTPUT CURRENT: Io [mA]
Fig. 1 Total Supply Current
Fig. 2 Output Voltage vs Power
Supply Voltage
70
6
Fig. 3 Output Voltage vs Load
1
RIPPLE REJECTION: R.R. [dB]
DROPOUT VOLTAGE:
∆Vd
[V]
OUTPUT VOLTAGE: Vo [V]
60
50
40
30
20
10
0
0.8
5
Ta = 25°C
4
0.6
Ta = 125°C
3
2
1
0
Ta =
−40°C
0.4
0.2
0
0
100
200
300
400
500
10
100
1000
10000 100000 1E+06
20
25
30
35
40
OUTPUT CURRENT: Io [mA]
FREQUENCY: f [Hz]
SUPPLY VOLTAGE: Vcc [V]
Fig. 4 I/O Voltage Difference
Fig. 5 Ripple Rejection
Fig. 6 Overvoltage Protection
0.2
6
5.5
CIRCUIT CURRENT: Icc [mA]
OUTPUT VOLTAGE: Vo [V]
0.15
OUTPUT VOLTAGE: Vo [V]
120
140
160
180
200
5
4
3
2
1
0
100
5.25
0.1
5
0.05
4.75
0
0
100
200
300
400
500
4.5
-40
0
40
80
120
OUTPUT CURRENT: Io [mA]
AMBIENT TEMPERATURE: Ta [
℃
]
AMBIENT TEMPERATURE: Ta [
℃
]
Fig. 7 Total Supply Current
Classified by Load
65
Fig. 8 Thermal Shutdown Circuit
Fig. 9 Output Voltage vs
Temperature
50
0.6
DROPOUT VOLTAGE:
∆Vd
[V]
RIPPLE REJECTION: R.R. [dB]
0.5
0.4
0.3
0.2
0.1
0
CIRCUIT CURRENT: Icc [µA]
60
40
30
55
20
50
10
45
-40
0
40
80
120
0
-40
0
40
80
120
-40
0
40
80
120
AMBIENT TEMPERATURE: Ta [℃]
AMBIENT TEMPERATURE: Ta [℃]
AMBIENT TEMPERATURE: Ta [℃]
Fig. 10 Ripple Rejection vs
Temperature
Fig. 11 Min. I/O Voltage Differential vs
Temperature
Fig. 12 Total Supply Current vs
Temperature
3/8
Block diagram
Vcc
1
Cin
Vref
Vo
3
OCP
OVP
GND
Fin
TSD
2
N.C
GND
Fin
3
Co
OCP
OVP
TSD
2
N.C
.
4
N.C
GND
2
5
Co
OCP
OVP
TSD
Cin
Vref
Vo
3
Co
Vcc
1
Cin
Vref
Vo
Vcc
1
Fig.13
TO252-3
Fig.14
HRP5
Fig.15
TO220FP-3
Cin : 0.33
µF
to 1000
µF
Co : 0.1
µF
to 1000
µF
Pin assignments
•
TO252-3
FIN
Pin No.
1
2
3
Pin No.
Vcc
N.C.
Vo
GND
Function
Power supply pin
NC pin
Voltage output pin
Ground pin
1 2 3
Fig.16
Fin
•
HRP5
FIN
Pin No.
1
2
3
4
Pin No.
Vcc
N.C.
GND
N.C.
Vo
GND
Function
Power supply pin
NC pin
Ground pin
NC pin
Voltage output pin
Ground pin
1 2 34 5
Fig.17
5
Fin
•
TO220FP-3
Pin No.
1
2
3
Pin No.
Vcc
GND
Vo
Function
Power supply pin
Ground pin
Voltage output pin
1 23
Fig.18
4/8
Thermal design
TO252-3
2.0
IC mounted on a ROHM standard board
HRP5
2.0
IC mounted on a ROHM standard board
TO220FP-3
25
POWER DISSIPATION: Pd [W]
POWER DISSIPATION: Pd [W]
POWER DISSIPATION: Pd [W]
1.6
1.2W
Board size: 70 mm ×70 mm × 1.6mm
θja
= 104.2 (°C /W)
1.6
1.6W
Board size: 70 mm ×70 mm × 1.6mm
θja
= 78.1 (°C /W)
(1)20W
20
15
10
5
(1)無限大放熱板½用時
θja=6.25(
/W)
(2)IC
単½時
θja=62.5(℃/W)
1.2
1.2
0.8
0.8
0.4
0
0
25
50
75
100
125
150
0.4
0
0
25
50
75
100
125
150
(2)2.0W
0
0
25
50
75
100
125
150
AMBIENT TEMPERATURE: Ta [
℃
]
AMBIENT TEMPERATURE: Ta [
℃
]
AMBIENT TEMPERATURE: Ta [
℃
]
Fig.19
Fig.20
Fig.21
Refer to the dissipation reduction illustrated in Figs. 19 to 21 when using the IC in an environment where Ta
≥
25°C. The characteristics of the IC
are greatly influenced by the operating temperature. If the temperature exceeds the maximum junction temperature Tjmax, the elements of the IC
may be damaged. It is necessary to give sufficient consideration to the heat of the IC in view of two points, i.e., the protection of the IC from
instantaneous damage and the maintenance of the reliability of the IC in long-time operation.
In order to protect the IC from thermal destruction, the operating temperature of the IC must not exceed the maximum junction temperature Tjmax.
Fig. 19 illustrates the power dissipation/power reduction for the TO252 package. Operate the IC within the power dissipation Pd. The following
method is used to calculate the power consumption Pc (W).
Pc = (Vcc
−
Vo)
×
Io + Vcc
×
Icc
Power dissipation Pd
≤
Pc
Vcc:
Vo:
Io:
Icc:
Input voltage
Output voltage
Load current
Total supply current
The load current Io is obtained to operate the IC within the power dissipation.
Io
≤
Pd
−
Vcc
×
Icc
Vcc
−
Vo
(Refer to Icc in Fig.12)
The maximum load current Iomax for the applied voltage Vcc can be calculated during the thermal design process.
Calculation example
Example) Vcc = 12 V and Vo = 5.0 V at Ta = 85°C, BD3941FP
Io
≤
0.624
−12
×
Icc
12
−
5
Io
≤
89 mA
(Icc = 30
µA)
θja
= 104.2°C/W
→
−9.6
mAW/°C
25°C = 1.2 W
→
85°C = 0.624 W
Make a thermal calculation in consideration of the above equations so that the whole operating temperature range will be within the power
dissipation. The power consumption Pc of the IC, in the event of shorting (i.e., if the Vo and GND pins are shorted), will be obtained from the
following equation:
Pc = Vcc
×
(Icc + Ishort)
Ishort: Short current
External settings for pins and precautions
1) Vcc pin
Insert capacitors with a capacitance of 0.33
µF
to 1,000
µF
between the Vcc and GND pins.
The capacitance varies with the application. Be sure to design the capacitance with a sufficient margin.
2) Capacitors for stopping oscillation at output pins
Capacitors for stopping oscillation must be placed between each output pin and the GND pin. Use a capacitor within a capacitance range
between 1
µF
and 1,000 µF. A ceramic capacitor with low ESR values, from 0.001
Ω
to 100, can be used. Unstable input voltage and load
fluctuations can affect output voltages. Output capacitor capacitance values should be determined for actual application.
5/8
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