TECHNICAL NOTE
Single-chip Type with Built-in FET Switching Regulator Series
2-output High-efficiency Step-down
Switching Regulators
with Built-in Power MOSFET
BD9302FP
Description
The BD9302FP is a 2-channel step-down switching regulator controller with a 2.5-MHz, 2-A power switch and available for
2.5-MHz high speed switching operation, which facilitates settings of switching frequency with external resistance, supporting
for a wide input voltage range of 6 to 18 V. Furthermore, due to a low reference voltage of 0.6 V, this BD9302FP is an L/C best
suited to high-voltage input/low-voltage output applications, for example, to step down a voltage from 12 V to 1.2 V.
Features
1)
2)
3)
4)
5)
6)
7)
A wide input voltage range of 6 V to 18 V
Easy switching frequency setting in the range of 200 k to 2.5 MHz.
Two built-in power switches of 0.4
Ω,
2 A.
180˚ phase shift
Built-in Under Voltage Lock Out circuit
Built-in overcurrent protection circuit
Built-in Thermal Shutdown circuit
Use
Power supply for DPS requiring two power sources
ADSL modem/plasma display
Audio devices
Dec. 2008
Absolute maximum ratings (Ta=25˚C)
Item
Power supply voltage
Power dissipation
Operating temperature
Storage temperature
Output current
Maximum junction temperature
Symbol
Vcc
Pd
Topr
Tstg
Io
Tjmax
Rating
20
1450*
-40 ~ +85
-55 ~ +150
2**
150
Unit
V
mW
˚C
˚C
A
˚C
* Should be derated by 11.6 mW/˚C at Ta=25˚C or more. When mounted on a glass epoxy PCB of 70¥70¥1.6 mm)
** Should not exceed Pd-value.
Recommended operating range (Ta=25˚C)
Item
Power supply voltage
Output current
Timing resistance
Oscillation frequency
Symbol
Vcc
Io
RT
Fosc
Limits
Typ
12
–
–
–
Unit
V
A
kΩ
kHz
Min
6
–
10
100
Max
18
1.8
100
2500
Electrical characteristics
Electrical characteristics (Unless otherwise specified, Ta=25˚C, Vcc=12 V, R
T
=10 kΩ)
Item
[Triangular wave oscillator block]
Oscillation frequency
Frequency variation
Overcurrent limit
F
OSC
F
DVO
Isw
1800
–
2
2000
1
4
3.3
3.0
10
1.7
1.95
–
Symbol
Limits
Min
Typ
Max
Unit
Conditions
2200
–
6
3.6
3.3
14
5
2.15
0.3
kHz
%
A
V
V
uA
mA
V
V
RT=10kΩ
~ 18V
*
[Overcurrent protection circuit block]
[Under-voltage malfunction prevention circuit block]
3.0
Upper limit threshold voltage
VtH
2.7
Lower limit threshold voltage
VtL
[Soft start circuit block]
Source current
Sink current
Clamp voltage
Shutdown voltage
Isso
I
SSI
Vcl
V
SDWN
6
0.6
1.75
–
Vss=1V
Vss=1V, Vcc=3V
Vcc=3V
Not designed for radiation resistance.
* Design guarantee (No 100% pre-shipment inspections are conducted.)
2/16
Electrical characteristics
Electrical characteristics (Unless otherwise specified, Ta=25˚C, Vcc=12 V, R
T
=10 kΩ)
Item
[Error amplifier block]
Input bias current
Voltage gain
COMP maximum output voltage
COMP minimum output voltage
Output sink current
Output source current
Feedback voltage
[Output block]
Upper-side ON resistance
Low-side ON resistance
OFF current
[Total device]
Average supply current
I
CC
Ronh
Ronl
I
OFF
I
IB
AV
V
OH
V
OL
I
OI
I
OO
V
FB
Symbol
Min
Limits
Typ
0.4
200
1.95
0.8
2
Max
1
Unit
Conditions
–
–
1.75
uA
V/V
V
V
mA
mA
V
Ω
Ω
mA
mA
I
COMP
= -0.1mA
I
COMP
=0.1mA
V
FB
=0.8V
V
FB
=0.4V
Buffer
Io=1A*
Io=20mA*
SW=0V
R
T
=1.0V
–
–
1.0
4
–
1
–
8
0.588
–
4
0.600
0.4
2
0.2
–
1
0.612
0.6
3
0.4
–
–
0.1
–
5
–
Not designed for radiation resistance.
* Design guarantee (No 100% pre-shipment inspections are conducted.)
Measurement circuit diagram
10pF
30kΩ
NULL AMP
+
V
–
V
A
PGND1
COMP1
V
A
SW1L
SW1
SW1
BOOT1
PVcc
PVcc
1uF
Ω
A
30kΩ
100kΩ
1kΩ
0.6V
1000pF
FB1
1V
10K
10kΩ
1000pF
A
RT
NC
SS1
V
5V
1V
10pF
30kΩ
30kΩ
A
V
A
12V
1V
V
A
Vcc
SS2
NC
FB2
COMP2
PVcc
PVcc
BOOT2
SW2
SW2
SW2L
1uF
Ω
A
NULL AMP
100kΩ
1kΩ
0.6V
1000pF
V
+
–
5V
10kΩ
1000pF
V
A
GND
PGND2
Fig. 1 Typical measurement circuit
3/16
Reference characteristics data
0.66
0.65
0.64
0.63
0.62
0.61
0.60
0.59
0.58
0.57
0.56
0.55
0.54
0.53
0.52
0.51
0.50
-40 -30 -20 -10 0 10 20 30 40 50 60 70 80 85
AMBIENT TEMPERATURE : Ta [˚C]
800
750
700
650
600
550
500
450
400
350
300
250
200
150
100
50
0
-40 -30 -20 -10 0 10 20 30 40 50 60 70 80 85
AMBIENT TEMPERATURE : Ta [˚C]
8.0
7.5
7.0
6.5
6.0
5.5
5.0
4.5
4.0
3.5
3.0
2.5
2.0
1.5
1.0
0.5
0.0
SWITCHING FREQUENCY : FSW [kHz]
FEED BACK VOLTAGE : VFB [V]
CIRCUIT CURRENT : ICC [mA]
85˚C
-40˚C
25˚C
0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18
INPUT VOLTAGE : VCC [V]
Fig.2
Feedback voltage –
Ambient temperature
0.80
0.75
0.70
0.65
0.60
0.55
0.50
0.45
0.40
0.35
0.30
0.25
0.20
0.15
0.10
0.05
0.00
-40 -30 -20 -10 0 10 20 30 40 50 60 70 80 85
AMBIENT TEMPERATURE : Ta [˚C]
SWL ON RESISTANCE : RONL [Ω]
SW ON RESISTANCE : RONH [Ω]
Fig.3
Switching frequency –
Ambient temperature
3.2
3.0
2.8
2.6
2.4
2.2
2.0
1.8
1.6
1.4
1.2
1.0
0.8
0.6
0.4
0.2
0.0
-40 -30 -20 -10 0 10 20 30 40 50 60 70 80 85
AMBIENT TEMPERATURE : Ta [˚C]
SWITCHING FREQUENCY : FSW [kHz]
100000
Fig.4
Power supply voltage –
Circuit current
10000
1000
100
10
10
100
TIMING RESISTANCE : RT [kΩ]
Fig.5
SW ON resistance –
Ambient temperature
100
90
80
MAX DUTY [%]
70
60
50
40
30
20
10
0
200
1000
2000
SWITCHING FREQUENCY : FSW [kHz]
SWITCHING FREQUENCY : FSW [kHz]
2.6
2.5
2.4
2.3
2.2
2.1
2.0
1.9
1.8
1.7
1.6
1.5
1.4
1.3
1.2
1.1
1.0
Fig.6
SWL ON resistance –
Ambient temperature
100
90
80
EFFICIENCY :
h
[%]
70
60
50
40
30
20
10
6 7
8 9 10 11 12 13 14 15 16 17 18
INPUT VOLTAGE : VCC [V]
0
Fig.7
Setting resistance –
Switching frequency
0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 1.1 1.2 1.3 1.4 1.5 1.6 1.7 1.8
OUTPUT CURRENT : IO [A]
Fig.8
Switching frequency – MAX Duty
Fig.9
Switching frequency – Power supply voltage
Fig.10
Output current – Efficiency
(*) The data shown above represent real values sampled but not guarantee values.
4/16
Reference characteristics data
100
90
80
EFFICIENCY :
h
[%]
EFFICIENCY :
h
[%]
70
60
50
40
30
20
10
0
6
7
8 9 10 11 12 13 14 15 16 17 18
INPUT VOLTAGE : VCC [V]
100
90
DELAY TIME : TV01 [ms]
80
70
60
50
40
30
20
10
0
400 600 800 1000 1200 1400 1600 1800 2000 2200 2400
SWITCHING FREQUENCY : FSW [kHz]
0
0.01
0.10
SS CAPACITOR : CSS [μF]
1.00
100
10
1
Fig.11
Power supply voltage – Efficiency
Fig.12
Switching frequency – Efficiency
Fig.13
Set capacitance – Delay time
12V
INPUT
VOLTAGE
OUTPUT
CURRENT
OUTPUT
CURRENT
1.47ms
OUTPUT
VOLTAGE
2.5V
OUTPUT
VOLTAGE
(AC)
OUTPUT
VOLTAGE
(AC)
Fig.14
Startup waveform
Fig.15
Load transient response No. 1
Fig.16
Load transient response No. 2
Application measurement circuit diagram
33pF
100
3300pF
kΩ
20kΩ
10μH
Vo1=3.3V
BD9302FP
22 51kΩ
kΩ
0.1μF
0.1μF
10μF
10μF
Vcc
12V
0.1
μ
F
20kΩ
30kΩ
30
kΩ
3300
pF
33
pF
0.1μF
10μH
Vo2=1.2V
10μF
Fig.17 Application measurement circuit diagram
(*) The data shown above represent real values sampled but not guarantee values.
5/16
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