Datasheet
4.2V to 18V, 3A 1ch
Synchronous Buck Converter with
Integrated FET
BD9329AEFJ
General Description
The BD9329AEFJ is a synchronous step-down
switching regulator with built-in two low-resistance
N-Channel MOSFETs. This IC can supply continuous
output current of 3A over a wide input range, and
provides not only fast transient response, but also easy
phase compensation because of current mode control.
Key Specifications
Input Voltage Range:
Output Voltage Range:
Output Current:
Switching Frequency
Hi-Side FET ON-Resistance:
Lo-Side FET ON-Resistance:
Standby Current:
Operating Temperature Range:
4.2V to 18V
0.9V to (V
IN
x 0.7)V
3.0A (Max)
380kHz(Typ)
0.15Ω(Typ)
0.13Ω(Typ)
15μA (Typ)
-40°C to +85°C
D(Typ)
H(Max)
Features
Uses Low ESR Output Ceramic Capacitors
Low Standby Current
380 kHz Fixed Operating Frequency
Feedback Voltage
0.9V ± 1.5%(Ta=25°C)
0.9V ± 2.0%(Ta=-25°C to +85°C)
Under Voltage Protection
Thermal Shutdown
Over Current Protection
Package
W(Typ)
Applications
Distributed Power Systems
Pre-Regulator for Linear Regulators
HTSOP-J8
4.90mm x 6.00mm x 1.00mm
C_PC
3300pF
C_SS
0.1μF
COMP
SS
EN
Typical Application Circuit
R_PC
7.5kΩ
R_UP
FB
R_DW
10kΩ
27kΩ
Thermal Pad
(to be shorted to GND)
BST
GND
VIN
SW
L
V
OUT
= 3.3V
10µH
V
IN
= 12V
C_VC1
10μF
R_BS
22Ω
C_CO1
20μF
C_BS
0.1μF
R_BS protects from VIN-BST short destruction.
Figure 1. Typical Application Circuit
〇Product
structure : Silicon monolithic integrated circuit
〇This
product has no designed protection against radioactive rays
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TSZ02201-0323AAJ00010-1-2
© 2012 ROHM Co., Ltd. All rights reserved.
1/19
TSZ22111・14・001
16.Feb.2015 Rev.003
BD9329AEFJ
Pin Configuration
(TOP
SS
EN
Block Diagram
VIEW)
COMP
FB
V
IN
VIN
BST
VIN
SW
GND
Figure 2. Pin Configuration
Figure 3. Block Diagram
Pin Description
Pin No.
1
2
3
4
5
6
7
8
Pin Name
BST
VIN
SW
GND
FB
COMP
EN
SS
Function
High-side gate drive boost input
Power input
Power switching output
Ground
Feedback input
Compensation node
Enable input
Soft start control input
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© 2012 ROHM Co., Ltd. All rights reserved.
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BD9329AEFJ
Absolute Maximum Ratings
(Ta = 25°C)
Parameter
Supply Voltage
Switch Voltage
Power Dissipation for HTSOP-J8
Package Thermal Resistance
θja
Package Thermal Resistance
θjc
Operating Temperature Range
Storage Temperature Range
Maximum Junction Temperature
BST Voltage
EN Voltage
All Other Pins
(Note 2)
(Note 2)
Symbol
V
IN
V
SW
Pd
θja
θjc
Topr
Tstg
Tjmax
V
BST
V
EN
V
OTH
Rating
20
20
3.76
(Note 1)
Unit
V
V
W
°C/W
°C/W
°C
°C
°C
V
V
V
29.27
3.75
-40 to +85
-55 to +150
150
V
SW
+7
20
20
(Note 1) Reduced by 30.08 mW/°C over 25°C (Mount on 4-layer 70.0mm x 70.0mm x 1.6mm board)
(Note 2) Mount on 4-layer 50mm x 30mm x 1.6mm application board
Caution:
Operating the IC over the absolute maximum ratings may damage the IC. The damage can either be a short circuit between pins or an open circuit
between pins and the internal circuitry. Therefore, it is important to consider circuit protection measures, such as adding a fuse, in case the IC is operated over
the absolute maximum ratings.
Recommended Operating Conditions
(Ta= -40°C to +85°C)
Parameter
Supply Voltage
SW Voltage
Output Current
Output Voltage Range
Symbol
V
IN
V
SW
I
SW3
V
RANGE
Rating
Min
4.2
-0.5
-
0.9
Typ
12
-
-
-
Max
18
+18
3
V
IN
x 0.7
Unit
V
V
A
V
Electrical Characteristics
(Unless otherwise specified V
IN
=12V Ta=25°C)
Parameter
Error Amplifier Block
FB Input Bias Current
Feedback Voltage1
Feedback Voltage2
SW Block – SW
Hi-Side FET ON-Resistance
Lo-Side FET ON-Resistance
Hi/Lo-Side FET Leak Current
Switch Current Limit
Maximum Duty Cycle
General
Enable Sink Current
Enable Threshold Voltage
Under Voltage Lockout Threshold
Under Voltage Lockout Hysteresis
Soft Start Current
Soft Start Time
Operating Frequency
Circuit Current
Standby Current
I
EN
V
EN
V
UVLO
V
HYS
I
SS
t
SS
f
OSC
I
CC
I
QUI
90
1.0
3.5
-
5
-
300
-
-
180
1.2
3.75
0.3
10
22
380
1.2
15
270
1.4
4.0
-
15
-
460
3
27
µA
V
V
V
µA
ms
kHz
mA
µA
V
FB
= 1.5V, V
EN
= 12V
V
EN
= 0V
V
SS
= 0V
C
SS
= 0.1 µF
V
IN
Rising
V
EN
= 12V
R
ONH
R
ONL
I
LEAKN
I
LIMIT3
M
DUTY
-
-
-
3.5
-
0.15
0.13
0
-
90
-
-
10
-
-
Ω
Ω
µA
A
%
V
FB
= 0V
I
SW
= -0.8A
I
SW
= 0.8A
V
IN
= 18V,
V
SW
= 0V / 18V
I
FB
V
FB1
V
FB2
-
0.886
0.882
0.02
0.900
0.900
2
0.914
0.918
µA
V
V
Voltage Follower
Ta=-25°C to +85°C
Symbol
Limit
Min
Typ
Max
Unit
Conditions
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© 2012 ROHM Co., Ltd. All rights reserved.
TSZ22111・15・001
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TSZ02201-0323AAJ00010-1-2
16.Feb.2015 Rev.003
BD9329AEFJ
Typical Performance Curves
(Unless otherwise specified, V
IN
= 12V Ta = 25°C)
I
CC
(mA)
V
IN
[V]
Figure 4. Circuit Current vs Input Voltage
(No Switching)
I
CC
(µA)
V
IN
[V]
Figure 5. Standby Current vs Input Voltage
(Shutdown Mode)
I
FB
(µA)
V
FB
[V]
Figure 6. Input Bias Current vs
Feedback Voltage
Temp [°C]
Figure 7. Feedback Voltage vs
Temperature
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© 2012 ROHM Co., Ltd. All rights reserved.
TSZ22111・15・001
4/19
TSZ02201-0323AAJ00010-1-2
16.Feb.2015 Rev.003
BD9329AEFJ
Typical Performance Curves - continued
390
385
380
f
OSC
(kHz)
FOSC (kHz)
R
ON
(Ω)
375
370
365
360
-40
-20
0
20
40
60
80
Temp [°C]
Figure 8. Hi-Side, Low-Side FET
ON-Resistance vs Temperature
TEMP (°C)
Temp [°C]
Figure 9. Operating Frequency vs
Temperature
Soft Start Time [ms]
Efficiency
I
O
[mA]
Figure 10. STEP-Down Efficiency vs I
O
(V
IN
= 12V V
OUT
= 3.3V L=10µH)
C
SS
[µF]
Figure 11. Soft Start Time vs C
SS
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© 2012 ROHM Co., Ltd. All rights reserved.
TSZ22111・15・001
5/19
TSZ02201-0323AAJ00010-1-2
16.Feb.2015 Rev.003
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