English

BL9382B
20V 2A Synchronous Buck Converter
DESCRIPTION
FEATURES
The BL9382B is a high efficiency current-mode
synchronous, 20V/2A buck converter. Its input
voltage ranges from 4.5V to 20V and it provides
an adjustable regulated output voltage from
0.923V to 17V while delivering up to 2A of output
current.








The internal synchronous switches increase
efficiency and eliminate the need for an external
Schottky diode. The switching frequency is set to
350KHz.
Adjustable Output Voltage, Vfb=0.923V
Maximum output current is 2A
Range of operation input voltage: Max 20V
Standby current: 60uA (typ.)
Operating current at zero load: 0.1mA (typ.)
Line regulation: 0.1%/V (typ.)
Load regulation: 10mV (typ.)
High efficiency, up to 94%
APPLICATIONS






BL9382B consists of many protection block such
as UVLO, thermal protection and output short
circuit protection.
The BL9382B is available in the SOP8 and ESOP8
(with exposed pad for heat dissipation) package
Set-top-box
Consumer Electronic Device for automobile
LCD Monitor and LCD TV
Portable DVD
ADSL Modem, WLAN router
Other 12V or double cell Li-ion battery
powered device
TYPICAL APPLICATION
PIN OUT
SOP8 and ESOP8
www.belling.com.cn
1
V1.3
BL9382B
MARK and ORDERING INFORMATION
Mark Explanation
Ordering Information
XX: Year
YY: Week
ZZ: Internal code
SOP8
2500pcs/reel
BL9382BCD8TR
ESOP8
2500pcs/reel
BL9382BCS8TR
PINOUT DESCRIPTION
PIN #
1
2
3
4
5
6
NAME
BST
VIN
SW
GND
FB
NC
7
EN
8
SS
DESCRIPTION
High side power transistor gate drive boost input
Power input, the input capacitor should be placed as close to VIN and GND pin as possible
Power switching node to connect inductor
Ground.
Feedback input with reference voltage set to 0.923
No Connection.
Enable input. Setting it to high level or connecting to Vin via a resistor may turn on the chip,
while setting it to ground level will turn off the chip.
Soft-start node. Connecting a 0.1uF capacitor to ground make the Buck converter output rise
smoothly.
BLOCK DIAGRAM
www.belling.com.cn
2
V1.3
BL9382B
ABSOLUTE MAXIMUM RATING
Parameter
Value
Max Input Voltage
Junction Temperature(Tj)
Package Thermal Resistance (jc)
22V
125C
45C / W
10C / W
-65C to +150C
260C, 10S
SOP-8L
ESOP-8L
Storage Temperature(Ts)
Lead Temperature & Time
Note: Exceed these limits to damage to the device. Exposure to absolute maximum
rating conditions may affect device reliability.
RECOMMENDED WORK CONDITIONS
Parameter
Value
Input Voltage Range
Operating Junction Temperature(Tj)
4.5~20V
-40C to +85C
ELECTRICAL CHARACTERISTICS
(VIN=12V, TA=25C)
Symbol
Parameter
Conditions
Min
VDD
Input Voltage Range
4.5
UVLO_UP
UVLO
Threshold
Hysterisis
Vref
UVLO,IN UVLO Rising
4.0
Typ
4.2
Max
Unit
20
V
4.4
V
310
Feedback Voltage
Ifb
Feedback Leakage current
Iq
Quiescent Current
Vin=12V, Ven=5V
0.900
0.923
0.1
Active, Vfb=1V, No Switching
60
mV
0.946
V
0.4
uA
uA
Shutdown, Vin=8V
0.1
LnReg
Line Regulation
Vin=5V to 12V
0.1
%/V
LdReg
Load Regulation
Iout=0.1 to 2A
0.02
%/A
Switching Frequency
Ven=2V, Vin=12V
Fsoc
3
uA
350
KHz
RdsonP
PMOS Rdson
100
mohm
RdsonN
NMOS Rdson
100
mohm
2.7
A
Ilimit
Peak Current Limit
Venh
EN High Threshold
Venl
EN Low Threshold
TSD
Over Temperature Proection
1.3
V
0.5
V
150
C
TYPICAL PERFORMANCE CHARACTERISTICS
www.belling.com.cn
3
V1.3
BL9382B
(Vin=12V, Vout=3.3V, L=10uH, Cin=10uF, Cout=22uF, TA=25C, unless otherwise stated)
Fast Transient Response
Startup through Enable
Shutdown through Enable
Short Circuit Recovery
Switching waveform Vin=18V, Iout=0
Switching waveform Vin=18V, Iout=2A
VIN
VOUT
VIN
VOUT
SW
I_L
I_L
SW
www.belling.com.cn
4
V1.3
BL9382B
Switching waveform Vin=5V, Iout=0
Switching waveform Vin=5V, Iout=2A
VOUT
VOUT
VIN
VIN
SW
SW
I_L
I_L
FUNCTIONAL DECRIPTIONS
The BL9382B is a synchronous, current-mode, step-down regulator. It regulates input voltages from 4.5V to 20V down to
an output voltage as low as 0.923V, and is capable of supplying up to 2A of load current.
Current-Mode Control
The BL9382B utilizes current-mode control to regulate the output voltage. The output voltage is measured at the FB pin
through a resistive voltage divider and the error is amplified by the internal transconductance error amplifier. Output of
the internal error amplifier is compared with the switch current measured internally to control the output current limit.
PFM Mode
The BL9382B operates in PFM mode at light load. In PFM mode, switch frequency is continuously controlled in
proportion to the load current, i.e. switch frequency is decreased when load current drops to boost power efficiency at
light load by reducing switch-loss, while switch frequency is increased when load current rises, minimizing both load
current and output voltage ripples.
Shut-Down Mode
The BL9382B operates in shut-down mode when voltage at EN pin is driven below 0.5V. In shut-down mode, the entire
regulator is off and the supply current consumed by the BL9382B drops below 0.1uA.
Power Switch
N-Channel MOSFET switches are integrated on the BL9382B to down convert the input voltage to the regulated output
voltage. Since the top MOSFET needs a gate voltage great than the input voltage, a boost capacitor connected between
BST and SW pins is required to drive the gate of the top switch. The boost capacitor is charged by the internal 3.3V rail
when SW is low.
Vin Under-Voltage Protection
A resistive divider can be connected between Vin and ground, with the central tap connected to EN, so that when Vin
drops to the pre-set value, EN drops below 1.1V to trigger input under voltage lockout protection.
Vout Over-Voltage Protection
When output voltage rises above its regulated value, both the top and bottom power switches are turned off. Switching
of the internal clock is also disabled. Only when output voltage falls to its regulated value can the internal clock, top
power switch, and bottom power switch become active again.
Output Current Run-Away Protection
www.belling.com.cn
5
V1.3
BL9382B
At start-up, due to the high voltage at input and low voltage at output, current inertia of the output inductance can be
easily built up, resulting in a large start-up output current. A valley current limit is designed in the BL9382B so that only
when output current drops below the valley current limit can the bottom power switch be turned off. By such control
mechanism, the output current at start-up is well controlled.
Output Short Protection
When output is shorted to ground, output current rapidly reaches its peak current limit and the top power switch is
turned off. Right after the top power switch is turned off, the bottom power switch is turned on and stay on until the
output current falls below the valley current limit. When output current is below the valley current limit, the top power
switch will be turned on again and if the output short is still present, the top power switch is turned off when the peak
current limit is reached and the bottom power switch is turned on. This cycle goes on until the output short is removed
and the regulator comes into normal operation again.
Thermal Protection
When the temperature of the BL9382B rises above 150°C, it is forced into thermal shut-down. Only when core
temperature drops below 125°C can the regulator becomes active again.
COMPONENT SELECTRION
When setting up the BL9382B for different output voltage, please use following recommended component value for the
best performance.
VOUT (V)
8
5
3.3
2.5
1.8
1.2
COUT (F)
22x2
22x2
22x2
22x2
22x2
22x2
L (H)
22
15
10
6.8
4.7
3.3
THERMAL CONSIDERATION
BL9382B is high efficiency Buck converter, which means it consumes very few power when converting the high voltage
to low voltage. However, when output power is very large, like 5V/2A, the output power is as high as 10W, a heat
dissipation path is strongly recommended to be routed on PCB. BL9382B has two different SOP8 package. For the normal
SOP8, the heat is conducted out via Pin 4 (GND), so the heat dissipation route on PCB should be connected to the Pin 4
of the chip. If ESOP8 is selected, the heat dissipation copper area should be exposed and connected to the exposed pad
underneath the chip body.
When output power is larger than 10W, the ESOP8 package is recommended.
www.belling.com.cn
6
V1.3
BL9382B
PACKAGE OUTLINE
Package
SOP8
Unit
mm
Unit
mm
Package specification：
Package
ESOP8
Package specification：
www.belling.com.cn
7
V1.3