Belling BL9641 Schematic [ru]
42V Input Standoff Voltage, 0.7A Step-Down Converter
BL9641
1
2
3
6
4
SOT23-6
SW
BST
FB
EN
GND
5
IN
GND
FB
IN
SW
V
OUT
3.3V/0.5A
10μH
49.9K
16.2K
EN
50V
10μF
6.3V
22μF
5
4
6
3
2
BST
10nF
1
D1
VIN Standoff up to 42V
DESCRIPTION
The BL9641 is a wide input range, high-efficiency,
and high frequency DC-to-DC step-down
switching regulator, capable of delivering up to
0.7A of output current. With a fixed switching
frequency of 660KHz, this current mode PWM
controlled converter allows the use of small
external components, such as ceramic input and
output caps, as well as small inductors.BL9641
also employs a proprietary control scheme that
switches the device into a power save mode
during light load, thereby extending the range of
high efficiency operation. An OVP function
protects the IC itself and its downstream system
against input voltage surges. With this OVP
function, the IC can stand off input voltage as
high as 42V, making it an ideal solution for
industrial applications such as smart meters as
well as automotive applications.
In automotive systems, power comes from the
battery, with its voltage typically between 9V and
24V. Including cold crank and double battery
jump-starts, the minimum input voltage may be
as low as 4V and the maximum up to 36V, with
even higher transient voltages. With these high
input voltages, linear regulators cannot be used
for high supply currents without overheating the
regulator. Instead, high efficiency switching
regulators such as BL9641 must be used to
minimize thermal dissipation.
BL9641 is available SOT23-6 Packages.
TYPICAL APPLICATION
FEATURES
Wide Input Operating Range from 4V to 38V
Standoff Input Voltage: 42V
High Efficiency at 12V In 5V Out: Up to 92%:
High Efficiency PFM mode at light load
Capable of Delivering 0.7A
No External Compensation Needed
Current Mode control
Logic Control Shutdown
Thermal shutdown and UVLO
Available in SOT23-6 Package
APPLICATIONS
Smart Meters
Industrial Applications
Automotive Applications
PIN OUT
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BL9641
Mark Explanation
aa: Type
b: Year
c: Week
PIN #
NAME
DESCRIPTION
1
BST
Bootstrap pin. Connect a 10nF capacitor from this pin to SW
2
GND
Ground
3
FB
Feedback Input. Connect an external resistor divider from the output to FB and GND to set VOUT
4
EN
Enable pin for the IC. Drive this pin high to enable the part, low to disable.
5
IN
Supply Voltage. Bypass with a 10μF ceramic capacitor to GND
6
SW
Inductor Connection. Connect an inductor Between SW and the regulator output.
REG
&REF
PWM
Logic
DRIVER
FB
+
+
-
Slope Comp
OSC
Σ
IN
BST
SW
GND
UVLO &
Thermal
shutdown
Current
Sense
EA
+
-
-
EN
COMP
network
MARK and ORDERING INFORMATION
PINOUT DESCRIPTION
BLOCK DIAGRAM
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BL9641
Parameter
Value
Input Voltage Range
-0.3V-42V
SW, EN Voltage
–0.3V to VIN+0.3V
BST Voltage
–0.3V to SW+6V
FB Voltage
–0.3V to 6V
SW to ground curren
Internally limited
Operating Junction Temperature(Tj)
-40C –85C
Package Thermal Resistance (jc)
SOT23-6
110C / W
Storage Temperature(Ts)
-55C - 150C
PARAMETER
CONDITIONS
MIN
TYP
MAX
UNITS
Input Standoff Voltage
42
V
Input Voltage Range
4 38
V
Input UVLO
Rising, Hysteresis=140mV
3.80 V
Input OVP
Rising, Hysteresis=1.3V
38 V
Input Supply Current
VFB =0.85V
0.6 mA
Input Shutdown Current
6
μA
FB Feedback Voltage
0.800 V
FB Input Current
0.01 μA
Switching Frequency
660 KHz
Maximum Duty Cycle
90
%
FoldBack Frequency
VFB = 0V
60 KHz
High side Switch On Resistance
ISW =200mA
400 mΩ
High side Switch Current Limit
1.2 A
SW Leakage Current
VIN=12V,VSW=0, EN= GND
10
μA
EN Input Current
VIN=12V ,VEN =5V
1 5
μA
EN Input Low Voltage
Rising, Hysteresis=100mV
0.8
1.1
1.4
V
Thermal Shutdown
Hysteresis=40°C
150 °C
ABSOLUTE MAXIMUM RATING
Note: Exceed these limits to damage to the device. Exposure to absolute maximum
rating conditions may affect device reliability.
ELECTRICAL CHARACTERISTICS
(VIN = 12V, unless otherwise specified. Typical values are at TA = 25C .)
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