BELLING BL8523

BL8523
PWM/PFM Step-down DC-DC Controller
DESCRIPTION
FEATURES
The BL8523 is a CMOS-based PWM step-down
DC-DC Controller. The device offers the following
advantages: lower supply current and wider
operating input-voltage range.


The BL8523 consists of an oscillator, a PWM
control circuit, a reference voltage unit, an error
amplifier, a soft-start circuit, a protection circuit,
a PWM/PFM alternative circuit, a Chip Enable
circuit, and under voltage lockout circuit. A low
ripple, high efficiency step-down DC-DC converter
can be easily composed of this IC. Output Voltage
can be adjusted with external resistors.






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Range of Input Voltage: 3V~16V
Built-in Soft-start Function and Protection
Function(Reset type protection)
<1μA Shutdown Current and 80uA Quiescent
Current
Oscillation Frequency: 500KHz
High efficiency: 95%
High Accuracy Output Voltage:±2.0%
Low Temperature Coefficient: ±100ppm/°C
Operating Temperature Range: -40°C ~85°C
Small Package:SOT23-5
Demo Board Available

The BL8523 uses voltage type PWM/PFM mixed
operation mode. When the load current is small,
the operation will switch into the PFM mode
from PWM mode. Therefore the efficiency at
small load is improved, and then the chip works
on PWM mode.
APPLICATIONS

Power source for hand-held communication
equipment, cameras, video instruments such
as VCRs, camcorders.
Power source for battery-powered
equipment.
Power source for household electrical
appliance

The BL8523 embeds reset type protection circuit.
If the term of maximum duty cycle keeps on a
certain time, the protection circuit restarts the
operation with soft-start and repeat this
operation until maximum duty cycle condition is
released. When the cause of large load current is
removed, the chip returns to normal condition.

ORDERING INFORMATION
PIN CONFIGURATION
BL8523CB5TR
Product ID
Code
BL8523
C
B5
TR
Description
Marking
Product code
HE
Temperature & Rohs:
C: -40~85C, Pb Free Rohs Std.
Package Type: SOT23-5
Tape & Reel (Standard), 3000pcs/Reel
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1
Product Code
Y
Year
W
Week
BL8523CB5TR
4
5
HEYW
1
2
3
BL8523
PIN DESCRIPTION
Pin No.
Symbol
Description
1
CE
2
GND
3
FB
Pin for Feedback Voltage
4
EXT
Switching Pin
5
VIN
Power Supply Pin
Chip Enable Pin (Active with “H”)
Ground Pin
BLOCK DIAGRAM
ABSOLUTE MAXIMUM RATING
Supply Voltage
CE Pin Voltage
EXT Pin Voltage
FB Pin Voltage
Operating Ambient Temperature Range
Storage Temperature Range
Lead Temperature (Soldering, 10 sec)
Thermal resistance: ΘJA
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-0.3V to 18V
–0.3V to Vin+0.3V
–0.3V to Vin+0.3V
–0.3V to 6V
–40°C to 85°C
–65°C to 150°C
260°C
150°C/W
2
BL8523
ELECTRICAL CHARACTERISTICS
(Test condition: Ta=25°C, VIN=12V, unless otherwise noted.)
Symbol
Item
VIN
VFB
Conditions
Min.
IDD1
Operating Input Voltage
Feedback Voltage
Feedback Voltage
Temperature Coefficient
Oscillator Frequency
Oscillator Frequency
Temperature Coefficient
Supply Current 1
Istb
ICEH
Standby Current
CE “H” Input Current
VIN=12V, VCE =0V
VIN = VCE =12V
ICEL
CE “L” Input Current
VIN =12V, VCE = 0V
-0.5
VCEH
CE “H” Input Voltage
VIN = 12V
1.5
VCEL
CE “L” Input Voltage
VIN = 12V
VUVLO1
UVLO Threshold Voltage
VIN=VCE=5 to 0V
1.5
VUVLO2
UVLO Release Voltage
Oscillator Maximum Duty
Cycle
Delay Time by Soft-start
function
Delay Time for protection
circuit
VIN=VCE=0 to 5V
1.6
△ VFB/△ T
fosc
△ fOSC/△ T
Maxdty
Tstart
Tprot
VIN=VCE=12V, Iout=100mA
3
1.196
-25℃ ≤ Topt≤ 85℃
Typ.
Max.
Unit
1.221
16
1.246
V
V
±100
VIN=VCE=12V, Iout=100mA
300
-25℃ ≤ Topt≤ 85℃
500
ppm/℃
700
±0.2
%/℃
VIN = VCE =12V VFB =1.4V
80
μA
0
0
VIN = 12V,
VCE = 0―>8V
VIN = VCE = 12V
VFB = 2.5V―>0V
1
0.5
0
V
0.3
V
1.9
2.3
V
2.0
2.4
V
100
%
2
5
10
ms
150
200
250
μs
L1
Q1
VOUT
R1
U1
VIN EXT
CE
CE
GND
C2
FB
D1
LC2300
BL8523
C1
R2
GND
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3
μA
μA
μA
TYPICAL APPLICATION CIRCUIT
VIN
KHz
BL8523
DEMO BOARD BOM
No.
Reference
Type
Specification
1
C1
Capacitor
Tantalum Capacitor; 25V/47uF; SMD
2
C2
Capacitor
Tantalum Capacitor; 25V/47uF; SMD
3
D1
Diode
SS34; 40V, 3A; SMD
4
L1
Inductor
10uH; 3A; SMD, Shielding
5
IC1
IC
BL8523; SMD SOT23-5
6
R1
Resistor
SMD 0805; 1%
7
R2
Resistor
SMD 0805; 1%
8
Q1
MOSFET
2301;-20V,-3.4A,P-MOS;SMD SOT23-3
ELECTRICAL PERFORMANCE
(Test condition: Ta=25°C, configuration as what is listed in above demo board BOM, unless otherwise
noted.)
Standby Current Vs. Vin
Efficiency Vs. Output Current
100.0
250
95.0
Standby Current (uA)
90.0
Effiency (%)
85.0
80.0
Vin=3.6V
75.0
Vin=4V
70.0
Vin=5V
65.0
60.0
Vin=6V
55.0
Vout=3.3V
200
400
600
800
150
Test condition:
The chip is on, system
in switching,
Iout=0mA
measure input current
100
50
0
50.0
0
200
3.00
1000
3.50
4.00
4.50
5.00
5.50
6.00
6.50
Vin (V)
Output Current (mA)
Load regulation at Vin=6V
Line Regulation at Iout=500mA
5
3.5
4.5
4
3.5
Vout (V)
Vout (V)
3.45
3.4
3
2.5
2
1.5
3.35
1
0.5
0
3.3
3
3.5
4
4.5
5
5.5
6
0
6.5
400
600
Output current (mA)
Vin (V)
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200
4
800
1000
BL8523
PACKAGE OUTLINE
Package
SOT23-5
Devices per reel
3000Pcs
Package specification：
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5
Unit
mm