Fairchild FAN5331 service manual
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FAN5331 High Efficiency Serial LED Driver and OLED Supply with 20V Integrated Switch
August 2005
FAN5331
High Efficiency Serial LED Driver and OLED Supply with
20V Integrated Switch
Features
1.6MHz Switching Frequency
Low Noise
Low R
Adjustable Output Voltage
1A Peak Switch Current
1W Output Power Capability
Low Shutdown Current: <1µA
Cycle-by-Cycle Current Limit
Over-Voltage Protection
Fixed-Frequency PWM Operation
Internal Compensation
5-lead SOT-23 Package
DS(ON)
: 0.5 Ω
Applications
Cell Phones
PDAs
Handheld Equipment
Display Bias
LED Bias
Typical Application
C
IN
4.7µF
2.7V to 5.5V
VIN
L
10µH
Description
The FAN5331 is a general purpose, fixed-frequency boost converter designed to operate at high switching frequencies in
order to minimize switching noise measured at the battery terminal of hand-held communications equipment. Quiescent current in normal mode of operation as well as in shutdown mode
is designed to be minimal in order to extend battery life. Normal
mode of operation or shutdown mode can be selected by a logic
level shutdown circuitry.
The low ON-resistance of the internal N-channel switch ensures
high efficiency and low power dissipation. A cycle-by-cycle current limit circuit keeps the peak current of the switch below a
typical value of 1A. The FAN5331 is available in a 5-lead SOT23 package.
BAT54
C
OUT
4.7µF
V
OUT
ON
OFF
©2004 Fairchild Semiconductor Corporation
FAN5331 Rev. 1.0.1
5
V
IN
1
SW
3
FB
R1
FAN5331
R2
4
SHDN
GND
2
Figure 1. Typical Application Diagram
1
C
F
120pF
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Pin Assignment
FAN5331 High Efficiency Serial LED Driver and OLED Supply with 20V Integrated Switch
Top View
SW
V
IN
GND
FB
SHDN
5-Lead SOT-23
Figure 2. Pin Assignment
Pin Description
Pin No. Pin Name Pin Description
1SWSwitching node.
2 GND Analog and power ground.
3FBFeedback node that connects to an external voltage divider.
4 SHDN
5V
IN
Absolute Maximum Ratings (
V
to GND 6.0 V
IN
FB, SHDN
SW to GND -0.3 23 V
Lead Soldering Temperature (10 seconds) 300 °C
Junction Temperature 150 °C
Storage Temperature -55 150 °C
Thermal Resistance ( Θ
Electrostatic Discharge Protection (ESD) Level (Note 2) HBM 2.5 kV
to GND -0.3 V
) 265 °C/W
JA
Shutdown control pin. Logic HIGH enables, logic LOW disables the device.
Input voltage.
Note1)
Parameter Min Max Unit
+ 0.3 V
IN
CDM 1
Recommended Operating Conditions
Parameter Min Typ Max Unit
Input Voltage 2.7 5.5 V
Output Voltage V
Operating Ambient Temperature -40 25 85 °C
Output Capacitance (Note 3) 1.6 µF
IN
Notes:
1. Stresses above those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. This
is a stress rating only and functional operation of the device at these or any other conditions above those indicated
in the operational section of this specification is not implied. Exposure to absolute maximum rating conditions for
extended periods may affect device reliability. Absolute maximum ratings apply individually only, not in combination.
2. Using EIA/JESD22A114B (Human Body Model) and EIA/JESD22C101-A (Charge Device Model).
3. This load capacitance value is required for the loop stability. Tolerance, temperature variation, and voltage
dependency of the capacitance must be considered. Typically a 4.7µF ceramic capacitor is required to achieve
specified value at V
FAN5331 Rev. 1.0.1
OUT
= 15V.
2
20 V
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≥
≥
Ω
Ω
µ
µ
Electrical Characteristics
Unless otherwise noted, V
Figure 3.
Parameter Conditions Min. Typ. Max. Units
Switch Current Limit V
Load Current Capability V
Switch On-resistance V
Quiescent Current V
OFF Mode Current V
Shutdown Threshold Device ON 1.5 V
Shutdown Pin Bias Current V
Feedback Voltage I
Feedback Pin Bias Current 10 nA
Feedback Voltage Line Regulation 2.7V < V
Switching Frequency 1.15 1.6 1.85 MHz
Maximum Duty Cycle 87 93 %
Enable Delay V
Power on Delay V
Switch Leakage Current No Switching, V
= 3.6V, T
IN
V
V
V
= -40°C to +85°C, Typical values are at T
A
= 3.2V 0.7 1 A
IN
= 15V, V
OUT
= 15V, V
OUT
= 5V 0.5
IN
= 3.6V 0.7
IN
= 3.6V, No Switching 0.7 mA
SHDN
= 3.6V, Switching 1.6 3.0 mA
SHDN
= 0V 0.1 2
SHDN
2.7V 35 mA
IN
3.2V 50 mA
IN
= 25°C, Test Circuit,
A
Device OFF 0.5 V
= 0V or V
SHDN
= 0mA 1.205 1.230 1.255 V
Load
< 5.5V, I
IN
= 2.7V, I
IN
= 2.7V, I
IN
OUT
OUT
= 5.5V 10 nA
SHDN
= 0mA 0.6 1.2 %
LOAD
= 35mA, V
= 35mA, V
= 5.5V 1
IN
= 15V 0.8 5 mS
OUT
= 15V 0.8 5 mS
OUT
FAN5331 High Efficiency Serial LED Driver and OLED Supply with 20V Integrated Switch
A
A
Test Circuit
VIN
C
IN
4.7µF
ON
2.7V to 5.5V
OFF
5
4
V
IN
SHDN
L
10µH
SW
FB
BAT54
1
3
FAN5331
2
GND
Figure 3. Test Circuit
R1
R2
150KΩ
13.4KΩ
C
F
120pF
C
OUT
4.7µF
V
OUT
FAN5331 Rev. 1.0.1
3
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