Document
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 RDS(ON): 0.5Ω ■ 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
Applications
■ Cell Phones ■ PDAs ■ Handheld Equipment ■ Display Bias ■ LED Bias
Typical Application
VIN 2.7V to 5.5V CIN
4.7µF
5 VIN
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.
L 10µH
BAT54
SW 1
R1
VOUT COUT 4.7µF
CF 120pF
3 FB
FAN5331
ON OFF
4 SHDN
2 GND
R2
©2004 Fairchild Semiconductor Corporation FAN5331 Rev. 1.0.1
Figure 1. Typical Application Diagram
1
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FAN5331 High Efficiency Serial LED Driver and OLED Supply with 20V Integrated Switch
Pin Assignment
Top View
SW
GND FB
VIN SHDN
5-Lead SOT-23
Figure 2. Pin Assignment
Pin Description
Pin No.
1 2 3 4 5
Pin Name
SW GND FB SHDN VIN
Pin Description
Switching node. Analog and power ground. Feedback node that connects to an external voltage divider. Shutdown control pin. Logic HIGH enables, logic LOW disables the device. Input voltage.
Absolute Maximum Ratings (Note1)
Parameter
VIN to GND FB, SHDN to GND SW to GND Lead Soldering Temperature (10 seconds) Junction Temperature Storage Temperature Thermal Resistance (ΘJA) Electrostatic Discharge Protection (ESD) Level (Note 2)
HBM CDM
Min
-0.3 -0.3
-55 2.5 1
Max
6.0 VIN + 0.3
23 300 150 150 265
Unit
V V V °C °C °C °C/W kV
Recommended Operating Conditions
Parameter
Input Voltage Output Voltage Operating Ambient Temperature Output Capacitance (Note 3)
Min
2.7 VIN -40 1.6
Typ
25
Max
5.5 20 85
Unit
V V °C µF
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 VOUT = 15V.
2 www.fairchildsemi.com FAN5331 Rev. 1.0.1
FAN5331 High Efficiency Serial LED Driver and OLED Supply with 20V Integrated Switch
Electrical Characteristics
Unless otherwise noted, VIN = 3.6V, TA = -40°C to +85°C, Typical values are at TA = 25°C, Test Circuit, Figure 3.
Parameter
Switch Current Limit Load Current Capability
Switch On-resistance
Quiescent Current
OFF Mode Current Shutdown Threshold
Shutdown Pin Bias Current Feedback Voltage Feedback Pin Bias Current Feedback Voltage Line Regulation Switching Frequency Maximum Duty Cycle Enable Delay Power on Delay Switch Leakage Current
Conditions
VIN = 3.2V VOUT = 15V, VIN ≥ 2.7V VOUT = 15V, VIN ≥ 3.2V VIN = 5V VIN = 3.6V VSHDN = 3.6V, No Switching VSHDN = 3.6V, Switching VSHDN = 0V Device ON Device OFF VSHDN = 0V or VSHDN = 5.5V ILoad = 0mA
2.7V < VIN < 5.5V, ILOAD = 0mA
VIN = 2.7V, IOUT = 35mA, VOUT = 15V VIN = 2.7V, IOUT = 35mA, VOUT = 15V No Switching, VIN = 5.5V
Min.
0.7 35 50
1.5
1.205
1.15 87
Typ.
1
0.5 0.7 0.7 1.6 0.1
10 1.230
10 0.6 1.6 93 0.8 0.8
Max.
3.0 2 0.5 1.255 1.2 1.85 5 5 1
Units
A mA mA Ω Ω mA mA µA V V nA V nA % MHz % mS mS µA
Test Circuit
VIN 2.7V to 5.5V CIN 4.7µF
5 VIN
L 10µH
SW 1
BAT54 R1 150KΩ
VOUT COUT 4.7µF
CF 120pF
3 FB
FAN5331
ON OFF
4 SHDN
2 GND
R2 13.4KΩ
Figure 3. Test Circuit
3 www.fairchildsemi.com FAN5331 Rev. 1.0.1
FAN5331 High Efficiency Serial LED Driver and OLED Supply with 20V Integrated Switch
Typical Performance Characteristics
TA = 25°C, Test Circuit Figure 3, unless otherwise noted.
Output Voltage (V)
.