©2005 Fairchild Semiconductor Corporation
1
www.fairchildsemi.com
August 2005
FAN5330 Rev. 1.0.1
FAN5330 High Efficiency Serial LED Driver with 30V Integrated Switch
FAN5330
High Efficiency Serial LED Driver with 30V Integrated
Switch
Features
■
1.5MHz Switching Frequency
■
Low Noise
■
Adjustable Output Voltage
■
0.7W Output Power Capability
■
Low Shutdown Current: <1µA
■
Cycle-by-Cycle Current Limit
■
Low Feedback Voltage (110mV)
■
Over-Voltage Protection
■
Fixed-Frequency PWM Operation
■
Internal Compensation
■
Thermal Shutdown
■
5-Lead SOT23 Package
Applications
■
Cell Phones
■
PDAs
■
Handheld Equipment
■
Display Bias
■
LED Bias
Description
The FAN5330 is an LED driver that features fixed frequency
mode operation and an integrated FET switch. This device is
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
both normal and shutdown mode is designed to be minimal in
order to extend battery life. Normal 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 cur-
rent limit circuit keeps the peak current of the switch below a
typical value of 1.5A. The FAN5330 is available in a 5-lead
SOT23 package.
Typical Application
Figure 1. Typical Application Diagram
SHDN
VIN VOUT
R
GND
V
IN
FB
SW
CIN
6.8µH to 10µH
1
3
2
4
5
2.2µF
COUT
L BAT54
ILED
0.47µF
ON
OFF
FAN5330
2
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FAN5330 Rev. 1.0.1
FAN5330 High Efficiency Serial LED Driver with 30V Integrated Switch
Pin Assignment
Figure 2. Pin Assignment
Pin Description
Pin No. Pin Name Pin Description
1SW
Switching Node.
2 GND
Analog and Power Ground.
3FB
Feedback Pin.
Feedback node that connects to an external current set resistor.
4 SHDN
Shutdown Control Pin.
Logic HIGH enables, logic LOW disables the device.
5V
IN
Input Voltage Pin.
SW
GND
FB
VIN
SHDN
Top View
5-Lead SOT-23
3
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FAN5330 Rev. 1.0.1
FAN5330 High Efficiency Serial LED Driver with 30V Integrated Switch
Absolute Maximum Ratings
(
Note1)
Recommended Operating Conditions
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 0.47µF ceramic capacitor is required to achieve specified value at V
OUT
= 30V.
Parameter Min. Max. Unit
V
IN
to GND 6.0 V
FB, SHDN to GND -0.3 V
IN
+ 0.3 V
SW to GND -0.3 35 V
Lead Soldering Temperature (10 seconds) 300 °C
Junction Temperature 150 °C
Storage Temperature -55 150 °C
Thermal Resistance (
Θ
JA
) 210 °C/W
Electrostatic Discharge Protection (ESD) Level (Note 2) HBM 2 KV
CDM 1
Parameter Min. Typ. Max. Unit
Input Voltage 1.8 5.5 V
Output Voltage V
IN
30 V
Operating Ambient Temperature -40 25 85 °C
Output Capacitance Rated at the Required Output (Note 3) 0.1 µF
4
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FAN5330 Rev. 1.0.1
FAN5330 High Efficiency Serial LED Driver with 30V Integrated Switch
Electrical Characteristics
Test Circuit
Figure 3. Test Circuit
Unless otherwise noted, V
IN
= 3.6V, I
LED
= 20mA, T
A
= -40°C to 85°C, Typical values are at T
A
= 25°C, Test
Circuit, Figure 3.
Parameter Conditions Min. Typ. Max. Units
Feedback Voltage 99 110 121 mV
Switch Current Limit V
IN
= 3.2V 1.1 1.5 A
Load Current Capability V
OUT
≤
20V V
IN
= 3.2V 35 mA
Switch On-resistance V
IN
= 5V 0.6
Ω
V
IN
= 3.6V 0.7
Ω
Quiescent Current V
SHDN
= 3.6V, No Switching 0.6 mA
OFF Mode Current V
SHDN
= 0V 0.1 3
µ
A
Shutdown Threshold Device ON 1.5 V
Device OFF 0.5 V
Shutdown Pin Bias Current V
SHDN
= 0V or V
SHDN
= 5.5V 1 300 nA
Feedback Pin Bias Current 1 300 nA
Feedback Voltage Line Regulation 2.7V < V
IN
< 5.5V, V
OUT
≤
20V 0.3 %
Switching Frequency 1.25 1.5 1.75 MHz
Maximum Duty Cycle 87 93 %
Switch Leakage Current No Switching, V
IN
= 5.5V 1
µ
A
OVP 15 %
Thermal Shutdown Temperature 150 °C
SHDN
VIN VOUT
R
GND
VIN
FB
SW
CIN
10µH
1
3
2
4
5
10µF
COUT
L BAT54
ILED
1µF
ON
OFF
Electronic Load
FAN5330
5
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FAN5330 Rev. 1.0.1
FAN5330 High Efficiency Serial LED Driver with 30V Integrated Switch
Typical Performance Characteristics
T
A
= 25°C, C
IN
= 4.7µF, C
OUT
= 0.47µF, L = 10µH, unless otherwise noted.
-40 -20 0 20406080
9.6
9.8
10.0
10.2
10.4
10.6
10.8
LED Current vs Temperature
LED Current (
mA
)
V
IN
= 2.2V
V
IN
= 3.6V
V
IN
= 5.5V
V
OUT
= 15V
-40 -20 0 20406080
1.2
1.4
1.6
1.8
2.0
SW Frequency vs. Temperature
Temperature (
°C
)
SW Frequency (MHz)
V
IN
= 2.2V
V
OUT
= 15V
V
IN
= 3.6V
V
IN
= 5.5V
2345
0
5
10
15
20
25
V
OUT
= 15V
Load Current vs. Input Voltage
Input Voltage (
V
)
Load Current (mA)
Start-Up Response
Time (100
µ
s/div)
(5V/div)
Voltage
Output
Voltage
Battery
Current
(5V/div)
(0.5A/div)
EN
L = 10µH
C
IN
= 10µF
C
OUT
= 1µF
V
IN
= 2.7V
2.0 2.5 3.0 3.5 4.0 4.5 5.0 5.5
50
60
70
80
90
100
2.0 2.5 3.03.54.04.5 5.0 5.5
50
60
70
80
90
100
Input Voltage (
V
)
Efficiency (%)
I
LE
D
= 10mA
V
OUT
= 9V
I
LED
= 20mA
I
LED
= 30mA
I
LED
= 35mA
Efficiency vs. Input Voltage
Input Voltage (
V
)
Efficiency (%)
V
OUT
= 15V
I
LED
= 20mA
I
LED
= 30mA
I
LED
= 35mA
I
LED
= 10mA
Efficiency vs. Input Voltage
6
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FAN5330 Rev. 1.0.1
FAN5330 High Efficiency Serial LED Driver with 30V Integrated Switch
Block Diagram
Figure 4. Block Diagram
Circuit Description
The FAN5330 is a pulse-width modulated (PWM) current-mode
boost converter. The FAN5330 improves the performance of bat-
tery powered equipment by significantly minimizing the spectral
distribution of noise at the input caused by the switching action of
the regulator. In order to facilitate effective noise filtering, the
switching frequency was chosen to be high, 1.5MHz. The device
architecture is that of a current mode controller with an internal
sense resistor connected in series with the N-channel switch.
The voltage at the feedback pin tracks the output voltage at the
cathode of the external Schottky diode (shown in the test cir-
cuit). The error amplifier amplifies the difference between the
feedback voltage and the internal bandgap reference. The
amplified error voltage serves as a reference voltage to the
PWM comparator. The inverting input of the PWM comparator
consists of the sum of two components: the amplified control
signal received from the 30m
Ω
current sense resistor and the
ramp generator voltage derived from the oscillator. The oscilla-
tor sets the latch, and the latch turns on the FET switch. Under
normal operating conditions, the PWM comparator resets the
latch and turns off the FET, thus terminating the pulse. Since
the comparator input contains information about the output volt-
age and the control loop is arranged to form a negative feed-
back loop, the value of the peak inductor current will be adjusted
to maintain regulation.
Every time the latch is reset, the FET is turned off and the cur-
rent flow through the switch is terminated. The latch can be
reset by other events as well. Over-current condition is moni-
tored by the current limit comparator which resets the latch and
turns off the switch instantaneously within each clock cycle.
Over-Voltage Protection
The voltage on the feedback pin is sensed by an OVP Compar-
ator. When the feedback voltage is 15% higher than the nominal
voltage, the OVP Comparator stops switching of the power tran-
sistor, thus preventing the output voltage from going higher.
Open-circuit protection
As in any current regulator, if the feedback loop is open, the out-
put voltage increases until it is limited by some additional exter-
nal circuitry. In the particular case of the FAN5330, the output
voltage is limited by the switching transistor breakdown at
around 45V, typically (assuming that C
OUT
and the Schottky
diode rating voltage are higher). Since at such high output volt-
age the output current is inherently limited by the discontinuous
conduction mode, in most cases, the switching transistor enters
non-destructive breakdown and the IC survives.
However, to ensure 100% protection for LED disconnection, we
recommend limiting V
OUT
with an external Zener diode or stop-
ping the boost switching with an external voltage supervisory
circuit.
Applications Information
Setting the Output Current
The internal reference (V
REF
) is 110mV (Typical). The output
current is set by a resistor divider R connected between FB pin
and ground. The output current is given by
Reference
Oscillator
n
FB
FB
Amp Driver
Comp
Over
Voltage
Comp
-
-
+
+
Σ
Ramp
Generator
R
R
R
Q
S
Current Limit
Comparator
30mΩ
1.15 x VREF
Shutdown
Circuitry
Thermal
Shutdown
SHDN
GND
SW
VIN
Amp
Error
45 1
2
3
+
+
-
-
+-
ILED
VREF
R
--------------=
7
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FAN5330 Rev. 1.0.1
FAN5330 High Efficiency Serial LED Driver with 30V Integrated Switch
Inductor Selection
The inductor parameters directly related to device performances
are saturation current and dc resistance. The FAN5330 oper-
ates with a typical inductor value of 10µH. The lower the dc
resistance, the higher the efficiency. Usually a trade-off between
inductor size, cost and overall efficiency is needed to make the
optimum choice.
The inductor saturation current should be rated around 1.5A,
which is the threshold of the internal current limit circuit. This
limit is reached only during the start-up and with heavy load
condition; when this event occurs the converter can shift over in
discontinuous conduction mode due to the automatic turn-off of
the switching transistor, resulting in higher ripple and reduced
efficiency.
Some recommended inductors are suggested in the table
below:
Table 1: Recommended Inductors
Capacitors Selection
For best performance, low ESR input and output capacitors are
required. Ceramic capacitors of C
IN
= 4.7µF and C
OUT
= 0.47µF
placed close to the IC pins, are required for optimum perfor-
mance. The capacitances (C
OUT
) may be reduced to 0.1µF, if
higher ripple is acceptable. The output capacitor voltage rating
should be according to the V
OUT
setting.
Some capacitors are
suggested in the table below
Table 2: Recommended Capacitors
Diode Selection
The external diode used for rectification is usually a Schottky
diode. Its average forward current and reverse voltage maxi-
mum ratings should exceed the load current and the voltage at
the output of the converter respectively. A barrier Schottky diode
such as BAT54 is preferred, due to its lower reverse current over
the temperature range.
Care should be taken to avoid any short circuit of V
OUT
to GND,
even with the IC disabled, since the diode can be instantly dam-
aged by the excessive current.
Brightness Control
1. Dimming Using PWM Logic Signal
A PWM signal applied to SHDN Ta b le 5 on page 7 can control
the LED’s brightness in direct dependence with the duty cycle.
The maximum frequency should not exceed 1kHz to ensure a
linear dependence of the LED’s average current. The amplitude
of the PWM signal should be suitable to turn the FAN5333 ON
and OFF.
Alternatively, a PWM logic signal can be used to switch a FET
ON/OFF to change the resistance that sets the LED’s current
Ta b le 6 on page 7. Adjusting the duty cycle from 0% to 100%
results in varying the LED’s current between I
MIN
and I
MAX
.
Where
Figure 5. Dimming Using a PWM Signal
Figure 6. Dimming Using a PWM Logic Signal
2. Dimming Using DC Voltage
An external adjustable DC voltage Table 7 on page 7 between
0V to 2V can control the LED’s current from 15mA to 0mA,
respectively.
Figure 7. Dimming Using DC Voltage
Inductor
Value Vendor Part Number
Com-
ment
10µH TDK SLF6025&-100M1R0
10µH MURATA LQH66SN100M01C Highest
Efficiency
10µH COOPER SD414-100 Small Size
Capacitor
Value Vendor Part Number
0.47µF Panasonic ECJ-3YB1E474K
4.7µF Murata GRM21BR61A475K
IMIN
VFB
RMIN
-------------= and IMAX
VFB
RMIN RSET
--------------------------------=
SHDN
FAN5330
FB
FAN5330
RMIN
RSET
FB
V
DC
90KΩ
5Ω1.6KΩ
FAN5330
8
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FAN5330 Rev. 1.0.1
FAN5330 High Efficiency Serial LED Driver with 30V Integrated Switch
3. Dimming Using Filtered PWM Signal
This method allows the use of a greater than 1kHz PWM fre-
quency signal with minimum impact on the battery ripple. The
filtered PWM signal Table 8 on page 8 acts as an adjustable DC
voltage as long as its frequency is significantly higher than the
corner frequency of the RC low pass filter.
Figure 8. Dimming Using Filtered PWM Signal
Thermal Shutdown
When the die temperature exceeds 150°C, a reset occurs and
will remain in effect until the die cools to 130°C, at that time the
circuit will be allowed to restart.
PCB Layout Recommendations
The inherently high peak currents and switching frequency of
power supplies require careful PCB layout design. Therefore,
use wide traces for high current paths and place the input
capacitor, the inductor, and the output capacitor as close as
possible to the integrated circuit terminals. The FB pin connec-
tion should be routed away from the inductor proximity to pre-
vent RF coupling. A PCB with at least one ground plane
connected to pin 2 of the IC is recommended. This ground plane
acts as an electromagnetic shield to reduce EMI and parasitic
coupling between components.
FB
20KΩ15KΩ
5Ω1.6KΩ
FAN5330
0.1µF
9www.fairchildsemi.com
FAN5330 Rev. 1.0.1
FAN5330 High Efficiency Serial LED Driver with 30V Integrated Switch
Mechanical Dimensions
5-Lead SOT-23
Ordering Information
Symbol Inches Millimeters Notes
Min Max Min Max
A .035 .057 .90 1.45
A1 .000 .006 .00 .15
B .008 .020 .20 .50
c .003 .010 .08 .25
D .106 .122 2.70 3.10
E .059 .071 1.50 1.80
e .037 BSC .95 BSC
e1 .075 BSC 1.90 BSC
H .087 .126 2.20 3.20
L .004 .024 .10 .60
0º 10º 0º 10º
Product Number Package Type Order Code
FAN5330 5-Lead SOT23 FAN5330SX
D
e1
e
B
EH
A
A1
α
L
c
α
10 www.fairchildsemi.com
FAN5330 Rev. 1.0.1
FAN5330 High Efficiency Serial LED Driver with 30V Integrated Switch
DISCLAIMER
FAIRCHILD SEMICONDUCTOR RESERVES THE RIGHT TO MAKE CHANGES WITHOUT FURTHER NOTICE TO ANY
PRODUCTS HEREIN TO IMPROVE RELIABILITY, FUNCTION OR DESIGN. FAIRCHILD DOES NOT ASSUME ANY LIABILITY
ARISING OUT OF THE APPLICATION OR USE OF ANY PRODUCT OR CIRCUIT DESCRIBED HEREIN; NEITHER DOES IT
CONVEY ANY LICENSE UNDER ITS PATENT RIGHTS, NOR THE RIGHTS OF OTHERS.
TRADEMARKS
The following are registered and unregistered trademarks Fairchild Semiconductor owns or is authorized to use and is
not intended to be an exhaustive list of all such trademarks.
LIFE SUPPORT POLICY
FAIRCHILD’S PRODUCTS ARE NOT AUTHORIZED FOR USE AS CRITICAL COMPONENTS IN LIFE SUPPORT
DEVICES OR SYSTEMS WITHOUT THE EXPRESS WRITTEN APPROVAL OF FAIRCHILD SEMICONDUCTOR CORPORATION.
As used herein:
1. Life support devices or systems are devices or
systems which, (a) are intended for surgical implant into
the body, or (b) support or sustain life, or (c) whose
failure to perform when properly used in accordance
with instructions for use provided in the labeling, can be
reasonably expected to result in significant injury to the
user.
2. A critical component is any component of a life
support device or system whose failure to perform can
be reasonably expected to cause the failure of the life
support device or system, or to affect its safety or
effectiveness.
PRODUCT STATUS DEFINITIONS
Definition of Terms
Datasheet Identification Product Status Definition
Advance Information
Preliminary
No Identification Needed
Obsolete
This datasheet contains the design specifications for
product development. Specifications may change in
any manner without notice.
This datasheet contains preliminary data, and
supplementary data will be published at a later date.
Fairchild Semiconductor reserves the right to make
changes at any time without notice in order to improve
design.
This datasheet contains final specifications. Fairchild
Semiconductor reserves the right to make changes at
any time without notice in order to improve design.
This datasheet contains specifications on a product
that has been discontinued by Fairchild semiconductor.
The datasheet is printed for reference information only.
Formative or
In Design
First Production
Full Production
Not In Production
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