GRM21BR61A475K [FAIRCHILD]
High Efficiency Serial LED Driver with 30V Integrated Switch; 高效率的串行LED驱动器，集成30V开关
| 型号： | GRM21BR61A475K |
| 厂家： | 
FAIRCHILD SEMICONDUCTOR |
| 描述： | High Efficiency Serial LED Driver with 30V Integrated Switch |
| 文件： | 总10页 (文件大小：521K) |
| 中文： | 中文翻译 | 下载： | 下载PDF数据表文档文件 |
August 2005
FAN5330
High Efficiency Serial LED Driver with 30V Integrated
Switch
Features
Description
■ 1.5MHz Switching Frequency
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.
■ 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
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.
■ Thermal Shutdown
■ 5-Lead SOT23 Package
Applications
■ Cell Phones
■ PDAs
■ Handheld Equipment
■ Display Bias
■ LED Bias
Typical Application
BAT54
VOUT
L
VIN
6.8µH to 10µH
COUT
CIN
2.2µF
0.47µF
ILED
5
1
3
SW
FB
V
IN
R
2
4
ON
SHDN
GND
OFF
Figure 1.Typical Application Diagram
©2005 Fairchild Semiconductor Corporation
FAN5330 Rev. 1.0.1
1
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Pin Assignment
Top View
SW
VIN
GND
FB
SHDN
5-Lead SOT-23
Figure 2. Pin Assignment
Pin Description
Pin No.
Pin Name
Pin Description
1
2
3
4
5
SW
GND
FB
Switching Node.
Analog and Power Ground.
Feedback Pin. Feedback node that connects to an external current set resistor.
Shutdown Control Pin. Logic HIGH enables, logic LOW disables the device.
Input Voltage Pin.
SHDN
V
IN
2
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FAN5330 Rev. 1.0.1
Absolute Maximum Ratings (Note1)
Parameter
Min.
Max.
Unit
V
V
to GND
6.0
IN
FB, SHDN to GND
-0.3
-0.3
V
+ 0.3
V
IN
SW to GND
35
V
Lead Soldering Temperature (10 seconds)
Junction Temperature
Storage Temperature
300
150
150
210
°C
°C
-55
°C
Thermal Resistance (Θ
)
°C/W
KV
JA
Electrostatic Discharge Protection (ESD) Level (Note 2)
HBM
CDM
2
1
Recommended Operating Conditions
Parameter
Input Voltage
Min.
Typ.
Max.
5.5
Unit
V
1.8
Output Voltage
V
30
V
IN
Operating Ambient Temperature
Output Capacitance Rated at the Required Output (Note 3)
-40
0.1
25
85
°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 0.47µF ceramic capacitor is required to achieve specified value at V
= 30V.
OUT
3
www.fairchildsemi.com
FAN5330 Rev. 1.0.1
Electrical Characteristics
Unless otherwise noted, V = 3.6V, I
= 20mA, T = -40°C to 85°C, Typical values are at T = 25°C, Test
IN
LED
A
A
Circuit, Figure 3.
Parameter
Conditions
Min.
99
Typ.
110
Max.
Units
mV
A
Feedback Voltage
121
Switch Current Limit
Load Current Capability
Switch On-resistance
V
V
V
V
V
V
= 3.2V
1.1
35
1.5
IN
≤ 20V V = 3.2V
mA
Ω
OUT
IN
= 5V
0.6
0.7
0.6
0.1
IN
= 3.6V
Ω
IN
Quiescent Current
OFF Mode Current
Shutdown Threshold
= 3.6V, No Switching
= 0V
mA
µA
V
SHDN
SHDN
3
Device ON
1.5
Device OFF
0.5
300
300
V
Shutdown Pin Bias Current
Feedback Pin Bias Current
Feedback Voltage Line Regulation
Switching Frequency
V
= 0V or V
= 5.5V
SHDN
1
nA
nA
%
SHDN
1
2.7V < V < 5.5V, V
≤ 20V
0.3
1.5
93
IN
OUT
1.25
87
1.75
1
MHz
%
Maximum Duty Cycle
Switch Leakage Current
OVP
No Switching, V = 5.5V
µA
%
IN
15
Thermal Shutdown Temperature
150
°C
Test Circuit
BAT54
VOUT
L
VIN
10µH
COUT
CIN
1µF
10µF
ILED
5
1
3
SW
FB
VIN
Electronic Load
R
2
4
ON
SHDN
GND
OFF
Figure 3. Test Circuit
4
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FAN5330 Rev. 1.0.1
Typical Performance Characteristics
T = 25°C, C = 4.7µF, C = 0.47µF, L = 10µH, unless otherwise noted.
OUT
A
IN
LED Current vs Temperature
SW Frequency vs. Temperature
10.8
10.6
10.4
10.2
10.0
9.8
2.0
1.8
1.6
1.4
1.2
VIN = 5.5V
VIN = 2.2V
VOUT = 15V
VOUT = 15V
VIN = 3.6V
VIN = 3.6V
VIN = 5.5V
VIN = 2.2V
9.6
-40
-20
0
20
40
60
80
-40
-20
0
20
40
60
80
Temperature (°C
)
Start-Up Response
Load Current vs. Input Voltage
25
20
15
10
5
VOUT = 15V
L = 10µH
CIN = 10µF
COUT = 1µF
VIN = 2.7V
0
2
3
4
5
Input Voltage (V)
Time (100µs/div)
Efficiency vs. Input Voltage
Efficiency vs. Input Voltage
100
90
80
70
60
50
100
90
80
70
60
50
VOUT = 9V
VOUT = 15V
ILED = 35mA
ILED = 35mA
ILED = 30mA
ILED = 20mA
ILED = 30mA
IL = 10mA
DE
ILED = 20mA
ILED = 10mA
2.5
2.0
2.5
3.0
3.5
4.0
4.5
5.0
5.5
2.0
3.0
3.5
4.0
4.5
5.0
5.5
Input Voltage (V)
Input Voltage (
V
)
5
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FAN5330 Rev. 1.0.1
Block Diagram
V
IN
SHDN
4
SW
1
5
Shutdown
Circuitry
FB
+
-
Over
Voltage
Comp
1.15 x V
REF
Thermal
Shutdown
R
R
R
-
3
FB
Error
Amp
+
+
n
Q
Driver
Comp
-
Σ
Reference
S
Ramp
Generator
Current Limit
Comparator
-
+
Oscillator
+
Amp
30mΩ
-
2
GND
Figure 4. Block Diagram
Over-Voltage Protection
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 30mΩ 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.
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
and the Schottky
OUT
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
with an external Zener diode or stop-
OUT
ping the boost switching with an external voltage supervisory
circuit.
Applications Information
Setting the Output Current
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.
The internal reference (V
current is set by a resistor divider R connected between FB pin
and ground. The output current is given by
) is 110mV (Typical). The output
REF
VREF
ILED = -------------
R
6
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FAN5330 Rev. 1.0.1
Inductor Selection
Brightness Control
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.
1. Dimming Using PWM Logic Signal
A PWM signal applied to SHDN Table 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.
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.
Alternatively, a PWM logic signal can be used to switch a FET
ON/OFF to change the resistance that sets the LED’s current
Table 6 on page 7. Adjusting the duty cycle from 0% to 100%
results in varying the LED’s current between I
and I
.
MIN
MAX
Where
Some recommended inductors are suggested in the table
below:
VFB
IMIN = ------------- and IMAX = --------------------------------
RMIN RMIN RSET
VFB
Inductor
Value
Com-
ment
Vendor
TDK
Part Number
SLF6025&-100M1R0
LQH66SN100M01C
10µH
10µH
MURATA
Highest
FAN5330
Efficiency
SHDN
10µH
COOPER
SD414-100
Small Size
Table 1: Recommended Inductors
Capacitors Selection
Figure 5. Dimming Using a PWM Signal
For best performance, low ESR input and output capacitors are
required. Ceramic capacitors of C = 4.7µF and C = 0.47µF
IN
OUT
placed close to the IC pins, are required for optimum perfor-
mance. The capacitances (C ) may be reduced to 0.1µF, if
FAN5330
OUT
higher ripple is acceptable. The output capacitor voltage rating
FB
RSET
should be according to the V
suggested in the table below
setting. Some capacitors are
OUT
RMIN
Capacitor
Value
0.47µF
4.7µF
Vendor
Part Number
ECJ-3YB1E474K
GRM21BR61A475K
Figure 6. Dimming Using a PWM Logic Signal
2. Dimming Using DC Voltage
Panasonic
Murata
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.
Table 2: Recommended Capacitors
Diode Selection
FAN5330
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.
FB
VDC
1.6KΩ
90KΩ
5Ω
Care should be taken to avoid any short circuit of V
even with the IC disabled, since the diode can be instantly dam-
aged by the excessive current.
to GND,
OUT
Figure 7. Dimming Using DC Voltage
7
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FAN5330 Rev. 1.0.1
3. 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.
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.
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.
FAN5330
FB
20KΩ
15KΩ
1.6KΩ
5Ω
0.1µF
Figure 8. Dimming Using Filtered PWM Signal
8
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FAN5330 Rev. 1.0.1
Mechanical Dimensions
5-Lead SOT-23
B
e
H
E
e1
D
A
A1
Symbol
Inches
Millimeters
Notes
Min
.035
.000
.008
.003
.106
.059
Max
.057
.006
.020
.010
.122
.071
Min
Max
1.45
.15
A
A1
B
.90
.00
.20
.50
c
.08
.25
D
E
2.70
1.50
3.10
1.80
e
.037 BSC
.075 BSC
.95 BSC
e1
H
L
1.90 BSC
.087
.004
0º
.126
.024
10º
2.20
.10
0º
3.20
.60
α
10º
Ordering Information
Product Number
Package Type
Order Code
FAN5330
5-Lead SOT23
FAN5330SX
9
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FAN5330 Rev. 1.0.1
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.
ACEx™
PowerSaver™
SuperSOT™-8
SyncFET™
TinyLogic
ISOPLANAR™
LittleFET™
MICROCOUPLER™
MicroFET™
MicroPak™
MICROWIRE™
MSX™
FAST
ActiveArray™
Bottomless™
Build it Now™
CoolFET™
CROSSVOLT™
DOME™
EcoSPARK™
E2CMOS™
EnSigna™
FACT™
PowerTrench
FASTr™
FPS™
FRFET™
GlobalOptoisolator™
GTO™
QFET
QS™
TINYOPTO™
TruTranslation™
UHC™
QT Optoelectronics™
Quiet Series™
RapidConfigure™
RapidConnect™
µSerDes™
SILENT SWITCHER
SMART START™
SPM™
UltraFET
HiSeC™
I2C™
UniFET™
VCX™
Wire™
MSXPro™
OCX™
i-Lo™
ImpliedDisconnect™
IntelliMAX™
OCXPro™
OPTOLOGIC
OPTOPLANAR™
PACMAN™
POP™
Power247™
PowerEdge™
FACT Quiet Series™
Stealth™
Across the board. Around the world.™
SuperFET™
SuperSOT™-3
SuperSOT™-6
The Power Franchise
Programmable Active Droop™
DISCLAIMER
FAIRCHILD SEMICONDUCTOR RESERVESTHE RIGHTTO MAKE CHANGES WITHOUTFURTHER NOTICETOANY
PRODUCTS HEREINTO IMPROVE RELIABILITY, FUNCTION OR DESIGN. FAIRCHILD DOES NOTASSUMEANYLIABILITY
ARISING OUTOFTHEAPPLICATION OR USE OFANYPRODUCTOR CIRCUITDESCRIBED HEREIN; NEITHER DOES IT
CONVEYANYLICENSE UNDER ITS PATENTRIGHTS, NORTHE RIGHTS OF OTHERS.
LIFE SUPPORT POLICY
FAIRCHILD’S PRODUCTS ARE NOT AUTHORIZED FOR USE AS CRITICAL COMPONENTS IN LIFE SUPPORT
DEVICES OR SYSTEMS WITHOUTTHE EXPRESS WRITTENAPPROVALOF 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
Formative or
In Design
This datasheet contains the design specifications for
product development. Specifications may change in
any manner without notice.
Preliminary
First Production
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.
No Identification Needed
Obsolete
Full Production
This datasheet contains final specifications. Fairchild
Semiconductor reserves the right to make changes at
any time without notice in order to improve design.
Not In Production
This datasheet contains specifications on a product
that has been discontinued by Fairchild semiconductor.
The datasheet is printed for reference information only.
Rev. I16
10
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FAN5330 Rev. 1.0.1
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