FAN5341UMPX [FAIRCHILD]
Series Boost LED Driver with Integrated Schottky Diode and Single-Wire Digital Interface; 系列升压LED驱动器，集成肖特基二极管和单线数字接口
| 型号： | FAN5341UMPX |
| 厂家： | 
FAIRCHILD SEMICONDUCTOR |
| 描述： | Series Boost LED Driver with Integrated Schottky Diode and Single-Wire Digital Interface |
| 文件： | 总11页 (文件大小：693K) |
| 中文： | 中文翻译 | 下载： | 下载PDF数据表文档文件 |
November 2009
FAN5341
Series Boost LED Driver with Integrated Schottky Diode and
Single-Wire Digital Interface
Features
Description
The FAN5341 is an asynchronous constant-current LED
driver capable of efficiently delivering up to 500mW to a
string of up to five LEDs in series. Optimized for small form-
factor applications, the 1.2MHz fixed switching frequency
allows the use of small chip inductors and capacitors.
Asynchronous Boost Converter
Internal Schottky Diode
Up to 500mW Output Power
Drives 3 to 5 LEDs in Series
2.7V to 5.5V Input Voltage Range
The FAN5341 uses a simple single-wire digital control
interface to program the brightness levels of the LEDs in 32
linear steps by applying digital pulses.
Single-Wire Digital Control Interface to Set LED
Brightness Levels
For safety, the device features integrated over-voltage, over-
current, short-circuit detection, and thermal-shutdown
protection. In addition, input under-voltage lockout protection
is triggered if the battery voltage is too low.
−
32 Linear Steps
1.2MHz Fixed Switching Frequency
Soft-Start Capability
The FAN5341 is available in a very low profile, small form-
factor 2mm x 2mm x 0.55mm 6-lead UMLP package that is
green and RoHS compliant.
Input Under-Voltage Lockout (UVLO)
Output Over-Voltage Protection (OVP)
Short-Circuit Detection
Thermal Shutdown (TSD) Protection
Low Profile 6-lead 2.0 x 2.0 x 0.55mm UMLP Package
Applications
Cellular Mobile Handsets
Mobile Internet Devices
Portable Media Players
PDA, DSC, MP3 Players
Ordering Information
Part Number
Temperature Range
-40 to 85°C
Package
Packing
Eco Status
FAN5341UMPX
Green
6-lead, 2.0 x 2.0mm UMLP
Tape and Reel
For Fairchild’s definition of Eco Status, please visit: http://www.fairchildsemi.com/company/green/rohs_green.html.
© 2009 Fairchild Semiconductor Corporation
FAN5341 • Rev. 1.0.0
www.fairchildsemi.com
Typical Application Diagram
Figure 1. Typical Application
Block Diagram
Figure 2. Functional Block Diagram
© 2009 Fairchild Semiconductor Corporation
FAN5341 • Rev. 1.0.0
www.fairchildsemi.com
2
Pin Configuration
VOUT 1
6 GND
P1
GND
2
3
5
VIN
EN
SW
FB
4
Figure 3. UMLP6 Package, ^Top View
Pin Definitions
Pin #
Name Description
Boost Output Voltage. Output of the boost regulator. Connect the LEDs to this pin. Connect COUT
(Output Capacitor) to GND.
1
VOUT
Input Voltage. Connect to power source and decouple with CIN to GND.
2
3
VIN
EN
Enable Brightness Control. Program dimming levels by driving pin with digital pulses.
Voltage Feedback. The boost regulator regulates this pin to 0.253V to control the LED string current.
Tie this pin to a current setting resistor (RSET) between GND and the cathode of the LED string.
4
FB
Switching node. Tie inductor L1 from VIN to SW pin.
Ground. Tie directly to a GND plane.
5
6
SW
GND
© 2009 Fairchild Semiconductor Corporation
FAN5341 • Rev. 1.0.0
www.fairchildsemi.com
3
Absolute Maximum Ratings
Stresses exceeding the absolute maximum ratings may damage the device. The device may not function or be operable above
the recommended operating conditions and stressing the parts to these levels is not recommended. In addition, extended
exposure to stresses above the recommended operating conditions may affect device reliability. The absolute maximum ratings
are stress ratings only.
Symbol Parameter
VIN VIN
VFB, VEN FB, EN Pins
Min.
-0.3
-0.3
-0.3
–0.3
Max.
6.0
Units
V
V
V
V
VIN + 0.3
22.0
VSW
SW Pin
VOUT
VOUT Pin
22.0
Human Body Model per JESD22-A114
Charged Device Model per JESD22-C101
3.3
2.0
Electrostatic Discharge Protection
Level
ESD
kV
TJ
TSTG
TL
Junction Temperature
Storage Temperature
-40
-65
+150
+150
+260
°C
°C
°C
Lead Soldering Temperature, 10 Seconds
Recommended Operating Conditions
The Recommended Operating Conditions table defines the conditions for actual device operation. Recommended operating
conditions are specified to ensure optimal performance to the datasheet specifications. Fairchild does not recommend exceeding
them or designing to absolute maximum ratings.
Symbol Parameter
Comments
Min.
2.7
6.2
5
Max.
5.5
Units
V
VIN
VOUT
IOUT
TA
VIN Supply Voltage
VOUT Voltage(1)
17.5
25
V
VOUT Load Current
Ambient Temperature
Junction Temperature
500mW Maximum Output Power
mA
°C
-40
-40
+85
+125
TJ
°C
Note:
1. Application should guarantee that minimum and maximum duty-cycle should fall between 20-85% to meet the specified
range
Thermal Properties
Junction-to-ambient thermal resistance is a function of application and board layout. This data is measured with four-layer 2s2p
boards in accordance to JEDEC standard JESD51. Special attention must be paid not to exceed junction temperature TJ(max) at a
given ambient temperature TA.
Symbol Parameter
Typical
Units
Junction-to-Ambient Thermal Resistance, UMLP6 Package
70
°C/W
θJA
© 2009 Fairchild Semiconductor Corporation
FAN5341 • Rev. 1.0.0
www.fairchildsemi.com
4
Electrical Specifications
VIN = 2.7V to 5.5V and TA = -40°C to +85°C unless otherwise noted. Typical values are at TA = 25°C and VIN = 3.6V.
Symbol Parameter
Power Supplies
Conditions
Min.
Typ.
Max. Units
ISD
Shutdown Supply Current
EN = GND, VIN = 3.6V
VIN Rising
0.30
2.35
2.15
0.75
2.60
2.40
μA
2.10
1.90
Under-Voltage Lockout
Threshold
VUVLO
V
VIN Falling
Under-Voltage Lockout
Hysteresis
VUVHYST
250
mV
EN: Enable Pin
VIH
VIL
HIGH-Level Input Voltage
1.2
V
V
LOW-Level Input Voltage
EN Pull-Down Resistance
EN Low Time for Dimming
Time Delay Between Steps
EN Low, Shutdown Pulse Width
0.4
400
300
REN
TLO
THI
200
0.5
0.5
1
300
kΩ
µs
µs
ms
VIN = 3.6V; See Figure 14
VIN = 3.6V; See Figure 14
TSD
VIN = 3.6V; from Falling Edge of EN
Feedback and Reference
ILED = 20mA from -40°C to +85°C,
2.7V ≤ VIN ≤ 5.5V
VFB
IFB
Feedback Voltage
240
253
0.1
266
1.0
mV
Feedback Input Current
VFB = 253mV
μA
Power Outputs
V
IN = 3.6V, ISW = 100mA
600
650
RDS(ON)_Q1 Boost Switch On-Resistance
mΩ
VIN = 2.7V, ISW = 100mA
EN = 0, VIN = VSW = VOUT = 5.5V,
VLED = 0
ISW(OFF)
SW Node Leakage(1)
0.1
2.0
μA
ILIM-PK
Boost Switch Peak Current Limit VIN = 3.6V
750
mA
Oscillator
Boost Regulator Switching
Frequency
fSW
1.0
1.2
1.4
MHz
V
Output and Protection
Boost Output Over-Voltage
18.0
18.9
0.8
21.0
Protection
VOVP
OVP Hysteresis
VOUT Short Circuit Detection
Threshold
VTLSC
VOUT Falling
VOUT Rising
VIN – 1.4
V
V
VOUT Short Circuit Detection
Threshold
Maximum Boost Duty Cycle(2,3)
Minimum Boost Duty Cycle(2,3)
VTHSC
DMAX
VIN – 1.2
85
%
DMIN
TTSD
THYS
20
Thermal Shutdown
150
35
°C
°C
Thermal Shutdown Hysteresis
Notes:
1. SW leakage current includes the leakage current of 2 internal switches; SW to GND and SW to VOUT.
2. Not tested in production and guaranteed by design.
3. Application should guarantee that minimum and maximum duty cycle should fall between 20-85% to meet the specified
range.
© 2009 Fairchild Semiconductor Corporation
FAN5341 • Rev. 1.0.0
www.fairchildsemi.com
5
Electrical Specifications
90
80
70
60
50
90
5 LEDs
L = 10µH
5 LEDs
L = 4.7µH
C
OUT = 1.0µF
C
OUT = 1.0µF
ILED = 25mA
ILED = 25mA
80
70
60
50
VIN=2.7V
VIN=2.8V
VIN=3.6V
VIN=4.2V
VIN=3.6V
VIN=4.2V
5
10
15
20
25
5
10
15
20
25
LED Current (mA)
LED Current (mA)
Figure 4. 5 LEDs: Efficiency vs. LED Current
vs. Input Voltage
Figure 5. 5 LEDs: Efficiency vs. LED Current
vs. Input Voltage
90
80
70
60
50
0.8
4 LEDs
L = 10µH
0.6
0.4
0.2
0
C
OUT = 1.0µF
ILED = 25mA
-0.2
-0.4
-0.6
VIN=2.7V
-40°C
+25°C
+85°C
VIN=3.6V
VIN=4.2V
5
10
15
20
25
2.7
3
3.3
3.6
3.9
4.2
LED Current (mA)
Input Voltage (V)
Figure 7. Delta of VFB Over Input Voltage and
Figure 6. 4 LEDs: Efficiency vs. LED Current
vs. Input Voltage
Temperature for 4 LEDs with L=10µH and
COUT=1.0µF at ILED=25mA
90
80
70
60
50
20.0
19.5
19.0
18.5
18.0
17.5
17.0
3 LEDs
L = 10µH
4 LEDs
L = 10µH
COUT = 1.0µF
ILED = 25mA
C
OUT = 1.0µF
ILED = 25mA
VIN=2.8V
VIN=3.6V
VIN=4.2V
2.7
3
3.3
3.6
3.9
4.2
5
10
15
20
25
Input Voltage (V)
LED Current (mA)
Figure 8. 3 LEDs: Efficiency vs. LED Current
vs. Input Voltage
Figure 9. Over-Voltage Protection vs. Input Voltage
© 2009 Fairchild Semiconductor Corporation
FAN5341 • Rev. 1.0.0
www.fairchildsemi.com
6
Electrical Specifications
Figure 10.Line Transient Response for 4 LEDs at
VIN=3.6V ± 0.6V with L=10µH, COUT=1.0µF and
ILED=25mA
Figure 11.FAN5341 Dimming Operation at VIN=3.6V for 4
LEDs with L=10µH, COUT=1.0µF and ILED=25mA
Figure 12.Startup Waveform for Switch Voltage, Inductor Figure 13.Steady-State Waveform for VOUT, Switch Voltage
Current, VFB and EN for 4 LEDs at VIN=3.6V±
0.6V with L=10µH, COUT=1.0µF and ILED=25mA
and Inductor Current for 4 LEDs at VIN=3.6V ±
0.6V with L=10µH, COUT=1.0µF and ILED=25mA
© 2009 Fairchild Semiconductor Corporation
FAN5341 • Rev. 1.0.0
www.fairchildsemi.com
7
Circuit Description
Overview
FAN5341 does not require the system processor to
constantly supply a signal to it to drive the LEDs.
The FAN5341 is an inductive current-mode boost serial
LED driver that achieves LED current regulation by
maintaining 0.253V across the RSET resistor. The current
through the LED string (ILED) is therefore given by:
Digital Dimming Control
The FAN5341 starts driving the LEDs at the maximum
brightness level. After startup, the control logic is ready to
accept programming pulses to decrease the brightness
level by the number of positive edges applied to the EN pin.
Figure 14 shows the digital pulse dimming control.
0.253
ILED
=
(1)
RSET
The voltage VOUT is determined by the sum of the forward
Over-Current and Short-Circuit Detection
voltages across each LED, plus the voltage across RSET
,
The boost regulator employs a cycle-by-cycle peak inductor
current limit of ~750mA.
which is always 253mV.
Driving Five LEDs in Series
Over-Voltage / Open-Circuit Protection
FAN5341 can drive five LEDs in series but, the forward
voltage (VF) of the LED MUST be less than 3.5V such that it
remains under the over-voltage specification of 18.9V.
If the LED string is an open circuit, FB remains at 0V and
the output voltag continues to increase in the absence of an
over-voltage protection (OVP) circuit. The FAN5341’s OVP
circuit disables the boost regulator when VOUT exceeds
18.9V and continues to keep the regulator off until VOUT
drops below 18.1V.
UVLO and Soft-Start
If EN has been low for more than 1ms, the IC may initiate a
“cold start” soft-start cycle when EN rises, provided VIN is
above the UVLO threshold.
Thermal Shutdown
When the die temperature exceeds 150°C, a reset occurs
and remains in effect until the die cools to 125°C, at which
time, the circuit is allowed to begin the soft-start sequence.
Digital Interface
The FAN5341 implements a single-wire digital interface to
program the LED brightness to one of thirty-two (32) levels
spaced in linear steps. With this single-wire solution, the
Figure 14. Digital Pulse-Dimming Control Diagram
© 2009 Fairchild Semiconductor Corporation
FAN5341 • Rev. 1.0.0
www.fairchildsemi.com
8
Application Information
Inductor & Output Capacitor Selection
# of LEDs
Inductor (L)
Part Number
Manufacturer
Murata
TDK
Min COUT Part Number
Manufacturer
LQH43MN100K03
NLCV32T-100K-PFR
VLF3010AT-100MR49-1
LQH43MN4R7K03
NLCV32T-4R7M-PFR
LPF2010T-4R7M
1.00µF
CV105X5R105K25AT
AVX/Kyocera
10.0µH
TDK
3, 4, 5
Murata
TDK
1.00µF
CV105X5R105K25AT
AVX/Kyocera
4.7µH
ABCO
Table 1. Recommended External Components
Component Placement and PCB Recomendations
Figure 1. Recommended Component Placement
Input Capacitance
PCB Recommendations
In a typical application, the input and output capacitors
should be placed as close to the IC as possible; no
additional capacitance is needed to ensure proper
functionality. However, in a testing environment, where the
FAN5341 is typically powered by a power supply with
relatively long cables, an additional input capacitor (10µF)
may be needed to ensure stable functioning. This capacitor
should be placed close to where the power supply cables
attach to the FAN5341 evaluation board.
The inductor can be connected to VIN with vias through
another layer if needed.
The feedback pin should be connected back to the IC on
a sub-layer.
© 2009 Fairchild Semiconductor Corporation
FAN5341 • Rev. 1.0.0
www.fairchildsemi.com
9
Physical Dimensions
0.10 C
2.0
A
2X
B
1.60
1.50
2.0
6
4
0.27
0.50
0.85
0.10 C
2X
1.40 2.40
PIN1
IDENT
TOP VIEW
1
3
0.30
0.55 MAX
0.10 C
0.65
(0.15)
C
RECOMMENDED LAND PATTERN
0.08 C
0.05
0.00
SEATING
PLANE
SIDE VIEW
NOTES:
1.35
1.45
PIN1
IDENT
1
3
0.70
0.80
0.35
0.25
6x
6
4
0.35
0.25
6x
0.65
1.30
0.10 C A B
0.05 C
BOTTOM VIEW
Figure 15. 6-Lead Molded Leadless Package (UMLP)
Package drawings are provided as a service to customers considering Fairchild components. Drawings may change in any manner without
notice. Please note the revision and/or date on the drawing and contact a Fairchild Semiconductor representative to verify or obtain the most
recent revision. Package specifications do not expand the terms of Fairchild’s worldwide terms and conditions, specifically the warranty therein, which covers
Fairchild products.
Always visit Fairchild Semiconductor’s online packaging area for the most recent package drawings:
http://www.fairchildsemi.com/packaging/.
© 2009 Fairchild Semiconductor Corporation
FAN5341 • Rev. 1.0.0
www.fairchildsemi.com
10
© 2009 Fairchild Semiconductor Corporation
FAN5341 • Rev. 1.0.0
www.fairchildsemi.com
11
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