AME AME5142AEEYADJY

AME, Inc.
White LED Boost Converter
In Tiny Package
AME5142
n Pin Configuration
SOT-25/TSOT-25
Top View
5
4
SOT-26/TSOT-26
Top View
AME5142AEEV
6
5
4
1. SW
1. SW
2. GND
AME5142
3. FB
2. GND
AME5142
4. EN
2
3. FB
4. EN
5. IN
1
AME5142AEEY
5. OVP
1
3
* Die Attach:
2
3
6. IN
* Die Attach:
Conductive Epoxy
Conductive Epoxy
n Pin Description
AME5142AEEV
Pin Number
Pin Name
Pin Description
1
SW
Power Switch input.
This is the drain of the internal NMOS power switch. Minimize the metal
trace area connected to this pin to minimize EMI.
2
GND
Ground.
Tie directly to ground plane.
3
FB
Output voltage feedback input.
Connect the ground of the feedback network to an AGND (Analog Ground)
plane which should be tied directly to the GND pin.
4
EN
Enable control input, active high.
The enable pin is an active high control. Tie this pin above 1.5V to enable
the device. Tie this pin below 0.4V to turn off the device.
5
IN
Analog and Power input.
Input Supply Pin. Bypass this pin with a capacitor as close to the device
as possible.
Rev. A.01
3
AME, Inc.
White LED Boost Converter
In Tiny Package
AME5142
n Pin Description
AME5142AEEY
4
Pin Number
Pin Name
Pin Description
1
SW
Power Switch input.
This is the drain of the internal NMOS power switch. Minimize the metal
trace area connected to this pin to minimize EMI.
2
GND
Ground.
Tie directly to ground plane.
3
FB
Output voltage feedback input.
Connect the ground of the feedback network to an AGND(Analog Ground)
plane which should be tied directly to the GND pin.
4
EN
Enable control input, active high.
The enable pin is an active high control. Tie this pin above 1.5V to enable
the device. Tie this pin below 0.4V to turn off the device.
5
OVP
6
IN
Over Voltage Protection.
Analog and Power input.
Input Supply Pin. Bypass this pin with a capacitor as close to the device
as possible.
Rev. A.01
AME, Inc.
White LED Boost Converter
In Tiny Package
AME5142
n Ordering Information
AME5142 x x x x xxx x
Special Feature
Output Voltage
Number of Pins
Package Type
Operating Ambient Temperature Range
Pin Configuration
Pin
Configuration
A
(SOT-25)
(TSOT-25)
A
(SOT-26)
(TSOT-26)
1. SW
2. GND
3. FB
4. EN
5. IN
Operating Ambient
Temperature
Range
Package
Type
E: -40OC to 85OC
E: SOT-2X
Number
of
Pins
V: 5
Y: 6
Output Voltage
Special Feature
ADJ: Adjustable
Y: Lead free & Low
profile
Z: Lead free
1. SW
2. GND
3. FB
4. EN
5. OVP
6. IN
n Ordering Information
Part Number
Marking*
Output Voltage
Package
Operating Ambient
Temperature Range
AME5142AEEYADJZ
BJGww
ADJ
SOT-26
-40OC to 85OC
AME5142AEEYADJY
BJGww
ADJ
TSOT-26
-40OC to 85OC
AME5142AEEVADJZ
BJHww
ADJ
SOT-25
-40OC to 85OC
AME5142AEEVADJY
BJHww
ADJ
TSOT-25
-40OC to 85OC
Note: ww represents the date code and pls refer to Date Code Rule page on Package Dimension.
* A line on top of the first letter represents lead free plating such as BJGww.
Please consult AME sales office or authorized Rep./Distributor for the availability of package type.
Rev. A.01
5
AME, Inc.
White LED Boost Converter
In Tiny Package
AME5142
n Absolute Maximum Ratings
Parameter
Symbol
Maximum
Unit
VIN
6
V
V EN ,VFB
VIN
V
V SW,VOVP
30
V
Input Supply Voltage
EN, FB Voltages
SW, OVP Voltage
B*
ESD Classification
Caution: Stress above the listed in absolute maximum ratings may cause permanent damage to the device.
* HBM B: 2000V ~ 3999V
n Recommended Operating Conditions
Parameter
Symbol
Rating
Ambient Temperature Range
TA
-40 to 85
Junction Temperature Range
TJ
-40 to 125
Storage Temperature Range
TSTG
-65 to 150
Unit
o
C
n Thermal Information
Parameter
Thermal Resistance*
(Junction to Case)
Thermal Resistance
(Junction to Ambient)
Package
SOT-25
TSOT-25
SOT-26
TSOT-26
Die Attach
Symbol
Maximum
θJC
81
Unit
o
C/W
Conductive Epoxy
Internal Power Dissipation
Solder Iron (10Sec)**
θJA
260
PD
400
350
mW
o
C
* Measure θJC on center of molding compound if IC has no tab.
** MIL-STD-202G 210F
6
Rev. A.01
AME, Inc.
White LED Boost Converter
In Tiny Package
AME5142
n Electrical Specifications
VIN = 4.2V, EN = VIN, TA = 25oC, Unless otherwise noted.
Parameter
Input Voltage
Quiescent Current
Symbol
V IN
IQ
Feedback Trip Point
VFB
FB Pin Bias Current
IFB
Switch Current Limit
ICL
Switch On-Resistance
Test Condition
RDSON
Min
Typ
2.7
5.5
V
0.85
1
mA
Not Switching, VFB = 0.2V
180
250
µA
0.15
0.163
V
0.1
1
µA
850
1000
mA
0.7
1.4
Ω
1
10
µA
1.5
MHz
0.137
VFB = 0.2V
650
ISW = 100mA, VFB = 0.2V
ISW
VSW = 20V
Swich frequency
fSW
VFB = 0.1V
0.9
1.2
Dmax
VFB = 0V
88
92
ISD
VEN = 0V
0.01
OTP
Shutdown, temperature increasing
160
TRS
Restore, temperature decreasing
140
Shutdown Supply Current
Units
Switching, VFB = 0V
SW Leakage Current
Maximum Duty Cycle
Max
%
1
o
Over Temperature Protection
C
Over Voltage Protection
OVP
Rising edge
Input Undervoltage Lockout
UVP
VIN rising or falling
EN Input Low
V EL
EN Input High
VEH
EN Input Current
IEN
Rev. A.01
µA
24
26
28
V
2.35
2.5
2.65
V
0.4
V
1.5
EN = GND or VIN
0.1
2
µA
7
AME, Inc.
AME5142
White LED Boost Converter
In Tiny Package
n Detailed Description
n Application Hints
The AME5142 is a constant frequency step-up converter with an internal switch. The operations of AME5142
can be understood from block diagram clearly figure.2.
The oscillator triggers the SET input of SR latch to turn
on the power switch MS at the start of each cycle. A
current sense voltage sum with a stabilizing ramp is connected to the positive terminal of the PWM comparator.
When this voltage exceeds the output voltage of the error
amplifier, the SR latch is reset to turn off the power switch
till next cycle starts. The output voltage of the error amplifier is amplified from the difference between the reference voltage 0.15V and the feedback voltage. In this manner, if the error amplifiers voltage increases, more current
is delivered to the output; if it decreases, less current is
delivered. A 26V Zener diode connects from OVP pin to
FB pin internally to provide an optional protection function which prevents SW pin from over-voltage damage.
Especially when the case of the feedback loop broken
due to component wear-out or improper connection occurs. The behavior of OVP is to clamp the output voltage
to 26V typically. This function is suitable for the applications while driving white LEDs less than 6 in series.
Inductor Selection
The recommended value of inductor for AME5142 applications is 10µH. Small size and better efficiency are
the major concerns for portable device, such as AME5142
used for dual panel mobile phone. The inductor should
have low DCR for better efficiency. To avoid inductor saturation, current rating should be at least 1A. The input
range is 2.7V to 5.5V.
Current Limit Protection
The AME5142 has current limiting protection to prevent
excessive stress on itself and external components during overload conditions. The internal current limit comparator will disable the NMOS power device at a typical
switch peak current limit of 850mA.
Output Over-Voltage Protection
The AME5142 contains dedicated circuitry for monitoring the output voltage. In the event that the primary LED
network is disconnected the output will increase and be
limited to 26V (TYP), which will turn the NMOS off when
the output voltage is at 26V (max.) until the output voltage reach 26V (TYP.) or lower. The 26V limit allows the
use of 26V 1µF ceramic output capacitors creating an
overall small solution for white LED applications.
Capacitor Selection
4.7µF input capacitor can reduce input ripple. For better voltage stability, to increase the input capacitor value
or using LC filter is feasible, especially in the Li-ion battery application. 1µF output capacitor is sufficient to reduce output voltage ripple. For better voltage filtering,
ceramic capacitors with low ESR are recommended. X5R
and X7R types are suitable because of their wider voltage and temperature ranges.
Diode Selection
Schottky diode is a good choice for AME5142 because
of its lower forward voltage drop and faster reverse recovery. Using schottky diode can get better efficiency. The
high speed rectification is also a good characteristic of
schottky diode for high switching frequency. Current rating of the diode must meet the root mean square of the
peak current and output average current multiplication.
Duty Cycle
The maximum duty cycle of the switching regulator
determines the maximum boost ratio of output-toinput voltage that the converter can attain in mode of
operation. The duty cycle for a given boost application is
defined as: This applies for continuous mode operation.
D=
VOUT + VDIODE - VIN
VOUT + VDIODE - VSW
Under Voltage Protection
The AME5142 has an UVP comparator to turn the NMOS
power device off in case the input voltage or battery voltage is too low preventing an on state of the power device
conducting large amounts of current.
8
Rev. A.01
AME, Inc.
White LED Boost Converter
In Tiny Package
AME5142
n Application Hints
Calculating Load Current
Dimming Control
The load current is related to the average inductor current by the relation:
ILOAD = IIND (AVG) x (1 - D)
Where “D” is the duty cycle of the application. The
switch current can be found by:
ISW = IIND (AVG) + 1 /2 (IRIPPLE)
A. Using a PWM Signal to EN Pin
For controlling the LED brightness, the AME5142 can
perform the dimming control by applying a PWM signal to
EN pin.
The average LED current is proportional to the PWM
signal duty cycle. The magnitude of the PWM signal should
be higher than the maximum enable voltage of EN pin, in
order to let the dimming control perform correctly.
Inductor ripple current is dependent on inductance, duty
cycle, input voltage and frequency:
IRIPPLE = D x (VIN-VSW ) / (f x L)
Combining all terms, we can develop an expression
which allows the maximum available load current to be
calculated:
ILOAD = ( 1-D ) x ( ISW (max) -
L1
10µH
VIN 2.7V to 5.5V
D ( VIN-VSW )
)
2fL
Thermal Considerations
At higher duty cycles, the increased ON time of the
FET means the maximum output current will be determined by power dissipation within the AME5142 switch.
The switch power dissipation from ON-state conduction
is calculated by:
CIN
4.7µF
VOUT
IN
EN
Dimming
Control
25KHz to 100KHz
COUT
1µF
SW
AME5142 OVP
GND
FB
R1
7.5Ω
Figure 5. PWM Dimming Control Using the EN Pin
P(SW) = D x IIND(AVE)2 x RDS(ON)
There will be some switching losses as well, so some
derating needs to be applied when calculating IC power
dissipation.
Shutdown Pin Operation
The device is turned off by pulling the shutdown pin low.
If this function is not going to be used, the pin should be
tied directly to VIN. If the SHDN function will be needed, a
pull-up resistor must be used to VIN (approximately 50k100k recommended). The EN pin must not be left
unterminated.
Rev. A.01
9
AME, Inc.
White LED Boost Converter
In Tiny Package
AME5142
n Application Hints
Dimming Control
B. Using a DC Voltage
C. Using a Filtered PWM Signal
Using a variable DC voltage to adjust the brightness
is a popular method in some applications. The dimming control using a DC voltage circuit is shown in
Figure 6. According to the Superposition Theorem,
as the DC voltage increases, the voltage contributed
to VFB increases and the voltage drop on R2 decreases,
i.e. the LED current decreases. For example, if the
VDC range is from 0V to 3V, the selection of resistors
in Figure 6 sets dimming control of LED current from
20mA to 0mA.
L1
10µH
VIN 2.7V to 5.5V
CIN
4.7µF
The filtered PWM signal can be considered as an adjustable DC voltage. It can be used to replace the variable DC
voltage source in dimming control. The circuit is shown in
Figure 7.
L1
10µH
VIN 2.7V to 5.5V
CIN
4.7µF
VOUT
IN
EN
AME5142 OVP
VOUT
IN
EN
COUT
1µF
SW
R3
5.1K
FB
GND
R4
91K
AME5142 OVP
RDC
10K
R3
5.1K
GND
R2
7.5Ω
CDC
0.1µF
3V
FB
R4
91K
COUT
1µF
SW
R2
7.5Ω
0V
PWM Signal
Figure 7. Dimming Control Using a Filtered PWM Signal
VDC Dimming
0V to 3V
Figure6. Dimming Control Using a DC Voltage
10
Rev. A.01
AME, Inc.
White LED Boost Converter
In Tiny Package
AME5142
92.0
91.8
91.6
91.4
91.2
91.0
90.8
90.6
90.4
90.2
90.0
89.8
89.6
89.4
89.2
89.0
88.8
88.6
88.4
88.2
88.0
-25
Oscillator Frequency vs. Temperature
1.50
Oscillator Frequency (MHz)
Max Duty Cycle (%)
Max Duty Cycle vs. Temperature
0
25
50
75
o
100
125
1.45
1.40
1.35
1.30
1.25
1.20
1.15
1.10
1.05
1.00
0.95
0.90
-25
0
25
50
75
100
Temperature ( C)
Temperature (oC)
Switch RDSON
Efficiency vs. Load Current
Dirving 3 LEDs
125
100
1.80
1.60
90
1.20
Efficiency (%)
RDSON (Ω)
1.40
TA = 85oC
1.00
0.80
o
TA = 25 C
0.60
80
70
60
0.40
3.1
3.5
3.9
4.3
4.7
5.1
50
2.7
5.5
3.9
4.3
4.7
5.1
Efficiency vs. Load Current
Dirving 4 LEDs
Efficiency vs. Load Current
Dirving 6 LEDs
100
90
90
80
70
60
5.5
80
70
60
3.1
3.5
3.9
4.3
VIN (V)
Rev. A.01
3.5
VIN (V)
100
50
2.7
3.1
VIN (V)
Efficiency (%)
Efficiency (%)
0.20
2.7
4.7
5.1
5.5
50
2.7
3.1
3.5
3.9
4.3
4.7
5.1
5.5
VIN (V)
11
AME, Inc.
White LED Boost Converter
In Tiny Package
AME5142
Current Limit vs. VIN
VFB vs. Temperature
1000
0.177
0.173
0.169
900
0.165
VFB (V)
Current Limit (mA)
950
850
0.161
0.157
800
0.153
750
0.149
0.145
700
0.141
650
2.7
3.1
3.5
3.9
4.3
4.7
5.5
0.137
-25
0
25
50
75
100
125
VIN (V)
Temperature (oC)
Dimming Control for Driving 6LEDs
Dimming Control for Driving 6LEDs
2
2
3
3
1
1
1mS / div
12
5.1
1mS / div
VIN = 2.7V; 6 LEDs
IOUT = 20mA
VIN = 5.5V; 6 LEDs
IOUT = 20mA
2) EN = 1V / div, DC f = 200Hz
3) VOUT , 10V / div, DC
1) VSW = 10V / div, DC
2) EN = 1V / div, DC f = 200Hz
3) VOUT , 10V / div, DC
1) VSW = 10V / div, DC
Rev. A.01
AME, Inc.
White LED Boost Converter
In Tiny Package
AME5142
Dimming Control for Driving 6LEDs
Dimming Control for Driving 6LEDs
2
2
3
3
1
1
4µS / div
4µS / div
VIN = 2.7V; 6 LEDs
IOUT = 20mA
VIN = 5.5V; 6 LEDs
IOUT = 20mA
2) EN = 1V / div, DC f = 200KHz
3) VOUT , 10V / div, DC
1) VSW = 10V / div, DC
2) EN = 1V / div, DC f = 200KHz
3) VOUT , 10V / div, DC
1) VSW = 10V / div, DC
Start-Up / Shutdown
Start-Up / Shutdown
1
1
2
2
3
3
200µS / Div
Rev. A.01
200µS / div
VIN = 2.7V; 1 LEDs
IOUT = 20mA
VIN = 2.7V; 6 LEDs
IOUT = 20mA
1) EN = 2V/div, DC
2) Inductor Current, 100mA / div, DC
3) VOUT , 2V / div, DC
1) EN = 2V / div, DC
2) Inductor Current, 500mA / div, DC
3) VOUT , 10V / div, DC
13
AME, Inc.
White LED Boost Converter
In Tiny Package
AME5142
Start-Up / Shutdown
Typical Switching Waveform
1
1
2
2
3
3
200µS / div
1µS / div
VIN = 5.5V; 6 LEDs
IOUT = 20mA
VIN = 2.7V; 6 LEDs
IOUT = 20mA
1) EN = 2V / div, DC
2) Inductor Current, 500mA / div, DC
3) VOUT , 10V / div, DC
1) VSW = 10V / div, DC
2) VOUT , 20mV / div, AC
3) Input Current, 100mA / div, DC
Inductor = 10µH, COUT = 1µF
Typical Switching Waveform
1
2
3
1µS / div
VIN = 5.5V; 6 LEDs
IOUT = 20mA
1) VSW = 10V / div, DC
2) VOUT , 20mV / div, AC
3) Input Current, 100mA / div, DC
Inductor = 10µH, COUT = 1µF
14
Rev. A.01
AME, Inc.
White LED Boost Converter
In Tiny Package
AME5142
n Date Code Rule
Marking
Date Code
Year
A
A
A
W
W
xxx0
A
A
A
W
W
xxx1
A
A
A
W
W
xxx2
A
A
A
W
W
xxx3
A
A
A
W
W
xxx4
A
A
A
W
W
xxx5
A
A
A
W
W
xxx6
A
A
A
W
W
xxx7
A
A
A
W
W
xxx8
A
A
A
W
W
xxx9
n Tape and Reel Dimension
SOT-25
P
W
AME
AME
PIN 1
Carrier Tape, Number of Components Per Reel and Reel Size
Rev. A.01
Package
Carrier Width (W)
Pitch (P)
Part Per Full Reel
Reel Size
SOT-25
8.0±0.1 mm
4.0±0.1 mm
3000pcs
180±1 mm
15
AME, Inc.
White LED Boost Converter
In Tiny Package
AME5142
n Tape and Reel Dimension
TSOT-25
P
W
AME
AME
PIN 1
Carrier Tape, Number of Components Per Reel and Reel Size
Package
Carrier Width (W)
Pitch (P)
Part Per Full Reel
Reel Size
TSOT-25
8.0±0.1 mm
4.0±0.1 mm
3000pcs
180±1 mm
SOT-26
P
W
AME
AME
PIN 1
Carrier Tape, Number of Components Per Reel and Reel Size
16
Package
Carrier Width (W)
Pitch (P)
Part Per Full Reel
Reel Size
SOT-26
8.0±0.1 mm
4.0±0.1 mm
3000pcs
180±1 mm
Rev. A.01
AME, Inc.
White LED Boost Converter
In Tiny Package
AME5142
n Tape and Reel Dimension
TSOT-26
P
W
AME
AME
PIN 1
Carrier Tape, Number of Components Per Reel and Reel Size
Rev. A.01
Package
Carrier Width (W)
Pitch (P)
Part Per Full Reel
Reel Size
TSOT-26
8.0±0.1 mm
4.0±0.1 mm
3000pcs
180±1 mm
17
AME, Inc.
White LED Boost Converter
In Tiny Package
AME5142
n Package Dimension
SOT-25
Top View
Side View
SYMBOLS
D
MILLIMETERS
MAX
MIN
MAX
L
MIN
INCHES
1.20REF
E
H
A
θ1
S1
A1
0.00
0.15
0.0000
0.0059
b
0.30
0.55
0.0118
0.0217
D
2.70
3.10
0.1063
0.1220
E
1.40
1.80
0.0551
0.0709
1.90 BSC
e
H
e
2.60
θ1
0
o
3.00
10
0.10236 0.11811
0.0146BSC
o
0o
10 o
0.95BSC
0.0374BSC
MILLIMETERS
INCHES
S1
A1
A
0.07480 BSC
0.37BSC
L
Front View
0.0472REF
b
TSOT-25
Top View
Side View
SYMBOLS
MIN
MAX
MIN
MAX
A+A1
0.90
1.25
0.0354
0.0492
b
0.30
0.50
0.0118
0.0197
c
0.09
0.25
0.0035
0.0098
D
2.70
3.10
0.1063
0.1220
E
1.40
1.80
0.0551
0.0709
E
H
L
D
θ1
S1
e
H
e
1.90 BSC
2.40
b
18
S1
0
o
10
0.95BSC
0.09449 0.11811
0.0138BSC
o
0o
10 o
0.0374BSC
A1
A
θ1
3.00
0.35BSC
L
Front View
0.07480 BSC
Rev. A.01
AME, Inc.
White LED Boost Converter
In Tiny Package
AME5142
n Package Dimension
SOT-26
Top View
Side View
MILLIMETERS
MIN
E
L
D
e
H
SYMBOLS
θ1
A
0.0472REF
0.15
0.0000
0.0059
b
0.30
0.55
0.0118
0.0217
D
2.70
3.10
0.1063
0.1220
E
1.40
1.80
0.0551
0.0709
e
θ1
S1
1.90 BSC
2.60
3.00
0.37REF
0o
10 o
0.0748 BSC
0.10236 0.11811
0.0146REF
0o
10 o
0.95REF
0.0374REF
MILLIMETERS
INCHES
A1
A
MAX
0.00
L
Front View
1.20REF
MIN
A1
H
S1
MAX
INCHES
b
TSOT-26
Top View
Side View
SYMBOLS
MIN
MAX
MIN
MAX
A+A1
0.90
1.25
0.0354
0.0492
b
0.30
0.50
0.0118
0.0197
D
2.70
3.10
0.1063
0.1220
E
1.40
1.80
0.0551
0.0709
L
E
H
D
e
θ1
e
H
S1
L
θ1
Front View
2.40
3.00
0.35BSC
0o
10o
0.95BSC
0.07480 BSC
0.09449 0.11811
0.0138BSC
0o
10o
0.0374BSC
A1
A
S1
1.90 BSC
b
Rev. A.01
19
www.ame.com.tw
E-Mail: [email protected]
Life Support Policy:
These products of AME, Inc. are not authorized for use as critical components in life-support
devices or systems, without the express written approval of the president
of AME, Inc.
AME, Inc. reserves the right to make changes in the circuitry and specifications of its devices and
advises its customers to obtain the latest version of relevant information.
 AME, Inc. , July 2007
Document: 1229-DS5142-A.01
Corporate Headquarter
U.S.A. (Subsidiary)
AME, Inc.
Analog Microelectronics, Inc.
2F, 302 Rui-Guang Road, Nei-Hu District
Taipei 114, Taiwan.
3100 De La Cruz Blvd., Suite 201
Santa Clara, CA. 95054-2438
Tel: 886 2 2627-8687
Fax: 886 2 2659-2989
Tel : (408) 988-2388
Fax: (408) 988-2489