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AME, Inc.
AME5142
n Pin Configuration
SOT-25/TSOT-25 Top View
5 4
White LED Boost Converter In Tiny Package
SOT-26/TSOT-26 Top View AME5142AEEV 1. SW 2. GND
6 5 4
AME5142AEEY 1. SW 2. GND
AME5142
3. FB 4. EN 5. IN
AME5142
3. FB 4. EN 5. OVP
1
2
3
1
2
3
6. IN * Die Attach: Conductive Epoxy
* Die Attach: Conductive Epoxy
n Pin Description
AME5142AEEV
Pin Number
1
Pin Name
SW
Pin Description
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. Ground. Tie directly to ground plane. 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. 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. Analog and Power input. Input Supply Pin. Bypass this pin with a capacitor as close to the device as possible.
2
GND
3
FB
4
EN
5
IN
Rev. A.01
3
AME, Inc.
AME5142
n Pin Description
AME5142AEEY
White LED Boost Converter In Tiny Package
Pin Number
1
Pin Name
SW
Pin Description
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. Ground. Tie directly to ground plane. 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. 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. Over Voltage Protection. Analog and Power input. Input Supply Pin. Bypass this pin with a capacitor as close to the device as possible.
2
GND
3
FB
4
EN
5
OVP
6
IN
4
Rev. A.01
AME, Inc.
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
Operating Ambient Temperature Range E: -40OC to 85OC Number of Pins V: 5 Y: 6
White LED Boost Converter In Tiny Package
Pin Configuration A
(SOT-25) (TSOT-25)
Package Type E: SOT-2X
Output Voltage
Special Feature
1. SW 2. GND 3. FB 4. EN 5. IN 1. SW 2. GND 3. FB 4. EN 5. OVP 6. IN
ADJ: Adjustable
Y: Lead free & Low profile Z: Lead free
A
(SOT-26) (TSOT-26)
n Ordering Information
Part Number
AME5142AEEYADJZ AME5142AEEYADJY AME5142AEEVADJZ AME5142AEEVADJY
Marking*
BJGww BJGww BJHww BJHww
Output Voltage
ADJ ADJ ADJ ADJ
Package
SOT-26 TSOT-26 SOT-25 TSOT-25
Operating Ambient Temperature Range
-40OC to 85OC -40OC to 85OC -40OC to 85OC -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.
AME5142
n Absolute Maximum Ratings
Parameter
Input Supply Voltage EN, FB Voltages SW, OVP Voltage ESD Classification
White LED Boost Converter In Tiny Package
Symbol
VIN V EN ,VFB V SW,VOVP
Maximum
6 VIN 30 B*
Unit
V V V
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
Ambient Temperature Range Junction Temperature Range Storage Temperature Range
Symbol
TA TJ TSTG
Rating
-40 to 85 -40 to 125 -65 to 150
Unit
o
C
n Thermal Information
Parameter
Thermal Resistance* (Junction to Case) Thermal Resistance (Junction to Ambient) Internal Power Dissipation Solder Iron (10Sec)**
Package
Die Attach
Symbol
JC
Maximum
81
Unit
SOT-25 TSOT-25 SOT-26 TSOT-26
o
C/W
Conductive Epoxy
JA
PD
260
400 350
mW
o
C
* Measure JC on center of molding compound if IC has no tab. ** MIL-STD-202G 210F
6
Rev. A.01
AME, Inc.
AME5142
n Electrical Specifications
VIN = 4.2V, EN = VIN, TA = 25oC, Unless otherwise noted.
Parameter Input Voltage Quiescent Current Feedback Trip Point FB Pin Bias Current Switch Current Limit Switch On-Resistance SW Leakage Current Swich frequency Maximum Duty Cycle Shutdown Supply Current Over Temperature Protection TRS Over Voltage Protection Input Undervoltage Lockout EN Input Low EN Input High EN Input Current OVP UVP V EL VEH IEN EN = GND or VIN 1.5 0.1 2 A Restore, temperature decreasing Rising edge VIN rising or falling 24 2.35 140 26 2.5 28 2.65 0.4 V V V Symbol V IN Switching, VFB = 0V IQ VFB IFB ICL RDSON ISW fSW Dmax ISD OTP ISW = 100mA, VFB = 0.2V VSW = 20V VFB = 0.1V VFB = 0V VEN = 0V Shutdown, temperature increasing 0.9 88 VFB = 0.2V 650 Not Switching, VFB = 0.2V 0.137 Test Condition Min 2.7 0.85 180 0.15 0.1 850 0.7 1 1.2 92 0.01 160 1 Typ Max 5.5 1 250 0.163 1 1000 1.4 10 1.5 Units V mA A V A mA A MHz % A
o
White LED Boost Converter In Tiny Package
C
Rev. A.01
7
AME, Inc.
AME5142
n Detailed Description
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. 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 1F ceramic output capacitors creating an overall small solution for white LED applications. 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.
White LED Boost Converter In Tiny Package
n Application Hints
Inductor Selection The recommended value of inductor for AME5142 applications is 10H. 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. Capacitor Selection 4.7F 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. 1F 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
8
Rev. A.01
AME, Inc.
AME5142
n Application Hints
Calculating Load Current 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) 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:
VIN 2.7V to 5.5V CIN 4.7F
White LED Boost Converter In Tiny Package
Dimming Control 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.
L1 10H VOUT IN SW COUT 1F
EN Dimming Control 25KHz to 100KHz
AME5142 OVP
ILOAD = ( 1-D ) x ( ISW (max) Thermal Considerations
D ( VIN-VSW ) 2fL
)
GND
FB R1 7.5
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: 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.
Figure 5. PWM Dimming Control Using the EN Pin
Rev. A.01
9
AME, Inc.
AME5142
n Application Hints
Dimming Control B. Using a DC Voltage 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 10H VOUT IN SW COUT 1F
GND FB R4 91K RDC 10K 3V CDC 0.1F R2 7.5
White LED Boost Converter In Tiny Package
C. Using a Filtered PWM Signal 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 10H VOUT IN SW COUT 1F
VIN 2.7V to 5.5V CIN 4.7F
EN
AME5142 OVP
R3 5.1K
VIN 2.7V to 5.5V CIN 4.7F
EN
AME5142 OVP
R3 5.1K
GND
FB R4 91K VDC Dimming 0V to 3V R2 7.5
0V
PWM Signal
Figure 7. Dimming Control Using a Filtered PWM Signal
Figure6. Dimming Control Using a DC Voltage
10
Rev. A.01
AME, Inc.
AME5142
Max Duty Cycle vs. Temperature
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
White LED Boost Converter In Tiny Package
Oscillator Frequency vs. Temperature
1.50 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 75 100 125
0
25
50
Temperature ( C)
75 o
100
125
Oscillator Frequency (MHz)
Max Duty Cycle (%)
Temperature (oC)
Switch RDSON
1.80 1.60
Efficiency vs. Load Current Dirving 3 LEDs
100
90
1.40 1.20 1.00 0.80 0.60 0.40 0.20 2.7 TA = 25 C
o
TA = 85oC
Efficiency (%)
RDSON ()
80
70
60
3.1
3.5
3.9
4.3
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)
VIN (V)
Efficiency vs. Load Current Dirving 4 LEDs
100
100
Efficiency vs. Load Current Dirving 6 LEDs
90
90
Efficiency (%)
80
Efficiency (%)
3.1 3.5 3.9 4.3 4.7 5.1 5.5
80
70
70
60
60
50 2.7
50 2.7
3.1
3.5
3.9
4.3
4.7
5.1
5.5
VIN (V)
VIN (V)
Rev. A.01
11
AME, Inc.
AME5142
Current Limit vs. VIN
1000
White LED Boost Converter In Tiny Package
VFB vs. Temperature
0.177
950
0.173 0.169 0.165
Current Limit (mA)
900 850 800 750 700
650 2.7
3.1
3.5
3.9
4.3
4.7
5.1
5.5
VFB (V)
0.161 0.157 0.153 0.149 0.145 0.141 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
1mS / div
VIN = 2.7V; 6 LEDs IOUT = 20mA 2) EN = 1V / div, DC f = 200Hz 3) VOUT , 10V / div, DC 1) VSW = 10V / div, DC
VIN = 5.5V; 6 LEDs IOUT = 20mA 2) EN = 1V / div, DC f = 200Hz 3) VOUT , 10V / div, DC 1) VSW = 10V / div, DC
12
Rev. A.01
AME, Inc.
AME5142
Dimming Control for Driving 6LEDs
White LED Boost Converter In Tiny Package
Dimming Control for Driving 6LEDs
2
2
3
3
1
1
4S / div
4S / div
VIN = 2.7V; 6 LEDs IOUT = 20mA 2) EN = 1V / div, DC f = 200KHz 3) VOUT , 10V / div, DC 1) VSW = 10V / div, DC Start-Up / Shutdown
VIN = 5.5V; 6 LEDs IOUT = 20mA 2) EN = 1V / div, DC f = 200KHz 3) VOUT , 10V / div, DC 1) VSW = 10V / div, DC Start-Up / Shutdown
1
1
2
2
3
3
200S / Div
200S / div
VIN = 2.7V; 1 LEDs IOUT = 20mA 1) EN = 2V/div, DC 2) Inductor Current, 100mA / div, DC 3) VOUT , 2V / div, DC
VIN = 2.7V; 6 LEDs IOUT = 20mA 1) EN = 2V / div, DC 2) Inductor Current, 500mA / div, DC 3) VOUT , 10V / div, DC
Rev. A.01
13
AME, Inc.
AME5142
Start-Up / Shutdown
White LED Boost Converter In Tiny Package
Typical Switching Waveform
1
1
2
2
3
3
200S / div
1S / div
VIN = 5.5V; 6 LEDs IOUT = 20mA 1) EN = 2V / div, DC 2) Inductor Current, 500mA / div, DC 3) VOUT , 10V / div, DC Typical Switching Waveform
VIN = 2.7V; 6 LEDs IOUT = 20mA 1) VSW = 10V / div, DC 2) VOUT , 20mV / div, AC 3) Input Current, 100mA / div, DC Inductor = 10H, COUT = 1F
1
2
3
1S / 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 = 10H, COUT = 1F
14
Rev. A.01
AME, Inc.
AME5142
n Date Code Rule
Marking A A A A A A A A A A A A A A A A A A A A A A A A A A A A A A Date Code W W W W W W W W W W W W W W W W W W W W Year xxx0 xxx1 xxx2 xxx3 xxx4 xxx5 xxx6 xxx7 xxx8 xxx9
White LED Boost Converter In Tiny Package
n Tape and Reel Dimension
SOT-25
P
W AME PIN 1 AME
Carrier Tape, Number of Components Per Reel and Reel Size
Package SOT-25
Carrier Width (W) 8.00.1 mm
Pitch (P) 4.00.1 mm
Part Per Full Reel 3000pcs
Reel Size 1801 mm
Rev. A.01
15
AME, Inc.
AME5142
n Tape and Reel Dimension
TSOT-25
P
White LED Boost Converter In Tiny Package
W AME PIN 1 AME
Carrier Tape, Number of Components Per Reel and Reel Size
Package TSOT-25 Carrier Width (W) 8.00.1 mm Pitch (P) 4.00.1 mm Part Per Full Reel 3000pcs Reel Size 1801 mm
SOT-26
P
W AME PIN 1 AME
Carrier Tape, Number of Components Per Reel and Reel Size
Package SOT-26 Carrier Width (W) 8.00.1 mm Pitch (P) 4.00.1 mm Part Per Full Reel 3000pcs Reel Size 1801 mm
16
Rev. A.01
AME, Inc.
AME5142
n Tape and Reel Dimension
TSOT-26
P
White LED Boost Converter In Tiny Package
W AME PIN 1 AME
Carrier Tape, Number of Components Per Reel and Reel Size
Package TSOT-26 Carrier Width (W) 8.00.1 mm Pitch (P) 4.00.1 mm Part Per Full Reel 3000pcs Reel Size 1801 mm
Rev. A.01
17
AME, Inc.
AME5142
n Package Dimension
SOT-25
Top View D
L
White LED Boost Converter In Tiny Package
Side View
SYMBOLS A A1
MILLIMETERS MIN
0.00 0.30 2.70 1.40
INCHES MIN
0.0000 0.0118 0.1063 0.0551
MAX
0.15 0.55 3.10 1.80
MAX
0.0059 0.0217 0.1220 0.0709
1.20REF
0.0472REF
E
b D E
S1 e c1
H
e H L 1
1.90 BSC 2.60 3.00
0.07480 BSC 0.10236 0.11811 0.0146BSC
o
0.37BSC 0
o
Front View
A
10
0o
10 o
S1
0.95BSC
0.0374BSC
b
TSOT-25
Top View D
L
A1
Side View
SYMBOLS A+A1 b
MILLIMETERS MIN
0.90 0.30 0.09 2.70 1.40
INCHES MIN
0.0354 0.0118 0.0035 0.1063 0.0551
MAX
1.25 0.50 0.25 3.10 1.80
MAX
0.0492 0.0197 0.0098 0.1220 0.0709
E
c D E
S1 e c1
H
e H L 1 S1
1.90 BSC 2.40 3.00
0.07480 BSC 0.09449 0.11811 0.0138BSC
o
0.35BSC 0
o
Front View
A
10
0o
10 o
0.95BSC
0.0374BSC
b
A1
18
Rev. A.01
AME, Inc.
AME5142
n Package Dimension
SOT-26
Top View D e Side View
White LED Boost Converter In Tiny Package
SYMBOLS A A1 b
MILLIMETERS MIN MAX
0.15 0.55 3.10 1.80
INCHES MIN
0.0000 0.0118 0.1063 0.0551
MAX
0.0059 0.0217 0.1220 0.0709
1.20REF 0.00 0.30 2.70 1.40
0.0472REF
H
E
L
D E
c1 S1
e H L 1
1.90 BSC 2.60 3.00
0.0748 BSC 0.10236 0.11811 0.0146REF 0o 10 o
0.37REF 0o 10 o
Front View A
S1
0.95REF
0.0374REF
b
TSOT-26
Top View D e Side View
A1
SYMBOLS
L
MILLIMETERS MIN MAX
1.25 0.50 3.10 1.80
INCHES MIN
0.0354 0.0118 0.1063 0.0551
MAX
0.0492 0.0197 0.1220 0.0709
A+A1 b
H E
0.90 0.30 2.70 1.40
D E
c1 S1
e H L 1 S1
1.90 BSC 2.40 3.00
0.07480 BSC 0.09449 0.11811 0.0138BSC 0o 10o
0.35BSC 0o 10o
Front View A
0.95BSC
0.0374BSC
b
Rev. A.01
A1
19
www.ame.com.tw
E-Mail: sales@ame.com.tw
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. (c) AME, Inc. , July 2007
Document: 1229-DS5142-A.01
Corporate Headquarter
AME, Inc.
2F, 302 Rui-Guang Road, Nei-Hu District Taipei 114, Taiwan. Tel: 886 2 2627-8687 Fax: 886 2 2659-2989
U.S.A. (Subsidiary)
Analog Microelectronics, Inc.
3100 De La Cruz Blvd., Suite 201 Santa Clara, CA. 95054-2438 Tel : (408) 988-2388 Fax: (408) 988-2489

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