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Datasheet
AS1344
4 2 V, D C - D C B o o s t C o n v e r t e r w it h a d j u s ta b l e S o fts ta r t
1 General Description
The AS1344 boost converter contains a 1.4A internal switch in a tiny TDFN-10 3x3mm package. The device operates from a 0.9V to 3.6V supply, and can boost voltages up to 42V output. The output voltage can easily be adjusted by an external resistor divider. The AS1344 uses a unique control scheme providing the highest efficiency over a wide range of load conditions. An internal 1.4A MOSFET reduces external component count, and a fixed high switching frequency (1MHz) allows for tiny surface-mount components. The AS1344 also features power-OK circuitry which monitors the output voltage. The device also offers a Softstart function which limits the current during startup. The current during startup can be easily adjusted with the value of RV. For RV = 0, there is no softstart. Additionally the AS1344 features a low quiescent supply current and a shutdown mode to save power. During shutdown an output disconnect switch separates the input from the output. The AS1344 is ideal for LCD or OLED panels with low current requirements and can also be used in a wide range of other applications. The device is available in a low-profile TDFN-10 3x3mm package.
2 Key Features
! ! !
5.5V to 42V Adjustable Output Voltage 0.9V to 3.6V Supply Voltage Range High Output Current: - 30mA @ 12V VOUT, from 1.5V VCC Efficiency: Up to 85% Switching Frequency: 1MHz Output Disconnect Function Softstart Function with adjustable Current Limit Output Discharge Function Power-OK Output Quiescent Current: 22A Shutdown Current: 0.1A TDFN-10 3x3mm Package
! ! ! ! ! ! ! ! !
3 Applications
The device is ideal for OLED display power supply, LCD bias generators, mobile/cordless phones, palmtop computers, PDAs and organizers, handy terminals, driving LEDs or any other portable, battery-powered device.
Figure 1. AS1344 - Typical Application Diagram
RV VCC = 0.9V to 3.6V CIN VCC R3 POK On Off VCC GND EN FB R2 GND LX L1
VIN
SWOUT VOUT D1 VOUT = 5.5V to 42V COUT
AS1344
R1
PGND
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AS1344
Datasheet - P i n o u t
4 Pinout
Pin Assignments
Figure 2. Pin Assignments (Top View)
EN 1 POK 2 GND 3 VCC 4 PGND 5
10 FB 9 VOUT
AS1344
8 VIN 7 SWOUT 6 LX
Pin Descriptions
Table 1. Pin Descriptions Pin Number 1 Pin Name EN Description Active-High Enable Input. A logic low on this pin shuts down the device and reduces the supply current to 0.1A. GND: device in shutdown. VCC : normal operation. Power-OK. 0: VOUT < 90% of VOUTNOM. 1: VOUT > 90% of VOUTNOM. Ground +0.9V to +3.6V Supply Voltage. Bypass this pin to GND with a 10F capacitor. Ground. Should be the starpoint of CIN and COUT. Inductor. The drain of the internal N-channel MOSFET. Note: This pin is high impedance in shutdown. Shutdown Disconnect Switch Out. Disconnects the input from the output during shutdown. Supply Connection. Connect a resistor between pin VIN and pin VCC for limiting the input current during startup. +5.5 to +42V Output Voltage. This pin also powers the AS1344 after startup. Bypass this pin to GND with a 4.7F capacitor. Feedback Pin. Feedback input to the gm error amplifier. Connect a resistor divider tap to this pin. The output voltage can be adjusted from 5.5V to 42V by: VOUT = 1.25V[1 + (R1/R2)]
2 3 4 5 6 7 8 9 10
POK GND VCC PGND LX SWOUT VIN VOUT FB
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AS1344
Datasheet - A b s o l u t e M a x i m u m R a t i n g s
5 Absolute Maximum Ratings
Stresses beyond those listed in Table 2 may cause permanent damage to the device. These are stress ratings only, and functional operation of the device at these or any other conditions beyond those indicated in Electrical Characteristics on page 4 is not implied. Exposure to absolute maximum rating conditions for extended periods may affect device reliability. Table 2. Absolute Maximum Ratings Parameter VCC, VIN, EN, SWOUT, POK, FB to GND VOUT, LX to GND Thermal Resistance JA ESD Latch-Up Operating Temperature Range Storage Temperature Range Junction Temperature -200 -40 -65 36.7 2 +100 +85 +150 125 Min Max 5 45 Units V C/W kV mA C C C The reflow peak soldering temperature (body temperature) specified is in accordance with IPC/JEDEC J-STD-020D "Moisture/Reflow Sensitivity Classification for Non-Hermetic Solid State Surface Mount Devices". The lead finish for Pb-free leaded packages is matte tin (100% Sn). on PCB HBM MIL-Std. 883E 3015.7 methods @25C, JEDEC 78 Comments
Package Body Temperature
+260
C
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AS1344
Datasheet - E l e c t r i c a l C h a r a c t e r i s t i c s
6 Electrical Characteristics
VCC = EN = 3.6V, TAMB = -40 to +85C (unless otherwise specified). Typ values are at TAMB = +25C. Table 3. Electrical Characteristics Symbol VCC Parameter Maximum Supply Voltage Minimum Supply Voltage Minimum Start-Up Voltage VOUT IQ ISHDN VLNR VLDR VFB IFB Output Voltage Range Quiescent Current Shutdown Current VCC Line Regulation Load Regulation Efficiency Feedback Voltage Feedback Input Bias Current VFB = 1.3V VOUT = 6V, VFB=1.3V EN = GND, TAMB = +25C VOUT = 15V, ILOAD = 1mA, VCC = 1.8 to 3.6V VOUT = 15V, ILOAD = 0 to 20mA L1 = 6.8H, VOUT = 12V, ILOAD = 50mA 1.225 VOUT = 12V, RV = 0, no load VOUT = 12V, ILOAD = 1mA, RV = 0 5.5 22 0.02 0.05 0.01 85 1.25 1 1.275 100 0.9 0.95 Condition Min Typ Max 3.6 1.1 1.2 42 30 1 Unit V V V V A A %/V %/mA % V nA
DC-DC Switches RLX RP_ON ILX_LEAK IP_LEAK Control Inputs VIH EN Input Threshold VIL VEN IEN POK Output VOL POK Output Low Voltage POK Output High Leakage Current POK Threshold Oscillator fCLK Oscillator Frequency Maximum Duty Cycle 0.85 90 1 95 1.15 MHz % POK sinking 1mA POK = 3.6V Falling edge, referenced to VOUT(NOM) 87 0.01 1 90 0.2 500 93 V nA % EN Input Voltage EN Input Current VEN = 0 to 3.6V 0 1 1.1V VCC 3.6V 0.7 x VCC 0.3 x VCC 3.6 NMOS Switch OnResistance PMOS Switch OnResistance LX Leakage Current Switch Leakage Current ILX = 100mA ISWout = -100mA VLX = 42V P-channel 0.9 0.3 15 10 1.5 1.0 nA
V
V nA
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AS1344
Datasheet - Ty p i c a l O p e r a t i n g C h a r a c t e r i s t i c s
7 Typical Operating Characteristics
Parts used for measurments: 6.8H (MOS6020-682) Inductor, 10F (GRM21BR60J106KE19) CIN and 4.7F (GRM32ER71H475KA88) COUT, (PMEG4010BEA) D1; Figure 3. Efficiency vs. Output Current; VOUT = 6V
100 90 80 70 60 50 40 30 0.1 1 10 100
Vin = 2.0V Vin = 2.5V Vin = 3.0V Vin = 3.3V
Figure 4. Efficiency vs. Output Current; VOUT = 12V
100 90 80 70 60 50 40 30 0.1 1 10 100
Vin = 2.0V Vin = 2.5V Vin = 3.0V Vin = 3.3V
Efficiency (%)
Output Current (mA) Figure 5. Efficiency vs. Output Current; VOUT = 18V
100 90 80 70 60 50
Vin = 2.5V
Efficiency (%)
Output Current (mA) Figure 6. Efficiency vs. Output Current; VOUT = 24V
80 70 60
Efficiency (%)
Efficiency (%)
50 40 30 20 10 0
Vin = 2.5V Vin = 3.0V Vin = 3.3V
40 30 0.1 1 10
Vin = 3.0V Vin = 3.3V
100
0.1
1
10
100
Output Current (mA) Figure 7. Efficiency vs. Input Voltage; VOUT = 12V
100 90 80 70 60 50
Iout = 10mA
Output Current (mA) Figure 8. Efficiency vs. Input Voltage; IOUT = 10mA
100 90 80 70 60 50
Vout = 5.5V Iout = 50mA Iout = 100mA
Efficiency (%)
Efficiency (%)
40 30 0.9 1.2 1.5 1.8 2.1 2.4 2.7
40 30
Vout = 10V Vout = 12V Vout = 15V
3
3.3 3.6
0.9 1.2 1.5 1.8 2.1
2.4 2.7
3
3.3 3.6
Input Voltage (V) www.austriamicrosystems.com Revision 1.05
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AS1344
Datasheet - Ty p i c a l O p e r a t i n g C h a r a c t e r i s t i c s
Figure 9. Output Voltage vs. Temperature; VOUT=18V
18.2
no l oad Iout = 10mA Iout = 20mA Iout = 50mA
Figure 10. Output voltage vs. Input Voltage; VOUT=12V, (line regulation)
13
Iout = 1mA Iout = 10mA Iout = 50mA Iout = 100mA
Output Voltage (V)
18
Output Voltage (V)
0 15 30 45 60 75 90
18.1
12.5
12
17.9
11.5
17.8 -45 -30 -15
11 0.9 1.2 1.5 1.8 2.1 2.4 2.7 3 3.3 3.6
Temperature (C) Figure 11. Output Voltage vs. Load Current; VOUT=12V, VIN=1.5V, (load regualtion)
12.5 12.4
Input Voltage (V) Figure 12. Maximum Output current vs. Input Voltage; VOUT = 12, 15, 18, 24, 36V; (90% Voutnom)
300
Vout = 12V Vout = 15V Vout = 18V
Output Current (mA)
12.3
Output Voltage (V) .
Vout = 24V Vout = 36V
12.2 12.1 12 11.9 11.8 11.7 11.6 11.5 0 10 20 30
200
100
0 0.9 1.2 1.5 1.8 2.1 2.4 2.7 3 3.3 3.6
Output Current (mA) Figure 13. Maximum Output current vs. VOUT; VCC = 1.5V, 3V
400
Vi n = 1.5V Vi n = 3V
Input Voltage (V) Figure 14. Start-Up Voltage vs. Output Current; VCC = 0.9V to 3.6V, (95% Voutnom)
3.6 3.3 3
Output Current (mA)
300
Start-Up Voltage (V)
2.7 2.4 2.1 1.8 1.5 1.2 0.9 0.6
Vout = 5.5V Vout = 15V Vout = 24V Vout = 12V Vout = 18V Vout = 36V
200
100
0 5 15 25 35 45
0.3 0 10 20 30 40 50 60 70 80 90 100
Output Voltage (V)
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Output Current (mA)
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AS1344
Datasheet - Ty p i c a l O p e r a t i n g C h a r a c t e r i s t i c s
Figure 15. Shutdown Current vs. Input Voltage
0.025
Figure 16. Shutdown Current vs. Temperature
3
Shutdown Current (A) .
0.02
Shutdown Current (A) .
0.9 1.2 1.5 1.8 2.1 2.4 2.7 3 3.3 3.6
2.5 2 1.5 1 0.5 0 -45 -30 -15
0.015
0.01
0.005
0
0
15
30
45
60
75
90
Input Voltage (V)
Temperature (C)
Figure 17. Switching Frequency vs. Temperature
1.1
Figure 18. Feedback Voltage vs. Temperature
1.3
Switching Frequency (MHz) .
1.05
Feedback Voltage (V) .
0 15 30 45 60 75 90
1.275
1
1.25
0.95
1.225
0.9 -45 -30 -15
1.2 -45 -30 -15
0
15
30
45
60
75
90
Temperature (C)
Temperature (C)
Figure 19. Quiescent Current vs. Input Voltage
22
Quiescent Current (A) .
21.5
21
20.5
20 0.9 1.2 1.5 1.8 2.1 2.4 2.7 3 3.3 3.6
Input Voltage (V)
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AS1344
Datasheet - Ty p i c a l O p e r a t i n g C h a r a c t e r i s t i c s
Figure 20. Startup Waveform; VIN = 1.8V, COUT = 170F, RV = 3
Figure 21. Startup Waveform, detail; VIN = 1.8V, COUT = 170F, RV = 3
2V/Div
200mA/Div
10V/DIV
100ms/Div
2.5ms/Div
Figure 22. Startup Waveform; VIN = 2.4V, COUT = 170F, RV = 3
Figure 23. Startup Waveform, detail; VIN = 2.4V, COUT = 170F, RV = 3
2V/Div
200mA/Div
10V/DIV
100ms/Div
2.5ms/Div
Figure 24. Startup Waveform; VIN = 3.0V, COUT = 170F, RV = 3
Figure 25. Startup Waveform, detail; VIN = 3.0V, COUT = 170F, RV = 3
2V/Div
200mA/Div
10V/DIV
100ms/Div
2.5ms/Div
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10V/DIV
VOUT
VOUT
200mA/Div
IIN
IIN
2V/Div
EN
EN
10V/DIV
VOUT
VOUT
200mA/Div
IIN
IIN
2V/Div
EN
EN
10V/DIV
VOUT
VOUT
200mA/Div
IIN
IIN
2V/Div
EN
EN
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AS1344
Datasheet - Ty p i c a l O p e r a t i n g C h a r a c t e r i s t i c s
Figure 26. Transient Line Regulation; VOUT = 18V, ILOAD = 1mA
Figure 27. Transient Line Regulation; VOUT = 18V, ILOAD = 20mA
2.5V 3.0V
200mV/DIV
500s/Div
500s/Div
Figure 28. Output Voltage Ripple; VOUT = 18V, IOUT = 1mA
Figure 29. Output Voltage Ripple; VOUT = 18V, IOUT = 20mA
VIN = 3.6V
VIN = 3.6V
VIN = 3.0V 200mV/Div VOUT VOUT
VIN = 3.0V 200mV/Div VIN = 1.5V 1s/Div 5ms/Div 1mA 20mA 200mV/Div
VIN = 1.5V
1s/Div
Figure 30. Load Transient Response ON; VCC = 3V, VOUT = 18V
Figure 31. Load Transient Response OFF; VCC = 3V, VOUT = 18V
200mV/Div
VOUT(AC)
1mA 20mA
IOUT
5ms/Div
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IOUT
VOUT(AC)
200mV/DIV
VOUT(AC)
VOUT(AC)
2.5V 3.0V
VIN
VIN
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AS1344
Datasheet - D e t a i l e d D e s c r i p t i o n
8 Detailed Description
The AS1344 features a current limiting circuitry, a fixed-frequency PWM architecture, power-OK circuitry, thermal protection, and an automatic powersave mode in a tiny package, and maintains high efficiency at light loads.
Figure 32. Block Diagram with Shutdown Disconnect Switch
RV 8 VIN Input Voltage 0.9V to 3.6V 7 SWOUT Short Delay PWM Control 1 MHz Spread Spectrum Ramp Generator + PWM - Comp - 1 EN Shutdown Control 0.3 PMOS Sync Drive Control Slope Compensator L1 6.8H 2 POK 6 LX - VOUT Good + 0.9 NMOS 1.13V 9 VOUT Output Voltage 5.5V to 42V D1
4 VCC
CIN 10F
Current Sense
R1
AS1344
VC RC - gm Error Amp + 10 FB
COUT
4.7F
Shutdown
Powersave Operation Control
CP2 CC
1.25V Ref R2
Powersave
3 GND
5
PGND
Automatic powersave mode regulates the output and also reduces average current flow into the device, resulting in high efficiency at light loads. When the output increases sufficiently, the powersave comparator output remains high, resulting in continuous operation. For each oscillator cycle, the power switch is enabled. A voltage proportional to switch current is added to a stabilizing ramp and the resulting sum is delivered to the positive terminal of the PWM comparator. The error amplifier compares the voltage at FB with the internal 1.25V reference and generates an error signal (VC). When VC is below the powersave mode threshold voltage the automatic powersave-mode is activated and the hysteretic comparator disables the power circuitry, with only the low-power circuitry still active (total current consumption is minimized). When a load is applied, VFB decreases; VC increases and enables the power circuitry and the device starts switching. In light loads, the output voltage (and the voltage at FB) will increase until the powersave comparator disables the power circuitry, causing the output voltage to decrease again. This cycle is repeated resulting in low-frequency ripple at the output.
POK Function
The POK output indicates if the output voltage is within 90% of the nominal voltage level. As long as the output voltage is within regulation the open-drain POK output is high impedance. The POK output can be tied to any external voltage up to a maximum of 5V via a pull-up resistance R3 (see Typical Application on page 12). If the output voltage drops below 90% of the nominal voltage the POK pin is pulled to GND.
Note: It is important to consider that in shutdown mode the POK output is pulled to VCC in order to save current.
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AS1344
Datasheet - A p p l i c a t i o n I n f o r m a t i o n
9 Application Information
Shutdown and Output Discharge
A logic low on the EN pin shuts down the AS1344 and a logic high on the EN pin powers on the device. In shutdown mode the supply current drops to below 3A and the POK pin is set to high impedance to maximize battery life. When the battery disconnect switch is used, the battery is disconnected from the output and the output is discharged down to 0V. The time for fully discharging the output depends on the COUT and on the load.
Note: Pin EN should not be left floating. If the shutdown feature is not used, connect EN to VCC. The output will be discharged during shutdown but the output also must be fully discharged before the device is enabled again.
Battery Disconnect
The AS1344 has an integrated PMOS switch that can be used to disconnect the battery during shutdown. The operation voltage of this switch is limited to 3.6V. When EN is high, the switch is closed and supplies the inductor. Due to the RON resistance the efficiency is slightly lower if the battery disconnect switch is used.
PLOSS = IIN x RON (EQ 1)
Softstart Function
To limit the input current during startup a resistor RV can be connected between the pins VIN and VCC. For the correlation between the resistor value, the supply voltage and the startup time see Figure 33. For the correlation between resistor value, the supply voltage and the peak current see Figure 34. Connect VIN directly to VCC (no resistor) to disable the softstart Function. As an example some peak current and time values are listed at a given Rv in Table 4.
Table 4. Timing for Softstart @ VCC= 2.4V, COUT = 155F,
RV [] IPEAK [A] t [ms]
0 1.76 25
1.0 0.81 76
1.5 0.66 100
2.0
0.56
2.4
0.50
3.0 0.42 204
130
156
Figure 33. Startup Time; CIN = 150F, COUT = 155F
800
0 Ohm
Figure 34. Peak Current; CIN = 10F, COUT = 155F
3.5
0 Ohm
700
1.0 Ohm 1.5 Ohm 2.0 Ohm
3
1.0 Ohm 1.5 Ohm 2.0 Ohm
Start-up Time (ms)
Peak Current (A)
600 500 400 300 200 100 0 1 1.4 1.8 2.2 2.6 3
2.4 Ohm 3.0 Ohm
2.5 2 1.5 1 0.5 0
2.4 Ohm 3.0 Ohm 5.1 Ohm
3.4
1
1.4
1.8
2.2
2.6
3
3.4
Input Voltage (V)
Input Voltage (V)
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AS1344
Datasheet - A p p l i c a t i o n I n f o r m a t i o n
Thermal Protection
To protect the device from short circuit or excessive power dissipation of the auxiliary NPNs, the integrated thermal protection switches off the device when the junction temperature (TJ) reaches 140C (typ). When TJ decreases to approximately 135C, the device will resume normal operation. If the thermal overload condition is not corrected, the device will switch on and off while maintaining TJ within the range between 135 and 140C.
Setting Output Voltage
Output voltage can be adjusted by connecting a voltage divider between pins VOUT and FB (see Figure 35).
Figure 35. Typical Application
RV L1 6.8H 8 VCC = 0.9V to 3.6V C1 10F 4 VCC R3 100k 9 2 POK On Off 1 EN 5 PGND 3 GND VOUT VIN 7 SWOUT 6 LX D1 VOUT = 18V COUT 4.7F
AS1344
10 FB
R1 2.2M
R2 165k
The output voltage can adjusted by selecting different values for R1 and R2. For R2, select a value between 10k and 200k. Calculate R1 by: VOUT R1 = R2 -------------- - 1 VFB
Where: (EQ 2)
VOUT = 5.5V to 42V, VFB = 1.25V; VOUT > VIN The input bias current of FB has a maximum value of 100nA which allows for large-value resistors. For less than 1% error, the current through R2 should be 100 times the feedback input bias current (IFB). That's why the feeback current can be neglected in the calculation of VOUT.
Note: For the optimal operation condition the following ratio between VOUT and VIN should be used: VOUT / VIN 12 (EQ 3)
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AS1344
Datasheet - A p p l i c a t i o n I n f o r m a t i o n
LED Power Supply Application
The AS1344 can also be used for driving LEDs. Just simply connect the LEDs between the pins VOUT and FB. (see Figure 36).
Figure 36. LED Supply Application
RV L1 6.8H 8 VCC = 0.9V to 3.6V C1 10F 4 VCC R3 100k 9 2 POK On Off 1 EN 5 PGND 3 GND VOUT VIN 7 SWOUT 6 LX D1 COUT 4.7F
AS1344
10 FB R2 100 ILED
The output voltage is adjusted automatically to the required voltage of the LEDs. This voltage depends on the forward voltage (VF) of the used LEDs and the Feeback Voltage VFB. Calculate VOUT by:
VOUT = VF ( ILED ) x n + VFB (EQ 4)
Note: The brightness of the LEDs can directly be adjusted by setting the current ILED via the corresponding R2.
Calculate R2 by: VFB ILED = --------R2
Where: (EQ 5)
VFB = 1.25V n .... number of LEDs
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AS1344
Datasheet - A p p l i c a t i o n I n f o r m a t i o n
Inductor Selection
For the external inductor, a 4.7H or 6.8H inductor will usually suffice. Minimum inductor size is dependant on the desired efficiency and output current. Inductors with low core losses and small DCR at 1MHz are recommended. It's also recommended to choose an inductor which can handle at least 1.2A without saturating. The MOS6020 is a very good choice because the DCR is quite small and the saturation current exceeds 1.2A. For space limiting applications and input currents below 650mA the EPL2014 can be selected. Efficiency losses due to higher DCR should be considered. (see Figure 37 and Figure 38)
Table 5. Recommended Inductors Part Number L DCR ISAT @ 20% drop Dimensions (L/W/T) Manufacturer Coilcraft www.coilcraft.com
EPL2014-472MLC LPS3015-472MLC LPS4018-682MLC LPS5030-682ML_ MOS6020-682MLC MOS6020-472MLC
4.7H 4.7H 6.8H 6.8H 6.8H 4.7H
0.231 0.200 0.150 0.099 0.078 0.050
0.65A 1.2A 1.3A 1.7A 1.56A 1.82A
2.2x2.0x1.4mm 3.1x3.1x1.5mm 4.1x4.1x1.8mm 4.88x4.88x3.0mm 6.0x6.8x2.4mm 6.0x6.8x2.4mm
Note: For the Efficiency measurements in Figure 37 and Figure 38 a MBR0540 diode was used for D1.
Figure 37. Efficiency Comparison of different Inductors; VIN = 3V, VOUT = 18V
90 80 70
Figure 38. Efficiency Comparison of different Inductors; VIN = 3.6V, VOUT = 18V
90 80 70
Efficiency (%)
60 50 40 30 20 10 0 0.1 1 10 100
MOS6020 6.8H LPS5030 6.8H LPS4018 6.8H MOS6020 4.7H LPS3015 4.7H EPL2014 4.7H
Efficiency (%)
60 50 40 30 20 10 0 0.1 1 10 100
MOS6020 6.8H LPS5030 6.8H LPS4018 6.8H MOS6020 4.7H LPS3015 4.7H EPL2014 4.7H
Output Current (mA)
Output Current (mA)
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AS1344
Datasheet - A p p l i c a t i o n I n f o r m a t i o n
Capacitor Selection
A 10F capacitor is recommended for CIN as well as a 4.7F for COUT. Small-sized X5R or X7R ceramic capacitors should be used as they retain capacitance over wide ranges of voltages and temperatures.
Output Capacitor Selection
Low ESR capacitors should be used to minimize VOUT ripple. Multi-layer ceramic capacitors are recommended since they have extremely low ESR and are available in small footprints. A 4.7 to 10F output capacitor is sufficient for most applications. Larger values up to 22F may be used to obtain extremely low output voltage ripple and improve transient response. The rated voltage of the capacitor should not be lower than the output voltage.
Table 6. Recommended Output Capacitors Part Number C TC Code Rated Voltage Dimensions (L/W/T) Manufacturer Murata www.murata.com
GRM32DR71H335KA88B GRM32ER71H475KA88 GRM31CR61E106KA12 C3225X5R1H335K C3216X5R1E475K C3225X5R1E106K
3.3F 4.7F 10F 3.3F 4.7F 10F
X7R X7R X5R X5R X5R X5R
50V 50V 25V 50V 25V 25V
1210 1210 1206 1210 1206 1210
TDK www.tdk.com
Input Capacitor Selection
Low ESR input capacitors reduce input switching noise and reduce the peak current drawn from the battery. Ceramic capacitors are recommended for input decoupling and should be located as close to the device as is practical. A 10F input capacitor is sufficient for most applications. Larger values may be used for a better stabilization of the supply voltage.
Table 7. Recommended Input Capacitors Part Number C TC Code Rated Voltage Dimensions (L/W/T) Manufacturer Murata www.murata.com
GRM21BR60J106KE19 GRM188R60J106ME47 GRM21BR60J226ME39 C1608X5R0J106MB C2012X5R0J226M
10F 10F 22F 10F 22F
X5R X5R X5R X5R X5R
6.3V 6.3V 6.3V 6.3V 6.3V
0805 0603 0805 0603 0805
TDK www.tdk.com
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AS1344
Datasheet - A p p l i c a t i o n I n f o r m a t i o n
Diode Selection
A Schottky diode must be used to carry the output current into the Cout and load during the NMOS switch-off time.
Note: Do not use ordinary rectifier diodes, since the slow recovery times will compromise efficiency.
The MBR0520 is a good choice because of the very low forward voltage and the extremely fast switching. If the output voltage exceeds 20V the use of the PMEG4005 or the MBR0540 (40V Schottky diodes) is recommended. These diodes are designed to handle an average forward current of 500mA. In applications with higher loads, the PMEG4010 or the MBRM140 should be used, due to the rated average forward current of 1A.
Table 8. Recommended Diodes Part Number Reverse Voltage Forward Current Package Manufacturer MCC www.mccsemi.com
MBR0540 MBR0520 PMEG4005 PMEG4010 MBRM140
40V 20V 40V 40V 40V
0.5A 0.5A 0.5A 1A 1A
SOD123 SOD123 SOD123 SOD123 SOD123
Philips www.nxp.com ON Semiconductor www.onsemi.com
Figure 39. Efficiency Comparison of different Diodes; VIN = 3V, VOUT = 18V, L1 = 6.8H
90 80 70
Figure 40. Efficiency Comparison of different Diodes; VIN = 3.6V, VOUT = 18V, L1 = 6.8H
90 80 70
Efficiency (%)
60 50 40 30 20 10 0 0.1 1 10 100
PMEG4010 MBR0540 MBR0520 PMEG4005
Efficiency (%)
60 50 40 30 20 10 0 0.1 1 10 100
PMEG4010 MBR0540 MBR0520 PMEG4005
Output Current (mA)
Output Current (mA)
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AS1344
Datasheet - P a c k a g e D r a w i n g s a n d M a r k i n g s
10 Package Drawings and Markings
The devices are available in a TDFN-10 3x3mm package.
Figure 41. TDFN-10 3x3mm Package
D D2 SEE DETAIL B B A L E2/2
aaa C 2x PIN 1 INDEX AREA (D/2 xE/2)
D2/2
E2 K N N-1 e (ND-1) X e b ddd bbb C CAB
BTM VIEW
PIN 1 INDEX AREA (D/2 xE/2)
aaa C
2x TOP VIEW
e DETAIL B
Terminal Tip
ccc C
E
A3
C
SEATING PLANE
0.08 C
A
Datum A or B ODD TERMINAL SIDE
Symbol A A1 A3 L1 L2 aaa bbb ccc ddd eee ggg Notes:
Min 0.70 0.00
Typ 0.75 0.02 0.20 REF
Max 0.80 0.05
0.03 0.15 0.10 0.10 0.05 0.08 0.10
0.15 0.13
Notes 1, 2 1, 2 1, 2 1, 2 1, 2 1, 2 1, 2 1, 2 1, 2 1, 2 1, 2
Symbol D BSC E BSC D2 E2 L K b e N ND
Min
Typ 3.00 3.00
A1
SIDE VIEW
Max
1.60 1.35 0.30 0 0.20 0.18
0.40
2.50 1.75 0.50 14 0.30
0.25 0.50 10 5
Notes 1, 2 1, 2 1, 2 1, 2 1, 2 1, 2 1, 2 1, 2, 5
1, 2 1, 2, 5
1. Figure 41 is shown for illustration only. 2. All dimensions are in millimeters; angles in degrees. 3. Dimensioning and tolerancing conform to ASME Y14.5 M-1994. 4. N is the total number of terminals. 5. The terminal #1 identifier and terminal numbering convention shall conform to JEDEC 95-1, SPP-012. Details of terminal #1 identifier are optional, but must be located within the zone indicated. The terminal #1 identifier may be either a mold or marked feature. 6. Dimension b applies to metallized terminal and is measured between 0.15mm and 0.30mm from the terminal tip. 7. ND refers to the maximum number of terminals on side D. 8. Unilateral coplanarity zone applies to the exposed heat sink slug as well as the terminals
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Revision 1.05
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AS1344
Datasheet - O r d e r i n g I n f o r m a t i o n
11 Ordering Information
The device is available as the standard products shown in Table 9.
Table 9. Ordering Information Ordering Code Marking Description Delivery Form Package
AS1344-BTDT
ASR7
42V, DC-DC Boost Converter with adjustable Softstart
Tape and Reel
TDFN-10 3x3mm
Note: All products are RoHS compliant and Pb-free. Buy our products or get free samples online at ICdirect: http://www.austriamicrosystems.com/ICdirect
For further information and requests, please contact us mailto:sales@austriamicrosystems.com or find your local distributor at http://www.austriamicrosystems.com/distributor
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AS1344
Datasheet
Copyrights
Copyright (c) 1997-2009, austriamicrosystems AG, Tobelbaderstrasse 30, 8141 Unterpremstaetten, Austria-Europe. Trademarks Registered (R). All rights reserved. The material herein may not be reproduced, adapted, merged, translated, stored, or used without the prior written consent of the copyright owner. All products and companies mentioned are trademarks or registered trademarks of their respective companies.
Disclaimer
Devices sold by austriamicrosystems AG are covered by the warranty and patent indemnification provisions appearing in its Term of Sale. austriamicrosystems AG makes no warranty, express, statutory, implied, or by description regarding the information set forth herein or regarding the freedom of the described devices from patent infringement. austriamicrosystems AG reserves the right to change specifications and prices at any time and without notice. Therefore, prior to designing this product into a system, it is necessary to check with austriamicrosystems AG for current information. This product is intended for use in normal commercial applications. Applications requiring extended temperature range, unusual environmental requirements, or high reliability applications, such as military, medical life-support or life-sustaining equipment are specifically not recommended without additional processing by austriamicrosystems AG for each application. For shipments of less than 100 parts the manufacturing flow might show deviations from the standard production flow, such as test flow or test location. The information furnished here by austriamicrosystems AG is believed to be correct and accurate. However, austriamicrosystems AG shall not be liable to recipient or any third party for any damages, including but not limited to personal injury, property damage, loss of profits, loss of use, interruption of business or indirect, special, incidental or consequential damages, of any kind, in connection with or arising out of the furnishing, performance or use of the technical data herein. No obligation or liability to recipient or any third party shall arise or flow out of austriamicrosystems AG rendering of technical or other services.
Contact Information
Headquarters austriamicrosystems AG Tobelbaderstrasse 30 A-8141 Unterpremstaetten, Austria Tel: +43 (0) 3136 500 0 Fax: +43 (0) 3136 525 01 For Sales Offices, Distributors and Representatives, please visit: http://www.austriamicrosystems.com/contact
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