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 2 Key Features 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 = 0Ω, 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. ! 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: 22µA ! Shutdown Current: 0.1µA ! 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 L1 RV VCC = 0.9V to 3.6V VIN CIN VOUT R3 D1 POK On Off SWOUT VCC AS1344 LX R1 VOUT = 5.5V to 42V COUT VCC GND FB EN R2 GND PGND www.austriamicrosystems.com Revision 1.05 1 - 19 AS1344 Datasheet - P i n o u t 4 Pinout Pin Assignments Figure 2. Pin Assignments (Top View) EN 1 10 FB POK 2 GND 3 9 VOUT AS1344 VCC 4 8 VIN 7 SWOUT PGND 5 6 LX Pin Descriptions Table 1. Pin Descriptions Pin Number Pin Name 1 EN 2 POK 3 4 5 GND VCC PGND 6 LX 7 SWOUT 8 VIN 9 VOUT 10 FB www.austriamicrosystems.com Description Active-High Enable Input. A logic low on this pin shuts down the device and reduces the supply current to 0.1µA. 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 ≥10µF 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 ≥4.7µF 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)] Revision 1.05 2 - 19 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 Min Max VCC, VIN, EN, SWOUT, POK, FB to GND 5 VOUT, LX to GND 45 Units Comments V Thermal Resistance ΘJA 36.7 ºC/W on PCB ESD 2 kV HBM MIL-Std. 883E 3015.7 methods @25°C, JEDEC 78 Latch-Up -200 +100 mA Operating Temperature Range -40 +85 ºC Storage Temperature Range -65 +150 ºC 125 ºC Junction Temperature Package Body Temperature www.austriamicrosystems.com +260 ºC Revision 1.05 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). 3 - 19 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 +85ºC (unless otherwise specified). Typ values are at TAMB = +25ºC. Table 3. Electrical Characteristics Symbol VCC Parameter Condition Min Typ Maximum Supply Voltage Max Unit 3.6 V Minimum Supply Voltage VOUT = 12V, RV = 0Ω, no load 0.9 1.1 V Minimum Start-Up Voltage VOUT = 12V, ILOAD = 1mA, RV = 0Ω 0.95 1.2 V 42 V VOUT Output Voltage Range 5.5 IQ Quiescent Current VOUT = 6V, VFB=1.3V 22 30 µA ISHDN Shutdown Current EN = GND, TAMB = +25ºC 0.02 1 µA ΔVLNR VCC Line Regulation VOUT = 15V, ILOAD = 1mA, VCC = 1.8 to 3.6V 0.05 %/V ΔVLDR Load Regulation VOUT = 15V, ILOAD = 0 to 20mA 0.01 %/mA η Efficiency L1 = 6.8µH, VOUT = 12V, ILOAD = 50mA 85 % VFB Feedback Voltage IFB Feedback Input Bias Current 1.225 1.25 1.275 V VFB = 1.3V 1 100 nA DC-DC Switches RLX NMOS Switch OnResistance ILX = 100mA 0.9 1.5 RP_ON PMOS Switch OnResistance ISWout = -100mA 0.3 1.0 ILX_LEAK LX Leakage Current VLX = 42V 15 IP_LEAK Switch Leakage Current P-channel 10 Ω nA Control Inputs VIH EN Input Threshold 1.1V ≤ VCC ≤ 3.6V 0.7 x VCC 0.3 x VCC VIL 0 3.6 V VEN EN Input Voltage V IEN EN Input Current VEN = 0 to 3.6V 1 POK Output Low Voltage POK sinking 1mA 0.01 0.2 V POK Output High Leakage Current POK = 3.6V 1 500 nA POK Threshold Falling edge, referenced to VOUT(NOM) 87 90 93 % Oscillator Frequency 0.85 1 1.15 MHz Maximum Duty Cycle 90 95 nA POK Output VOL Oscillator fCLK www.austriamicrosystems.com Revision 1.05 % 4 - 19 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: 6.8µH (MOS6020-682) Inductor, 10µF (GRM21BR60J106KE19) CIN and 4.7µF (GRM32ER71H475KA88) COUT, (PMEG4010BEA) D1; Figure 4. Efficiency vs. Output Current; VOUT = 12V 100 100 90 90 80 80 Efficiency (%) Efficiency (%) Figure 3. Efficiency vs. Output Current; VOUT = 6V 70 60 50 70 60 50 Vin = 2.0V Vin = 2.0V Vin = 2.5V 40 Vin = 2.5V 40 Vin = 3.0V Vin = 3.0V Vin = 3.3V Vin = 3.3V 30 30 0.1 1 10 100 0.1 Output Current (mA) 10 100 Figure 6. Efficiency vs. Output Current; VOUT = 24V 100 80 90 70 60 80 Efficiency (%) Efficiency (%) Figure 5. Efficiency vs. Output Current; VOUT = 18V 70 60 50 Vin = 3.0V 40 50 40 30 20 Vin = 2.5V Vin = 2.5V Vin = 3.0V 10 Vin = 3.3V 30 Vin = 3.3V 0 0.1 1 10 0.1 100 Output Current (mA) 1 10 100 Output Current (mA) Figure 7. Efficiency vs. Input Voltage; VOUT = 12V Figure 8. Efficiency vs. Input Voltage; IOUT = 10mA 100 100 90 90 80 80 Efficiency (%) Efficiency (%) 1 Output Current (mA) 70 60 50 70 60 50 Vout = 5.5V Iout = 10mA 40 Vout = 10V 40 Iout = 50mA Vout = 12V Iout = 100mA Vout = 15V 30 30 0.9 1.2 1.5 1.8 2.1 2.4 2.7 3 3.3 3.6 0.9 1.2 1.5 1.8 2.1 Input Voltage (V) www.austriamicrosystems.com 2.4 2.7 3 3.3 3.6 Input Voltage (V) Revision 1.05 5 - 19 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 Figure 10. Output voltage vs. Input Voltage; VOUT=12V, (line regulation) 18.2 13 no l oad Iout = 1mA Iout = 10mA Iout = 10mA Iout = 20mA Iout = 50mA Iout = 100mA 18.1 Output Voltage (V) Output Voltage (V) Iout = 50mA 18 17.9 17.8 -45 -30 -15 12.5 12 11.5 11 0 15 30 45 60 75 90 0.9 1.2 1.5 1.8 2.1 2.4 2.7 Temperature (°C) 3 3.3 3.6 Input Voltage (V) Figure 11. Output Voltage vs. Load Current; VOUT=12V, VIN=1.5V, (load regualtion) Figure 12. Maximum Output current vs. Input Voltage; VOUT = 12, 15, 18, 24, 36V; (90% Voutnom) 12.5 300 Vout = 12V 12.4 Vout = 15V Vout = 18V Output Current (mA) Output Voltage (V) . 12.3 12.2 12.1 12 11.9 11.8 Vout = 24V Vout = 36V 200 100 11.7 11.6 0 11.5 0 10 20 0.9 1.2 1.5 1.8 2.1 30 Output Current (mA) 2.4 2.7 3 3.3 3.6 Input Voltage (V) Figure 13. Maximum Output current vs. VOUT; VCC = 1.5V, 3V Figure 14. Start-Up Voltage vs. Output Current; VCC = 0.9V to 3.6V, (95% Voutnom) 400 3.6 Vi n = 1.5V 3.3 Vi n = 3V Start-Up Voltage (V) Output Current (mA) 3 300 200 100 2.7 2.4 2.1 1.8 1.5 1.2 0.9 0.6 0 Vout = 5.5V Vout = 12V Vout = 15V Vout = 18V Vout = 24V Vout = 36V 0.3 5 15 25 35 45 Output Voltage (V) www.austriamicrosystems.com 0 10 20 30 40 50 60 70 80 90 100 Output Current (mA) Revision 1.05 6 - 19 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 Figure 16. Shutdown Current vs. Temperature 3 Shutdown Current (µA) . Shutdown Current (µA) . 0.025 0.02 0.015 0.01 0.005 0 0.9 1.2 1.5 1.8 2.1 2.4 2.7 3 2.5 2 1.5 1 0.5 0 -45 -30 -15 3.3 3.6 Input Voltage (V) Figure 17. Switching Frequency vs. Temperature 15 30 45 60 75 90 75 90 Figure 18. Feedback Voltage vs. Temperature 1.1 1.3 Feedback Voltage (V) . Switching Frequency (MHz) . 0 Temperature (°C) 1.05 1 0.95 0.9 -45 -30 -15 0 15 30 45 60 75 90 1.275 1.25 1.225 1.2 -45 -30 -15 Temperature (°C) 0 15 30 45 60 Temperature (C°) Figure 19. Quiescent Current vs. Input Voltage Quiescent Current (µA) . 22 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) www.austriamicrosystems.com Revision 1.05 7 - 19 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 2V/Div 10V/DIV 2.5ms/Div 200mA/Div EN 10V/DIV IIN VOUT 200mA/Div 10V/DIV 2V/Div Figure 25. Startup Waveform, detail; VIN = 3.0V, COUT = 170µF, RV = 3Ω 2V/Div Figure 24. Startup Waveform; VIN = 3.0V, COUT = 170µF, RV = 3Ω EN 200mA/Div EN IIN VOUT VOUT 10V/DIV IIN 200mA/Div EN 2V/Div Figure 23. Startup Waveform, detail; VIN = 2.4V, COUT = 170µF, RV = 3Ω 100ms/Div IIN 200mA/Div EN IIN 2.5ms/Div Figure 22. Startup Waveform; VIN = 2.4V, COUT = 170µF, RV = 3Ω VOUT 10V/DIV 10V/DIV VOUT 200mA/Div EN IIN VOUT 100ms/Div 100ms/Div www.austriamicrosystems.com 2V/Div Figure 21. Startup Waveform, detail; VIN = 1.8V, COUT = 170µF, RV = 3Ω 2V/Div Figure 20. Startup Waveform; VIN = 1.8V, COUT = 170µF, RV = 3Ω 2.5ms/Div Revision 1.05 8 - 19 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 200mV/DIV VIN VOUT(AC) 200mV/DIV VIN VOUT(AC) 2.5V 3.0V Figure 27. Transient Line Regulation; VOUT = 18V, ILOAD = 20mA 2.5V 3.0V Figure 26. Transient Line Regulation; VOUT = 18V, ILOAD = 1mA 500µs/Div 500µs/Div Figure 28. Output Voltage Ripple; VOUT = 18V, IOUT = 1mA Figure 29. Output Voltage Ripple; VOUT = 18V, IOUT = 20mA VIN = 3.0V VIN = 3.0V 1µs/Div 1µs/Div VOUT(AC) IOUT 1mA 20mA VOUT(AC) IOUT 200mV/Div Figure 31. Load Transient Response OFF; VCC = 3V, VOUT = 18V 200mV/Div Figure 30. Load Transient Response ON; VCC = 3V, VOUT = 18V 1mA 20mA VOUT VOUT VIN = 1.5V VIN = 1.5V 5ms/Div www.austriamicrosystems.com 200mV/Div VIN = 3.6V 200mV/Div VIN = 3.6V 5ms/Div Revision 1.05 9 - 19 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 L1 6.8µH RV Input Voltage 0.9V to 3.6V 8 7 2 6 VIN SWOUT POK LX 0.3Ω PMOS VCC PWM Control Sync Drive Control 1 MHz Spread Spectrum Ramp Generator Slope Compensator Shutdown Control Powersave Shutdown Powersave Operation Control Output Voltage 5.5V to 42V VOUT R1 Current Sense Σ AS1344 PWM – Comp – 1 9 0.9Ω NMOS + EN 1.13V – VOUT Good + Short Delay 4 CIN 10µF D1 VC RC COUT 10 – gm Error Amp + 4.7µF FB CP2 CC 3 GND 1.25V Ref 5 R2 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. www.austriamicrosystems.com Revision 1.05 10 - 19 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 3µA 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 = IIN² 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 = 155µF, RV [Ω] 0 1.0 1.5 2.0 2.4 3.0 IPEAK [A] 1.76 0.81 0.66 0.56 0.50 0.42 t [ms] 25 76 100 130 156 204 Figure 33. Startup Time; CIN = 150µF, COUT = 155µF Figure 34. Peak Current; CIN = 10µF, COUT = 155µF 3.5 800 0 Ohm 1.0 Ohm 3 1.5 Ohm 1.5 Ohm 2.0 Ohm 600 2.4 Ohm 3.0 Ohm 500 400 300 200 2.0 Ohm Peak Current (A) Start-up Time (ms) 0 Ohm 1.0 Ohm 700 2.5 2.4 Ohm 3.0 Ohm 5.1 Ohm 2 1.5 1 0.5 100 0 0 1 1.4 1.8 2.2 2.6 3 3.4 1 Input Voltage (V) www.austriamicrosystems.com 1.4 1.8 2.2 2.6 3 3.4 Input Voltage (V) Revision 1.05 11 - 19 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 140ºC (typ). When TJ decreases to approximately 135ºC, 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 140ºC. 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 6.8µH VCC = 0.9V to 3.6V C1 10µF 4 8 7 VIN SWOUT D1 6 VCC VOUT = 18V LX COUT 4.7µF R3 100kΩ 9 2 POK On 1 Off EN VOUT R1 2.2MΩ AS1344 10 FB R2 165kΩ 5 3 PGND GND The output voltage can adjusted by selecting different values for R1 and R2. For R2, select a value between 10k and 200kΩ. Calculate R1 by: V OUT R 1 = R 2 ⋅ ⎛ -------------- – 1⎞ ⎝ V FB ⎠ (EQ 2) Where: 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: V OUT ÷ V IN ≤ 12 www.austriamicrosystems.com Revision 1.05 (EQ 3) 12 - 19 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 6.8µH VCC = 0.9V to 3.6V C1 10µF 4 8 7 VIN SWOUT 6 VCC D1 LX COUT 4.7µF R3 100kΩ 9 2 POK On 1 Off EN VOUT AS1344 10 FB ILED R2 100Ω 5 3 PGND GND 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: V OUT = V F ( I LED ) × n + V FB (EQ 4) Note: The brightness of the LEDs can directly be adjusted by setting the current ILED via the corresponding R2. Calculate R2 by: V FB I LED = ---------R2 (EQ 5) Where: VFB = 1.25V n .... number of LEDs www.austriamicrosystems.com Revision 1.05 13 - 19 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 4.7µH or 6.8µH 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 ISAT @ 20% drop Dimensions (L/W/T) Part Number L DCR EPL2014-472MLC 4.7µH 0.231Ω 0.65A 2.2x2.0x1.4mm LPS3015-472MLC 4.7µH 0.200Ω 1.2A 3.1x3.1x1.5mm LPS4018-682MLC 6.8µH 0.150Ω 1.3A 4.1x4.1x1.8mm LPS5030-682ML_ 6.8µH 0.099Ω 1.7A 4.88x4.88x3.0mm MOS6020-682MLC 6.8µH 0.078Ω 1.56A 6.0x6.8x2.4mm MOS6020-472MLC 4.7µH 0.050Ω 1.82A 6.0x6.8x2.4mm Manufacturer Coilcraft www.coilcraft.com Note: For the Efficiency measurements in Figure 37 and Figure 38 a MBR0540 diode was used for D1. Figure 38. Efficiency Comparison of different Inductors; VIN = 3.6V, VOUT = 18V 90 90 80 80 70 70 Efficiency (%) Efficiency (%) Figure 37. Efficiency Comparison of different Inductors; VIN = 3V, VOUT = 18V 60 50 40 30 MOS6020 6.8µH LPS5030 6.8µH LPS4018 6.8µH MOS6020 4.7µH LPS3015 4.7µH 20 10 60 50 40 30 MOS6020 6.8µH LPS5030 6.8µH LPS4018 6.8µH MOS6020 4.7µH LPS3015 4.7µH 20 10 EPL2014 4.7µH EPL2014 4.7µH 0 0 0.1 1 10 100 0.1 Output Current (mA) www.austriamicrosystems.com 1 10 100 Output Current (mA) Revision 1.05 14 - 19 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 10µF capacitor is recommended for CIN as well as a 4.7µF 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 10µF output capacitor is sufficient for most applications. Larger values up to 22µF 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) GRM32DR71H335KA88B 3.3µF X7R 50V 1210 GRM32ER71H475KA88 4.7µF X7R 50V 1210 GRM31CR61E106KA12 10µF X5R 25V 1206 C3225X5R1H335K 3.3µF X5R 50V 1210 C3216X5R1E475K 4.7µF X5R 25V 1206 C3225X5R1E106K 10µF X5R 25V 1210 Manufacturer Murata www.murata.com 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 10µF 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 GRM21BR60J106KE19 10µF X5R 6.3V 0805 GRM188R60J106ME47 10µF X5R 6.3V 0603 GRM21BR60J226ME39 22µF X5R 6.3V 0805 C1608X5R0J106MB 10µF X5R 6.3V 0603 C2012X5R0J226M 22µF X5R 6.3V 0805 www.austriamicrosystems.com TC Code Rated Voltage Dimensions (L/W/T) Revision 1.05 Manufacturer Murata www.murata.com TDK www.tdk.com 15 - 19 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 MBR0540 40V 0.5A SOD123 MBR0520 20V 0.5A SOD123 PMEG4005 40V 0.5A SOD123 PMEG4010 40V 1A SOD123 MBRM140 40V 1A SOD123 90 90 80 80 70 70 60 50 40 30 20 PMEG4010 10 MBR0520 MBR0540 Philips www.nxp.com ON Semiconductor www.onsemi.com Figure 40. Efficiency Comparison of different Diodes; VIN = 3.6V, VOUT = 18V, L1 = 6.8µH Efficiency (%) Efficiency (%) Figure 39. Efficiency Comparison of different Diodes; VIN = 3V, VOUT = 18V, L1 = 6.8µH Manufacturer MCC www.mccsemi.com 60 50 40 30 20 PMEG4010 10 MBR0520 MBR0540 PMEG4005 PMEG4005 0 0 0.1 1 10 100 0.1 Output Current (mA) www.austriamicrosystems.com 1 10 100 Output Current (mA) Revision 1.05 16 - 19 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 D2 SEE DETAIL B A D D2/2 B aaa C 2x E E2 E2/2 L PIN 1 INDEX AREA (D/2 xE/2) K PIN 1 INDEX AREA (D/2 xE/2) aaa C N N-1 2x e TOP VIEW e b (ND-1) X e ddd bbb C C A B BTM VIEW Terminal Tip DETAIL B A3 ccc C A C 0.08 C SIDE VIEW A1 SEATING PLANE Datum A or B ODD TERMINAL SIDE Symbol A A1 A3 L1 L2 aaa bbb ccc ddd eee ggg Min 0.70 0.00 Typ 0.75 0.02 0.20 REF 0.03 Max 0.80 0.05 0.15 0.13 0.15 0.10 0.10 0.05 0.08 0.10 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 θ K b e N ND Min 1.60 1.35 0.30 0º 0.20 0.18 Typ 3.00 3.00 0.40 0.25 0.50 10 5 Max 2.50 1.75 0.50 14º 0.30 Notes 1, 2 1, 2 1, 2 1, 2 1, 2 1, 2 1, 2 1, 2, 5 1, 2 1, 2, 5 Notes: 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 www.austriamicrosystems.com Revision 1.05 17 - 19 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 AS1344-BTDT Marking Description Delivery Form Package 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:[email protected] or find your local distributor at http://www.austriamicrosystems.com/distributor www.austriamicrosystems.com Revision 1.05 18 - 19 AS1344 Datasheet Copyrights Copyright © 1997-2009, austriamicrosystems AG, Tobelbaderstrasse 30, 8141 Unterpremstaetten, Austria-Europe. Trademarks Registered ®. 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 www.austriamicrosystems.com Revision 1.05 19 - 19