om5448 Hendon Semiconductors, om5448 Datasheet
om5448
Related parts for om5448
om5448 Summary of contents
Page 1
... It is held low until it reaches an internal current level threshold set by a resistor from the SETI pin to VEE. The output drive then switches OFF for a period set internally in the OM5448. At the end of this time OP is switched ON again. The enable input provides an electronic control to disable the OM5448 output, when pulled low it switches the OM5448 into a low current standby mode ...
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... 3.5 V sup OPmax I 250 mA outavg I 500 mA outmax I 700 µA typ. active I 1.7 mA typ active I 700 µA typ. stb F 80 kHz typ −590 200 mW max tot T −40 to +85 °C amb T 150 °C jmax 2 OM5448 DESCRIPTION Product Specification ...
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... EN pin; so that if this pin is not connected it is pulled high, and 3 OM5448 Low Voltage LED Driver and Boost Converter the OM5448 is active. EN can also be connected pulled low, for example by connecting the OM5448 is ...
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... Choke selection: Efficiency The optimum choke inductance for the OM5448 has been found to be 220 µH. This offers the best balance between cost and performance. In addition to the optimum value of the inductance, the core must not saturate at the peak current. Also the ...
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... V = 2.4 V, IOP = − CC 1.2 mA, inductor = 220 µ 1.6 Ω), kΩ SETI 2.4V 1 − V with respect 2. OM5448 TYP MAX UNIT − 3.5 V 250 − µA 700 − µA 400 − µA 70 − − % − 450 − ...
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... These offer a number of application ideas for use of the OM5448. They have been chosen to illustrate the different ways in which the OM5448 can be used, and show how different circuit options can be chosen to emphasise the useful possibilities of this low voltage circuit. The first circuit is the simplest, using a ...
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... R1 needed for white LED drive becomes 82 kilohms. As 2.4 volts exceeds the sum of the forward 7 OM5448 Low Voltage LED Driver and Boost Converter This circuit will also drive a white LED from a 2.4 volt supply. Note that 2.4 volts is greater than the ...
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... Diode, 2V4) Fig.6 OM5448 efficiency when driving a white LED in DC mode. See figure 4. 2007 May 28, Revision 1 ( 00uH (No Cap, No Diode, 2V4) 220uH (No Cap, No Diode, 2V4) 1 00uH (No Cap, No Diode, 1V2) 220uH (No Cap, No Diode ...
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... LED brightness. By using switch SW1 on the SETI pin with a second current setting resistor R2, actuation of the 9 OM5448 Low Voltage LED Driver and Boost Converter As the typical forward voltage drop of an amber LED is 2.1 volts at 20 mA, and significant forward current flows at about 1 ...
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... Out put Curre sist or for wit h 2.4 V supply (mA ) 100uH 1.6ohms Whit e 100uH 0.7ohms Whit e 10 OM5448 Low Voltage LED Driver and Boost Converter 220uH 1.6ohms Amber 220uH 1.6ohms Whit e ...
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... Fig.10 OM5448 LED drive circuit with switched light level using the R 9.5 Series and parallel LED connection Earlier application circuits have shown single LED drive. However the OM5448 is also suitable for driving multiple LEDs in either series or Fig.11 Series and parallel LED drive using the OM5448 2007 May 28, Revision 1 ...
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... Fig.12 Parallel LED drive using the OM5448 (with current sharing resistors). In figure 12 4.7 ohm resistors have been used in series with each of the three parallel LEDs to force current sharing the voltage drop across the resistors will be approximately 100 mV. 2007 May 28, Revision 1.0 Series LED connection is shown in figure 13 ...
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... Supply voltage sensitivity As the base drive to the output transistor in the OM5448 is set by the input current to the SETI pin, the resulting LED current is therefore dependent on the voltage across the SETI resistor R1. The graph in figure 14 shows this dependence for a 1.2 volt circuit LED ...
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... Fig.15 Simple stabilization circuit for LED current variation against supply voltage. Fig.16 LED current against supply voltage, showing stabilized and uncompensated curves (fig 15 & 4). 2007 May 28, Revision 1.0 Low Voltage LED Driver and Boost Converter 14 OM5448 Product Specification ...
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... Whit e LED cur r ent , 2.4V supply Whit e LED cur rent , 1.2V Supply 15 OM5448 Low Voltage LED Driver and Boost Converter well as tracking the lower output provided by cold batteries. 100 125 150 ...
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... The most simple boost power supply circuit is that shown in figure 18. Fig.18 Voltage boost power supply circuit using the OM5448. Fig.19 Regulated boost power supply circuit using the OM5448. 2007 May 28, Revision 1.0 The circuit is the same as the DC LED drive circuit of figure 4, except that the LED has been replaced by a zener diode ...
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... OM5448 provides drive to the output regulating circuit until the zener diode begins to conduct. When the zener diode conducts, and sufficient current flows Fig.20 Voltage multiplier boost power supply circuit using the OM5448. 9.11 Voltage multiplier power supply The voltage output of the OM5448 ...
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... Fig.21 Regulated voltage multiplier boost power supply circuit using the OM5448. 9.13 Negative regulated power supply The circuit shown in figure 22 shows how the OM5448 can generate a regulated -5 volt supply from a single cell battery. The pulsed signal level shifted in a capacitor, and rectified to provide the negative output voltage ...
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... Fig.22 Negative regulated power supply from single cell supply using the OM5448. 2007 May 28, Revision 1.0 Low Voltage LED Driver and Boost Converter 19 OM5448 Product Specification ...
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... May 28, Revision 1.0 PACKAGE DESCRIPTION DESCRIPTION Initial Draft Typograpical corrections HS formatting and ESD Caution Update email address 20 OM5448 Low Voltage LED Driver and Boost Converter VERSION ROHS SOP-003 Yes ATTENTION OBSERVE PRECAUTIONS FOR HANDLING ELECTROSTATIC SENSITIVE DEVICES Product Specification ...
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... Port Adelaide SA 5015 AUSTRALIA Telephone: +61 8 8348 5200 Facsimile: +61 8 8243 1048 World Wide Web: www.hendonsemiconductors.com www.bus-buffer.com Email: hendon.info@ies-sa.com.au 2007 May 28, Revision 1.0 Low Voltage LED Driver and Boost Converter Street Address: Hendon Semiconductors 1 Butler Drive Hendon SA 5014 AUSTRALIA 21 OM5448 Product Specification ...
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... Customers using or selling Hendon products for use in such applications their own risk and agree to fully indemnify Hendon for any damages resulting from such improper use or sale. 2007 May 28, Revision 1.0 Low Voltage LED Driver and Boost Converter 22 OM5448 Product Specification ...