a8430 Allegro MicroSystems, Inc., a8430 Datasheet
a8430
Available stocks
Related parts for a8430
a8430 Summary of contents
Page 1
... The high switching frequency of 1.2 MHz allows the use of small inductor and capacitor values. The A8430 is provided in a 5-pin MLP package (part number suffix EK), that has a nominal height of only 0.75 mm. The lead-free version (part number suffix EK-T) has 100% lead-free matte tin leadframe plating ...
Page 2
... FB I – SWLIM F – – V – CE(SAT) I – – – IH Leakage I IL www.allegromicro.com 115 Northeast Cutoff, Box 15036 Worcester, Massachusetts 01615-0036 (508) 853-5000 A8430 Driver S Min. Typ. Max. Units 2.5 – – 2.5 3.5 mA – 0.1 1 µ 104 mV – ...
Page 3
... Switching Frequency versus Temperature 1.25 1.20 1.15 1.10 1.05 1.00 150 –50 0 Conversion Efficiency versus Current 150 0 5 www.allegromicro.com 115 Northeast Cutoff, Box 15036 Worcester, Massachusetts 01615-0036 (508) 853-5000 A8430 50 100 150 Temperature (°C) 50 100 150 Temperature (° LED Current (mA) 3 ...
Page 4
... PCB that are connected to this pin should be minimized. In addition, the inductor (L1) and diode (D1) should be connected as close to this pin as possible. EN. Setting lower than 0.4 V disables the A8430 and puts the control circuit into the low-power Sleep mode. Greater than 1.5 V fully enables the A8430. ...
Page 5
... White LED Driver Constant Current Step-up Converter Device Operation The A8430 uses a constant-frequency, current-mode control scheme to regulate the current through the load. The load current produces a voltage across the external sense resistor (R1) and the input at the FB pin. This voltage is then compared to the internal 95 mV reference to produce an error signal ...
Page 6
... However, as the current rating increases, the diode capacitance also increases result, the optimal selection is usually the lowest current rating above the circuit maximum. With the A8430, a current rating in the range from 100 mA to 200 mA is usually sufficient. . Because the capacitor values are ...
Page 7
... White LED Driver Constant Current Step-up Converter By applying a PWM signal directly to the EN pin, the A8430 is turned on or off, and I is either full (as defined by LOAD R1) or zero. By varying the duty cycle of the PWM signal, the LED brightness can be controlled from off (0% duty cycle) to full (100% duty cycle) ...
Page 8
... LED string. The Zener diode also should be able to sink more than 0 current. Parallel LED Strings The A8430 can be used to power parallel strings of LEDs, which have the same number of LEDs on each string important that the voltage drop is the same across all of the parallel strings, to ensure that all of the LEDs are illuminated and that the current though each string is equal ...
Page 9
... D BSC 2.10 .083 MAX www.allegromicro.com 115 Northeast Cutoff, Box 15036 Worcester, Massachusetts 01615-0036 (508) 853-5000 A8430 .031 .028 Dimensions in millimeters U.S. Customary dimensions (in.) in brackets, for reference only A Pin index area B Exposed thermal pad Optional thermal vias, ∅0.30 [.012], pitch 1.2 [.047 Typical pad layout including solder pad for exposed thermal pad ...
Page 10
... Copyright©2003, 2004, 2005 AllegroMicrosystems, Inc. www.allegromicro.com 115 Northeast Cutoff, Box 15036 Worcester, Massachusetts 01615-0036 (508) 853-5000 A8430 10 ...