Electronic Components Datasheet Search |
|
LM2596 Datasheet(PDF) 10 Page - First Components International |
|
LM2596 Datasheet(HTML) 10 Page - First Components International |
10 / 14 page 10 PROCEDURE (Adjustable Output Voltage Version) EXAMPLE (Adjustable Output Voltage Version) ILOAD(max) = Maximum Load Current ILOAD(max) = 3A F=Switching Frequency (Fixed at a nominal 150 kHz). F=Switching Frequency (Fixed at a nominal 150 kHz). 1. Programming Output Voltage (Selecting R1 and R2, as shown in Figure 1) Use the following formula to select the appropriate resistor values. ) R R (1 V V 1 2 REF OUT + = where V 1.23 VREF = Select a value for R1 between 240Ω and 1.5kΩ. The lower resistor values minimize noise pickup in the sensitive feedback pin. (For the lowest temperature coefficient and the best stability with time, use 1% metal film resistors.) 1) V V ( R R REF OUT 1 2 − = 1. Programming Output Voltage (Selecting R1 and R2, as shown in Figure 1) Select R1 to be 1 kΩ, 1%. Solve for R2. 1) V 1.23 V 20 k( 1 1) V V ( R R REF OUT 1 2 − = − = R2=1k (16.26-1)=15.26k, closest 1% value is 15.4kΩ R2 = 15.4 kΩ. 2. Inductor Selection (L1) 2. Inductor Selection (L1) A. Calculate the inductor Volt • microsecond constant E •T (V •Us), from the following formula: s) (V kHz 150 1000 V V V V V ) V V (V T E D SAT IN D OUT SAT OUT IN µ • • + − + • − − = • where VSAT = internal switch saturation voltage = 1.16V and VD = diode forward voltage drop = 0.5V A. Calculate the inductor Volt • microsecond constant (E •T), s) (V 150 1000 5 . 0 16 . 1 28 5 . 0 20 ) 16 . 1 20 28 ( T E µ • • + − + • − − = • s) (V . s) (V . . . ) . ( T E µ µ • = • • • = • 2 34 67 6 34 27 5 20 84 6 B. Use the E •T value from the previous formula and match it with the E •T number on the vertical axis of the Inductor Value Selection Guide shown in Figure 7. B. E •T=34.2 (V•Us) C. on the horizontal axis, select the maximum load current. C. ILOAD (max) = 3A D. Identify the inductance region intersected by the E •T value and the Maximum Load Current value. Each region is identified by an inductance value and an inductor code (LXX). D. From the inductor value selection guide shown in Figure 7, the inductance region intersected by the 34 (V •Us) horizontal line and the 3A vertical line is 47 UH, and the inductor code is L39. E. Select an appropriate inductor from the four manufacturer’s part numbers listed in Figure 8. E. From the table in Figure 8, locate line L39, and select an inductor part number from the list of manufacturers part numbers. 3. Output Capacitor Selection (COUT) 3. Output Capacitor SeIection (COUT) A. In the majority of applications, low ESR electrolytic or solid tantalum capacitors between 82 UF and 820 UF provide the best results. This capacitor should be located close to the IC using short capacitor leads and short copper traces. Do not use capacitors larger than 820 UF. B. To simplify the capacitor selection procedure, refer to the quick design table shown in Figure 3. This table contains different output voltages, and lists various output capacitors that will provide the best design solutions. B. From the quick design table shown in Figure 3, locate the output voltage column. From that column, locate the output voltage closest to the output voltage in your application. In this example, select the 24V line. Under the output capacitor section, select a capacitor from the list of through hole electrolytic or surface mount tantalum types from four different capacitor manufacturers. It is recommended that both the manufacturers and the manufacturers series that are listed in the table be used. In this example, through hole aluminum electrolytic capacitors from several different manufacturers are available. 220 UF/35V Panasonic HFQ Series 150 UF/35V Nichicon PL Series C. The capacitor voltage rating should be at least 1.5 times greater than the output voltage, and often much higher voltage ratings are needed to satisfy the low ESR requirements needed for low output ripple voltage. C. For a 20V output, a capacitor rating of at least 30V or more is needed. In this example, either a 35V or 50V capacitor would work. A 35V rating was chosen, although a 50V rating could also be used if a lower output ripple voltage is needed. Other manufacturers or other types of capacitors may also be used, provided the capacitor specifications LM2596 Simple switcher Power Converter 150kHz 3A Step-Down Voltage Regulator |
Similar Part No. - LM2596 |
|
Similar Description - LM2596 |
|
|
Link URL |
Privacy Policy |
ALLDATASHEET.COM |
Does ALLDATASHEET help your business so far? [ DONATE ] |
About Alldatasheet | Advertisement | Datasheet Upload | Contact us | Privacy Policy | Link Exchange | Manufacturer List All Rights Reserved©Alldatasheet.com |
Russian : Alldatasheetru.com | Korean : Alldatasheet.co.kr | Spanish : Alldatasheet.es | French : Alldatasheet.fr | Italian : Alldatasheetit.com Portuguese : Alldatasheetpt.com | Polish : Alldatasheet.pl | Vietnamese : Alldatasheet.vn Indian : Alldatasheet.in | Mexican : Alldatasheet.com.mx | British : Alldatasheet.co.uk | New Zealand : Alldatasheet.co.nz |
Family Site : ic2ic.com |
icmetro.com |