Datasheet
Table Of Contents
- Features
- Applications
- Description
- Absolute Maximum Ratings
- Operating Conditions
- LM2596-3.3 Electrical Characteristics
- LM2596-5.0 Electrical Characteristics
- LM2596-12 Electrical Characteristics
- LM2596-ADJ Electrical Characteristics
- All Output Voltage Versions Electrical Characteristics
- Typical Performance Characteristics
- Test Circuit and Layout Guidelines
- Application Information
- EXTERNAL COMPONENTS
- FEEDFORWARD CAPACITOR (Adjustable Output Voltage Version)
- OUTPUT CAPACITOR
- CATCH DIODE
- INDUCTOR SELECTION
- DISCONTINUOUS MODE OPERATION
- OUTPUT VOLTAGE RIPPLE AND TRANSIENTS
- OPEN CORE INDUCTORS
- THERMAL CONSIDERATIONS
- DELAYED STARTUP
- UNDERVOLTAGE LOCKOUT
- INVERTING REGULATOR
- INVERTING REGULATOR SHUTDOWN METHODS
- Revision History

LM2596
SNVS124C –NOVEMBER 1999–REVISED APRIL 2013
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Table 1. LM2596 Fixed Voltage Quick Design Component Selection Table (continued)
Conditions Inductor Output Capacitor
Through Hole Electrolytic Surface Mount Tantalum
Output Load Max Input Panasonic Nichicon AVX TPS Sprague
Inductance Inductor
Voltage Current Voltage HFQ Series PL Series Series 595D Series
(μH) (#)
(V) (A) (V) (μF/V) (μF/V) (μF/V) (μF/V)
5 3 8 22 L41 470/25 560/16 220/10 330/10
10 22 L41 560/25 560/25 220/10 330/10
15 33 L40 330/35 330/35 220/10 330/10
40 47 L39 330/35 270/35 220/10 330/10
9 22 L33 470/25 560/16 220/10 330/10
2 20 68 L38 180/35 180/35 100/10 270/10
40 68 L38 180/35 180/35 100/10 270/10
12 3 15 22 L41 470/25 470/25 100/16 180/16
18 33 L40 330/25 330/25 100/16 180/16
30 68 L44 180/25 180/25 100/16 120/20
40 68 L44 180/35 180/35 100/16 120/20
15 33 L32 330/25 330/25 100/16 180/16
2 20 68 L38 180/25 180/25 100/16 120/20
40 150 L42 82/25 82/25 68/20 68/25
LM2596 Series Buck Regulator Design Procedure (Adjustable Output)
PROCEDURE (Adjustable Output Voltage Version) EXAMPLE (Adjustable Output Voltage Version)
Given: Given:
V
OUT
= Regulated Output Voltage V
OUT
= 20V
V
IN
(max) = Maximum Input Voltage V
IN
(max) = 28V
I
LOAD
(max) = Maximum Load Current I
LOAD
(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 R
1
and R
2
, as shown in 1. Programming Output Voltage (Selecting R
1
and R
2
, as shown in
Figure 20 ) Figure 20 )
Use the following formula to select the appropriate resistor values. Select R
1
to be 1 kΩ, 1%. Solve for R
2
.
(3)
(1)
R
2
= 1k (16.26 − 1) = 15.26k, closest 1% value is 15.4 kΩ.
Select a value for R
1
between 240Ω and 1.5 kΩ. The lower resistor
values minimize noise pickup in the sensitive feedback pin. (For the
R
2
= 15.4 kΩ.
lowest temperature coefficient and the best stability with time, use
1% metal film resistors.)
(2)
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