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