Datasheet
LM2595
www.ti.com
SNVS122B –MAY 1999–REVISED APRIL 2013
Table 2. LM2595 Fixed Voltage Quick Design Component Selection Table (continued)
Conditions Inductor Output Capacitor
Through Hole Electrolytic Surface Mount Tantalum
Output Load Max Input Inductance Inductor Panasonic Nichicon AVX TPS Sprague
Voltage Current Voltage (μH) (#) HFQ Series PL Series Series 595D Series
(V) (A) (V) (μF/V) (μF/V) (μF/V) (μF/V)
8 33 L28 330/16 330/16 220/10 270/10
10 47 L31 220/25 220/25 220/10 220/10
1
15 68 L30 180/35 180/35 220/10 150/16
5 40 100 L29 180/35 120/35 100/16 120/16
9 68 L21 180/16 180/16 220/10 150/16
0.5 20 150 L19 120/25 1200/25 100/16 100/20
40 150 L19 100/25 100/25 68/20 68/25
15 47 L31 220/25 220/25 68/20 120/20
18 68 L30 180/35 120/25 68/20 120/20
1
30 150 L36 82/25 82/25 68/20 100/20
12 40 220 L35 82/25 82/25 68/20 68/25
15 68 L21 180/25 180/25 68/20 120/20
0.5 20 150 L19 82/25 82/25 68/20 100/20
40 330 L26 56/25 56/25 68/20 68/25
Table 3. LM2595 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) = 1A
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 21) Figure 21)
Use the following formula to select the appropriate resistor values. Select R
1
to be 1 kΩ, 1%. Solve for R
2
.
(1)
(3)
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
2
= 15.4 kΩ.
lowest temperature coefficient and the best stability with time, use
1% metal film resistors.)
(2)
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