Datasheet

LM2597, LM2597HV
SNVS119C –MARCH 1998–REVISED APRIL 2013 www.ti.com
Table 1. LM2597/LM2597HV Fixed Voltage Quick Design Component Selection Table (continued)
Conditions Inductor Output Capacitor
Through Hole Surface Mount
Voltage Current Voltage Panasonic Nichicon AVX TPS Sprague
Inductance Inductor
Output Load Max Input HFQ Series PL Series Series 595D Series
(μH) (#)
(V) (A) (V) (μF/V) (μF/V) (μF/V) (μF/V)
8 47 L13 180/16 180/16 100/16 33/25
10 68 L21 180/16 180/16 100/16 33/25
0.5
15 100 L20 120/25 120/25 100/16 33/25
5 40 150 L19 120/25 120/25 100/16 33/25
9 150 L10 82/16 82/16 100/16 33/25
0.2 20 220 L9 120/16 120/16 100/16 33/25
40 330 L8 120/16 120/16 100/16 33/25
15 68 L21 82/25 82/25 100/16 15/25
18 150 L19 82/25 82/25 100/16 15/25
0.5
30 220 L27 82/25 82/25 100/16 15/25
12 40 330 L26 82/25 82/25 100/16 15/25
15 100 L11 82/25 82/25 100/16 15/25
0.2 20 220 L9 82/25 82/25 100/16 15/25
40 330 L17 82/25 82/25 100/16 15/25
LM2597/LM2597HV 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) = 0.5A
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 31) Figure 31)
Use the following formula to select the appropriate resistor values. Select R
1
to be 1 kΩ, 1%. Solve for R
2
.
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.)
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