Datasheet

LM22676-ADJ
+
GND
+
VIN
EN
SW
BOOT
FB
GND
VIN 4.5V to 42V
C2
22 PF
C1
6.8 PF
EN
C3
10 nF
L1
8.2 PH
C4
120 PF
GND
R
FBT
1.54 k:
R
FBB
976:
D1
60V, 5A
VOUT 3.3V
100 1k 10k 100k 1M 10M
0
5
10
15
20
25
30
35
40
COMPENSATOR GAIN (dB)
FREQUENCY (Hz)
-ADJ
-5.0
LM22676
LM22676-Q1
www.ti.com SNVS587K –SEPTEMBER 2008–REVISED APRIL 2013
(9)
The Q factor depends on the parasitic resistance of the power stage components and is not typically in the
control of the designer. Of course, loop compensation is only one consideration when selecting power stage
components; see the Application Information section for more details.
Figure 15. Compensator Gain
In general, hand calculations or simulations can only aid in selecting good power stage components. Good
design practice dictates that load and line transient testing should be done to verify the stability of the application.
Also, Bode plot measurements should be made to determine stability margins. Application note AN-1889
(SNVA364) shows how to perform a loop transfer function measurement with only an oscilloscope and function
generator.
Application Information
TYPICAL BUCK REGULATOR APPLICAION
Figure 16 shows an example of converting an input voltage range of 5.5V to 42V, to an output of 3.3v at 3A. See
the application note for the LM22670, AN-1885 (SNVA361), for more information.
Figure 16. Typical Buck Regulator Application
EXTERNAL COMPONENTS
The following guidelines should be used when designing a step-down (buck) converter with the LM22676.
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