LT3973-3.3 Buck Converter overview
Description
LT3973-3.3 is a 42.00 V sync Buck Converter from with 0.75 A output current. The maximum 42.00 V input voltage can be regulated down into a 3.30 V to 3.30 V output voltage.
It requires are a typical inductor size of 15.00 µH, a typical external component count of 6 and achieves a peak efficiency of 88 %. Further LT3973-3.3 characteristics are a adjustable 800 kHz switching frequency and 2 available package option(s): MSOP-10 DFN-10 .
Parameter overview and features with replacement search
For the LT3973-3.3 replacement search, please select a main parameter tolerance value and adjust the checkboxes for feature match. The product counter within the button shows the number of available equivalents and a click on the replacement button shows all possible replacements within a parametric overview.
Parameter | Value | Replacement Search Filter |
V-IN min. | 4.20 V | |
V-IN max. | 42.00 V | |
I-OUT? | 0.75 A | |
V-OUT min. | 3.30 V | |
V-OUT max. | 3.30 V | |
V-OUT | 3.300 V | |
V-OUT programmable | ![]() |
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sync/non-sync | sync | |
Frequency typ. | 800 kHz | |
Frequency | adjustable | |
Frequency selectable | ||
ext.clock sync. | ![]() |
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Frequency adj./ ext.clock min. | 195 kHz | |
Frequency adj./ ext.clock max | 2150 kHz | |
Softstart | ![]() |
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Softstart adjustable | ![]() |
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Tracking | ![]() |
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PG/Power OK | ![]() |
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Quiescent current max. | 6 µA | |
Operating min. | ||
Operating max. | ||
Junction min. | -40 °C | |
Junction max. | 125 °C | |
thermal shutdown typ. | ||
Inductor size typ. | 15.00 µH | |
Inductor suggested by Würth Elektronik | ||
Automotive AEC-Q100 | ![]() |
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Light-Load-Mode | ![]() |
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Topology | Buck | |
Peak Efficiency | 88 % | |
Component count min. | 6 | |
current limit adjustable | ![]() |
|
Nr.of packages | 2 | |
CSP | ||
SC70 | ||
SOT | ||
MSOP | MSOP-10 | |
QFN/DFN | DFN-10 | |
SO/SOIC | ||
SOP | ||
DIP | ||
TO | ||
DDPAK |
LT3973-3.3 Datasheet
Link to the most up-to-date LT3973-3.3 datasheet and the product page for EVM, tools and support information.
LT3973-3.3 Sample stock and distributor price breaks
LT3973-3.3 prices and online available distributors.


Available Distributors with stock: 0
Available Distributors with stock: 0
List of equivalents and alternatives
The following DC/DC Buck Converter are similar to LT3973-3.3. Optional, compare LT3973-3.3 side-by-side with other Buck Converter via the Comparison function.
Inductor suggestions
Below you can find matching inductors from Wuerth Elektronik calculated on the maximum parameters of LT3973-3.3.
Order Code | Spec | L (µH) | IR (A) | ISAT (A) | RDC (mΩ) | L x W x H (mm) |
744025100 | 10.0 | 1.0 | 1.1 | 170.00 | 2.8 x 2.8 x 3 | |
74404032100 | 10.0 | 0.8 | 0.9 | 230.00 | 3 x 3 x 1.5 | |
74404041100 | 10.0 | 1.3 | 1.0 | 168.00 | 4 x 4 x 1.2 | |
74404042100 | 10.0 | 1.2 | 1.5 | 150.00 | 4 x 4 x 1.8 | |
74404042150 | 15.0 | 0.9 | 1.2 | 210.00 | 4 x 4 x 1.8 | |
744042100 | 10.0 | 1.3 | 1.0 | 120.00 | 4.8 x 4.8 x 2 | |
744042120 | 12.0 | 1.2 | 1.0 | 150.00 | 4.8 x 4.8 x 2 | |
744043100 | 10.0 | 1.2 | 1.0 | 95.00 | 4.8 x 4.8 x 3 | |
744043120 | 12.0 | 1.1 | 1.0 | 100.00 | 4.8 x 4.8 x 3 | |
744045100 | 10.0 | 1.0 | 1.5 | 240.00 | 4.5 x 3.2 x 2.9 | |
744045120 | 12.0 | 0.8 | 1.4 | 336.00 | 4.5 x 3.2 x 2.9 | |
744052100 | 10.0 | 1.1 | 1.3 | 105.00 | 5.8 x 5.8 x 2 | |
744052120 | 12.0 | 1.0 | 1.2 | 130.00 | 5.8 x 5.8 x 2 | |
744052150 | 15.0 | 1.0 | 1.1 | 175.00 | 5.8 x 5.8 x 2 | |
744053100 | 10.0 | 1.5 | 1.4 | 60.00 | 5.8 x 5.8 x 3 | |
744053120 | 12.0 | 1.5 | 1.3 | 70.00 | 5.8 x 5.8 x 3 | |
744053150 | 15.0 | 1.4 | 1.2 | 80.00 | 5.8 x 5.8 x 3 | |
744062100 | 10.0 | 1.6 | 1.4 | 53.00 | 6.8 x 6.8 x 2.5 | |
744062120 | 12.0 | 1.4 | 1.3 | 70.00 | 6.8 x 6.8 x 2.5 | |
744062150 | 15.0 | 1.3 | 1.1 | 80.00 | 6.8 x 6.8 x 2.5 | |
7440680100 | 10.0 | 1.2 | 1.0 | 177.00 | 8 x 8 x 1.2 | |
7440680120 | 12.0 | 1.2 | 1.0 | 195.00 | 8 x 8 x 1.2 | |
7440690100 | 10.0 | 1.6 | 1.3 | 112.00 | 8 x 8 x 1.5 | |
7440690120 | 12.0 | 1.4 | 1.2 | 148.00 | 8 x 8 x 1.5 | |
7440690150 | 15.0 | 1.3 | 1.1 | 179.00 | 8 x 8 x 1.5 | |
7440700100 | 10.0 | 2.0 | 1.6 | 78.00 | 8 x 8 x 2 | |
7440700150 | 15.0 | 1.7 | 1.3 | 117.00 | 8 x 8 x 2 | |
74408941100 | 10.0 | 0.9 | 1.6 | 248.00 | 4.8 x 4.8 x 2.1 | |
74408941150 | 15.0 | 0.8 | 1.4 | 430.00 | 4.8 x 4.8 x 2.1 | |
74408942150 | 15.0 | 1.1 | 1.6 | 207.00 | 4.8 x 4.8 x 3.1 | |
74408943150 | 15.0 | 1.4 | 1.7 | 118.00 | 4.8 x 4.8 x 4.1 | |
74477310 | 10.0 | 1.5 | 1.7 | 118.00 | 4 x 4.5 x 3.5 | |
744773112 | 12.0 | 1.3 | 1.6 | 156.00 | 4 x 4.5 x 3.5 | |
744773115 | 15.0 | 1.2 | 1.5 | 204.00 | 4 x 4.5 x 3.5 | |
744778115 | 15.0 | 1.5 | 1.8 | 100.00 | 7.3 x 7.3 x 3.4 | |
744778510 | 10.0 | 1.9 | 1.6 | 100.00 | 5.9 x 6.2 x 3.3 | |
7447785115 | 15.0 | 1.6 | 1.4 | 165.00 | 5.9 x 6.2 x 3.3 | |
744778610 | 10.0 | 2.1 | 1.8 | 74.00 | 5.9 x 6.2 x 5.1 | |
7447789115 | 15.0 | 1.5 | 1.8 | 100.00 | 7.3 x 7.3 x 3.5 | |
78477310 | 10.0 | 1.5 | 1.7 | 118.00 | 4 x 4.5 x 3.5 | |
784773112 | 12.0 | 1.3 | 1.6 | 156.00 | 4 x 4.5 x 3.5 | |
784773115 | 15.0 | 1.2 | 1.5 | 204.00 | 4 x 4.5 x 3.5 |