LT3991 Buck Converter overview

Description

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LT3991 is a 55.00 V non-sync Buck Converter from with 1.20 A output current. The maximum 55.00 V input voltage can be regulated down into a 1.20 V to 30.00 V output voltage.

It requires are a typical inductor size of 12.00 µH, a typical external component count of 8 and achieves a peak efficiency of 89 %. Further LT3991 characteristics are a adjustable 1000 kHz switching frequency and 2 available package option(s): MSOP-10 DFN-10 .

For the LT3991 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.

ParameterValueReplacement
Search Filter
V-IN min. 4.30 V
V-IN max. 55.00 V
I-OUT? 1.20 A
V-OUT min. 1.20 V
V-OUT max. 30.00 V
V-OUT adjustable V
V-OUT programmable no
sync/non-sync non-sync
Frequency typ. 1000 kHz
Frequency adjustable
Frequency selectable
ext.clock sync. yes
Frequency adj./ ext.clock min. 200 kHz
Frequency adj./ ext.clock max 2200 kHz
Softstart yes
Softstart adjustable yes
Tracking no
PG/Power OK yes
Quiescent current max. 4.5 µA
Operating min.
Operating max.
Junction min. -40 °C
Junction max. 125 °C
thermal shutdown typ.
Inductor size typ. 12.00 µH
Inductor suggested by Würth Elektronik
Automotive AEC-Q100 no
Light-Load-Mode yes
Topology Buck
Peak Efficiency 89 %
Component count min. 8
current limit adjustable no
Nr.of packages 2
CSP
SC70
SOT
MSOP MSOP-10
QFN/DFN DFN-10
SO/SOIC
SOP
DIP
TO
DDPAK

LT3991 Datasheet

Link to the most up-to-date LT3991 datasheet and the product page for EVM, tools and support information.

LT3991

LT3991 Sample stock and distributor price breaks

LT3991 prices and online available distributors.

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Available Distributors with stock: 0

no online Distributor with LT3991 stock available

Available Distributors with stock: 0

no online Distributor with LT3991 stock available

List of equivalents and alternatives

The following DC/DC Buck Converter are similar to LT3991. Optional, compare LT3991 side-by-side with other Buck Converter via the Comparison function.

Variation Compare Product Manufacturer Package
0% LT3980 LT3980 product overviewLT3980 product overview Linear Technology DFN-14, MSOP-16
10% TPS54162-Q1 TPS54162-Q1 product overviewTPS54162-Q1 product overview Texas Instruments HTSSOP-20
10% TPS54262-Q1 TPS54262-Q1 product overviewTPS54262-Q1 product overview Texas Instruments HTSSOP-20
10% TPS57160-Q1 TPS57160-Q1 product overviewTPS57160-Q1 product overview Texas Instruments SON-10, MSOP-10
25% TPS54140A TPS54140A product overviewTPS54140A product overview Texas Instruments SON-10, MSOP-10
50% LT3682 LT3682 product overviewLT3682 product overview Linear Technology DFN-12
50% LT3971 LT3971 product overviewLT3971 product overview Linear Technology DFN-10, MSOP-10
50% MP2454 MP2454 product overviewMP2454 product overview MPS QFN-10, MSOP-10
50% MPQ2454 MPQ2454 product overviewMPQ2454 product overview MPS QFN-10, MSOP-10
50% MPQ2454-AEC1 MPQ2454-AEC1 product overviewMPQ2454-AEC1 product overview MPS QFN-10, MSOP-10

Inductor suggestions

Below you can find matching inductors from Wuerth Elektronik calculated on the maximum parameters of LT3991.

V-IN max. 55 V, I-OUT 1.2 A, V-OUT min. 1.2 V, Frequency typ. 1000 kHz
Order Code Spec L (µH) IR (A) ISAT (A) RDC (mΩ) L x W x H (mm)
744025002 2.2 1.8 2.4 57.00 2.8 x 2.8 x 3
744025003 3.3 1.5 1.8 85.00 2.8 x 2.8 x 3
74404024022 2.2 1.8 2.0 80.00 2.5 x 2 x 1.2
74404032022 2.2 1.8 1.7 50.00 3 x 3 x 1.5
74404032033 3.3 1.5 1.5 70.00 3 x 3 x 1.5
74404041033 3.3 1.8 2.1 69.00 4 x 4 x 1.2
74404042033 3.3 2.0 2.9 55.00 4 x 4 x 1.8
74404052033 3.3 2.6 3.0 42.20 5 x 5 x 2
74404052039 3.9 2.4 2.8 50.50 5 x 5 x 2
7440420027 2.7 2.0 2.2 47.00 4.8 x 4.8 x 2
744042003 3.3 2.0 1.8 50.00 4.8 x 4.8 x 2
7440420039 3.9 1.8 1.7 60.00 4.8 x 4.8 x 2
7440430022 2.2 2.5 2.4 27.00 4.8 x 4.8 x 3
7440430027 2.7 2.4 2.0 25.00 4.8 x 4.8 x 3
744043003 3.3 2.2 1.8 30.00 4.8 x 4.8 x 3
7440430039 3.9 1.7 1.7 50.00 4.8 x 4.8 x 3
744045002 2.2 1.6 2.8 88.00 4.5 x 3.2 x 2.9
7440450027 2.7 1.5 2.7 96.00 4.5 x 3.2 x 2.9
744045003 3.3 1.4 2.7 104.00 4.5 x 3.2 x 2.9
7440450039 3.9 1.3 2.5 112.00 4.5 x 3.2 x 2.9
744052002 2.5 2.4 2.7 20.00 5.8 x 5.8 x 2
744052003 3.0 2.2 2.4 40.00 5.8 x 5.8 x 2
7440520039 3.9 2.0 2.1 50.00 5.8 x 5.8 x 2
744053002 2.6 3.0 2.7 20.00 5.8 x 5.8 x 3
744053003 3.0 2.8 2.5 20.00 5.8 x 5.8 x 3
744062002 2.2 3.4 2.7 10.00 6.8 x 6.8 x 2.5
744062003 3.3 2.8 2.5 20.00 6.8 x 6.8 x 2.5
7440680027 2.7 2.2 1.9 52.00 8 x 8 x 1.2
7440680033 3.3 2.0 1.8 61.00 8 x 8 x 1.2
7440690022 2.2 2.8 2.9 35.00 8 x 8 x 1.5
7440690033 3.3 2.6 2.3 42.00 8 x 8 x 1.5
7440700033 3.3 3.2 2.6 30.00 8 x 8 x 2
74408941029 2.9 1.6 3.0 101.00 4.8 x 4.8 x 2.1
74408941035 3.5 1.5 2.8 113.00 4.8 x 4.8 x 2.1
74438322022 2.2 1.3 2.2 252.00 2.5 x 2 x 0.8
74438323022 2.2 1.3 2.5 147.00 2.5 x 2 x 1
74438323033 3.3 1.3 2.1 220.00 2.5 x 2 x 1
74438324022 2.2 1.6 2.9 123.00 2.5 x 2 x 1.2
74438324033 3.3 1.3 2.6 226.00 2.5 x 2 x 1.2
744773027 2.7 2.3 3.0 39.00 4 x 4.5 x 3.5
744773033 3.3 2.0 2.9 41.00 4 x 4.5 x 3.5
744773039 3.9 1.9 2.6 54.00 4 x 4.5 x 3.5
7447785003 3.3 2.8 3.0 43.00 5.9 x 6.2 x 3.3
74479275222 2.2 1.3 1.7 166.00 2 x 1.25 x 1
74479276222 2.2 1.4 1.8 135.00 2 x 1.6 x 1
74479276222C 2.2 1.6 2.5 112.00 2 x 1.25 x 1
74479287222 2.2 1.5 2.5 132.00 2.5 x 2 x 1
74479288222 2.2 1.7 2.8 90.00 2.5 x 2 x 1.2
74479889222 2.2 1.3 1.7 250.00 2.5 x 2 x 1.2
78438322022 2.2 1.3 2.2 252.00 2.5 x 2 x 0.8
78438323022 2.2 1.3 2.5 147.00 2.5 x 2 x 1
78438323033 3.3 1.3 2.1 220.00 2.5 x 2 x 1
784773033 3.3 2.0 2.9 41.00 4 x 4.5 x 3.5
784773039 3.9 1.9 2.6 54.00 4 x 4.5 x 3.5
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