1 www.semtech.com
LM2575 & LM2576
1A & 3A Miniconverter
Switching Regulators
POWER MANAGEMENT
Revision 1, January 2001
uPin for pin replacement for Nationals LM2575/6
series
uDC-to-DC buck or buck/boost converter requiring
only 4 support components
uFixed or adjustable voltages
uPreset output voltages of 3.3V, 5V and 12V
uWide output voltage range, 1.23V to 35V
u82% typical efficiency @ 5V out
uWide input voltage range, 4V to 40V
uInhibit/enable control pin
uIndustrial temperature range
uTO-220 and TO-263 packages
The LM2575/6 series switching regulators are monolithic
integrated circuits designed for use in buck or buck/
boost regulator applications requiring accurate output
voltages over combined variations of line, load and
temperature. This unique series greatly simplifies
switching power supply design. The LM2575 has a
maximum output current of 1A and the LM2576 is rated
for 3A.
The LM2575/6 series miniconverters include a
switching regulator and compensation network all within
the same package. Just add a choke, catch diode and
two capacitors to obtain an efficient DC-to-DC converter.
The current limit and thermal shutdown features of the
LM2575/6 series fully protect the device against
overstress conditions.
The LM2575/6 series offers an alternative to popular 3
terminal linear regulators by providing higher efficiency
with reduced heatsink size. In many applications a heat
sink will not be required.
uMicro controller power supplies
uMedical equipment
uIndustrial power supplies
uInstrumentation power supplies
Description Features
Applications
Typical Application Circuits
5752ML6752ML
L
1
Hµ033Hµ001
D
1
A3A7
C
NI
Fµ86Fµ021
C
TUO
Fµ033Fµ000,1
2ã 2001 Semtech Corp. www.semtech.com
LM2575 & LM2576
POWER MANAGEMENT
retemaraPlobmySmumixaMstinU
egatloVtupnIV
NI
54V
egatloVtupnIniPffO/nOV
FFO/NO
3.0- £V
FFO/NO
£V
NI
V
)etatSydaetS(nommoCotegatloVtuptuO 1-V
noitapissiDrewoPP
D
detimiLyllanretnIW
tneibmAotnoitcnuJecnatsiseRlamrehT
022-OT
362-OT
q
AJ
55
06
W/C°
esaCotnoitcnuJecnatsiseRlamrehT
022-OT
362-OT
q
CJ
0.2
0.2
W/C°
egnaRerutarepmeTnoitcnuJgnitarepOT
J
521+ot04-C°
egnaRerutarepmeTegarotST
GTS
051+ot56-C°
.ceS01)gniredloS(erutarepmeTdaeLT
DAEL
003C°
)ledoMydoBnamuH(gnitaRDSEV
DSE
2Vk
retemaraPlobmySsnoitidnoCtseTniMpyTxaMstinU
egatloVtuptuOV
O
I
O
A5.0=32.303.373.3V
3.3-6752MLVotV8
NI
detaR02.304.3
41.374.3
egatloVtuptuOV
O
I
O
A5.0=09.400.501.5V
5-6752MLVotV8
NI
detaR58.451.5
57.452.5
egatloVtuptuOV
O
I
O
A5.0=67.1100.2142.21V
21-6752MLVotV51
NI
detaR25.1184.21
04.1106.21
egatloVkcabdeeFV
BF
I
O
A5.0=712.1032.1342.1V
V,JDA-6752ML
O
V5=VotV8
NI
detaR391.1762.1
081.1082.1
tnerruCsaiBkcabdeeFI
B
V
NI
I,V21=
O
A5.0=05001An
JDA-6752ML 005
Unless otherwise specified: VIN = 12V for 3.3V, 5V and ADJ options and 25V for 12V option; VOUT = 5V for ADJ option; TA = 25ºC; VIN rated = 40V;
IO = 0.5 to 3A (LM2576), 0.2 to 1A (LM2575). Values in bold apply over full operating temperature range.
Absolute Maximum Ratings
Electrical Characteristics
3ã 2001 Semtech Corp. www.semtech.com
LM2575 & LM2576
POWER MANAGEMENT
Electrical Characteristics (Cont.)
retemaraPlobmySsnoitidnoCtseTniMpyTxaMstinU
egatloVtuptuOV
O
I
O
A2.0=32.303.373.3V
3.3-5752MLVotV8
NI
detaR02.304.3
41.374.3
egatloVtuptuOV
O
I
O
A2.0=09.400.501.5V
5-5752MLVotV8
NI
detaR58.451.5
57.452.5
egatloVtuptuOV
O
I
O
A2.0=67.1100.2142.21V
21-5752MLVotV51
NI
detaR25.1184.21
04.1106.21
egatloVkcabdeeFV
BF
I
O
A2.0=712.1032.1342.1V
V,JDA-5752ML
O
V5=VotV8
NI
detaR391.1762.1
081.1082.1
tnerruCsaiBkcabdeeFI
B
V
NI
I,V21=
O
A2.0=05001An
JDA-5752ML 005
noitpO/ycneiciffE
V3.3 hV
NI
I,V21=
O
)6752MLrofA3,5752ML(A1=77%
V5 28
V21V
NI
I,V51=
O
)6752MLrofA3,5752ML(A1=88
V,JDA
O
V5=V
NI
I,V21=
O
)6752MLrofA3,5752ML(A1=28
ycneuqerFgnihctiwSf
XS
742585zHk
3426
egatloVnoitarutaS
)1(
V
TAS
I,5752ML
O
A1= 9.02.1 V
I,6752ML
O
A3= 9.04.1
)nO(elcyCytuD.xaM
)3(
CD3989%
5752MLtnerruCkaeP
)1(
I
LC
7.12.20.3 A
3.12.3
6752MLtnerruCkaeP
)1(
I
LC
2.48.59.6 A
5.35.7
Unless otherwise specified: VIN = 12V for 3.3V, 5V and ADJ options and 25V for 12V option; VOUT = 5V for ADJ option; TA = 25ºC; VIN rated = 40V;
IO = 0.5 to 3A (LM2576), 0.2 to 1A (LM2575). Values in bold apply over full operating temperature range.
4ã 2001 Semtech Corp. www.semtech.com
LM2575 & LM2576
POWER MANAGEMENT
Notes:
(1) Output sourcing current, resistive load, no inductor or capacitor.
(2) Feedback = VO + 1.0V.
(3) Feedback = 0V.
Electrical Characteristics (Cont.)
retemaraPlobmySsnoitidnoCtseTniMpyTxaMstinU
tnerruCegakaeLtuptuO
)2(
V0=tuptuOI
L
V
NI
V=
NI
detaR2
Am
V1-=tuptuO 5.703
tnerruCtnecseiuQ
)2(
I
Q
501Am
21
tnerruCtnecseiuQybdnatSI
YBTS
05Aµ
)V5=niPffO/nO( 005
leveLtupnIcigoLniPffO/nOV
HI
2.24.1V
4.2
V
LI
2.10.1 V
8.0
tnerruCtupnIniPffO/nOI
HI
V
FFO/NO
)ffO(V5=2103Aµ
I
LI
V
FFO/NO
)nO(V0=001
Unless otherwise specified: VIN = 12V for 3.3V, 5V and ADJ options and 25V for 12V option; VOUT = 5V for ADJ option; TA = 25ºC; VIN rated = 40V;
IO = 0.5 to 3A (LM2576), 0.2 to 1A (LM2575). Values in bold apply over full operating temperature range.
5ã 2001 Semtech Corp. www.semtech.com
LM2575 & LM2576
POWER MANAGEMENT
TO-220-5
TO-263-5
eciveD
)1(
egakcaPtnerruC
XX-T5752ML5-022-OT
)3()2(
A1
RT.XX-S5752ML5-362-OT
)4(
XX-T6752ML5-022-OT
)3()2(
A3
RT.XX-S6752ML5-362-OT
)4(
Notes:
(1) -XX = Voltage Option. Available voltages are 3.3V
(-3.3), 5V (-5.0), 12V (-12), and ADJ (-ADJ), which is
adjustable between 1.23V and 35V.
(2) Lead bend options for TO-220-5 are: T-XX = Straight
in-line; T-XX-V = Vertical Staggered; T-XX-H = Horizontal
Staggered. Please refer to outline drawings at the end of
this datasheet.
(3) Only available in tube packaging. A tube contains 50
devices.
(4) Only available in tape and reel packaging. A reel
contains 800 devices.
6752ML,5752ML
niPnoitcnuF
1V
NI
2TUPTUO
3NOMMOC
4KCABDEEF
5FFO/NO
NOMMOCsiBAT
Pin Configurations Ordering Information
Block Diagram
6ã 2001 Semtech Corp. www.semtech.com
LM2575 & LM2576
POWER MANAGEMENT
Typical Characteristics - LM2575
7ã 2001 Semtech Corp. www.semtech.com
LM2575 & LM2576
POWER MANAGEMENT
Typical Characteristics - LM2575 (Cont.)
8ã 2001 Semtech Corp. www.semtech.com
LM2575 & LM2576
POWER MANAGEMENT
Typical Characteristics - LM2575 (Cont.)
9ã 2001 Semtech Corp. www.semtech.com
LM2575 & LM2576
POWER MANAGEMENT
Typical Characteristics - LM2576
10ã 2001 Semtech Corp. www.semtech.com
LM2575 & LM2576
POWER MANAGEMENT
Typical Characteristics - LM2576 (Cont.)
11ã 2001 Semtech Corp. www.semtech.com
LM2575 & LM2576
POWER MANAGEMENT
Typical Characteristics - LM2576 (Cont.)
12ã 2001 Semtech Corp. www.semtech.com
LM2575 & LM2576
POWER MANAGEMENT
The above component selections will be adequate for
most applications for output currents from 250mA to 3A
(LM2576) or 150mA to 1A (LM2575). Applications with
VOUT below 5V or above 24V may require component
adjustment for maximum performance; please contact
factory for application assistance.
1. Device Selection. Select an appropriate device from
the Ordering Information guide based upon voltage
option and package.
2. Thermal Conditions. Most applications will not require
a heatsink for the TO-220 package. Approximate power
dissipation is:
IN
O
IN
IN
SATOO V
V
V02.0
VVIV
P+=
3. Catch Diode. If the output must be capable of a
sustained short, the IF rating must be above 3A for the
LM2575 and 7A for the LM2576. The use of an ultra
fast diode with soft recovery characteristics or a Schottky
will be adequate. The major impact on the selection of a
Schottky versus an ultra fast diode is efficiency. Schottkys
will provide approximately 4% to 5% improvement for
VOUTS below 12V, whereas above 12V the difference will
become less significant. Breakdown rating must be in
excess of VIN for margin.
4. Input Capacitor. The value shown will be adequate for
most applications. Ripple voltage at the switching
frequency is caused by the input capacitor supplying load
current during the on time of the power switch. The use
of a low ESR switching type capacitor will minimize ripple
to an acceptable level.
5. Layout. Use short connections with a central point
ground to prevent improper operation caused by stray
inductance and ground loops.
6. Output Capacitor. Ripple voltage on VOUT is directly
related to the value of COUT and the internal resistance
ESR of COUT. Output noise can be lowered by increasing
COUT or by selecting a capacitor with a lower ESR. ESR
must be a minimum of 0.03W for the LM2576 or 0.07W
for the LM2575 to maintain stability, otherwise raise the
value of COUT.
Applications Information - Buck Mode
5752ML6752ML
L
1
Hµ033Hµ001
D
1
A3A7
C
NI
Fµ86Fµ021
C
TUO
Fµ033Fµ000,1
13ã 2001 Semtech Corp. www.semtech.com
LM2575 & LM2576
POWER MANAGEMENT
7. Switching Spikes. Switching spikes will also occur due
to distributive capacitance across turns of the inductor
when combined with output capacitor series inductance
(ESL). Reduction to a level at or below the switching ripple
can be achieved by using a post filter as shown below.
Switching Spike Reduction
Typical Buck Shutdown
Applications Information (Cont.)
14ã 2001 Semtech Corp. www.semtech.com
LM2575 & LM2576
POWER MANAGEMENT
Turn-On Delay
Under Voltage Lockout
Turn-On Delay With Spike Filter
Applications Information (Cont.)
15ã 2001 Semtech Corp. www.semtech.com
LM2575 & LM2576
POWER MANAGEMENT
5752ML6752ML
C
NI
Fµ74Fµ001
1D A3A7
1L Hµ001Hµ86
C
TUO
Fµ007,2Fµ008,6
I
TUO
Am052Am005
5752ML6752ML
C
NI
Fµ74Fµ001
1D A3A7
1L Hµ001Hµ86
C
TUO
Fµ074Fµ007,2
I
TUO
Am001Am057
Inverting buck/boost operation is a different topology of
operation than buck. This difference reduces the output
current capability of the device, in that the inductor must
supply all of the load current during the time the power
switch is off. Maximum output current is approximately:
)2576LM(
V
V
12
5.3
I
IN
O
OUT
+
≈
)2575LM(
V
V
12
3.1
I
IN
O
OUT
+
≈
Component stress requirements are very similar to the
buck with a few exceptions:
(1) catch diode breakdown VBR must be greater than
VIN + |VOUT|
(2) input capacitor is larger due to the increased peak
current during switch turn on. Power dissipation is
approximately:
IN
O
INSAT
IN
O
O
INO
O
DV
V
V02.0V
V
V
1I
VV V
P+
+
+
≈
Please contact factory for additional assistance when
using the buck/boost topology.
Applications Information - Inverting Buck/Boost
16ã 2001 Semtech Corp. www.semtech.com
LM2575 & LM2576
POWER MANAGEMENT
Inverting Buck/Boost Shutdown
Applications Information (Cont.)
17ã 2001 Semtech Corp. www.semtech.com
LM2575 & LM2576
POWER MANAGEMENT
Pre-Wound Inductors:
Hurricane Electronics Lab
P.O. Box 1280
Hurricane Industrial Park
Hurricane, UT 84737
(801) 635-2003
Core Source:
Micro Metals, Inc.
1190 N. Hawk Circle
Anaheim, CA 92807
(714) 630-7420
Capacitors:
VPR Series
Mallory Capacitor Co.
4760 Kentucky Avenue
Indianapolis, IN 46241
(317) 856-3731
511D & 673 Series
Sprague Electric Co.
North Adams, MA
(413) 664-4411
HFQ, HFZ Series
Panasonic Industrial Co.
2 Panasonic Way
Secaucus, NJ 07094
(201) 392-6142
PF, PL Series
Nichicon Corp.
927 E. State Pkwy.
Schaumburg, IL 60195
(708) 843-7600
LXF Series
United Chemi-con
9801 West Higgins Road
Rosemont, IL 60018
(708) 696-2000
Heat Sinks:
AAVID Engineering Co.
P.O.Box 400
One Kool Path
Laconia, NH 03247
(603) 528-3400
Thermalloy, Inc.
2021 W. Valley View Lane
Dallas, TX 76381
(214) 243-4321
Diodes - Catch:
Ultra Fast/Soft Recovery
Semtech Corporation
652 Mitchell Road
Newbury Park, CA 91320
(805) 498-2111
Diodes - Schottky:
Fuji/Collmer Semiconductor
14368 Proton Road
Dallas, TX 76244
(800) 527-0521
Micro Quality
1000 N. Shiloh
Garland, TX 76046
(214) 272-7811
Support Components Information
18ã 2001 Semtech Corp. www.semtech.com
LM2575 & LM2576
POWER MANAGEMENT
Outline Drawing - TO-220-5 (T-XX-H Option)
Outline Drawing - TO-220-5 (T-XX Option)
Outline Drawing - TO-220-5 (T-XX-V Option)
19ã 2001 Semtech Corp. www.semtech.com
LM2575 & LM2576
POWER MANAGEMENT
Contact Information
Semtech Corporation
Power Management Products Division
652 Mitchell Rd., Newbury Park, CA 91320
Phone: (805)498-2111 FAX (805)498-3804
Outline Drawing - TO-263-5
Minimum Land Pattern - TO-263-5