NSC LM2577T-12, LM2577SX-ADJ, LM2577SX-12, LM2577S-ADJ, LM2577S-15 Datasheet

LM1577/LM2577 Series
SIMPLE SWITCHER

®

Step-Up Voltage Regulator

General Description

The LM1577/LM2577 are monolithic integrated circuits that
provide all of the power and control functions for step-up
(boost), flyback, and forward converter switching regulators.
The device is available in three different output voltage ver­sions: 12V, 15V, and adjustable.

Requiring a minimum number of external components, these
regulators are cost effective, and simple to use. Listed in this
data sheet are a family of standard inductors and flyback
transformers designed to work with these switching regula­tors.

Included on the chip is a 3.0A NPN switch and its associated
protection circuitry,consisting of current and thermal limiting,
and undervoltage lockout. Other features include a 52 kHz
fixed-frequency oscillator that requires no external compo­nents, a soft start mode to reduce in-rush current during
start-up, and current mode control for improved rejection of
input voltage and output load transients.

Features

n Requires few external components
n NPN output switches 3.0A, can stand off 65V
n Wide input voltage range: 3.5V to 40V
n Current-mode operation for improved transient

response, line regulation, and current limit

n 52 kHz internal oscillator
n Soft-start function reduces in-rush current during start-up
n Output switch protected by current limit, under-voltage

lockout, and thermal shutdown

Typical Applications

n Simple boost regulator
n Flyback and forward regulators
n Multiple-output regulator

Typical Application

Ordering Information

Temperature

Range

Package

Type

Output Voltage NSC

12V 15V ADJ Package Package

Drawing

−40˚C ≤ T

A

≤ +125˚C 24-Pin Surface Mount LM2577M-12 LM2577M-15 LM2577M-ADJ M24B SO

16-Pin Molded DIP LM2577N-12 LM2577N-15 LM2577N-ADJ N16A N
5-Lead Surface Mount LM2577S-12 LM2577S-15 LM2577S-ADJ TS5B TO-263
5-Straight Leads LM2577T-12 LM2577T-15 LM2577T-ADJ T05A TO-220
5-Bent Staggered LM2577T-12 LM2577T-15 LM2577T-ADJ T05D TO-220

Leads Flow LB03 Flow LB03 Flow LB03

−55˚C ≤ T

A

≤ +150˚C 4-Pin TO-3 LM1577K-12/883 LM1577K-15/883 LM1577K-

ADJ/883

K04A TO-3

SIMPLE SWITCHER®is a registered trademark ofNational Semiconductor Corporation.

DS011468-1

Note: Pin numbers shown are for TO-220 (T) package.

June 1999

LM1577/LM2577 Series SIMPLE SWITCHER Step-Up Voltage Regulator

© 1999 National Semiconductor Corporation DS011468 www.national.com

Absolute Maximum Ratings (Note 1)

If Military/Aerospace specified devices are required,
please contact the National Semiconductor Sales Office/
Distributors for availability and specifications.

Supply Voltage 45V
Output Switch Voltage 65V
Output Switch Current (Note 2) 6.0A
Power Dissipation Internally Limited
Storage Temperature Range −65˚C to +150˚C
Lead Temperature

(Soldering, 10 sec.) 260˚C

Maximum Junction Temperature 150˚C

Minimum ESD Rating

(C=100 pF, R=1.5 kΩ)2kV

Operating Ratings

Supply Voltage 3.5V ≤ VIN≤ 40V
Output Switch Voltage 0V ≤ V

SWITCH

≤ 60V

Output Switch Current I

SWITCH

≤ 3.0A

Junction Temperature Range

LM1577 −55˚C ≤ T

J

≤ +150˚C

LM2577 −40˚C ≤ T

J

≤ +125˚C

Electrical Characteristics—LM1577-12, LM2577-12

Specifications with standard type face are for T

J

=

25˚C, and those in bold type face apply over full Operating Temperature

Range. Unless otherwise specified, V

IN

=

5V, and I

SWITCH

=

0.

LM1577-12 LM2577-12 Units

Symbol Parameter Conditions Typical Limit Limit (Limits)

(Notes 3, 4) (Note 5)

SYSTEM PARAMETERS Circuit of

Figure 1

(Note 6)

V

OUT

Output Voltage V

IN

=

5V to 10V 12.0 V

I

LOAD

=

100 mA to 800 mA 11.60/11.40 11.60/11.40 V(min)

(Note 3) 12.40/12.60 12.40/12.60 V(max)

Line Regulation V

IN

=

3.5V to 10V 20 mV

I

LOAD

=

300 mA 50/100 50/100 mV(max)

Load Regulation V

IN

=

5V 20 mV

I

LOAD

=

100 mA to 800 mA 50/100 50/100 mV(max)

η Efficiency V

IN

=

5V, I

LOAD

=

800 mA 80

%

DEVICE PARAMETERS

I

S

Input Supply Current V

FEEDBACK

=

14V (Switch Off) 7.5 mA

10.0/14.0 10.0/14.0 mA(max)

I

SWITCH

=

2.0A 25 mA

V

COMP

=

2.0V (Max Duty Cycle) 50/85 50/85 mA(max)

V

UV

Input Supply I

SWITCH

=

100 mA 2.90 V

Undervoltage Lockout 2.70/2.65 2.70/2.65 V(min)

3.10/3.15 3.10/3.15 V(max)

f

O

Oscillator Frequency Measured at Switch Pin 52 kHz

I

SWITCH

=

100 mA 48/42 48/42 kHz(min)

56/62 56/62 kHz(max)

V

REF

Output Reference Measured at Feedback Pin V
Voltage V

IN

=

3.5V to 40V 12 11.76/11.64 11.76/11.64 V(min)

V

COMP

=

1.0V 12.24/12.36 12.24/12.36 V(max)

Output Reference V

IN

=

3.5V to 40V

7mV

Voltage Line Regulator

R

FB

Feedback Pin Input 9.7 kΩ
Resistance

G

M

Error Amp I

COMP

=

−30 µA to +30 µA 370 µmho

Transconductance V

COMP

=

1.0V 225/145 225/145 µmho(min)
515/615 515/615 µmho(max)

A

VOL

Error Amp V

COMP

=

1.1V to 1.9V 80 V/V

Voltage Gain R

COMP

=

1.0 MΩ 50/25 50/25 V/V(min)

(Note 7)

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Electrical Characteristics—LM1577-12, LM2577-12 (Continued)

Specifications with standard type face are for T

J

=

25˚C, and those in bold type face apply over full Operating Temperature

Range. Unless otherwise specified, V

IN

=

5V, and I

SWITCH

=

0.

LM1577-12 LM2577-12 Units

Symbol Parameter Conditions Typical Limit Limit (Limits)

(Notes 3, 4) (Note 5)

DEVICE PARAMETERS

Error Amplifier Upper Limit 2.4 V
Output Swing V

FEEDBACK

=

10.0V 2.2/2.0 2.2/2.0 V(min)
Lower Limit 0.3 V
V

FEEDBACK

=

15.0V 0.40/0.55 0.40/0.55 V(max)

Error Amplifier V

FEEDBACK

=

10.0V to 15.0V

±

200 µA

Output Current V

COMP

=

1.0V

±

130/±90±130/±90 µA(min)

±

300/±400±300/±400 µA(max)

I

SS

Soft Start Current V

FEEDBACK

=

10.0V 5.0 µA
V

COMP

=

0V 2.5/1.5 2.5/1.5 µA(min)

7.5/9.5 7.5/9.5 µA(max)

D Maximum Duty Cycle V

COMP

=

1.5V 95

%

I

SWITCH

=

100 mA 93/90 93/90

%

(min)

Switch
Transconductance

12.5 A/V

I

L

Switch Leakage V

SWITCH

=

65V 10 µA

Current V

FEEDBACK

=

15V (Switch Off) 300/600 300/600 µA(max)

V

SAT

Switch Saturation I

SWITCH

=

2.0A 0.5 V

Voltage V

COMP

=

2.0V (Max Duty Cycle) 0.7/0.9 0.7/0.9 V(max)
NPN Switch 4.5 A
Current Limit 3.7/3.0 3.7/3.0 A(min)

5.3/6.0 5.3/6.0 A(max)

Electrical Characteristics—LM1577-15, LM2577-15

Specifications with standard type face are for T

J

=

25˚C, and those in bold type face apply over full Operating Temperature

Range. Unless otherwise specified, V

IN

=

5V, and I

SWITCH

=

0.

LM1577-15 LM2577-15 Units

Symbol Parameter Conditions Typical Limit Limit (Limits)

(Notes 3, 4) (Note 5)

SYSTEM PARAMETERS Circuit of

Figure 2

(Note 6)

V

OUT

Output Voltage V

IN

=

5V to 12V 15.0 V

I

LOAD

=

100 mA to 600 mA 14.50/14.25 14.50/14.25 V(min)

(Note 3) 15.50/15.75 15.50/15.75 V(max)

Line Regulation V

IN

=

3.5V to 12V 20

50/100 50/100

mV

I

LOAD

=

300 mA mV(max)

Load Regulation V

IN

=

5V 20

50/100 50/100

mV

I

LOAD

=

100 mA to 600 mA mV(max)

η Efficiency V

IN

=

5V, I

LOAD

=

600 mA 80

%

DEVICE PARAMETERS

I

S

Input Supply Current V

FEEDBACK

=

18.0V 7.5 mA
(Switch Off) 10.0/14.0 10.0/14.0 mA(max)
I

SWITCH

=

2.0A 25 mA

V

COMP

=

2.0V 50/85 50/85 mA(max)

(Max Duty Cycle)

V

UV

Input Supply I

SWITCH

=

100 mA 2.90 V

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Electrical Characteristics—LM1577-15, LM2577-15 (Continued)

Specifications with standard type face are for T

J

=

25˚C, and those in bold type face apply over full Operating Temperature

Range. Unless otherwise specified, V

IN

=

5V, and I

SWITCH

=

0.

LM1577-15 LM2577-15 Units

Symbol Parameter Conditions Typical Limit Limit (Limits)

(Notes 3, 4) (Note 5)

DEVICE PARAMETERS

Undervoltage 2.70/2.65 2.70/2.65 V(min)
Lockout 3.10/3.15 3.10/3.15 V(max)

f

O

Oscillator Frequency Measured at Switch Pin 52 kHz

I

SWITCH

=

100 mA 48/42 48/42 kHz(min)

56/62 56/62 kHz(max)

V

REF

Output Reference Measured at Feedback Pin V
Voltage V

IN

=

3.5V to 40V 15 14.70/14.55 14.70/14.55 V(min)

V

COMP

=

1.0V 15.30/15.45 15.30/15.45 V(max)

Output Reference V

IN

=

3.5V to 40V 10 mV

Voltage Line Regulation

R

FB

Feedback Pin Input 12.2 kΩ
Voltage Line Regulator

G

M

Error Amp I

COMP

=

−30 µA to +30 µA 300 µmho

Transconductance V

COMP

=

1.0V 170/110 170/110 µmho(min)
420/500 420/500 µmho(max)

A

VOL

Error Amp V

COMP

=

1.1V to 1.9V 65 V/V

Voltage Gain R

COMP

=

1.0 MΩ 40/20 40/20 V/V(min)

(Note 7)
Error Amplifier Upper Limit 2.4 V
Output Swing V

FEEDBACK

=

12.0V 2.2/2.0 2.2/2.0 V(min)
Lower Limit 0.3 V
V

FEEDBACK

=

18.0V 0.4/0.55 0.40/0.55 V(max)

Error Amp V

FEEDBACK

=

12.0V to 18.0V

±

200 µA

Output Current V

COMP

=

1.0V

±

130/±90±130/±90 µA(min)

±

300/±400±300/±400 µA(max)

I

SS

Soft Start Current V

FEEDBACK

=

12.0V 5.0 µA
V

COMP

=

0V 2.5/1.5 2.5/1.5 µA(min)

7.5/9.5 7.5/9.5 µA(max)

D Maximum Duty V

COMP

=

1.5V 95

%

Cycle I

SWITCH

=

100 mA 93/90 93/90

%

(min)

Switch
Transconductance

12.5 A/V

I

L

Switch Leakage V

SWITCH

=

65V 10 µA

Current V

FEEDBACK

=

18.0V 300/600 300/600 µA(max)
(Switch Off)

V

SAT

Switch Saturation I

SWITCH

=

2.0A 0.5 V

Voltage V

COMP

=

2.0V 0.7/0.9 0.7/0.9 V(max)

(Max Duty Cycle)

NPN Switch V

COMP

=

2.0V 4.3 A

Current Limit 3.7/3.0 3.7/3.0 A(min)

5.3/6.0 5.3/6.0 A(max)

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Electrical Characteristics—LM1577-ADJ, LM2577-ADJ

Specifications with standard type face are for T

J

=

25˚C, and those in bold type face apply over full Operating Temperature

Range. Unless otherwise specified, V

IN

=

5V, V

FEEDBACK

=

V

REF

, and I

SWITCH

=

0.

LM1577-ADJ LM2577-ADJ Units

Symbol Parameter Conditions Typical Limit Limit (Limits)

(Notes 3, 4) (Note 5)

SYSTEM PARAMETERS Circuit of

Figure 3

(Note 6)

V

OUT

Output Voltage V

IN

=

5V to 10V 12.0 V

I

LOAD

=

100 mA to 800 mA 11.60/11.40 11.60/11.40 V(min)

(Note 3) 12.40/12.60 12.40/12.60 V(max)

∆V

OUT

/ Line Regulation V

IN

=

3.5V to 10V 20 mV

∆V

IN

I

LOAD

=

300 mA 50/100 50/100 mV(max)

∆V

OUT

/ Load Regulation V

IN

=

5V 20 mV

∆I

LOAD

I

LOAD

=

100 mA to 800 mA 50/100 50/100 mV(max)

η Efficiency V

IN

=

5V, I

LOAD

=

800 mA 80

%

DEVICE PARAMETERS

I

S

Input Supply Current V

FEEDBACK

=

1.5V (Switch Off) 7.5 mA

10.0/14.0 10.0/14.0 mA(max)

I

SWITCH

=

2.0A 25 mA

V

COMP

=

2.0V (Max Duty Cycle) 50/85 50/85 mA(max)

V

UV

Input Supply I

SWITCH

=

100 mA 2.90 V

Undervoltage Lockout 2.70/2.65 2.70/2.65 V(min)

3.10/3.15 3.10/3.15 V(max)

f

O

Oscillator Frequency Measured at Switch Pin 52 kHz

I

SWITCH

=

100 mA 48/42 48/42 kHz(min)

56/62 56/62 kHz(max)

V

REF

Reference Measured at Feedback Pin V
Voltage V

IN

=

3.5V to 40V 1.230 1.214/1.206 1.214/1.206 V(min)

V

COMP

=

1.0V 1.246/1.254 1.246/1.254 V(max)

∆V

REF

/ Reference Voltage V

IN

=

3.5V to 40V 0.5 mV

∆V

IN

Line Regulation

I

B

Error Amp V

COMP

=

1.0V 100 nA

Input Bias Current 300/800 300/800 nA(max)

G

M

Error Amp I

COMP

=

−30 µA to +30 µA 3700 µmho

Transconductance V

COMP

=

1.0V 2400/1600 2400/1600 µmho(min)
4800/5800 4800/5800 µmho(max)

A

VOL

Error Amp V

COMP

=

1.1V to 1.9V 800 V/V

Voltage Gain R

COMP

=

1.0 MΩ (Note 7) 500/250 500/250 V/V(min)

Error Amplifier Upper Limit 2.4 V
Output Swing V

FEEDBACK

=

1.0V 2.2/2.0 2.2/2.0 V(min)
Lower Limit 0.3 V
V

FEEDBACK

=

1.5V 0.40/0.55 0.40/0.55 V(max)

Error Amp V

FEEDBACK

=

1.0V to 1.5V

±

200 µA

Output Current V

COMP

=

1.0V

±

130/±90

±

130/±90 µA(min)

±

300/±400±300/±400 µA(max)

I

SS

Soft Start Current V

FEEDBACK

=

1.0V 5.0 µA
V

COMP

=

0V 2.5/1.5 2.5/1.5 µA(min)

7.5/9.5 7.5/9.5 µA(max)

D Maximum Duty Cycle V

COMP

=

1.5V 95

%

I

SWITCH

=

100 mA 93/90 93/90

%

(min)

∆I

SWITCH

/ Switch 12.5 A/V

∆V

COMP

Transconductance

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Electrical Characteristics—LM1577-ADJ, LM2577-ADJ (Continued)

Specifications with standard type face are for T

J

=

25˚C, and those in bold type face apply over full Operating Temperature

Range. Unless otherwise specified, V

IN

=

5V, V

FEEDBACK

=

V

REF

, and I

SWITCH

=

0.

LM1577-ADJ LM2577-ADJ Units

Symbol Parameter Conditions Typical Limit Limit (Limits)

(Notes 3, 4) (Note 5)

DEVICE PARAMETERS

I

L

Switch Leakage V

SWITCH

=

65V 10 µA

Current V

FEEDBACK

=

1.5V (Switch Off) 300/600 300/600 µA(max)

V

SAT

Switch Saturation I

SWITCH

=

2.0A 0.5 V

Voltage V

COMP

=

2.0V (Max Duty Cycle) 0.7/0.9 0.7/0.9 V(max)

NPN Switch V

COMP

=

2.0V 4.3 A

Current Limit 3.7/3.0 3.7/3.0 A(min)

5.3/6.0 5.3/6.0 A(max)

THERMAL PARAMETERS (All Versions)

θ

JA

Thermal Resistance K Package, Junction to Ambient 35

˚C/W

θ

JC

K Package, Junction to Case 1.5

θ

JA

T Package, Junction to Ambient 65

θ

JC

T Package, Junction to Case 2

θ

JA

N Package, Junction to 85
Ambient (Note 8)

θ

JA

M Package, Junction 100
to Ambient (Note 8)

θ

JA

S Package, Junction to 37
Ambient (Note 9)

Note 1: Absolute Maximum Ratings indicate limits beyond which damage to the device may occur. Operating ratings indicate conditions the device is intended to
be functional, but device parameter specifications may not be guaranteed under these conditions. For guaranteed specifications and test conditions, see the Electrical
Characteristics.

Note 2: Due to timing considerations of the LM1577/LM2577 current limit circuit, output current cannot be internally limited when the LM1577/LM2577 is used as a
step-up regulator. To prevent damage to the switch, its current must be externally limited to 6.0A. However, output current is internally limited when the LM1577/
LM2577 is used as a flyback or forward converter regulator in accordance to the Application Hints.

Note 3: All limits guaranteed at room temperature (standard type face) and at temperature extremes (boldface type). All limits are used to calculate Outgoing Quality
Level, and are 100%production tested.

Note 4: A military RETS electrical test specification is available on request. At the time of printing, the LM1577K-12/883, LM1577K-15/883, and LM1577K-ADJ/883
RETS specifications complied fully with the boldface limits in these columns. The LM1577K-12/883, LM1577K-15/883, and LM1577K-ADJ/883 may also be procured
to Standard Military Drawing specifications.

Note 5: All limits guaranteed at room temperature (standard type face) and at temperature extremes (boldface type). All room temperature limits are 100%produc-
tion tested. All limits at temperature extremes are guaranteed via correlation using standard Statistical Quality Control (SQC) methods.

Note 6: External components such as the diode, inductor,input and output capacitors can affect switching regulator performance. When the LM1577/LM2577 is used
as shown in the Test Circuit, system performance will be as specified by the system parameters.

Note 7: A 1.0 MΩ resistor is connected to the compensation pin (which is the error amplifier’s output) to ensure accuracy in measuring A

VOL

. In actual applications,

this pin’s load resistance should be ≥10 MΩ, resulting in A

VOL

that is typically twice the guaranteed minimum limit.

Note 8: Junction to ambient thermal resistance with approximately 1 square inch of pc board copper surrounding the leads.Additional copper area will lower thermal
resistance further. See thermal model in “Switchers Made Simple” software.

Note 9: If the TO-263 package is used, the thermal resistance can be reduced by increasing the PC board copper area thermally connected to the package. Using

0.5 square inches of copper area, θ

JA

is 50˚C/W; with 1 square inch of copper area, θJAis 37˚C/W; and with 1.6 or more square inches of copper area, θJAis 32˚C/W.

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Typical Performance Characteristics

Reference Voltage
vs Temperature

DS011468-34

Reference Voltage
vs Temperature

DS011468-35

Reference Voltage
vs Temperature

DS011468-36

∆ Reference Voltage
vs Supply Voltage

DS011468-37

∆ Reference Voltage
vs Supply Voltage

DS011468-38

∆ Reference Voltage
vs Supply Voltage

DS011468-39

Error Amp Transconductance
vs Temperature

DS011468-40

Error Amp Transconductance
vs Temperature

DS011468-41

Error Amp Transconductance
vs Temperature

DS011468-42

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Typical Performance Characteristics (Continued)

Error Amp Voltage
Gain vs Temperature

DS011468-43

Error Amp Voltage
Gain vs Temperature

DS011468-44

Error Amp Voltage
Gain vs Temperature

DS011468-45

Quiescent Current
vs Temperature

DS011468-46

Quiescent Current
vs Switch Current

DS011468-47

Current Limit
vs Temperature

DS011468-48

Current Limit Response
Time vs Overdrive

DS011468-49

Switch Saturation Voltage
vs Switch Current

DS011468-50

Switch Transconductance
vs Temperature

DS011468-51

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Typical Performance Characteristics (Continued)

Connection Diagrams

Feedback Pin Bias
Current vs Temperature

DS011468-52

Oscillator Frequency
vs Temperature

DS011468-53

Maximum Power Dissipation
(TO-263) (Note 9)

DS011468-31

Straight Leads

5-Lead TO-220 (T)

DS011468-4

Top View

Order Number LM2577T-12, LM2577T-15,

or LM2577T-ADJ

See NS Package Number T05A

Bent, Staggered Leads

5-Lead TO-220 (T)

DS011468-5

Top View

Order Number LM2577T-12 Flow LB03, LM2577T-15

Flow LB03, or LM2577T-ADJ Flow LB03

See NS Package Number T05D

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