NSC LM2588T-ADJ, LM2588T-5.0, LM2588T-12, LM2588SX-ADJ, LM2588SX-5.0 Datasheet

LM2588
SIMPLE SWITCHER
Shutdown

®

5A Flyback Regulator with

LM2588 SIMPLE SWITCHER 5A Flyback Regulator with Shutdown

April 1998

General Description

The LM2588 series of regulators are monolithic integrated
circuits specifically designed for flyback, step-up (boost), and
forward converter applications. The device is available in 4
different output voltage versions: 3.3V, 5.0V,12V,andadjust­able.

Requiring a minimum number of external components,these
regulators are cost effective, and simple to use. Included in
the datasheet are typical circuits of boostandflybackregula­tors.Alsolistedare selector guides for diodes and capacitors
and a family of standard inductors and flyback transformers
designed to work with these switching regulators.

The power switch is a 5.0A NPN device that can stand-off
65V. Protecting the power switch are current and thermal
limiting circuits, and an undervoltage lockout circuit. This IC
contains an adjustable frequency oscillator that can be pro­grammed up to 200kHz. The oscillator can also be synchro­nized with other devices, so that multiple devices can oper­ate at the same switching frequency.

Other features includesoft start mode to reduce in-rush cur­rent during start up, and current mode control for improved
rejection of input voltage and output load transients and
cycle-by-cycle current limiting. The device also has a shut­down pin, so that it can be turned off externally. An output
voltage tolerance of
output load conditions, is guaranteed for the power supply
system.

±

4%, within specified input voltages and

Flyback Regulator

Features

n Requires few external components
n Family of standard inductors and transformers
n NPN output switches 5.0A, can stand off 65V
n Wide input voltage range: 4V to 40V
n Adjustable switching frequency: 100 kHz to 200 kHz
n External shutdown capability
n Draws less than 60 µA when shut down
n Frequency synchronization
n Current-mode operation for improved transient

response, line regulation, and current limit

n Internal soft-start function reduces in-rush current during

start-up

n Output transistor protected by current limit, under

voltage lockout, and thermal shutdown

n System output voltage tolerance of

and load conditions

±

4%max over line

Typical Applications

n Flyback regulator
n Forward converter
n Multiple-output regulator
n Simple boost regulator

DS012420-1

SIMPLE SWITCHER®and

© 1999 National Semiconductor Corporation DS012420 www.national.com

Switchers Made Simple

®

are registered trademarks of National SemiconductorCorporation.

Ordering Information

Package Type NSC Package Order Number

Drawing

7-Lead TO-220 Bent, Staggered Leads TA07B LM2588T-3.3, LM2588T-5.0, LM2588T-12, LM2588T-ADJ
7-Lead TO-263 TS7B LM2588S-3.3, LM2588S-5.0, LM2588S-12, LM2588S-ADJ
7-Lead TO-263 Tape and Reel TS7B LM2588SX-3.3, LM2588SX-5.0, LM2588SX-12,

LM2588SX-ADJ

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Absolute Maximum Ratings (Note 1)

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

Input Voltage −0.4V ≤ V
Switch Voltage −0.4V ≤ V
Switch Current (Note 2) Internally Limited
Compensation Pin Voltage −0.4V ≤ V
Feedback Pin Voltage −0.4V ≤ V
ON /OFF Pin Voltage −0.4V ≤ VSH≤ 6V
Sync Pin Voltage −0.4V ≤ V
Power Dissipation (Note 3) Internally Limited
Storage Temperature Range −65˚C to +150˚C

COMP

FB

IN

SW

≤ 2V

SYNC

≤ 45V
≤ 65V

≤ 2.4V

OUT

≤ 2V

Lead Temperature

(Soldering, 10 sec.) 260˚C

Maximum Junction Temperature

(Note 3) 150˚C

Minimum ESD Rating

(C=100 pF, R=1.5 kΩ)2kV

Operating Ratings

Supply Voltage 4V ≤ VIN≤ 40V
Output Switch Voltage 0V ≤ V
Output Switch Current I
Junction Temperature Range −40˚C ≤ T

≤ 60V

SW

≤ 5.0A

SW

≤ +125˚C

J

LM2588-3.3
Electrical Characteristics

Specifications with standard type face are for T
Range. Unless otherwise specified, V

IN

Symbol Parameters Conditions Typical Min Max Units

SYSTEM PARAMETERS Test Circuit of

V

OUT

∆V

OUT

∆V

IN

∆V

OUT

∆I

LOAD

η Efficiency V

Output Voltage V

/ Line Regulation V

/ Load Regulation V

I

LOAD

I

LOAD

I

LOAD

IN

IN

IN

IN

UNIQUE DEVICE PARAMETERS (Note 5)
V

∆V

REF

REF

Output Reference Measured at Feedback Pin 3.3 3.242/3.234 3.358/3.366 V
Voltage V
Reference Voltage V

COMP
IN

Line Regulation

G

M

A

VOL

Error Amp I
Transconductance V
Error Amp V
Voltage Gain R

COMP

COMP
COMP
COMP

=

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

J

=

5V.

Figure 1

(Note 4)

=

4V to 12V 3.3 3.17/3.14 3.43/3.46 V
=

400 mA to 1.75A

=

4V to 12V 20 50/100 mV
=

400 mA

=

12V 20 50/100 mV
=

400 mA to 1.75A

=

12V, I

=

=

4V to 40V 2.0 mV

=

=
=
=

=

1A 75

LOAD

1.0V

−30 µA to +30 µA 1.193 0.678 2.259 mmho

1.0V

0.5V to 1.6V 260 151/75 V/V

1.0 MΩ (Note 6)

%

LM2588-5.0
Electrical Characteristics

Specifications with standard type face are for T
Range. Unless otherwise specified, V

IN

Symbol Parameters Conditions Typical Min Max Units

SYSTEM PARAMETERS Test Circuit of

V

OUT

∆V

OUT

∆V

IN

∆V

OUT

∆I

LOAD

η Efficiency V

Output Voltage V

/ Line Regulation V

/ Load Regulation V

I

LOAD

I

LOAD

I

LOAD

IN

IN

IN

IN

UNIQUE DEVICE PARAMETERS (Note 5)
V

REF

Output Reference Measured at Feedback Pin 5.0 4.913/4.900 5.088/5.100 V
Voltage V

COMP

=

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

J

=

5V.

Figure 1

(Note 4)

=

4V to 12V 5.0 4.80/4.75 5.20/5.25 V
=

500 mA to 1.45A

=

4V to 12V 20 50/100 mV
=

500 mA

=

12V 20 50/100 mV
=

500 mA to 1.45A

=

12V, I

=

1.0V

=

750 mA 80

LOAD

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%

LM2588-5.0
Electrical Characteristics

Specifications with standard type face are for T

Range. Unless otherwise specified, V

Symbol Parameters Conditions Typical Min Max Units

UNIQUE DEVICE PARAMETERS (Note 5)

∆V

G

A

REF

M

VOL

Reference Voltage V
Line Regulation
Error Amp I
Transconductance V
Error Amp V
Voltage Gain R

(Continued)

=

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

J

=

5V.

IN

=

4V to 40V 3.3 mV

IN

=

−30 µA to +30 µA 0.750 0.447 1.491 mmho

COMP

=

1.0V

COMP

=

0.5V to 1.6V 165 99/49 V/V

COMP

=

1.0 MΩ (Note 6)

COMP

LM2588-12
Electrical Characteristics

Specifications with standard type face are for T
Range. Unless otherwise specified, V

IN

Symbol Parameters Conditions Typical Min Max Units

SYSTEM PARAMETERS Test Circuit of

V

OUT

∆V

OUT

∆V

IN

∆V

OUT

∆I

LOAD

η Efficiency V

Output Voltage V

/ Line Regulation V

/ Load Regulation V

I

LOAD

I

LOAD

I

LOAD

IN

IN

IN

IN

UNIQUE DEVICE PARAMETERS (Note 5)
V

∆V

REF

REF

Output Reference Measured at Feedback Pin 12.0 11.79/11.76 12.21/12.24 V
Voltage V
Reference Voltage V

COMP
IN

Line Regulation

G

M

A

VOL

Error Amp I
Transconductance V
Error Amp V
Voltage Gain R

COMP

COMP
COMP
COMP

=

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

J

=

5V.

Figure 2

(Note 4)

=

4V to 10V 12.0 11.52/11.40 12.48/12.60 V
=

300 mA to 1.2A

=

4V to 10V 20 100/200 mV
=

300 mA

=

10V 20 100/200 mV
=

300 mA to 1.2A

=

10V, I

=

=

4V to 40V 7.8 mV

=

=
=
=

=

1A 90

LOAD

1.0V

−30 µA to +30 µA 0.328 0.186 0.621 mmho

1.0V

0.5V to 1.6V 70 41/21 V/V

1.0 MΩ (Note 6)

%

LM2588-ADJ
Electrical Characteristics

Specifications with standard type face are for T
Range. Unless otherwise specified, V

IN

Symbol Parameters Conditions Typical Min Max Units

SYSTEM PARAMETERS Test Circuit of

V

OUT

∆V

OUT

∆V

IN

∆V

OUT

∆I

LOAD

η Efficiency V

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Output Voltage V

/ Line Regulation V

/ Load Regulation V

I

LOAD

I

LOAD

I

LOAD

IN

IN

IN

IN

=

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

J

=

5V.

Figure 2

(Note 4)

=

4V to 10V 12.0 11.52/11.40 12.48/12.60 V
=

300 mA to 1.2A

=

4V to 10V 20 100/200 mV
=

300 mA

=

10V 20 100/200 mV
=

300 mA to 1.2A

=

10V, I

=

1A 90

LOAD

%

LM2588-ADJ
Electrical Characteristics

Specifications with standard type face are for T

Range. Unless otherwise specified, V
Symbol Parameters Conditions Typical Min Max Units

UNIQUE DEVICE PARAMETERS (Note 5)

V

∆V

G

A

I

REF

REF

M

VOL

B

Output Reference Measured at Feedback Pin 1.230 1.208/1.205 1.252/1.255 V
Voltage V
Reference Voltage V
Line Regulation
Error Amp I
Transconductance V
Error Amp V
Voltage Gain R
Error Amp V
Input Bias Current

(Continued)

=

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

J

=

5V.

IN

=

1.0V

COMP

=

4V to 40V 1.5 mV

IN

=

−30 µA to +30 µA 3.200 1.800 6.000 mmho

COMP

=

1.0V

COMP

=

0.5V to 1.6V 670 400/200 V/V

COMP

=

1.0 MΩ (Note 6)

COMP

=

1.0V 125 425/600 nA

COMP

All Output Voltage Versions
Electrical Characteristics

Specifications with standard type face are for T

Range. Unless otherwise specified, V
Symbol Parameters Conditions Typical Min Max Units

I

S

I

S/D

V

UV

f

O

f

SC

V

EAO

I

EAO

I

SS

D

MAX

I

L

V

SUS

Input Supply Current Switch Off 11 15.5/16.5 mA

Shutdown Input V
Supply Current
Input Supply R
Undervoltage

Lockout
Oscillator Frequency Measured at Switch Pin

Short-Circuit Measured at Switch Pin
Frequency R

Error Amplifier Upper Limit 2.8 2.6/2.4 V
Output Swing (Note 7)

Error Amp (Note 9)
Output Current 165 110/70 260/320 µA
(Source or Sink)
Soft Start Current V

Maximum Duty
Cycle

Switch Leakage Switch Off 15 300/600 µA
Current V
Switch Sustaining

Voltage

(Note 5)

=

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

J

=

5V.

IN

(Note 8)

=

I

SWITCH

R

3.0A 85 140/165 mA

=

3V 16 100/300 µA

SH

=

100Ω 3.30 3.05 3.75 V

LOAD

LOAD

=

100Ω,V

=

1.0V 100 85/75 115/125 kHz

COMP

Freq. Adj. Pin Open (Pin 1)

=

R

22 kΩ 200 kHz

SET

=

100Ω 25 kHz

LOAD

V

FEEDBACK

=

1.15V

Lower Limit 0.25 0.40/0.55 V
(Note 8)

=

FEEDBACK

V

COMP

R

LOAD

0.92V 11.0 8.0/7.0 17.0/19.0 µA

=

1.0V

=

100Ω 98 93/90

(Note 7)

=

SWITCH

60V

dV/dT=1.5V/ns 65 V

%

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All Output Voltage Versions
Electrical Characteristics

Specifications with standard type face are for T

Range. Unless otherwise specified, V
Symbol Parameters Conditions Typical Min Max Units

V

SAT

I

CL

V

STH

I

SYNC

V

SHTH

I

SH

θ

JA

θ

JA

θ

JC

θ

JA

θ

JA

θ

JA

θ

JC

Note 1: Absolute Maximum Ratings indicate limits beyond which damage to the device may occur.These ratings apply when the current is limited to less than 1.2 mA
for pins 1, 2, 3, and 6. Operating ratings indicateconditions for which the device isintended to be functional, but deviceparameter specifications may not be guar­anteed under these conditions. For guaranteed specifications and test conditions, see the Electrical Characteristics.

Note 2: Note that switch current and output current are not identical in a step-up regulator. Output current cannot be internally limited when the LM2588 is used as
a step-up regulator. To prevent damage to the switch, the output current must be externally limited to 5A. However, output current is internally limited when the
LM2588 is used as a flyback regulator (see the Application Hints section for more information).

Note 3: The junction temperature of the device (T
dissipation of the device (P

(MAX)

allowable power dissipation, derate the maximum junction temperature — this ensures a margin of safety in the thermal design.
Note 4: External components such as the diode, inductor, input and output capacitors can affect switching regulator performance. When the LM2588 is used as

shown in
Note 5: All room temperature limits are 100%production tested, and all limits at temperature extremes are guaranteed via correlation using standard Statistical Qual-

ity Control (SQC) methods.

Note 6: A 1.0 MΩ resistor is connected to the compensation pin (which is the error amplifier output) to ensure accuracy in measuringA
Note 7: Tomeasure this parameter, the feedback voltage is set to a low value, depending on the output version of the device, to force the error amplifier output high

and the switch on.
Note 8: Tomeasure this parameter, the feedback voltage is set to a high value, depending on the output version of the device, to force the error amplifier output low

and the switch off.
Note 9: Tomeasure the worst-case error amplifier output current,the LM2588 is tested with the feedbackvoltage set to its low value (specifiedin (Note 7)) andat

its high value (specified in (Note 8)).
Note 10: When testing the minimum value, do not sink current from this pin — isolate it with a diode. If current is drawn from this pin, the frequency adjust circuit will

begin operation (see
Note 11: Junction to ambient thermal resistance (no external heat sink) for the 7 lead TO-220 package mounted vertically, with

board with minimum copper area.
Note 12: Junction to ambient thermal resistance (no external heat sink) for the 7 lead TO-220 package mounted vertically,with

containing approximately 4 square inches of (1 oz.) copper area surrounding the leads.
Note 13: Junction to ambient thermal resistance for the 7 lead TO-263 mounted horizontally against a PC board area of 0.136 square inches (the same size as the

TO-263 package) of 1 oz. (0.0014 in. thick) copper.
Note 14: Junction to ambient thermal resistance for the 7 leadTO-263 mounted horizontally against a PC board areaof 0.4896 square inches (3.6 times the area

of the TO-263 package) of 1 oz. (0.0014 in. thick) copper.

Switch Saturation
Voltage

NPN Switch Current
Limit

Synchronization F
Threshold Voltage V
Synchronization V
Pin Current V
ON /OFF Pin (Pin 1) V
Threshold Voltage (Note 10)
ON /OFF Pin (Pin 1) V
Current V
Thermal Resistance T Package, Junction to Ambient 65

). A thermal shutdown will occur if the temperature exceedsthe maximum junction temperature of the device: PDx θJA+T

and

Figure 41

D

Figure 2

, system performance will be as specified by the system parameters.

).

. For a safe thermal design, check that the maximum power dissipated by the device is less than: PD≤ [T

Figure 1

(Note 5) (Continued)

=

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

J

=

5V.

IN

=

I

SWITCH

5.0A 0.7 1.1/1.4 V

6.5 5.0 9.5 A

=

200 kHz 0.75 0.625/0.40 0.875/1.00 V

SYNC

=

COMP

=

5V 100 200 µA

IN

=

COMP

=

COMP

=

COMP

=

V

SH

=

1V, V

1V, V

IN

SYNC

5V

=

V

STH

1V 1.6 1.0/0.8 2.2/2.4 V

1V 40 15/10 65/75 µA

SHTH

(Note 11)
T Package, Junction to Ambient 45
(Note 12)
T Package, Junction to Case 2
S Package, Junction to Ambient 56 ˚C/W
(Note 13)
S Package, Junction to Ambient 35
(Note 14)
S Package, Junction to Ambient 26
(Note 15)
S Package, Junction to Case 2

) is a function of the ambient temperature (TA), the junction-to-ambient thermal resistance (θJA), and the power

J

J(MAX)−TA(MAX)

]/θJA. When calculating the maximum

VOL

1

⁄2inch leads in a socket, or on a PC

1

⁄2inch leads soldered to a PC board

A(MAX)

.

≥ T

-

J

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All Output Voltage Versions
Electrical Characteristics

Note 15: Junction to ambient thermal resistance for the 7 lead TO-263 mounted horizontally against a PC board copper area of 1.0064 square inches (7.4 times the

area of the TO-263 package) of 1 oz. (0.0014 in. thick) copper.Additional copper area will reduce thermal resistance further. See the thermal model in Switchers Made

®

software.

Simple

(Note 5) (Continued)

Typical Performance Characteristics

Supply Current
vs Temperature

Supply Current
vs Switch Current

Switch Saturation
Voltage vs Temperature

DS012420-2

DS012420-5

Reference Voltage
vs Temperature

Current Limit
vs Temperature

Switch Transconductance
vs Temperature

DS012420-3

DS012420-6

∆Reference Voltage
vs Supply Voltage

DS012420-4

Feedback Pin Bias
Current vs Temperature

DS012420-7

Oscillator Frequency
vs Temperature

DS012420-8

DS012420-9

DS012420-10

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Typical Performance Characteristics (Continued)

Error Amp Transconductance
vs Temperature

DS012420-11

Shutdown Supply Current
vs Temperature

DS012420-14

Connection Diagrams

Error Amp Voltage
Gain vs Temperature

ON /OFF Pin Current
vs Voltage

DS012420-12

DS012420-15

Short Circuit Frequency
vs Temperature

DS012420-13

Oscillator Frequency
vs Resistance

DS012420-16

Bent, Staggered Leads

7-Lead TO-220 (T)

Top View

DS012420-17

Order Number LM2588T-3.3, LM2588T-5.0,

LM2588T-12 or LM2588T-ADJ

See NS Package Number TA07B

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Bent, Staggered Leads

7-Lead TO-220 (T)

Side View

DS012420-18

Connection Diagrams (Continued)

Test Circuits

7-Lead TO-263 (S)

Top View

7-Lead TO-263 (S)

Side View

DS012420-20

DS012420-19

Order Number LM2588S-3.3, LM2588S-5.0,

LM2588S-12 or LM2588S-ADJ

Tape and Reel Order Number LM2588SX-3.3,

LM2588SX-5.0, LM2588SX-12 or LM2588SX-ADJ

See NS Package Number TS7B

C

— 100 µF, 25V Aluminum Electrolytic

IN1

C

— 0.1 µF Ceramic

IN2

T— 22 µH, 1:1 Schott#67141450
D— 1N5820
C

— 680 µF, 16V Aluminum Electrolytic

OUT

CC— 0.47 µF Ceramic

—2k

R

C

DS012420-21

FIGURE 1. LM2588-3.3 and LM2588-5.0

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