LM2577T-ADJ/LF03 - NATIONAL SEMICONDUCTOR

LM1577, LM2577

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LM1577/LM2577 SIMPLE SWITCHER

Step-Up Voltage Regulator

Check for Samples: LM1577,LM2577

1FEATURES DESCRIPTION

The LM1577/LM2577 are monolithic integrated

23• Requires Few External Components circuits that provide all of the power and control

• NPN Output Switches 3.0A, can Stand off 65V functions for step-up (boost), flyback, and forward

• Wide Input Voltage Range: 3.5V to 40V converter switching regulators. The device is

available in three different output voltage versions:

• Current-mode Operation for Improved 12V, 15V, and adjustable.

Transient Response, Line Regulation, and

Current Limit Requiring a minimum number of external

components, these regulators are cost effective, and

• 52 kHz Internal Oscillator simple to use. Listed in this data sheet are a family of

• Soft-start Function Reduces In-rush Current standard inductors and flyback transformers designed

During Start-up to work with these switching regulators.

• Output Switch Protected by Current Limit, Included on the chip is a 3.0A NPN switch and its

Under-voltage Lockout, and Thermal associated protection circuitry, consisting of current

Shutdown and thermal limiting, and undervoltage lockout. Other

features include a 52 kHz fixed-frequency oscillator

TYPICAL APPLICATIONS that requires no external components, a soft start

mode to reduce in-rush current during start-up, and

• Simple Boost Regulator current mode control for improved rejection of input

• Flyback and Forward Regulators voltage and output load transients.

• Multiple-output Regulator

Connection Diagrams

Figure 1. 5-Lead (Straight Leads) TO-220 (T) – Top Figure 2. 5-Lead (Bent, Staggered Leads) TO-220

View (T) – Top View

See Package Number KC See Package Number NDH0005D

1Please be aware that an important notice concerning availability, standard warranty, and use in critical applications of

Texas Instruments semiconductor products and disclaimers thereto appears at the end of this data sheet.

2SIMPLE SWITCHER is a registered trademark of Texas Instruments.

3All other trademarks are the property of their respective owners.

Products conform to specifications per the terms of the Texas

Instruments standard warranty. Production processing does not

necessarily include testing of all parameters.

LM1577, LM2577

SNOS658D –JUNE 1999–REVISED APRIL 2013

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*No Internal Connection

*No internal Connection

Figure 3. 16-Lead PDIP (N) – Top View Figure 4. 24-Lead SOIC Package (M) – Top View

See Package Number NBG0016G See Package Number DW

Figure 5. 5-Lead DDPAK/TO-263 (S) SFM Package – Figure 6. 5-Lead DDPAK/TO-263 (S) SFM Package –

Top View Side View

See Package Number KTT0005B

Figure 7. 4-Lead TO-220 (K) – Bottom View

See Package Number NEB0005B

Typical Application

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

These devices have limited built-in ESD protection. The leads should be shorted together or the device placed in conductive foam

during storage or handling to prevent electrostatic damage to the MOS gates.

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Absolute Maximum Ratings(1)(2)

Supply Voltage 45V

Output Switch Voltage 65V

Output Switch Current(3) 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 kΩ2 kV

(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 ensured under these conditions. For ensured

specifications and test conditions, see the Electrical Characteristics.

(2) If Military/Aerospace specified devices are required, please contact the Texas Instruments Sales Office/ Distributors for availability and

specifications.

(3) 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.

Operating Ratings

Supply Voltage 3.5V ≤VIN ≤40V

Output Switch Voltage 0V ≤VSWITCH ≤60V

Output Switch Current ISWITCH ≤3.0A

Junction Temperature Range LM1577 −55°C ≤TJ≤+150°C

LM2577 −40°C ≤TJ≤+125°C

Electrical Characteristics—LM1577-12, LM2577-12

Specifications with standard type face are for TJ= 25°C, and those in bold type face apply over full Operating Temperature

Range. Unless otherwise specified, VIN = 5V, and ISWITCH = 0.

Symbol Parameter Conditions Typical LM1577-12 LM2577-12 Units

Limit(1)(2) Limit(3) (Limits)

SYSTEM PARAMETERS Circuit of Figure 29(4)

VOUT Output Voltage VIN = 5V to 10V 12.0 V

ILOAD = 100 mA to 800 mA(1) 11.60/11.40 11.60/11.40 V(min)

12.40/12.60 12.40/12.60 V(max)

Line Regulation VIN = 3.5V to 10V 20 mV

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

(1) Load Regulation VIN = 5V 20 mV

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

(2)

ηEfficiency VIN = 5V, ILOAD = 800 mA 80 %

DEVICE PARAMETERS

ISInput Supply Current VFEEDBACK = 14V (Switch Off) 7.5 mA

10.0/14.0 10.0/14.0 mA(max)

ISWITCH = 2.0A 25 mA

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

(1) All limits ensured 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.

(2) 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.

(3) All limits ensured at room temperature (standard type face) and at temperature extremes (boldface type). All room temperature limits are

100% production tested. All limits at temperature extremes are ensured via correlation using standard Statistical Quality Control (SQC)

methods.

(4) 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.

Product Folder Links: LM1577 LM2577

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

Specifications with standard type face are for TJ= 25°C, and those in bold type face apply over full Operating Temperature

Range. Unless otherwise specified, VIN = 5V, and ISWITCH = 0.

Symbol Parameter Conditions Typical LM1577-12 LM2577-12 Units

Limit(1)(2) Limit(3) (Limits)

VUV Input Supply ISWITCH = 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)

fOOscillator Frequency Measured at Switch Pin 52 kHz

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

56/62 56/62 kHz(max)

VREF Output Reference Measured at Feedback Pin V

Voltage VIN = 3.5V to 40V 12 11.76/11.64 11.76/11.64 V(min)

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

Output Reference VIN = 3.5V to 40V 7 mV

Voltage Line Regulator

RFB Feedback Pin Input 9.7 kΩ

Resistance

GMError Amp ICOMP =−30 μA to +30 μA 370 μmho

Transconductance VCOMP = 1.0V 225/145 225/145 μmho(min)

515/615 515/615 μmho(max)

AVOL Error Amp VCOMP = 1.1V to 1.9V 80 V/V

Voltage Gain RCOMP = 1.0 MΩ(5) 50/25 50/25 V/V(min)

Error Amplifier Upper Limit 2.4 V

Output Swing VFEEDBACK = 10.0V 2.2/2.0 2.2/2.0 V(min)

Lower Limit 0.3 V

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

Error Amplifier VFEEDBACK = 10.0V to 15.0V ±200 μA

Output Current VCOMP = 1.0V ±130/±90 ±130/±90 μA(min)

±300/±400 ±300/±400 μA(max)

ISS Soft Start Current VFEEDBACK = 10.0V 5.0 μA

VCOMP = 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 VCOMP = 1.5V 95 %

ISWITCH = 100 mA 93/90 93/90 %(min)

Switch 12.5 A/V

Transconductance

ILSwitch Leakage VSWITCH = 65V 10 μA

Current VFEEDBACK = 15V (Switch Off) 300/600 300/600 μA(max)

VSAT Switch Saturation ISWITCH = 2.0A 0.5 V

Voltage VCOMP = 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)

(5) A 1.0 MΩresistor is connected to the compensation pin (which is the error amplifier's output) to ensure accuracy in measuring AVOL. In

actual applications, this pin's load resistance should be ≥10 MΩ, resulting in AVOL that is typically twice the ensured minimum limit.

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Electrical Characteristics—LM1577-15, LM2577-15

Specifications with standard type face are for TJ= 25°C, and those in bold type face apply over full Operating Temperature

Range. Unless otherwise specified, VIN = 5V, and ISWITCH = 0.

Symbol Parameter Conditions Typical LM1577-15 LM2577-15 Units

Limit(1)(2) Limit(3) (Limits)

SYSTEM PARAMETERS Circuit of Figure 30(4)

VOUT Output Voltage VIN = 5V to 12V 15.0 V

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

(1) 15.50/15.75 15.50/15.75 V(max)

Line Regulation VIN = 3.5V to 12V 20 mV

ILOAD = 300 mA mV(max)

50/100 50/100

Load Regulation VIN = 5V 20 mV

ILOAD = 100 mA to 600 mA mV(max)

50/100 50/100

ηEfficiency VIN = 5V, ILOAD = 600 mA 80 %

DEVICE PARAMETERS

ISInput Supply Current VFEEDBACK = 18.0V 7.5 mA

(Switch Off) 10.0/14.0 10.0/14.0 mA(max)

ISWITCH = 2.0A 25 mA

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

(Max Duty Cycle)

VUV Input Supply ISWITCH = 100 mA 2.90 V

Undervoltage 2.70/2.65 2.70/2.65 V(min)

Lockout 3.10/3.15 3.10/3.15 V(max)

fOOscillator Frequency Measured at Switch Pin 52 kHz

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

56/62 56/62 kHz(max)

VREF Output Reference Measured at Feedback Pin V

Voltage VIN = 3.5V to 40V 15 14.70/14.55 14.70/14.55 V(min)

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

Output Reference VIN = 3.5V to 40V 10 mV

Voltage Line Regulation

RFB Feedback Pin Input 12.2 kΩ

Voltage Line Regulator

GMError Amp ICOMP =−30 μA to +30 μA 300 μmho

Transconductance VCOMP = 1.0V 170/110 170/110 μmho(min)

420/500 420/500 μmho(max)

AVOL Error Amp VCOMP = 1.1V to 1.9V 65 V/V

Voltage Gain RCOMP = 1.0 MΩ(5) 40/20 40/20 V/V(min)

(1) All limits ensured 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.

(2) 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.

(3) All limits ensured at room temperature (standard type face) and at temperature extremes (boldface type). All room temperature limits are

100% production tested. All limits at temperature extremes are ensured via correlation using standard Statistical Quality Control (SQC)

methods.

(4) 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.

(5) A 1.0 MΩresistor is connected to the compensation pin (which is the error amplifier's output) to ensure accuracy in measuring AVOL. In

actual applications, this pin's load resistance should be ≥10 MΩ, resulting in AVOL that is typically twice the ensured minimum limit.

Product Folder Links: LM1577 LM2577

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

Specifications with standard type face are for TJ= 25°C, and those in bold type face apply over full Operating Temperature

Range. Unless otherwise specified, VIN = 5V, and ISWITCH = 0.

Symbol Parameter Conditions Typical LM1577-15 LM2577-15 Units

Limit(1)(2) Limit(3) (Limits)

Error Amplifier Upper Limit 2.4 V

Output Swing VFEEDBACK = 12.0V 2.2/2.0 2.2/2.0 V(min)

Lower Limit 0.3 V

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

Error Amp VFEEDBACK = 12.0V to 18.0V ±200 μA

Output Current VCOMP = 1.0V ±130/±90 ±130/±90 μA(min)

±300/±400 ±300/±400 μA(max)

ISS Soft Start Current VFEEDBACK = 12.0V 5.0 μA

VCOMP = 0V 2.5/1.5 2.5/1.5 μA(min)

7.5/9.5 7.5/9.5 μA(max)

D Maximum Duty VCOMP = 1.5V 95 %

Cycle ISWITCH = 100 mA 93/90 93/90 %(min)

Switch 12.5 A/V

Transconductance

ILSwitch Leakage VSWITCH = 65V 10 μA

Current VFEEDBACK = 18.0V 300/600 300/600 μA(max)

(Switch Off)

VSAT Switch Saturation ISWITCH = 2.0A 0.5 V

Voltage VCOMP = 2.0V 0.7/0.9 0.7/0.9 V(max)

(Max Duty Cycle)

NPN Switch VCOMP = 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 TJ= 25°C, and those in bold type face apply over full Operating Temperature

Range. Unless otherwise specified, VIN = 5V, VFEEDBACK = VREF, and ISWITCH = 0.

Symbol Parameter Conditions Typical LM1577-ADJ LM2577-ADJ Units

Limit(1)(2) Limit(3) (Limits)

SYSTEM PARAMETERS Circuit of Figure 31 (4)

VOUT Output Voltage VIN = 5V to 10V 12.0 V

ILOAD = 100 mA to 800 mA(1) 11.60/11.40 11.60/11.40 V(min)

12.40/12.60 12.40/12.60 V(max)

ΔVOUT/ΔVIN Line Regulation VIN = 3.5V to 10V 20 mV

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

ΔVOUT/ΔILOA Load Regulation VIN = 5V 20 mV

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

ηEfficiency VIN = 5V, ILOAD = 800 mA 80 %

DEVICE PARAMETERS

ISInput Supply Current VFEEDBACK = 1.5V (Switch Off) 7.5 mA

10.0/14.0 10.0/14.0 mA(max)

ISWITCH = 2.0A 25 mA

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

VUV Input Supply ISWITCH = 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)

fOOscillator Frequency Measured at Switch Pin 52 kHz

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

56/62 56/62 kHz(max)

VREF Reference Measured at Feedback Pin V

Voltage VIN = 3.5V to 40V 1.230 1.214/1.206 1.214/1.206 V(min)

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

ΔVREF/ΔVIN Reference Voltage VIN = 3.5V to 40V 0.5 mV

Line Regulation

IBError Amp VCOMP = 1.0V 100 nA

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

GMError Amp ICOMP =−30 μA to +30 μA 3700 μmho

Transconductance VCOMP = 1.0V 2400/1600 2400/1600 μmho(min)

4800/5800 4800/5800 μmho(max)

AVOL Error Amp Voltage Gain VCOMP = 1.1V to 1.9V 800 V/V

RCOMP = 1.0 MΩ(5) 500/250 500/250 V/V(min)

Error Amplifier Upper Limit 2.4 V

Output Swing VFEEDBACK = 1.0V 2.2/2.0 2.2/2.0 V(min)

Lower Limit 0.3 V

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

(1) All limits ensured 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.

(2) 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.

(3) All limits ensured at room temperature (standard type face) and at temperature extremes (boldface type). All room temperature limits are

100% production tested. All limits at temperature extremes are ensured via correlation using standard Statistical Quality Control (SQC)

methods.

(4) 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.

(5) A 1.0 MΩresistor is connected to the compensation pin (which is the error amplifier's output) to ensure accuracy in measuring AVOL. In

actual applications, this pin's load resistance should be ≥10 MΩ, resulting in AVOL that is typically twice the ensured minimum limit.

Product Folder Links: LM1577 LM2577

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

Specifications with standard type face are for TJ= 25°C, and those in bold type face apply over full Operating Temperature

Range. Unless otherwise specified, VIN = 5V, VFEEDBACK = VREF, and ISWITCH = 0.

Symbol Parameter Conditions Typical LM1577-ADJ LM2577-ADJ Units

Limit(1)(2) Limit(3) (Limits)

Error Amp VFEEDBACK = 1.0V to 1.5V ±200 μA

Output Current VCOMP = 1.0V ±130/±90 ±130/±90 μA(min)

±300/±400 ±300/±400 μA(max)

ISS Soft Start Current VFEEDBACK = 1.0V 5.0 μA

VCOMP = 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 VCOMP = 1.5V 95 %

ISWITCH = 100 mA 93/90 93/90 %(min)

ΔISWITCH/ΔVCSwitch 12.5 A/V

OMP Transconductance

ILSwitch Leakage VSWITCH = 65V 10 μA

Current VFEEDBACK = 1.5V (Switch Off) 300/600 300/600 μA(max)

VSAT Switch Saturation ISWITCH = 2.0A 0.5 V

Voltage VCOMP = 2.0V (Max Duty Cycle) 0.7/0.9 0.7/0.9 V(max)

NPN Switch VCOMP = 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)

θJA Thermal Resistance K Package, Junction to Ambient 35

θJC K Package, Junction to Case 1.5

θJA T Package, Junction to Ambient 65

θJC T Package, Junction to Case 2 °C/W

θJA N Package, Junction to Ambient (6) 85

θJA M Package, Junction to Ambient (6) 100

θJA S Package, Junction to Ambient (7) 37

(6) 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.

(7) If the DDPAK/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, θJA is 50°C/W; with 1 square inch of copper area, θJA is 37°C/W;

and with 1.6 or more square inches of copper area, θJA is 32°C/W.

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Typical Performance Characteristics

Reference Voltage Reference Voltage

vs Temperature vs Temperature

Figure 8. Figure 9.

Reference Voltage ΔReference Voltage

vs Temperature vs Supply Voltage

Figure 10. Figure 11.

ΔReference Voltage ΔReference Voltage

vs Supply Voltage vs Supply Voltage

Figure 12. Figure 13.

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Typical Performance Characteristics (continued)

Error Amp Transconductance Error Amp Transconductance

vs Temperature vs Temperature

Figure 14. Figure 15.

Error Amp Voltage

Gain

Error Amp Transconductance vs

vs Temperature Temperature

Figure 16. Figure 17.

Error Amp Voltage Error Amp Voltage

Gain Gain

vs vs

Temperature Temperature

Figure 18. Figure 19.

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Typical Performance Characteristics (continued)

Quiescent Current Quiescent Current

vs Temperature vs Switch Current

Figure 20. Figure 21.

Current Limit Response

Time

Current Limit vs

vs Temperature Overdrive

Figure 22. Figure 23.

Switch Saturation Voltage Switch Transconductance

vs Switch Current vs Temperature

Figure 24. Figure 25.

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Typical Performance Characteristics (continued)

Feedback Pin Bias

Current

vs Oscillator Frequency

Temperature vs Temperature

Figure 26. Figure 27.

Maximum Power Dissipation

(DDPAK/TO-263)(1)

Figure 28.

(1) If the DDPAK/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, θJA is 50°C/W; with 1 square inch of copper area, θJA is 37°C/W;

and with 1.6 or more square inches of copper area, θJA is 32°C/W.

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LM1577-12, LM2577-12 TEST CIRCUIT

L = 415-0930 (AIE)

D = any manufacturer

COUT = Sprague Type 673D

Electrolytic 680 μF, 20V

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

Figure 29. Circuit Used to Specify System Parameters for 12V Versions

LM1577-15, LM2577-15 Test Circuit

L = 415-0930 (AIE)

D = any manufacturer

COUT = Sprague Type 673D

Electrolytic 680 μF, 20V

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

Figure 30. Circuit Used to Specify System Parameters for 15V Versions

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LM1577-ADJ, LM2577-ADJ Test Circuit

L = 415-0930 (AIE)

D = any manufacturer

COUT = Sprague Type 673D

Electrolytic 680 μF, 20V

R1 = 48.7k in series with 511Ω(1%)

R2 = 5.62k (1%)

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

Figure 31. Circuit Used to Specify System Parameters for ADJ Versions

Application Hints

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

*Resistors are internal to LM1577/LM2577 for 12V and 15V versions.

Figure 32. LM1577/LM2577 Block Diagram and Boost Regulator Application

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STEP-UP (BOOST) REGULATOR

Figure 32 shows the LM1577-ADJ/LM2577-ADJ used as a Step-Up Regulator. This is a switching regulator used

for producing an output voltage greater than the input supply voltage. The LM1577-12/LM2577-12 and LM1577-

15/LM2577-15 can also be used for step-up regulators with 12V or 15V outputs (respectively), by tying the

feedback pin directly to the regulator output.

A basic explanation of how it works is as follows. The LM1577/LM2577 turns its output switch on and off at a

frequency of 52 kHz, and this creates energy in the inductor (L). When the NPN switch turns on, the inductor

current charges up at a rate of VIN/L, storing current in the inductor. When the switch turns off, the lower end of

the inductor flies above VIN, discharging its current through diode (D) into the output capacitor (COUT) at a rate of

(VOUT −VIN)/L. Thus, energy stored in the inductor during the switch on time is transferred to the output during

the switch off time. The output voltage is controlled by the amount of energy transferred which, in turn, is

controlled by modulating the peak inductor current. This is done by feeding back a portion of the output voltage

to the error amp, which amplifies the difference between the feedback voltage and a 1.230V reference. The error

amp output voltage is compared to a voltage proportional to the switch current (i.e., inductor current during the

switch on time).

The comparator terminates the switch on time when the two voltages are equal, thereby controlling the peak

switch current to maintain a constant output voltage.

Voltage and current waveforms for this circuit are shown in Figure 33, and formulas for calculating them are

given in Table 1.

Figure 33. Step-Up Regulator Waveforms

Table 1. Step-Up Regulator Formulas(1)

Duty Cycle D

Average Inductor Current IIND(AVE)

Inductor Current Ripple ΔIIND

Peak Inductor Current IIND(PK)

Peak Switch Current ISW(PK)

Switch Voltage When Off VSW(OFF) VOUT + VF

Diode Reverse Voltage VRVOUT −VSAT

Average Diode Current ID(AVE) ILOAD

Peak Diode Current ID(PK)

Power Dissipation of LM1577/2577 PD

(1) VF= Forward Biased Diode Voltage

ILOAD = Output Load Current

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STEP-UP REGULATOR DESIGN PROCEDURE

The following design procedure can be used to select the appropriate external components for the circuit in

Figure 32, based on these system requirements.

Given:

• VIN (min) = Minimum input supply voltage

• VOUT = Regulated output voltage

• ILOAD(max) = Maximum output load current

• Before proceeding any further, determine if the LM1577/LM2577 can provide these values of VOUT and

ILOAD(max) when operating with the minimum value of VIN. The upper limits for VOUT and ILOAD(max) are given by

the following equations.

where

• VOUT ≤60V

• VOUT ≤10 × VIN(min) (3)

These limits must be greater than or equal to the values specified in this application.

1. Inductor Selection (L)

A. Voltage Options:

1. For 12V or 15V output

From Figure 34 (for 12V output) or Figure 35 (for 15V output), identify inductor code for region

indicated by VIN (min) and ILOAD (max). The shaded region indicates conditions for which the LM1577/LM2577

output switch would be operating beyond its switch current rating. The minimum operating voltage for the

LM1577/LM2577 is 3.5V.

From here, proceed to step C.

2. For Adjustable version

Preliminary calculations:

The inductor selection is based on the calculation of the following three parameters:

D(max), the maximum switch duty cycle (0 ≤D≤0.9):

(4)

where VF= 0.5V for Schottky diodes and 0.8V for fast recovery diodes (typically);

E•T, the product of volts × time that charges the inductor:

(5)

IIND,DC, the average inductor current under full load;

(6)

B. Identify Inductor Value:

1. From Figure 36, identify the inductor code for the region indicated by the intersection of E•T and IIND,DC.

This code gives the inductor value in microhenries. The L or H prefix signifies whether the inductor is rated

for a maximum E•T of 90 V•μs (L) or 250 V•μs (H).

2. If D < 0.85, go on to step C. If D ≥0.85, then calculate the minimum inductance needed to ensure the

switching regulator's stability:

(7)

If LMIN is smaller than the inductor value found in step B1, go on to step C. Otherwise, the inductor value found in

step B1 is too low; an appropriate inductor code should be obtained from the graph as follows:

1. Find the lowest value inductor that is greater than LMIN.

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2. Find where E•T intersects this inductor value to determine if it has an L or H prefix. If E•T intersects both the L

and H regions, select the inductor with an H prefix.

Figure 34. LM2577-12 Inductor Selection Guide

Figure 35. LM2577-15 Inductor Selection Guide

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Note: These charts assume that the inductor ripple current is approximately 20% to 30% of the average inductor

current (when the regulator is under full load). Greater ripple current causes higher peak switch currents and greater

output ripple voltage; lower ripple current is achieved with larger-value inductors. The factor of 20 to 30% is chosen as

a convenient balance between the two extremes.

Figure 36. LM1577-ADJ/LM2577-ADJ Inductor Selection Graph

C. Select an inductor from Table 2 which cross-references the inductor codes to the part numbers of three

different manufacturers. Complete specifications for these inductors are available from the respective

manufacturers. The inductors listed in this table have the following characteristics:

•AIE: ferrite, pot-core inductors; Benefits of this type are low electro-magnetic interference (EMI), small

physical size, and very low power dissipation (core loss). Be careful not to operate these inductors too

far beyond their maximum ratings for E•T and peak current, as this will saturate the core.

•Pulse: powdered iron, toroid core inductors; Benefits are low EMI and ability to withstand E•T and peak

current above rated value better than ferrite cores.

•Renco: ferrite, bobbin-core inductors; Benefits are low cost and best ability to withstand E•T and peak

current above rated value. Be aware that these inductors generate more EMI than the other types, and

this may interfere with signals sensitive to noise.

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Table 2. Table of Standardized Inductors and

Manufacturer's Part Numbers(1)

Inductor Manufacturer's Part Number

Code Schott Pulse Renco

L47 67126980 PE - 53112 RL2442

L68 67126990 PE - 92114 RL2443

L100 67127000 PE - 92108 RL2444

L150 67127010 PE - 53113 RL1954

L220 67127020 PE - 52626 RL1953

L330 67127030 PE - 52627 RL1952

L470 67127040 PE - 53114 RL1951

L680 67127050 PE - 52629 RL1950

H150 67127060 PE - 53115 RL2445

H220 67127070 PE - 53116 RL2446

H330 67127080 PE - 53117 RL2447

H470 67127090 PE - 53118 RL1961

H680 67127100 PE - 53119 RL1960

H1000 67127110 PE - 53120 RL1959

H1500 67127120 PE - 53121 RL1958

H2200 67127130 PE - 53122 RL2448

(1) Schott Corp., (612) 475-1173

1000 Parkers Lake Rd., Wayzata, MN 55391

Pulse Engineering, (619) 268-2400

P.O. Box 12235, San Diego, CA 92112

Renco Electronics Inc., (516) 586-5566

60 Jeffryn Blvd. East, Deer Park, NY 11729

2. Compensation Network (RC, CC) and Output Capacitor (COUT) Selection

RCand CCform a pole-zero compensation network that stabilizes the regulator. The values of RCand CCare

mainly dependant on the regulator voltage gain, ILOAD(max), L and COUT. The following procedure calculates values

for RC, CC, and COUT that ensure regulator stability. Be aware that this procedure doesn't necessarily result in RC

and CCthat provide optimum compensation. In order to ensure optimum compensation, one of the standard

procedures for testing loop stability must be used, such as measuring VOUT transient response when pulsing

ILOAD (see Figure 39).

A. First, calculate the maximum value for RC.

(8)

Select a resistor less than or equal to this value, and it should also be no greater than 3 kΩ.

B. Calculate the minimum value for COUT using the following two equations.

(9)

The larger of these two values is the minimum value that ensures stability.

C. Calculate the minimum value of CC.

(10)

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The compensation capacitor is also part of the soft start circuitry. When power to the regulator is turned on, the

switch duty cycle is allowed to rise at a rate controlled by this capacitor (with no control on the duty cycle, it

would immediately rise to 90%, drawing huge currents from the input power supply). In order to operate properly,

the soft start circuit requires CC≥0.22 μF.

The value of the output filter capacitor is normally large enough to require the use of aluminum electrolytic

capacitors. Table 3 lists several different types that are recommended for switching regulators, and the following

parameters are used to select the proper capacitor.

Working Voltage (WVDC): Choose a capacitor with a working voltage at least 20% higher than the regulator

output voltage.

Ripple Current: This is the maximum RMS value of current that charges the capacitor during each switching

cycle. For step-up and flyback regulators, the formula for ripple current is

(11)

Choose a capacitor that is rated at least 50% higher than this value at 52 kHz.

Equivalent Series Resistance (ESR) : This is the primary cause of output ripple voltage, and it also affects the

values of RCand CCneeded to stabilize the regulator. As a result, the preceding calculations for CCand RCare

only valid if ESR doesn't exceed the maximum value specified by the following equations.

(12)

Select a capacitor with ESR, at 52 kHz, that is less than or equal to the lower value calculated. Most electrolytic

capacitors specify ESR at 120 Hz which is 15% to 30% higher than at 52 kHz. Also, be aware that ESR

increases by a factor of 2 when operating at −20°C.

In general, low values of ESR are achieved by using large value capacitors (C ≥470 μF), and capacitors with

high WVDC, or by paralleling smaller-value capacitors.

3. Output Voltage Selection (R1 and R2)

This section is for applications using the LM1577-ADJ/LM2577-ADJ. Skip this section if the LM1577-12/LM2577-

12 or LM1577-15/LM2577-15 is being used.

With the LM1577-ADJ/LM2577-ADJ, the output voltage is given by

VOUT = 1.23V (1 + R1/R2) (13)

Resistors R1 and R2 divide the output down so it can be compared with the LM1577-ADJ/LM2577-ADJ internal

1.23V reference. For a given desired output voltage VOUT, select R1 and R2 so that

(14)

4. Input Capacitor Selection (CIN)

The switching action in the step-up regulator causes a triangular ripple current to be drawn from the supply

source. This in turn causes noise to appear on the supply voltage. For proper operation of the LM1577, the input

voltage should be decoupled. Bypassing the Input Voltage pin directly to ground with a good quality, low ESR,

0.1 μF capacitor (leads as short as possible) is normally sufficient.

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Table 3. Aluminum Electrolytic Capacitors

Recommended for Switching Regulators

Cornell Dublier —Types 239, 250, 251, UFT, 300, or 350

P.O. Box 128, Pickens, SC 29671

(803) 878-6311

Nichicon —Types PF, PX, or PZ

927 East Parkway,

Schaumburg, IL 60173

(708) 843-7500

Sprague —Types 672D, 673D, or 674D

Box 1, Sprague Road,

Lansing, NC 28643

(919) 384-2551

United Chemi-Con —Types LX, SXF, or SXJ

9801 West Higgins Road,

Rosemont, IL 60018

(708) 696-2000

If the LM1577 is located far from the supply source filter capacitors, an additional large electrolytic capacitor (e.g.

47 μF) is often required.

5. Diode Selection (D)

The switching diode used in the boost regulator must withstand a reverse voltage equal to the circuit output

voltage, and must conduct the peak output current of the LM2577. A suitable diode must have a minimum

reverse breakdown voltage greater than the circuit output voltage, and should be rated for average and peak

current greater than ILOAD(max) and ID(PK). Schottky barrier diodes are often favored for use in switching regulators.

Their low forward voltage drop allows higher regulator efficiency than if a (less expensive) fast recovery diode

was used. See Table 4 for recommended part numbers and voltage ratings of 1A and 3A diodes.

Table 4. Diode Selection Chart

VOUT Schottky Fast Recovery

(max) 1A 3A 1A 3A

20V 1N5817 1N5820

MBR120P MBR320P

1N5818 1N5821

30V MBR130P MBR330P

11DQ03 31DQ03

1N5819 1N5822

40V MBR140P MBR340P

11DQ04 31DQ04

MBR150 MBR350 1N4933

50V 11DQ05 31DQ05 MUR105

1N4934 MR851

100V HER102 30DL1

MUR110 MR831

10DL1 HER302

BOOST REGULATOR CIRCUIT EXAMPLE

By adding a few external components (as shown in Figure 37), the LM2577 can be used to produce a regulated

output voltage that is greater than the applied input voltage. Typical performance of this regulator is shown in

Figure 38 and Figure 39. The switching waveforms observed during the operation of this circuit are shown in

Figure 40.

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

Figure 37. Step-up Regulator Delivers 12V from a 5V Input

Figure 38. Line Regulation (Typical) of Step-Up Regulator of Figure 37

A: Output Voltage Change, 100 mV/div. (AC-coupled)

B: Load current, 0.2 A/div

Horizontal: 5 ms/div

Figure 39. Load Transient Response of Step-Up

Regulator of Figure 37

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A: Switch pin voltage, 10 V/div

B: Switch pin current, 2 A/div

C: Inductor current, 2 A/div

D: Output ripple voltage, 100 mV/div (AC-coupled)

Horizontal: 5 μs/div

Figure 40. Switching Waveforms of Step-Up

Regulator of Figure 37

FLYBACK REGULATOR

A Flyback regulator can produce single or multiple output voltages that are lower or greater than the input supply

voltage. Figure 42 shows the LM1577/LM2577 used as a flyback regulator with positive and negative regulated

outputs. Its operation is similar to a step-up regulator, except the output switch contols the primary current of a

flyback transformer. Note that the primary and secondary windings are out of phase, so no current flows through

secondary when current flows through the primary. This allows the primary to charge up the transformer core

when the switch is on. When the switch turns off, the core discharges by sending current through the secondary,

and this produces voltage at the outputs. The output voltages are controlled by adjusting the peak primary

current, as described in the STEP-UP (BOOST) REGULATOR section.

Voltage and current waveforms for this circuit are shown in Figure 41, and formulas for calculating them are

given in Table 5.

FLYBACK REGULATOR DESIGN PROCEDURE

1. Transformer Selection

A family of standardized flyback transformers is available for creating flyback regulators that produce dual output

voltages, from ±10V to ±15V, as shown in Figure 42.Table 6 lists these transformers with the input voltage,

output voltages and maximum load current they are designed for.

2. Compensation Network (CC, RC) and

Output Capacitor (COUT) Selection

As explained in the Step-Up Regulator Design Procedure, CC, RCand COUT must be selected as a group. The

following procedure is for a dual output flyback regulator with equal turns ratios for each secondary (i.e., both

output voltages have the same magnitude). The equations can be used for a single output regulator by changing

∑ILOAD(max) to ILOAD(max) in the following equations.

A. First, calculate the maximum value for RC.

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(15)

Where ∑ILOAD(max) is the sum of the load current (magnitude) required from both outputs. Select a resistor less

than or equal to this value, and no greater than 3 kΩ.

B. Calculate the minimum value for ∑COUT (sum of COUT at both outputs) using the following two equations.

(16)

The larger of these two values must be used to ensure regulator stability.

Figure 41. Flyback Regulator Waveforms

T1 = Pulse Engineering, PE-65300

D1, D2 = 1N5821

Figure 42. LM1577-ADJ/LM2577-ADJ Flyback Regulator with ± Outputs

Table 5. Flyback Regulator Formulas

Duty Cycle D

(17)

Primary Current Variation ΔIP(18)

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Table 5. Flyback Regulator Formulas (continued)

Peak Primary Current IP(PK) (19)

Switch Voltage when Off VSW(OFF) (20)

Diode Reverse Voltage VRVOUT+N (VIN−VSAT)

Average Diode Current ID(AVE) ILOAD

Peak Diode Current ID(PK) (21)

Short Circuit Diode Current (22)

Power Dissipation of LM1577/LM2577

(23)

C. Calculate the minimum value of CC

(24)

D. Calculate the maximum ESR of the +VOUT and −VOUT output capacitors in parallel.

(25)

This formula can also be used to calculate the maximum ESR of a single output regulator.

At this point, refer to this same section in the STEP-UP REGULATOR DESIGN PROCEDURE section for more

information regarding the selection of COUT.

3. Output Voltage Selection

This section is for applications using the LM1577-ADJ/LM2577-ADJ. Skip this section if the LM1577-12/LM2577-

12 or LM1577-15/LM2577-15 is being used.

With the LM1577-ADJ/LM2577-ADJ, the output voltage is given by

VOUT = 1.23V (1 + R1/R2) (26)

Resistors R1 and R2 divide the output voltage down so it can be compared with the LM1577-ADJ/LM2577-ADJ

internal 1.23V reference. For a desired output voltage VOUT, select R1 and R2 so that

(27)

4. Diode Selection

The switching diode in a flyback converter must withstand the reverse voltage specified by the following

equation.

(28)

A suitable diode must have a reverse voltage rating greater than this. In addition it must be rated for more than

the average and peak diode currents listed in Table 5.

5. Input Capacitor Selection

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The primary of a flyback transformer draws discontinuous pulses of current from the input supply. As a result, a

flyback regulator generates more noise at the input supply than a step-up regulator, and this requires a larger

bypass capacitor to decouple the LM1577/LM2577 VIN pin from this noise. For most applications, a low ESR, 1.0

μF cap will be sufficient, if it is connected very close to the VIN and Ground pins.

Transformer Input Dual Maximum

Type Voltage Output Output

Voltage Current

LP= 100 μH 5V ±10V 325 mA

1 N = 1 5V ±12V 275 mA

5V ±15V 225 mA

10V ±10V 700 mA

10V ±12V 575 mA

2 LP= 200 μH 10V ±15V 500 mA

N = 0.5 12V ±10V 800 mA

12V ±12V 700 mA

12V ±15V 575 mA

3 LP= 250 μH 15V ±10V 900 mA

N = 0.5 15V ±12V 825 mA

15V ±15V 700 mA

Table 6. Flyback Transformer Selection Guide

Transformer Manufacturers' Part Numbers

Type AIE Pulse Renco

1 326-0637 PE-65300 RL-2580

2 330-0202 PE-65301 RL-2581

3 330-0203 PE-65302 RL-2582

In addition to this bypass cap, a larger capacitor (≥47 μF) should be used where the flyback transformer

connects to the input supply. This will attenuate noise which may interfere with other circuits connected to the

same input supply voltage.

6. Snubber Circuit

A “snubber” circuit is required when operating from input voltages greater than 10V, or when using a transformer

with LP≥200 μH. This circuit clamps a voltage spike from the transformer primary that occurs immediately after

the output switch turns off. Without it, the switch voltage may exceed the 65V maximum rating. As shown in

Figure 43, the snubber consists of a fast recovery diode, and a parallel RC. The RC values are selected for

switch clamp voltage (VCLAMP) that is 5V to 10V greater than VSW(OFF). Use the following equations to calculate R

and C;

(29)

Power dissipation (and power rating) of the resistor is;

(30)

The fast recovery diode must have a reverse voltage rating greater than VCLAMP.

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Figure 43. Snubber Circuit

FLYBACK REGULATOR CIRCUIT EXAMPLE

The circuit of Figure 44 produces ±15V (at 225 mA each) from a single 5V input. The output regulation of this

circuit is shown in Figure 45 and Figure 47, while the load transient response is shown in Figure 46 and

Figure 48. Switching waveforms seen in this circuit are shown in Figure 49.

T1 = Pulse Engineering, PE-65300

D1, D2 = 1N5821

Figure 44. Flyback Regulator Easily Provides Dual Outputs

Figure 45. Line Regulation (Typical) of Flyback

Regulator of Figure 44, +15V Output

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A: Output Voltage Change, 100 mV/div

B: Output Current, 100 mA/div

Horizontal: 10 ms/div

Figure 46. Load Transient Response of Flyback

Regulator of Figure 44, +15V Output

Figure 47. Line Regulation (Typical) of Flyback

Regulator of Figure 44,−15V Output

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A: Output Voltage Change, 100 mV/div

B: Output Current, 100 mA/div

Horizontal: 10 ms/div

Figure 48. Load Transient Response of Flyback

Regulator of Figure 44,−15V Output

A: Switch pin voltage, 20 V/div

B: Primary current, 2 A/div

C: +15V Secondary current, 1 A/div

D: +15V Output ripple voltage, 100 mV/div

Horizontal: 5 μs/div

Figure 49. Switching Waveforms of Flyback Regulator of Figure 44, Each Output Loaded with 60Ω

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REVISION HISTORY

Changes from Revision C (April 2013) to Revision D Page

• Changed layout of National Data Sheet to TI format .......................................................................................................... 29

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PACKAGE OPTION ADDENDUM

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Addendum-Page 1

PACKAGING INFORMATION

Orderable Device Status

(1)

Package Type Package

Drawing Pins Package

Qty Eco Plan

(2)

Lead finish/

Ball material

(6)

MSL Peak Temp

(3)

Op Temp (°C) Device Marking

(4/5)

Samples

LM2577S-ADJ NRND DDPAK/

TO-263 KTT 5 45 Non-RoHS

& Green Call TI Call TI -40 to 125 LM2577S

-ADJ P+

LM2577S-ADJ/NOPB ACTIVE DDPAK/

TO-263 KTT 5 45 RoHS-Exempt

& Green SN Level-3-245C-168 HR -40 to 125 LM2577S

-ADJ P+

LM2577SX-ADJ/NOPB ACTIVE DDPAK/

TO-263 KTT 5 500 RoHS-Exempt

& Green SN Level-3-245C-168 HR -40 to 125 LM2577S

-ADJ P+

LM2577T-ADJ NRND TO-220 KC 5 45 Non-RoHS

& Green Call TI Call TI -40 to 125 LM2577T

-ADJ

P+

LM2577T-ADJ/LB03 NRND TO-220 NDH 5 45 Non-RoHS

& Green Call TI Call TI LM2577T

-ADJ

P+

LM2577T-ADJ/LF03 ACTIVE TO-220 NDH 5 45 RoHS & Green SN Level-1-NA-UNLIM LM2577T

-ADJ

P+

LM2577T-ADJ/NOPB ACTIVE TO-220 KC 5 45 RoHS-Exempt

& Green SN Level-1-NA-UNLIM -40 to 125 LM2577T

-ADJ

P+

(1) The marketing status values are defined as follows:

ACTIVE: Product device recommended for new designs.

LIFEBUY: TI has announced that the device will be discontinued, and a lifetime-buy period is in effect.

NRND: Not recommended for new designs. Device is in production to support existing customers, but TI does not recommend using this part in a new design.

PREVIEW: Device has been announced but is not in production. Samples may or may not be available.

OBSOLETE: TI has discontinued the production of the device.

(2) RoHS: TI defines "RoHS" to mean semiconductor products that are compliant with the current EU RoHS requirements for all 10 RoHS substances, including the requirement that RoHS substance

do not exceed 0.1% by weight in homogeneous materials. Where designed to be soldered at high temperatures, "RoHS" products are suitable for use in specified lead-free processes. TI may

reference these types of products as "Pb-Free".

RoHS Exempt: TI defines "RoHS Exempt" to mean products that contain lead but are compliant with EU RoHS pursuant to a specific EU RoHS exemption.

Green: TI defines "Green" to mean the content of Chlorine (Cl) and Bromine (Br) based flame retardants meet JS709B low halogen requirements of <=1000ppm threshold. Antimony trioxide based

flame retardants must also meet the <=1000ppm threshold requirement.

(3) MSL, Peak Temp. - The Moisture Sensitivity Level rating according to the JEDEC industry standard classifications, and peak solder temperature.

PACKAGE OPTION ADDENDUM

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Addendum-Page 2

(4) There may be additional marking, which relates to the logo, the lot trace code information, or the environmental category on the device.

(5) Multiple Device Markings will be inside parentheses. Only one Device Marking contained in parentheses and separated by a "~" will appear on a device. If a line is indented then it is a continuation

of the previous line and the two combined represent the entire Device Marking for that device.

(6) Lead finish/Ball material - Orderable Devices may have multiple material finish options. Finish options are separated by a vertical ruled line. Lead finish/Ball material values may wrap to two

lines if the finish value exceeds the maximum column width.

Important Information and Disclaimer:The information provided on this page represents TI's knowledge and belief as of the date that it is provided. TI bases its knowledge and belief on information

provided by third parties, and makes no representation or warranty as to the accuracy of such information. Efforts are underway to better integrate information from third parties. TI has taken and

continues to take reasonable steps to provide representative and accurate information but may not have conducted destructive testing or chemical analysis on incoming materials and chemicals.

TI and TI suppliers consider certain information to be proprietary, and thus CAS numbers and other limited information may not be available for release.

In no event shall TI's liability arising out of such information exceed the total purchase price of the TI part(s) at issue in this document sold by TI to Customer on an annual basis.

TAPE AND REEL INFORMATION

*All dimensions are nominal

Device Package

Type Package

Drawing Pins SPQ Reel

Diameter

(mm)

Reel

Width

W1 (mm)

(mm) B0

(mm) K0

(mm) P1

(mm) W

(mm) Pin1

Quadrant

LM2577SX-ADJ/NOPB DDPAK/

TO-263 KTT 5 500 330.0 24.4 10.75 14.85 5.0 16.0 24.0 Q2

PACKAGE MATERIALS INFORMATION

www.ti.com 15-Sep-2018

Pack Materials-Page 1

*All dimensions are nominal

Device Package Type Package Drawing Pins SPQ Length (mm) Width (mm) Height (mm)

LM2577SX-ADJ/NOPB DDPAK/TO-263 KTT 5 500 367.0 367.0 45.0

PACKAGE MATERIALS INFORMATION

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Pack Materials-Page 2

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PACKAGE OUTLINE

9.25

7.67

6.86

5.69

3.05

2.54

14.73

12.29

5X 1.02

0.64

4X 1.7

8.89

6.86

12.88

10.08

(6.275)

4.83

4.06 1.40

1.14

3.05

2.03

0.61

0.30

-3.963.71

6.8

2X (R1)

OPTIONAL

16.51

MAX

10.67

9.65

(4.25)

4215009/A 01/2017

TO-220 - 16.51 mm max heightKC0005A

TO-220

NOTES:

1. All controlling linear dimensions are in inches. Dimensions in brackets are in millimeters. Any dimension in brackets or parenthesis are for

reference only. Dimensioning and tolerancing per ASME Y14.5M.

2. This drawing is subject to change without notice.

3. Shape may vary per different assembly sites.

0.25 C A B

PIN 1 ID

(OPTIONAL)

OPTIONAL

CHAMFER

SCALE 0.850

NOTE 3

AAAA

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EXAMPLE BOARD LAYOUT

0.07 MAX

ALL AROUND

0.07 MAX

ALL AROUND (1.45)

(2)

(R0.05) TYP

4X (1.45)

4X (2)

5X ( 1.2) (1.7) TYP

(6.8)

FULL R

TYP

TO-220 - 16.51 mm max heightKC0005A

TO-220

4215009/A 01/2017

LAND PATTERN

NON-SOLDER MASK DEFINED

SCALE:12X

PKG

METAL

TYP

SOLDER MASK

OPENING, TYP

MECHANICAL DATA

NDH0005D

www.ti.com

MECHANICAL DATA

KTT0005B

www.ti.com

BOTTOM SIDE OF PACKAGE

TS5B (Rev D)

MECHANICAL DATA

NEB0005B

www.ti.com

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