SNVS119D March   1998  – May 2016 LM2597 , LM2597HV

PRODUCTION DATA.  

  1. 1 Features
  2. 2 Applications
  3. 3 Description
  4. 4 Revision History
  5. 5 Description (continued)
  6. 6 Pin Configuration and Functions
  7. 7 Specifications
    1. 7.1  Absolute Maximum Ratings
    2. 7.2  ESD Ratings
    3. 7.3  Recommended Operating Conditions
    4. 7.4  Thermal Information
    5. 7.5  Electrical Characteristics - 3.3 V
    6. 7.6  Electrical Characteristics - 5 V
    7. 7.7  Electrical Characteristics - 12 V
    8. 7.8  Electrical Characteristics - Adjustable
    9. 7.9  Electrical Characteristics - All Output Voltage Versions
    10. 7.10 Typical Characteristics
  8. 8 Detailed Description
    1. 8.1 Overview
    2. 8.2 Functional Block Diagram
    3. 8.3 Feature Description
      1. 8.3.1 Bias Supply Feature
      2. 8.3.2 SHUTDOWN and Soft-Start
      3. 8.3.3 Inverting Regulator
      4. 8.3.4 Undervoltage Lockout
      5. 8.3.5 Negative Voltage Charge Pump
    4. 8.4 Device Functional Modes
      1. 8.4.1 Discontinuous Mode Operation
  9. 9 Application and Implementation
    1. 9.1 Application Information
      1. 9.1.1 Soft-Start Capacitor, CSS
      2. 9.1.2 Delay Capacitor, CDELAY
        1. 9.1.2.1 RPULLUP
      3. 9.1.3 Input Capacitor, CIN
      4. 9.1.4 Output Capacitor, COUT
      5. 9.1.5 Catch Diode
      6. 9.1.6 Inductor Selection
      7. 9.1.7 Output Voltage Ripple and Transients
      8. 9.1.8 Open Core Inductors
    2. 9.2 Typical Applications
      1. 9.2.1 Series Buck Regulator (Fixed Output)
        1. 9.2.1.1 Design Requirements
        2. 9.2.1.2 Detailed Design Procedure
          1. 9.2.1.2.1 Inductor Selection (L1)
          2. 9.2.1.2.2 Output Capacitor Selection (COUT)
          3. 9.2.1.2.3 Catch Diode Selection (D1)
          4. 9.2.1.2.4 Input Capacitor (CIN)
        3. 9.2.1.3 Application Curves
      2. 9.2.2 Series Buck Regulator (Adjustable Output)
        1. 9.2.2.1 Design Requirements
        2. 9.2.2.2 Detailed Design Procedure
          1. 9.2.2.2.1 Programming Output Voltage
          2. 9.2.2.2.2 Inductor Selection (L1)
          3. 9.2.2.2.3 Output Capacitor Selection (COUT)
          4. 9.2.2.2.4 Feedforward Capacitor (CFF)
          5. 9.2.2.2.5 Catch Diode Selection (D1)
          6. 9.2.2.2.6 Input Capacitor (CIN)
        3. 9.2.2.3 Application Curves
  10. 10Power Supply Recommendations
  11. 11Layout
    1. 11.1 Layout Guidelines
    2. 11.2 Layout Example
    3. 11.3 Thermal Considerations
  12. 12Device and Documentation Support
    1. 12.1 Related Links
    2. 12.2 Community Resources
    3. 12.3 Trademarks
    4. 12.4 Electrostatic Discharge Caution
    5. 12.5 Glossary
  13. 13Mechanical, Packaging, and Orderable Information

Package Options

Mechanical Data (Package|Pins)
Thermal pad, mechanical data (Package|Pins)
Orderable Information

7 Specifications

7.1 Absolute Maximum Ratings (1)(2)

MIN MAX UNIT
Maximum supply voltage, VIN(3) LM2597 45 V
LM2597HV 60 V
SD/SS pin input voltage(4) 6 V
Delay pin voltage(4) 1.5 V
Flag pin voltage –0.3 45 V
Bias supply voltage, VBS –0.3 30 V
Feedback pin voltage –0.3 25 V
Output voltage to ground (steady-state) –1 1 V
Power dissipation Internally limited
Lead temperature D package Vapor phase (60 sec) 215 °C
Infrared (15 sec) 220
P package (soldering, 10 sec) 260
Maximum junction temperature 150 °C
Storage temperature, Tstg –65 150 °C
(1) Stresses beyond those listed under Absolute Maximum Ratings may cause permanent damage to the device. These are stress ratings only, which do not imply functional operation of the device at these or any other conditions beyond those indicated under Recommended Operating Conditions. Exposure to absolute-maximum-rated conditions for extended periods may affect device reliability.
(2) If Military/Aerospace specified devices are required, please contact the Texas Instruments Sales Office/ Distributors for availability and specifications.
(3) VIN = 40V for the LM2597 and 60V for the LM2597HV.
(4) Voltage internally clamped. If clamp voltage is exceeded, limit current to a maximum of 1 mA.

7.2 ESD Ratings

VALUE UNIT
V(ESD) Electrostatic discharge Human-body model (HBM), per ANSI/ESDA/JEDEC JS-001(1)(2) ±2000 V
(1) JEDEC document JEP155 states that 500-V HBM allows safe manufacturing with a standard ESD control process.
(2) The human body model is a 100 pF capacitor discharged through a 1.5k resistor into each pin.

7.3 Recommended Operating Conditions

MIN MAX UNIT
Supply voltage LM2597 4.5 40 V
LM2597HV 4.5 60 V
Temperature –40 125 °C

7.4 Thermal Information

THERMAL METRIC(1) LM2597, LM2597HV UNIT
D (SOIC) P (PDIP)
8 PINS 8 PINS
RθJA Junction-to-ambient thermal resistance(2) 95 150 °C/W
(1) For more information about traditional and new thermal metrics, see the Semiconductor and IC Package Thermal Metrics application report, SPRA953.
(2) Junction-to-ambient thermal resistance with approximately 1 square inch of printed circuit board copper surrounding the leads. Additional copper area will lower thermal resistance further.

7.5 Electrical Characteristics – 3.3 V

Specifications are for TJ = 25°C, VINmax = 40 V for the LM2597, and 60 V for the LM2597HV (unless otherwise noted).
PARAMETER TEST CONDITIONS MIN(1) TYP (2) MAX(1) UNIT
SYSTEM PARAMETERS(3)(4) (See Figure 46 for test circuit)
VOUT Output voltage 4.75 V ≤ VIN ≤ VINmax,
0.1 A ≤ ILOAD ≤ 0.5 A		 TJ = 25°C 3.168 3.3 3.432 V
Over full operating temperature range 3.135 3.465
η Efficiency VIN = 12 V, ILOAD = 0.5 A 80%
(1) All room temperature limits are 100% production tested. All limits at temperature extremes are specified via correlation using standard Statistical Quality Control (SQC) methods. All limits are used to calculate Average Outgoing Quality Level (AOQL).
(2) Typical numbers are at 25°C and represent the most likely norm.
(3) External components such as the catch diode, inductor, input and output capacitors can affect switching regulator system performance. When the LM2597xx is used as shown in the Figure 46 test circuit, system performance is shown in the test conditions column.
(4) No diode, inductor or capacitor connected to output pin.

7.6 Electrical Characteristics – 5 V

Specifications are for TJ = 25°C, VINmax = 40 V for the LM2597, and 60 V for the LM2597HV (unless otherwise noted).
PARAMETER TEST CONDITIONS MIN(1) TYP(2) MAX(1) UNIT
SYSTEM PARAMETERS(3)(4) (See Figure 46 for test circuit)
VOUT Output voltage 7 V ≤ VIN ≤ VINmax,
0.1 A ≤ ILOAD ≤ 0.5 A		 TJ = 25°C 4.8 5 5.2 V
Over full operating temperature range 4.75 5.25
η Efficiency VIN = 12 V, ILOAD = 0.5 A 82%
(1) All room temperature limits are 100% production tested. All limits at temperature extremes are specified via correlation using standard Statistical Quality Control (SQC) methods. All limits are used to calculate Average Outgoing Quality Level (AOQL).
(2) Typical numbers are at 25°C and represent the most likely norm.
(3) External components such as the catch diode, inductor, input and output capacitors can affect switching regulator system performance. When the LM2597xx is used as shown in the Figure 46 test circuit, system performance is shown in the test conditions column.
(4) No diode, inductor or capacitor connected to output pin.

7.7 Electrical Characteristics – 12 V

Specifications are for TJ = 25°C, VINmax = 40 V for the LM2597, and 60 V for the LM2597HV (unless otherwise noted).
PARAMETER TEST CONDITIONS MIN(1) TYP(2) MAX(1) UNIT
SYSTEM PARAMETERS(3)(4) (See Figure 46 for test circuit)
VOUT Output voltage 15 V ≤ VIN ≤ VINmax,
0.1 A ≤ ILOAD ≤ 0.5 A		 TJ = 25°C 11.52 12 12.48 V
Over full operating temperature range 11.4 12.6
η Efficiency VIN = 25 V, ILOAD = 0.5 A 88%
(1) All room temperature limits are 100% production tested. All limits at temperature extremes are specified via correlation using standard Statistical Quality Control (SQC) methods. All limits are used to calculate Average Outgoing Quality Level (AOQL).
(2) Typical numbers are at 25°C and represent the most likely norm.
(3) External components such as the catch diode, inductor, input and output capacitors can affect switching regulator system performance. When the LM2597xx is used as shown in the Figure 46 test circuit, system performance is shown in the test conditions column.
(4) No diode, inductor or capacitor connected to output pin.

7.8 Electrical Characteristics – Adjustable

Specifications are for TJ = 25°C, VINmax = 40 V for the LM2597, and 60 V for the LM2597HV (unless otherwise noted).
PARAMETER TEST CONDITIONS MIN(1) TYP(2) MAX(1) UNIT
SYSTEM PARAMETERS(3)(4) (See Figure 46 for test circuit)
VFB Feedback voltage 4.5 V ≤ VIN ≤ VINmax, 0.1 A ≤ ILOAD ≤ 0.5 A 1.230 V
VOUT programmed for 3 V,
circuit of Figure 46		 TJ = 25°C 1.193 1.267
Over full operating temperature range 1.18 1.280
η Efficiency VIN = 12 V, VOUT = 3 V, ILOAD = 0.5 A 80%
(1) All room temperature limits are 100% production tested. All limits at temperature extremes are specified via correlation using standard Statistical Quality Control (SQC) methods. All limits are used to calculate Average Outgoing Quality Level (AOQL).
(2) Typical numbers are at 25°C and represent the most likely norm.
(3) External components such as the catch diode, inductor, input and output capacitors can affect switching regulator system performance. When the LM2597xx is used as shown in the Figure 46 test circuit, system performance is shown in the test conditions column.
(4) No diode, inductor or capacitor connected to output pin.

7.9 Electrical Characteristics – All Output Voltage Versions

Specifications are for TJ = 25°C, ILOAD = 100 mA, VIN = 12 V for the 3.3-V, 5-V, and Adjustable version, and VIN = 24 V for the 12-V version (unless otherwise noted).
PARAMETER TEST CONDITIONS MIN(1) TYP(2) MAX(1) UNIT
DEVICE PARAMETERS
Ib Feedback bias current Adjustable version only, VFB = 1.235 V TJ = 25°C 10 50 nA
Over full operating temperature range 100
fO Oscillator frequency(3) TJ = 25°C 127 150 173 kHz
Over full operating temperature range 110 173
VSAT Saturation voltage IOUT = 0.5 A(4)(5) TJ = 25°C 0.9 1.1 V
Over full operating temperature range 1.2
DC Max duty cycle (ON)(5) 100%
Min duty cycle (OFF)(6) 0%
ICL Current limit Peak current(4)(5) TJ = 25°C 0.65 0.8 1.3 A
Over full operating temperature range 0.58 1.4
IL Output leakage current Output = 0 V(4)(6)(7) 50 μA
Output = −1 V 2 15 mA
IQ Operating quiescent
current		 SD/SS pin open, VBS pin open(6) 5 10 mA
ISTBY Standby quiescent
current		 LM2597, SD/SS pin = 0 V(6) TJ = 25°C 85 200 μA
Over full operating temperature range 250
LM2597HV TJ = 25°C 140 250 μA
Over full operating temperature range 300
SHUTDOWN/SOFT-START CONTROL (see Figure 46 for test circuit)
VSD Shutdown threshold
voltage		 1.3 V
Low, shutdown mode, over full operating temperature range 0.6
High, soft-start mode 2
VSS Soft-start voltage VOUT = 20% of nominal output voltage 2 V
VOUT = 100% of nominal output voltage 3
ISD Shutdown current VSHUTDOWN = 0.5 V 5 10 μA
ISS Soft-start current VSoft-start = 2.5 V 1.6 5 μA
FLAG/DELAY CONTROL (see Figure 46 for test circuit)
Regulator dropout
detector
threshold voltage		 Low (Flag ON) 92% 96% 98%
VFSAT Flag output saturation
voltage		 ISINK = 3 mA 0.3 V
VDELAY = 0.5 V TJ = 25°C 0.7 V
Over full operating temperature range 1
IFL Flag output leakage
current		 VFLAG = 40 V 0.3 μA
Delay pin threshold
voltage		 1.25 V
Low (flag ON) 1.21 V
High (flag OFF) and VOUT regulated 1.29 V
Delay pin source
current		 VDELAY = 0.5 V 3 6 μA
Delay pin saturation Low (Flag ON) TJ = 25°C 55 350 mV
Over full operating temperature range 400
BIAS SUPPLY
IBS Bias supply pin current VBS = 2 V(6) 120 400 μA
VBS = 4.4 V(6) 4 10 mA
IQ Operating quiescent current VBS = 4.4 V , Vin pin current(6) 1 2 mA
(1) All room temperature limits are 100% production tested. All limits at temperature extremes are specified via correlation using standard Statistical Quality Control (SQC) methods. All limits are used to calculate Average Outgoing Quality Level (AOQL).
(2) Typical numbers are at 25°C and represent the most likely norm.
(3) The switching frequency is reduced when the second stage current limit is activated. The amount of reduction is determined by the severity of current overload.
(4) No diode, inductor or capacitor connected to output pin.
(5) Feedback pin removed from output and connected to 0 V to force the output transistor switch ON.
(6) Feedback pin removed from output and connected to 12 V for the 3.3-V, 5-V, and the adjustable version, and 15 V for the 12-V version, to force the output transistor switch OFF.
(7) VIN = 40 V for the LM2597 and 60 V for the LM2597HV.

7.10 Typical Characteristics

LM2597 LM2597HV 01244002.png Figure 1. Normalized Output Voltage
LM2597 LM2597HV 01244004.png Figure 3. Efficiency
LM2597 LM2597HV 01244006.png Figure 5. Switch Current Limit
LM2597 LM2597HV 01244008.png Figure 7. Quiescent Current
LM2597 LM2597HV 01244010.png Figure 9. Minimum Operating Supply Voltage
LM2597 LM2597HV 01244012.png Figure 11. Flag Saturation Voltage
LM2597 LM2597HV 01244014.png Figure 13. Soft-Start
LM2597 LM2597HV 01244016.png Figure 15. Delay Pin Current
LM2597 LM2597HV 01244018.png Figure 17. Soft-Start Response
LM2597 LM2597HV 01244003.png Figure 2. Line Regulation
LM2597 LM2597HV 01244005.png Figure 4. Switch Saturation Voltage
LM2597 LM2597HV 01244007.png Figure 6. Dropout Voltage
LM2597 LM2597HV 01244009.png Figure 8. Standby Quiescent Current
LM2597 LM2597HV 01244011.png Figure 10. Feedback Pin Bias Current
LM2597 LM2597HV 01244013.png Figure 12. Switching Frequency
LM2597 LM2597HV 01244015.png Figure 14. Shutdown/Soft-Start Current
LM2597 LM2597HV 01244017.png Figure 16. VIN and VBS Current vs VBS and Temperature
LM2597 LM2597HV 01244025.png Figure 18. Shutdown/Soft-Start Threshold Voltage