SNVS122C May   1999  – May 2016 LM2595

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 Delayed Start-Up
      2. 8.3.2 Undervoltage Lockout
      3. 8.3.3 Inverting Regulator
      4. 8.3.4 Inverting Regulator Shutdown Methods
    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 Input Capacitor (CIN)
      2. 9.1.2 Feedforward Capacitor (CFF) for Adjustable Output Voltage Version Only
      3. 9.1.3 Output Capacitor (COUT)
      4. 9.1.4 Catch Diode
      5. 9.1.5 Inductor Selection
      6. 9.1.6 Output Voltage Ripple and Transients
      7. 9.1.7 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 Examples
    3. 11.3 Thermal Considerations
  12. 12Device and Documentation Support
    1. 12.1 Community Resources
    2. 12.2 Trademarks
    3. 12.3 Electrostatic Discharge Caution
    4. 12.4 Glossary
  13. 13Mechanical, Packaging, and Orderable Information

Package Options

Refer to the PDF data sheet for device specific package drawings

Mechanical Data (Package|Pins)
  • NDH|5
  • KTT|5
Thermal pad, mechanical data (Package|Pins)
Orderable Information

7 Specifications

7.1 Absolute Maximum Ratings (1)(2)

MIN MAX UNIT
Maximum supply voltage 45 V
ON/OFF pin input voltage –0.3 25 V
Feedback pin voltage –0.3 25 V
Output voltage to ground (steady-state) –1 V
Power dissipation Internally limited
Lead temperature KTT package Vapor phase (60 sec) 215 °C
Infrared (10 sec) 245
NDH 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.

7.2 ESD Ratings

VALUE UNIT
V(ESD) Electrostatic discharge Human-body model (HBM), per ANSI/ESDA/JEDEC JS-001(1) ±2000 V
(1) JEDEC document JEP155 states that 500-V HBM allows safe manufacturing with a standard ESD control process.

7.3 Recommended Operating Conditions

MIN MAX UNIT
Supply voltage 4.5 40 V
Temperature range, TJ –40 125 °C

7.4 Thermal Information

THERMAL METRIC(1) LM2595 UNIT
KTT
(TO-263)		 NDH
(TO-220)
5 PINS 5 PINS
RθJA Junction-to-ambient
thermal resistance(2)(3) 		Printed-circuit board with 1-oz copper area of approximately 1 in2 — 50 °C/W
Printed-circuit board with 0.5 in2 of 1-oz copper area 50 —
Printed-circuit board with 2.5 in2 of 1-oz copper area 30 —
Double-sided, printed-circuit board with 3 in2 of 1-oz copper area 20 —
RθJC(top) Junction-to-case (top) thermal resistance 2 2 °C/W
(1) For more information about traditional and new thermal metrics, see the Semiconductor and IC Package Thermal Metrics application report, SPRA953.
(2) The package thermal impedance is calculated in accordance to JESD 51-7.
(3) Thermal resistances were simulated on a 4-layer, JEDEC board

7.5 Electrical Characteristics – 3.3 V

Specifications are for TJ = 25°C (unless otherwise noted).
PARAMETER TEST CONDITIONS MIN(1) TYP(2)   MAX(1)   UNIT
SYSTEM PARAMETERS(3) (see Figure 35 for test circuit)
VOUT Output voltage 4.75 V ≤ VIN ≤ 40 V,
0.1 A ≤ ILOAD ≤ 1 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 = 1 A 78%
(1) All limits specified at room temperature and temperature extremes. 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, and voltage programming resistors can affect switching regulator system performance. When the LM2595 is used as shown in the Figure 35 test circuit, system performance is shown in the test conditions column.

7.6 Electrical Characteristics – 5 V

Specifications are for TJ = 25°C (unless otherwise noted).
PARAMETER TEST CONDITIONS MIN(1) TYP(2) MAX(1) UNIT
SYSTEM PARAMETERS(3) (see Figure 35 for test circuit)
VOUT Output voltage 7 V ≤ VIN ≤ 40 V,
0.1 A ≤ ILOAD ≤ 1 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 = 1 A 82%
(1) All limits specified at room temperature and temperature extremes. 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, and voltage programming resistors can affect switching regulator system performance. When the LM2595 is used as shown in the Figure 35 test circuit, system performance is shown in the test conditions column.

7.7 Electrical Characteristics – 12 V

Specifications are for TJ = 25°C (unless otherwise noted).
PARAMETER TEST CONDITIONS MIN(1) TYP(2) MAX(1) UNIT
SYSTEM PARAMETERS(3) (see Figure 35 for test circuit)
VOUT Output voltage 15 V ≤ VIN ≤ 40 V,
0.1 A ≤ ILOAD ≤ 1 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 = 1 A 90%
(1) All limits specified at room temperature and temperature extremes. 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, and voltage programming resistors can affect switching regulator system performance. When the LM2595 is used as shown in the Figure 35 test circuit, system performance is shown in the test conditions column.

7.8 Electrical Characteristics – Adjustable

Specifications are for TJ = 25°C (unless otherwise noted).
PARAMETER TEST CONDITIONS MIN(1) TYP(2) MAX(1) UNIT
SYSTEM PARAMETERS(3) (see Figure 35 for test circuit)
VFB Feedback voltage 4.5 V ≤ VIN ≤ 40 V, 0.1 A ≤ ILOAD ≤ 1 A 1.23 V
VOUT programmed for 3 V,
circuit of Figure 35		 TJ = 25°C 1.193 1.267
Over full operating temperature range 1.18 1.28
η Efficiency VIN = 12 V, VOUT = 3 V, ILOAD = 1 A 78%
(1) All limits specified at room temperature and temperature extremes. 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, and voltage programming resistors can affect switching regulator system performance. When the LM2595 is used as shown in the Figure 35 test circuit, system performance is shown in the test conditions column.

7.9 Electrical Characteristics – All Output Voltage Versions

Specifications are for TJ = 25°C, ILOAD = 200 mA, VIN = 12 V for the 3.3-V, 5-V, and adjustable versions, 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 = 1.3 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 = 1 A, TJ = 25°C(4)(5) 1 1.2 V
Over full operating temperature range 1.3
DC Max duty cycle (ON)(5) 100%
Min duty cycle (OFF)(6) 0%
ICL Current limit Peak current(4)(5) TJ = 25°C 1.2 1.5 2.4 A
Over full operating temperature range 1.15 2.6
IL Output leakage current Output = 0 V(4)(6)(7) 50 μA
Output = −1 V 2 15 mA
IQ Quiescent current(6) 5 10 mA
ISTBY Standby quiescent current ON/OFF pin = 5 V (OFF)(7) TJ = 25°C 85 200 μA
Over full operating temperature range 250
ON/OFF CONTROL (see Figure 35 for test circuit)
ON/OFF pin logic input 1.3 V
VIH Threshold voltage, high Regulator ON, over full operating temperature range 0.6 V
VIL Threshold voltage, low Regulator OFF, over full operating temperature range 2 V
IH ON/OFF pin input current, high VLOGIC = 2.5 V (regulator OFF) 5 15 μA
IL ON/OFF pin input current, low VLOGIC = 0.5 V (regulator ON) 0.02 5 μA
(1) All limits specified at room temperature and temperature extremes. 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 adjustable versions, and 15 V for the 12-V version, to force the output transistor switch OFF.
(7) VIN = 40 V.

7.10 Typical Characteristics

Circuit of Figure 35
LM2595 01256511.png Figure 1. Normalized Output Voltage
LM2595 01256513.png Figure 3. Efficiency
LM2595 01256515.png Figure 5. Switch Current Limit
LM2595 01256504.png Figure 7. Operating Quiescent Current
LM2595 01256506.png Figure 9. Minimum Operating Supply Voltage
LM2595 01256508.png Figure 11. ON/OFF Pin Current (Sinking)
LM2595 01256510.png Figure 13. Feedback Pin Bias Current
LM2595 01256512.png Figure 2. Line Regulation
LM2595 01256514.png Figure 4. Switch Saturation Voltage
LM2595 01256516.png Figure 6. Dropout Voltage
LM2595 01256505.png Figure 8. Shutdown Quiescent Current
LM2595 01256507.png Figure 10. ON /OFF Threshold Voltage
LM2595 01256509.png Figure 12. Switching Frequency