SNVSB19 December   2017 LM25574-Q1

PRODUCTION DATA.  

  1. 1 Features
  2. 2 Applications
  3. 3 Description
  4. 4 Revision History
  5. 5 Pin Configuration and Functions
  6. 6 Specifications
    1. 6.1 Absolute Maximum Ratings
    2. 6.2 ESD Ratings
    3. 6.3 Recommended Operating Conditions
    4. 6.4 Thermal Information
    5. 6.5 Electrical Characteristics
    6. 6.6 Typical Characteristics
  7. 7 Detailed Description
    1. 7.1 Overview
    2. 7.2 Functional Block Diagram
    3. 7.3 Feature Description
      1. 7.3.1 High Voltage Start-Up Regulator
    4. 7.4 Device Functional Modes
      1. 7.4.1 Shutdown and Stand-by Mode
      2. 7.4.2 Oscillator and Sync Capability
      3. 7.4.3 Error Amplifier and PWM Comparator
      4. 7.4.4 Ramp Generator
      5. 7.4.5 Maximum Duty Cycle and Input Drop-out Voltage
      6. 7.4.6 Current Limit
      7. 7.4.7 Soft-Start
      8. 7.4.8 Boost Pin
      9. 7.4.9 Thermal Protection
  8. 8 Application and Implementation
    1. 8.1 Application Information
      1. 8.1.1  External Components
      2. 8.1.2  R3 (RT)
      3. 8.1.3  L1
      4. 8.1.4  C3 (CRAMP)
      5. 8.1.5  C9
      6. 8.1.6  C1
      7. 8.1.7  C8
      8. 8.1.8  C7
      9. 8.1.9  C4
      10. 8.1.10 R5, R6
      11. 8.1.11 R1, R2, C2
      12. 8.1.12 R4, C5, C6
      13. 8.1.13 Bias Power Dissipation Reduction
    2. 8.2 Typical Application
      1. 8.2.1 Typical Schematic for High Frequency (1 MHz) Application
  9. 9 Layout
    1. 9.1 Layout Guidelines
      1. 9.1.1 PCB Layout and Thermal Considerations
    2. 9.2 Layout Example
  10. 10Device and Documentation Support
    1. 10.1 Device Support
      1. 10.1.1 Developmental Support
        1. 10.1.1.1 Custom Design With WEBENCH® Tools
    2. 10.2 Receiving Notification of Documentation Updates
    3. 10.3 Community Resources
    4. 10.4 Trademarks
    5. 10.5 Electrostatic Discharge Caution
    6. 10.6 Glossary
  11. 11Mechanical, Packaging, and Orderable Information

Package Options

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

6 Specifications

6.1 Absolute Maximum Ratings

over operating free-air temperature range (unless otherwise noted)(1)(2)
MIN MAX UNIT
VIN to GND 45 V
BST to GND 60 V
PRE to GND 45 V
SW to GND (Steady State) –1.5 V
BST to VCC 45 V
SD, VCC to GND 14 V
BST to SW 14 V
OUT to GND Limited VIN V
SYNC, SS, FB, RAMP to GND 7 V
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.

6.2 ESD Ratings

VALUE UNIT
V(ESD) Electrostatic discharge Human-body model (HBM), per AEC Q100-002(1) ±2 kV
(1) AEC Q100-002 indicates that HBM stressing shall be in accordance with the ANSI/ESDA/JEDEC JS-001 specification.

6.3 Recommended Operating Conditions

over operating free-air temperature range (unless otherwise noted)
MIN MAX UNIT
VIN 6 42 V
TJ Operation junction temperature –40 125 °C

6.4 Thermal Information

THERMAL METRIC(1) LM25574-Q1 UNIT
PW (TSSOP)
16 PINS
RθJA Junction-to-ambient thermal resistance 90 °C/W
RθJC(top) Junction-to-case (top) thermal resistance 30 °C/W
(1) For more information about traditional and new thermal metrics, see the Semiconductor and IC Package Thermal Metrics application report.

6.5 Electrical Characteristics

at TJ = 25°C, and VIN = 24 V, RT = 32.4 kΩ (unless otherwise noted).(1)
PARAMETER TEST CONDITIONS MIN TYP MAX UNIT
STARTUP REGULATOR
VCCReg VCC Regulator Output TJ = –40°C to +125°C 6.85 7.15 7.45 V
VCC LDO Mode turn-off 9 V
VCC Current Limit VCC = 0 V 25 mA
VCC SUPPLY
VCC UVLO Threshold (VCC increasing) TJ = –40°C to +125°C 5.03 5.35 5.67 V
VCC Undervoltage Hysteresis 0.35 V
Bias Current (Iin) FB = 1.3 V TJ = –40°C to +125°C 3.7 4.5 mA
Shutdown Current (Iin) SD = 0 V TJ = –40°C to +125°C 48 70 µA
SHUTDOWN THRESHOLDS
Shutdown Threshold (SD Increasing) TJ = –40°C to +125°C 0.47 0.7 0.9 V
Shutdown Hysteresis 0.1 V
Standby Threshold (Standby Increasing) TJ = –40°C to +125°C 1.17 1.225 1.28 V
Standby Hysteresis 0.1 V
SD Pull-up Current Source 5 µA
SWITCH CHARACTERSICS
Buck Switch Rds(on) TJ = –40°C to +125°C 750 1500 mΩ
BOOST UVLO 4 V
BOOST UVLO Hysteresis 0.56 V
Pre-charge Switch Rds(on) 70 Ω
Pre-charge Switch on-time 250 ns
CURRENT LIMIT
Cycle by Cycle Current Limit RAMP = 0 V TJ = –40°C to +125°C 0.6 0.7 0.8 A
Cycle by Cycle Current Limit Delay RAMP = 2.5 V 75 ns
SOFT-START
SS Current Source TJ = –40°C to +125°C 7 10 14 µA
OSCILLATOR
Frequency 1 TJ = –40°C to +125°C 180 200 220 kHz
Frequency 2 RT = 11 kΩ TJ = –40°C to +125°C 425 485 545 kHz
SYNC Source Impedance 11 kΩ
SYNC Sink Impedance 110 Ω
SYNC Threshold (falling) 1.3 V
SYNC Frequency RT = 11 kΩ TJ = –40°C to +125°C 550 kHz
SYNC Pulse Width Minimum TJ = –40°C to +125°C 15 ns
RAMP GENERATOR
Ramp Current 1 VIN = 36 V,
VOUT = 10 V		 TJ = –40°C to +125°C 272 310 368 µA
Ramp Current 2 VIN = 10 V,
VOUT = 10 V		 TJ = –40°C to +125°C 36 50 64 µA
PWM COMPARATOR
Forced Off-time TJ = –40°C to +125°C 416 500 575 ns
Min On-time 80 ns
COMP to PWM Comparator Offset 0.7 V
ERROR AMPLIFIER
Feedback Voltage Vfb = COMP TJ = –40°C to +125°C 1.207 1.225 1.243 V
FB Bias Current 17 nA
DC Gain 70 dB
COMP Sink / Source Current TJ = –40°C to +125°C 3 mA
Unity Gain Bandwidth 3 MHz
DIODE SENSE RESISTANCE
DSENSE 250 mΩ
THERMAL SHUTDOWN
Tsd Thermal Shutdown Threshold 165 °C
Thermal Shutdown Hysteresis 25 °C
(1) Min and Max limits are 100% production tested at 25°C. Limits over the operating temperature range are assured through correlation using Statistical Quality Control (SQC) methods. Limits are used to calculate Texas Instruments' Average Outgoing Quality Level (AOQL).

6.6 Typical Characteristics


LM25574-Q1 20214120.gif
1.
Figure 1. Oscillator Frequency vs RT
LM25574-Q1 20214122.gif
Figure 3. Soft Start Current vs Temperature
LM25574-Q1 20214124.gif
A.
RL = 7 kΩ
Figure 5. VCC vs VIN
LM25574-Q1 20214126.gif
Figure 7. Demoboard Efficiency vs IOUT and VIN
LM25574-Q1 20214121.gif
FOSC = 200 kHz
Figure 2. Oscillator Frequency vs Temperature
LM25574-Q1 20214123.gif
VIN = 12V
Figure 4. VCC vs ICC
LM25574-Q1 20214125.gif
AVCL = 101
Figure 6. Error Amplifier Gain and Phase