SNVS239C October   2004  – October 2015 LM3475

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 Ratings
    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 Hysteretic Control Circuit
      2. 7.3.2 Soft-Start
      3. 7.3.3 Under Voltage Detection
      4. 7.3.4 PGATE
      5. 7.3.5 Minimum On or Off Time
      6. 7.3.6 Enable Pin (EN)
    4. 7.4 Device Functional Modes
  8. 8 Application and Implementation
    1. 8.1 Application Information
    2. 8.2 Typical Application
      1. 8.2.1 Design Requirements
      2. 8.2.2 Detailed Design Procedure
        1. 8.2.2.1 Setting Output Voltage
        2. 8.2.2.2 Setting Operating Frequency and Output Ripple
        3. 8.2.2.3 Using a Feed-forward Capacitor
        4. 8.2.2.4 Inductor Selection
        5. 8.2.2.5 Output Capacitor Selection
        6. 8.2.2.6 Input Capacitor Selection
        7. 8.2.2.7 Diode Selection
        8. 8.2.2.8 P-Channel MOSFET Selection
        9. 8.2.2.9 Reducing Switching Noise
      3. 8.2.3 Application Curves
  9. 9 Power Supply Recommendations
  10. 10Layout
    1. 10.1 Layout Guidelines
    2. 10.2 Layout Example
  11. 11Device and Documentation Support
    1. 11.1 Device Support
      1. 11.1.1 Third-Party Products Disclaimer
    2. 11.2 Community Resources
    3. 11.3 Trademarks
    4. 11.4 Electrostatic Discharge Caution
    5. 11.5 Glossary
  12. 12Mechanical, Packaging, and Orderable Information

パッケージ・オプション

メカニカル・データ（パッケージ｜ピン）
サーマルパッド・メカニカル・データ
発注情報

6 Specifications

6.1 Absolute Maximum Ratings

See (2)(1)
MIN MAX UNIT
VIN −0.3 16 V
PGATE −0.3 16 V
FB −0.3 5 V
EN −0.3 16 V
Power dissipation (3) 440 mW
Lead temperature Vapor phase (60 s)   215 °C
Infrared (15 s) 220
Tstg Storage temperature −65 1150 °C
(1) If Military/Aerospace specified devices are required, please contact the Texas Instruments Sales Office/ Distributors for availability and specifications.
(2) 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.
(3) The maximum allowable power dissipation is a function of the maximum junction temperature, TJ_MAX, the junction-to-ambient thermal resistance, θJA and the ambient temperature, TA. The maximum allowable power dissipation at any ambient temperature is calculated using: PD_MAX = (TJ_MAX - TA)/θJA. The maximum power dissipation of 0.44 W is determined using TA = 25°C, θJA = 225°C/W, and TJ_MAX = 125°C.

6.2 ESD Ratings

over operating free-air temperature range (unless otherwise noted)
VALUE UNIT
V(ESD) Electrostatic discharge Human-body model (HBM), per ANSI/ESDA/JEDEC JS-001(1) 2500 V
(1) JEDEC document JEP155 states that 500-V HBM allows safe manufacturing with a standard ESD control process.

6.3 Recommended Operating Ratings

MIN NOM MAX UNIT
Supply voltage 2.7 10 V
TJ Operating junction temperature -40 125 °C

6.4 Thermal Information

THERMAL METRIC(1) LM3475 UNIT
DBV (SOT-23)
5 PINS
RθJA Junction-to-ambient thermal resistance 164.2 °C/W
RθJC(top) Junction-to-case (top) thermal resistance 115.3 °C/W
RθJB Junction-to-board thermal resistance 27.0 °C/W
ψJT Junction-to-top characterization parameter 12.8 °C/W
ψJB Junction-to-board characterization parameter 26.5 °C/W
RθJC(bot) Junction-to-case (bottom) thermal resistance N/A °C/W
(1) For more information about traditional and new thermal metrics, see the Semiconductor and IC Package Thermal Metrics application report, SPRA953.

6.5 Electrical Characteristics

Typical limits are for TJ = 25°C, unless otherwise specified, VIN = EN = 5.0 V. Maximum and minimum specification limits are specified by design, test, or statistical analysis.
PARAMETER TEST CONDITIONS MIN TYP MAX UNIT
IQ Quiescent current EN = VIN (PGATE Open) TJ = 25°C 260 µA
TJ = −40°C to +125°C 170 320
EN = 0V TJ = 25°C 7
TJ = −40°C to +125°C 4 10
VFB Feedback voltage TJ = 25°C 0.8 V
TJ = −40°C to +125°C 0.788 0.812
%ΔVFB/ΔVIN Feedback voltage line regulation 2.7 V < VIN < 10 V 0.01 %/V
VHYST Comparator hysteresis 2.7 V < VIN < 10 V TJ = 25°C 21 28 mV
−40°C to +125°C 21 32
IFB FB bias current TJ = 25°C 50 nA
−40°C to +125°C 600
VthEN Enable threshold voltage Increasing TJ = 25°C 1.5 V
−40°C to +125°C 1.2 1.8
Hysteresis 365 mV
IEN Enable leakage current EN = 10 V TJ = 25°C 0.025 µA
−40°C to +125°C 1
RPGATE Driver resistance Source
ISOURCE = 100 mA		 2.8 Ω
Sink
ISink = 100 mA		 1.8
IPGATE Driver output current Source
VPGATE = 3.5 V
CPGATE = 1 nF		 0.475 A
Sink
VPGATE = 3.5 V
CPGATE = 1 nF		 1.0
TSS Soft-start time 2.7 V < VIN < 10 V (EN Rising) 4 ms
TONMIN Minimum on-time PGATE Open 180 ns
VUVD Undervoltage detection Measured at the FB Pin TJ = 25°C 0.56 V
−40°C to +125°C 0.487 0.613

6.6 Typical Characteristics

Unless specified otherwise, all curves taken at VIN = 5 V, VOUT = 2.5 V, L = 10 µH, COUT = 100 µF, ESR = 100 mΩ, and TA = 25°C.
LM3475 20070122.png
Figure 1. Quiescent Current vs Input Voltage
LM3475 20070124.png
Figure 3. Hysteresis Voltage vs Input Voltage
LM3475 20070126.gif
Figure 5. Efficiency vs Load Current
LM3475 20070128.gif
Figure 7. Start Up
LM3475 20070123.png
Figure 2. Feedback Voltage vs Temperature
LM3475 20070125.png
Figure 4. Hysteresis Voltage vs Temperature
LM3475 20070127.gif
IOUT = 2 A
Figure 6. Efficiency vs Input Voltage
LM3475 20070129.gif
Figure 8. Output Ripple Voltage