JAJS711X July   2000  – June 2017 LM3478

PRODUCTION DATA.  

  1. 1 特長
  2. 2 アプリケーション
  3. 3 説明
  4. 4 改訂履歴
  5. 5 Pin Configuration and Functions
  6. 6 Specifications
    1. 6.1 Absolute Maximum Ratings
    2. 6.2 ESD Ratings - LM3478
    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 Overvoltage Protection
      2. 7.3.2 Slope Compensation Ramp
      3. 7.3.3 Frequency Adjust/Shutdown
      4. 7.3.4 Short-Circuit Protection
    4. 7.4 Device Functional Modes
  8. 8 Application and Implementation
    1. 8.1 Application Information
    2. 8.2 Typical Applications
      1. 8.2.1 Typical High Efficiency Step-Up (Boost) Converter
        1. 8.2.1.1 Design Requirements
        2. 8.2.1.2 Detailed Design Procedure
          1. 8.2.1.2.1  Custom Design with WEBENCH Tools
          2. 8.2.1.2.2  Power Inductor Selection
          3. 8.2.1.2.3  Programming the Output Voltage
          4. 8.2.1.2.4  Setting the Current Limit
          5. 8.2.1.2.5  Current Limit with External Slope Compensation
          6. 8.2.1.2.6  Power Diode Selection
          7. 8.2.1.2.7  Power MOSFET Selection
          8. 8.2.1.2.8  Input Capacitor Selection
          9. 8.2.1.2.9  Output Capacitor Selection
          10. 8.2.1.2.10 Compensation
        3. 8.2.1.3 Application Curves
      2. 8.2.2 Typical SEPIC Converter
        1. 8.2.2.1 Design Requirements
        2. 8.2.2.2 Detailed Design Procedure
          1. 8.2.2.2.1 Power MOSFET Selection
          2. 8.2.2.2.2 Power Diode Selection
          3. 8.2.2.2.3 Selection of Inductors L1 and L2
          4. 8.2.2.2.4 Sense Resistor Selection
          5. 8.2.2.2.5 Sepic Capacitor Selection
          6. 8.2.2.2.6 Input Capacitor Selection
          7. 8.2.2.2.7 Output Capacitor Selection
        3. 8.2.2.3 Application Curves
  9. 9 Power Supply Recommendations
  10. 10Layout
    1. 10.1 Layout Guidelines
    2. 10.2 Layout Example
  11. 11デバイスおよびドキュメントのサポート
    1. 11.1 WEBENCHツールによるカスタム設計
    2. 11.2 ドキュメントの更新通知を受け取る方法
    3. 11.3 ドキュメントのサポート
      1. 11.3.1 関連資料
    4. 11.4 関連リンク
    5. 11.5 商標
    6. 11.6 静電気放電に関する注意事項
    7. 11.7 Glossary
  12. 12メカニカル、パッケージ、および注文情報

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

over operating free-air temperature (unless otherwise noted) (1)
MIN MAX UNIT
Input Voltage 45 V
FB Pin Voltage –0.4< V V FB < 7 V
FA/SD Pin Voltage –0.4 < VFA/SD VFA/SD< 7 V
Peak Driver Output Current (<10µs) 1 A
Power Dissipation Internally Limited
Junction Temperature +150 °C
Lead Temperature Vapor Phase (60 s) 215 °C
Infrared (15 s) 260 °C
DR Pin Voltage –0.4 ≤ VDR VDR ≤ 8 V
ISEN Pin Voltage 500 mV
Tstg Storage temperature −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.

6.2 ESD Ratings - LM3478

VALUE UNIT
V(ESD) Electrostatic discharge Human body model (HBM), per ANSI/ESDA/JEDEC JS-001, all pins(1) ±2000 V
Charged device model (CDM), per JEDEC specification JESD22-C101, all pins(2) ±750
(1) JEDEC document JEP155 states that 500-V HBM allows safe manufacturing with a standard ESD control process.
(2) JEDEC document JEP157 states that 250-V CDM allows safe manufacturing with a standard ESD control process.

6.3 Recommended Operating Conditions

over operating free-air temperature range (unless otherwise noted)
MIN NOM MAX UNIT
Supply Voltage 2.97 ≤ VIN VIN ≤ 40 V
Junction Temperature Range −40 ≤ TJ TJ ≤ +125 °C
Switching Frequency 100 ≤ FSW FSW ≤ 1 MHz

6.4 Thermal Information

THERMAL METRIC(1) LM3478 UNIT
D DGK
8 PINS 8 PINS
RθJA Junction-to-ambient thermal resistance 105.3 157.2 °C/W
RθJC(top) Junction-to-case (top) thermal resistance 50.3 49.9 °C/W
RθJB Junction-to-board thermal resistance 55.8 77.1 °C/W
ψJT Junction-to-top characterization parameter 6.8 4.7 °C/W
ψJB Junction-to-board characterization parameter 54.7 75.8 °C/W
RθJC(bot) Junction-to-case (bottom) thermal resistance N/A N/A °C/W
(1) For more information about traditional and new thermal metrics, see the IC Package Thermal Metrics application report, SPRA953.

6.5 Electrical Characteristics

Unless otherwise specified, VIN = 12V, RFA = 40kΩ, TJ = 25°C
PARAMETER TEST CONDITIONS MIN TYP MAX UNIT
VFB Feedback Voltage VCOMP = 1.4V, 2.97 ≤ VIN ≤ 40V 1.2416 1.26 1.2843 V
VCOMP = 1.4V, 2.97 ≤ VIN ≤ 40V, −40°C ≤ TJ ≤ 125°C 1.228 1.292
ΔVLINE Feedback Voltage Line Regulation 2.97 ≤ VIN ≤ 40V 0.001 %/V
ΔVLOAD Output Voltage Load Regulation IEAO Source/Sink ±0.5 %/A
VUVLO Input Undervoltage Lock-out 2.85   V
−40°C ≤ TJ ≤ 125°C 2.97
VUV(HYS) Input Undervoltage Lock-out Hysteresis 170   mV
−40°C ≤ TJ ≤ 125°C 130 210
Fnom Nominal Switching Frequency RFA = 40KΩ 400   kHz
RFA = 40KΩ, −40°C ≤ TJ ≤ 125°C 350 440
RDS1 (ON) Driver Switch On Resistance (top) IDR = 0.2A, VIN= 5V 16 Ω
RDS2 (ON) Driver Switch On Resistance (bottom) IDR = 0.2A 4.5
VDR (max) Maximum Drive Voltage Swing(2) VIN < 7.2V VIN V
VIN ≥ 7.2V 7.2
Dmax Maximum Duty Cycle(3) 100%
Tmin (on) Minimum On Time 325   ns
−40°C ≤ TJ ≤ 125°C 210 600
ISUPPLY Supply Current (non-switching) See (5) 2.7   mA
See (5), −40°C ≤ TJ ≤ 125°C 3.3
IQ Quiescent Current in Shutdown Mode VFA/SD = 5V (6), VIN = 5V 5   µA
VFA/SD = 5V (6), VIN = 5V, −40°C ≤ TJ ≤ 125°C 10
VSENSE Current Sense Threshold Voltage VIN = 5V 135 156 180 mV
VIN = 5V, −40°C ≤ TJ ≤ 125°C 125 190
VSC Short-Circuit Current Limit Sense Voltage VIN = 5V 343 mV
VIN = 5V, −40°C ≤ TJ ≤ 125°C 250 415
VSL Internal Compensation Ramp Voltage VIN = 5V 92   mV
VIN = 5V, −40°C ≤ TJ ≤ 125°C 52 132
VSL ratio VSL/VSENSE 0.30 0.49 0.70
VOVP Output Over-voltage Protection (with respect to feedback voltage) (4) VCOMP = 1.4V 32 50 mV
VCOMP = 1.4V, −40°C ≤ TJ ≤ 125°C 25
VSSOP Package 78
VSSOP Package, −40°C ≤ TJ ≤ 125°C 85
SOIC Package 78
SOIC Package, −40°C ≤ TJ ≤ 125°C 100
VOVP(HYS) Output Over-Voltage Protection Hysteresis(4) VCOMP = 1.4V 60   mV
VCOMP = 1.4V, −40°C ≤ TJ ≤ 125°C 20 110
Gm Error Amplifier Transconductance VCOMP = 1.4V, IEAO = 100µA (Source/Sink) 600 800 1000 µS
VCOMP = 1.4V, IEAO = 100µA (Source/Sink), −40°C ≤ TJ ≤ 125°C 365 1265
AVOL Error Amplifier Voltage Gain VCOMP = 1.4V, IEAO = 100µA (Source/Sink) 38   V/V
VCOMP = 1.4V, IEAO = 100µA (Source/Sink), −40°C ≤ TJ ≤ 125°C 26 44
IEAO Error Amplifier Output Current (Source/ Sink) Source, VCOMP = 1.4V, VFB = 0V 80 110  140 µA
Source, VCOMP = 1.4V, VFB = 0V, −40°C ≤ TJ ≤ 125°C 50 180
Sink, VCOMP = 1.4V, VFB = 1.4V −100 −140 −180 µA
Sink, VCOMP = 1.4V, VFB = 1.4V, −40°C ≤ TJ ≤ 125°C −85 −185
VEAO Error Amplifier Output Voltage Swing Upper Limit, VFB = 0V, COMP Pin = Floating 2.2   V
Upper Limit, VFB = 0V, COMP Pin = Floating, −40°C ≤ TJ ≤ 125°C 1.8 2.4
Lower Limit, VFB = 1.4V 0.56   V
Lower Limit, VFB = 1.4V, −40°C ≤ TJ ≤ 125°C 0.2 1.0
TSS Internal Soft-Start Delay VFB = 1.2V, VCOMP = Floating 4 ms
Tr Drive Pin Rise Time Cgs = 3000pf, VDR = 0 to 3V 25 ns
Tf Drive Pin Fall Time Cgs = 3000pf, VDR = 0 to 3V 25 ns
VSD Shutdown threshold (1) Output = High 1.27 V
Output = High, −40°C ≤ TJ ≤ 125°C 1.4
Output = Low 0.65 V
Output = Low, −40°C ≤ TJ ≤ 125°C 0.3
ISD Shutdown Pin Current VSD = 5V −1 µA
VSD = 0V +1
IFB Feedback Pin Current 15 nA
TSD Thermal Shutdown 165 °C
Tsh Thermal Shutdown Hysteresis 10 °C
(1) The FA/SD pin should be pulled to VIN through a resistor to turn the regulator off. The voltage on the FA/SD pin must be above the maximum limit for Output = High to keep the regulator off and must be below the limit for Output = Low to keep the regulator on.
(2) The voltage on the drive pin, VDR is equal to the input voltage when input voltage is less than 7.2 V. VDR is equal to 7.2 V when the input voltage is greater than or equal to 7.2 V.
(3) The limits for the maximum duty cycle can not be specified since the part does not permit less than 100% maximum duty cycle operation.
(4) The over-voltage protection is specified with respect to the feedback voltage. This is because the over-voltage protection tracks the feedback voltage. The overvoltage protection threshold is given by adding the feedback voltage, VFB to the over-voltage protection specification.
(5) For this test, the FA/SD pin is pulled to ground using a 40-K resistor.
(6) For this test, the FA/SD pin is pulled to 5 V using a 40-K resistor.

6.6 Typical Characteristics

Unless otherwise specified, VIN = 12V, TJ = 25°C.
LM3478 10135503.png
Figure 1. IQ vs Input Voltage (Shutdown)
LM3478 10135535.png
Figure 3. ISupply vs VIN (Switching)
LM3478 10135554.png
Figure 5. Frequency vs Temperature
LM3478 10135545.png
Figure 7. Current Sense Threshold vs Input Voltage
LM3478 10135559.png
Figure 9. Efficiency vs Load Current (3.3-V Input and 12-V Output)
LM3478 10135560.png
Figure 11. Efficiency vs Load Current (9-V Input and 12-V Output)
LM3478 10135555.png
Figure 13. Error Amplifier Gain
LM3478 10135536.png
Figure 15. COMP Pin Source Current vs Temperature
LM3478 10135551.png
Figure 17. Compensation Ramp vs Compensation Resistor
LM3478 10135594.png
Figure 19. Duty Cycle vs Current Sense Voltage
LM3478 10135534.png
Figure 2. ISupply vs Input Voltage (Non-Switching)
LM3478 10135504.png
Figure 4. Switching Frequency vs RFA
LM3478 10135505.png
Figure 6. Drive Voltage vs Input Voltage
LM3478 10135562.png
Figure 8. COMP Pin Voltage vs Load Current
LM3478 10135558.png
Figure 10. Efficiency vs Load Current (5-V Input and 12-V Output)
LM3478 10135553.png
Figure 12. Efficiency vs Load Current (3.3-V Input and 5-V Output)
LM3478 10135556.png
Figure 14. Error Amplifier Phase
LM3478 10135557.png
Figure 16. Short Circuit Sense Voltage vs Input Voltage
LM3478 10135546.png
Figure 18. Shutdown Threshold Hysteresis vs Temperature