SNVS699H February   2011  – January 2015 LM5045

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
      2. 7.3.2  Line Undervoltage Detector
      3. 7.3.3  Overvoltage Protection
      4. 7.3.4  Reference
      5. 7.3.5  Oscillator, Sync Input
      6. 7.3.6  Cycle-by-Cycle Current Limit
      7. 7.3.7  Hiccup Mode
      8. 7.3.8  PWM Comparator
      9. 7.3.9  Ramp Pin
      10. 7.3.10 Slope Pin
      11. 7.3.11 Soft-Start
      12. 7.3.12 Gate Driver Outputs
      13. 7.3.13 Synchronous Rectifier Control Outputs (SR1 and SR2)
      14. 7.3.14 Soft-Start of the Synchronous Rectifiers
      15. 7.3.15 Prebias Startup
      16. 7.3.16 Soft-Stop
      17. 7.3.17 Soft-Stop Off
      18. 7.3.18 Thermal Protection
    4. 7.4 Device Functional Modes
      1. 7.4.1 Control Method Selection
      2. 7.4.2 Voltage Mode Control Using the LM5045
      3. 7.4.3 Current Mode Control Using the LM5045
  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 VIN and VCC
        2. 8.2.2.2 For Applications With > 100 VIN
        3. 8.2.2.3 UVLO and OVP Voltage Divider Selection
        4. 8.2.2.4 Current Sense
        5. 8.2.2.5 Hiccup Mode Current Limit Restart
        6. 8.2.2.6 Augmenting the Gate Drive Strength
      3. 8.2.3 Application Curve
  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 Trademarks
    2. 11.2 Electrostatic Discharge Caution
    3. 11.3 Glossary
  12. 12Mechanical, 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 (1)

MIN MAX UNIT
VIN to GND –0.3 105 V
HS to GND(2) –5 105 V
BST1/BST2 to GND –0.3 116 V
BST1/BST2 to HS1/HS2 –0.3 16 V
HO1/HO2 to HS1/HS2(1) –0.3 BST1/BST2 + 0.3 V
LO1/LO2/SR1/SR2(1) –0.3 VCC + 0.3 V
VCC to GND –0.3 16 V
REF,SSOFF,RT,OVP,UVLO to GND –0.3 7 V
RAMP –0.3 7 V
COMP –0.3 V
COMP Input Current 10 mA
All other inputs to GND(1) –0.3 REF + 0.3 V
Junction Temperature 150 °C
Storage temperature, Tstg –55 150 °C
(1) Absolute Maximum Ratings are limits beyond which damage to the device may occur. Operating Ratings are conditions under which operation of the device is intended to be functional. For ensured specifications and test conditions, see the Electrical Characteristics.

6.2 ESD Ratings

VALUE UNIT
V(ESD) Electrostatic discharge Human body model (HBM), per ANSI/ESDA/JEDEC JS-001(1) ±2000 V
Charged-device model (CDM), per JEDEC specification JESD22-C101(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
VIN Voltage 14 100 V
External Voltage Applied to VCC 10 14 V
Junction Temperature –40 125 °C
SLOPE –0.3 2 V

6.4 Thermal Information

THERMAL METRIC(1) LM5045 UNIT
PWP RSG
28 PINS
RθJA Junction-to-ambient thermal resistance 40 40 °C/W
RθJC(top) Junction-to-case (top) thermal resistance 4 4
(1) For more information about traditional and new thermal metrics, see the IC Package Thermal Metrics application report, SPRA953.

6.5 Electrical Characteristics

Limits in standard typeface are for TJ = 25°C only; MIN and MAX limits apply the junction temperature range of –40°C to 125°C. Unless otherwise specified, the following conditions apply: VIN = 48 V, RT = 25 kΩ, RD1 = RD2 = 20 kΩ. No load on HO1, HO2, LO1, LO2, SR1, SR2, COMP = 0 V, UVLO = 2.5 V, OVP = 0 V, SSOFF = 0 V.
PARAMETER TEST CONDITIONS MIN TYP MAX UNIT
START-UP REGULATOR (VCC PIN)
VCC1 VCC voltage ICC= 10 mA (SSSR < 1 V) 9.3 9.6 9.9 V
VCC2 VCC voltage ICC= 10 mA (SSSR > 1 V) 7.5 7.8 8.1 V
ICC(Lim) VCC current limit VCC= 6 V 60 80 mA
ICC(ext) VCC supply current Supply current into VCC from an externally applied source. VCC = 10 V 4.6 mA
VCC load regulation ICC from 0 to 50 mA 35 mV
VCC(UV) VCC undervoltage threshold Positive going VCC VCC1–0.2 VCC1–0.1 V
Negative going VCC 5.9 6.3 6.7 V
IIN VIN operating current 4 mA
VIN shutdown current VIN = 20 V, VUVLO = 0 V 300 520 µA
VIN = 100 V, VUVLO = 0 V 350 550 µA
VIN start-up regulator leakage VCC=10 V 160 µA
VOLTAGE REFERENCE REGULATOR (REF PIN)
VREF REF voltage IREF = 0 mA 4.85 5 5.15 V
REF voltage regulation IREF = 0 to 10 mA 25 50 mV
IREF(Lim) REF current limit VREF = 4.5 V 15 20 mA
VREFUV VREF undervoltage threshold Positive going VREF 4.3 4.5 4.7 V
Hysteresis 0.25 V
UNDERVOLTAGE LOCK OUT AND SHUTDOWN (UVLO PIN)
VUVLO Under-voltage threshold 1.18 1.25 1.32 V
IUVLO Hysteresis current UVLO pin sinking current when VUVLO < 1.25 V 16 20 24 µA
Undervoltage standby enable threshold UVLO voltage rising 0.32 0.4 0.48 V
Hysteresis 0.05 V
VOVP OVP shutdown threshold OVP rising 1.18 1.25 1.32 V
OVP hysteresis current OVP sources current when OVP > 1.25 V 16 20 24 µA
SOFT-START (SS PIN)
ISS SS charge current VSS = 0 V 16 20 24 µA
SS threshold for SSSR charge current enable ICOMP < 800 µA 1.93 2 2.2 V
SS output low voltage Sinking 100 µA 40 mV
SS threshold to disable switching 200 mV
ISSSR SSSR charge current VSS > 2 V, ICOMP < 800 µA 16 20 24 µA
ISSSR-DIS1 SSSR discharge current 1 VUVLO < 1.25 V 54 65 75 µA
ISSSR-DIS2 SSSR discharge current 2 VRES > 1 V 109 125 147 µA
SSSR output low voltage Sinking 100 µA 50 mV
SSSR threshold to enable SR1/SR2 1.2 V
CURRENT SENSE INPUT (CS PIN)
VCS Current limit threshold 0.71 0.75 0.785 V
CS delay to output 65 ns
CS leading edge blanking 50 ns
RCS CS sink impedance (clocked) Internal FET sink impedance 18 45 Ω
SOFT-STOP DISABLE (SS OFF PIN)
VIH(min) SSOFF Input-threshold 2.8 V
SSOFF pulldown resistance 200 kΩ
CURRENT LIMIT RESTART (RES Pin)
RRES RES pulldown resistance Termination of hiccup timer 37 Ω
VRES RES hiccup threshold 1 V
RES upper counter threshold 4 V
RES lower counter threshold 2 V
IRES-SRC1 Charge current source 1 VRES < 1 V, VCS> 750 mV 30 µA
IRES-SRC2 Charge current source 2 1 V < VRES < 4 V 10 µA
IRES-DIS2 Discharge current source 1 VCS < 750 mV 5 µA
IRES-DIS2 Discharge current source 2 2 V < VRES < 4 V 5 µA
Ratio of time in hiccup mode to time in current limit VRES > 1 V, Hiccup counter 147
VOLTAGE FEED-FORWARD (RAMP PIN)
RAMP sink impedance (Clocked) 5.5 20 Ω
OSCILLATOR (RT PIN)
FSW1 Frequency (LO1, half oscillator frequency) RT = 25 kΩ 185 200 215 kHz
FSW2 Frequency (LO1, half oscillator frequency) RT = 10 kΩ 420 480 540 kHz
DC level 2 V
RT sync threshold 2.8 3 3.3 V
SYNCHRONOUS RECTIFIER TIMING CONTROL (RD1 and RD2 PINS)
T1 SR trailing edge delay
SR turnoff to HO&LO both on		 RD1 = 20 kΩ 45 65 90 ns
RD1 = 100 kΩ 232 300 388 ns
T2 SR leading edge
HO or LO turnoff to SR turnon		 RD2 = 20 kΩ 43 65 90 ns
RD2 = 100 kΩ 227 300 384 ns
COMP PIN
VPWM-OS COMP current to RAMP offset VRAMP = 0 V 680 800 940 µA
VSS-OS SS to RAMP offset VRAMP = 0 V 0.78 1.0 1.22 V
COMP current to RAMP gain ΔRAMP/ΔICOMP 2400 Ω
SS to RAMP gain ΔSS/ΔRAMP 0.5
COMP current for SSSR charge current enable VSS > 2 V 690 800 915 µA
COMP to output delay 120 ns
Minimum duty cycle ICOMP = 1 mA 0%
SLOPE COMPENSATION (SLOPE PIN)
ISLOPE Slope compensation current ramp Peak of RAMP current 100 µA
BOOST (BST PIN)
VBst uv BST under-voltage threshold VBST – VHS rising 3.8 4.7 5.6 V
Hysteresis 0.5 V
HO1, HO2, LO1, LO2 GATE DRIVERS
VOL Low-state output voltage IHO/LO = 100 mA 0.16 0.32 V
VOH High-state output voltage IHO/LO = 100 mA
VOHL = VCC – VLO
VOHH = VBST – VHO		 0.27 0.495 V
Rise Time C-load = 1000 pF 16 ns
Fall Time C-load = 1000 pF 11 ns
IOHL Peak Source Current VHO/LO = 0 V 1.5 A
IOLL Peak Sink Current VHO/LO = VCC 2 A
SR1, SR2 GATE DRIVERS
VOL Low-state output voltage ISR1/SR2 = 10 mA 0.05 0.1 V
VOH High-state output voltage ISR1/SR2 = 10 mA,
VOH = VREF – VSR		 0.17 0.28 V
Rise Time C-load = 1000 pF 60 ns
Fall Time C-load = 1000 pF 20 ns
IOHL Peak Source Current VSR = 0 V 0.1 A
IOLL Peak Sink Current VSR = VREF 0.4 A
THERMAL SHUTDOWN
TSD Thermal Shutdown Temp 160 °C
Thermal Shutdown Hysteresis 25 °C
(1) These pins are output pins and as such should not be connected to an external voltage source. The voltage range listed is the limits the internal circuitry is designed to reliably tolerate in the application circuit.
(2) The negative HS voltage must never be more negative than VCC–16 V. For example, if VCC = 12 V, the negative transients at HS must not exceed –4 V.

6.6 Typical Characteristics

30145452.gifFigure 1. Application Board Efficiency
30145455.pngFigure 3. VCC and VREF vs VIN
30145409.pngFigure 5. VREF vs IREF
30145457.pngFigure 7. Dead-Time T1, T2 vs RD1, RD2
30145413.pngFigure 9. CS Threshold vs Temperature
30145459.pngFigure 2. VCC vs ICC
30145460.gifFigure 4. IIN vs VIN
30145456.pngFigure 6. Oscillator Frequency vs RT
30145454.gifFigure 8. Dead-Time T1, T2 vs. Temperature