SNVSBP3B May   2020  – June 2021 LM62435-Q1

PRODUCTION DATA  

  1. 1 Features
  2. 2 Applications
  3. 3 Description
  4. 4 Revision History
  5. 5 Device Comparison Table
  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
    6. 7.6 Timing Characteristics
    7. 7.7 Systems Characteristics
    8. 7.8 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  EN Uses for Enable and VIN UVLO
      2. 8.3.2  MODE/SYNC Pin Operation
        1. 8.3.2.1 Level-Dependent MODE/SYNC Pin Control
        2. 8.3.2.2 Pulse-Dependent MODE/SYNC Pin Control
        3. 8.3.2.3 Clock Locking
      3. 8.3.3  PGOOD Output Operation
      4. 8.3.4  Internal LDO, VCC UVLO, and BIAS Input
      5. 8.3.5  Bootstrap Voltage and VCBOOT-UVLO (CBOOT Pin)
      6. 8.3.6  Adjustable SW Node Slew Rate
      7. 8.3.7  Spread Spectrum
      8. 8.3.8  Soft Start and Recovery From Dropout
      9. 8.3.9  Output Voltage Setting
      10. 8.3.10 Overcurrent and Short Circuit Protection
      11. 8.3.11 Thermal Shutdown
      12. 8.3.12 Input Supply Current
    4. 8.4 Device Functional Modes
      1. 8.4.1 Shutdown Mode
      2. 8.4.2 Standby Mode
      3. 8.4.3 Active Mode
        1. 8.4.3.1 CCM Mode
        2. 8.4.3.2 Auto Mode - Light Load Operation
          1. 8.4.3.2.1 Diode Emulation
          2. 8.4.3.2.2 Frequency Reduction
        3. 8.4.3.3 FPWM Mode - Light Load Operation
        4. 8.4.3.4 Minimum On-time (High Input Voltage) Operation
        5. 8.4.3.5 Dropout
  9. 9 Application and Implementation
    1. 9.1 Application Information
    2. 9.2 Typical Application
      1. 9.2.1 Design Requirements
      2. 9.2.2 Detailed Design Procedure
        1. 9.2.2.1  Choosing the Switching Frequency
        2. 9.2.2.2  Setting the Output Voltage
        3. 9.2.2.3  Inductor Selection
        4. 9.2.2.4  Output Capacitor Selection
        5. 9.2.2.5  Input Capacitor Selection
        6. 9.2.2.6  BOOT Capacitor
        7. 9.2.2.7  BOOT Resistor
        8. 9.2.2.8  VCC
        9. 9.2.2.9  BIAS
        10. 9.2.2.10 CFF and RFF Selection
        11. 9.2.2.11 External UVLO
      3. 9.2.3 Application Curves
  10. 10Power Supply Recommendations
  11. 11Layout
    1. 11.1 Layout Guidelines
      1. 11.1.1 Ground and Thermal Considerations
    2. 11.2 Layout Example
  12. 12Device and Documentation Support
    1. 12.1 Documentation Support
      1. 12.1.1 Related Documentation
    2. 12.2 Receiving Notification of Documentation Updates
    3. 12.3 Support Resources
    4. 12.4 Trademarks
    5. 12.5 Electrostatic Discharge Caution
    6. 12.6 Glossary
  13. 13Mechanical, Packaging, and Orderable Information

Package Options

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

7.5 Electrical Characteristics

Limits apply over the recommended operating junction temperature range of -40°C to +150°C, unless otherwise stated. Minimum and Maximum limits are specified through test, design or statistical correlation. Typical values represent the most likely parametric norm at TJ = 25°C, and are provided for reference purposes only. Unless otherwise stated the following conditions apply: VIN = 13.5 V.  VIN1 shorted to VIN2 = VIN.  VOUT is converter output voltage.
PARAMETER TEST CONDITIONS MIN TYP MAX UNIT
SUPPLY VOLTAGE AND CURRENT
VIN_OPERATE Input operating voltage(2) Needed to start up 3.95 V
Once operating 3.0
VIN_OPERATE_H Hysteresis(2) 1 V
IQ_VIN Operating quiescent current (not switching)(3) VFB = +5%, VBIAS = 5 V 9 18 µA
ISD Shutdown quiescent current; measured at VIN pin EN = 0 V, TJ = 25℃ 0.6 6 µA
ENABLE
VEN Enable input threshold voltage - rising 1.263 V
VEN-ACC Enable input threshold voltage - rising deviation from typical -5  5 %
VEN-HYST Enable threshold hysteresis as percentage of VEN  (TYP) 24 28 32 %
VEN-WAKE Enable wake-up threshold 0.4 V
IEN Enable pin input current VIN = EN = 13.5 V 2.3 nA 
LDO - VCC
VCC Internal VCC voltage VBIAS > 3.4  V, CCM Operation(2) 3.3 V
VBIAS = 3.1 V, Non-switching 3.1
VCC_UVLO Internal VCC input under voltage lock-out VCC rising under voltage threshold 3.6 V
VCC_UVLO_HYST Internal VCC input under voltage lock-out Hysteresis below VCC_UVLO 1.1 V
FEEDBACK
VFB_acc Initial reference voltage accuracy VIN = 3.3 V to 36 V, FPWM Mode -1 1 %
VOUT_acc Reference voltage accuracy for Fixed 3.3-V VOUT trim option VIN = 13.5 V, FPWM Mode 3.2587 3.3 3.3413 V
VOUT_acc Reference voltage accuracy for Fixed 5-V VOUT trim option VIN = 13.5 V, FPWM Mode 4.9375 5 5.0625 V
RFB Resistance from FB to AGND 5-V Option 1.85 MΩ
3.3-V Option 2.1
IFB Input current from FB to AGND  Adjustable versions only, FB = 1 V 10 nA
OSCILLATOR
fADJ Minimum adjustable frequency by SYNC 0.18 0.2 0.22 MHz
Adjustable frequency by SYNC 0.36 0.4 0.44 MHz
Maximum adjustable frequency by SYNC 1.98 2.2 2.42 MHz
fSW Switching frequency VIN = 13.5 V, Center frequency with or without spread spectrum, PWM operation 1.9 2.1 2.3 MHz
fS SS Frequency span of spread spectrum operation - largest deviation from center frequency Spread spectrum active 2 %
fPSS Spread spectrum pattern frequency(2) Spread spectrum active, fSW = 2.1 MHz 1.5 Hz
MODE/SYNC PIN
IMODE/SYNC MODE/SYNC pin leakage current after startup VIN = 13.5 V, VSYNC/MODE = 3.3 V 1 nA
VIN = 13.5 V, VSYNC/MODE = 5.5 V 1
VMODE_L MODE/SYNC input voltage low 0.4 V
VMODE_H MODE/SYNC input voltage high 1.6 V
VSYNCD_HYST MODE/SYNC input voltage hysteresis 0.155 1 V
VMODE_H2 Spread spectrum on if MODE/SYNC voltage is below this voltage and above VMODE_H Level dependent operation 2.5 V
VMODE_H3 Spread spectrum off if MODE/SYNC is above this voltage Level dependent operation 4.9 V
RMODE_H MODE/SYNC attached resistance indicating Spread Spectrum off Level dependent operation 30 kΩ
RMODE_L MODE/SYNC attached resistance indicating Spread Spectrum on Level dependent operation 6 kΩ
MOSFETS
RDS(ON)_HS Power switch on-resistance High side MOSFET RDS(ON) 41 82 mΩ
RDS(ON)_LS Power switch on-resistance Low side MOSFET RDS(ON) 21 45 mΩ
VBOOT_UVLO Voltage on CBOOT pin compared to SW which will turn off high-side switch 2.1 V
CURRENT LIMITS
IL-HS High side switch current limit(1) Duty cycle approaches 0% 6 7 8.1 A
IL-LS Low side switch current limit 3.7 4.8 5.4 A
IL-ZC Zero-cross current limit.  Positive  current direction is out of SW pin Auto Mode, static measurement 0.25 A
IL-NEG Negative current limit FPWM and SYNC Modes.  Positive current direction is out of SW pin. FPWM operation -2 A
IPK_MIN_0 Minimum peak command in Auto Mode / device current rating Pulse duration < 100 ns 25 %
IPK_MIN_100 Minimum peak command in Auto Mode / device current rating Pulse duration > 1 µs 12.5 %
VHICCUP Ratio of FB voltage to in-regulation FB voltage Not during soft start 40 %
POWER GOOD
PGDOV PGOOD upper threshold - rising % of VOUT setting 105 107 110 %
PGDU V PGOOD lower threshold - falling % of VOUT setting 92 94 96.5 %
PGDHYST PGOOD upper threshold (rising & falling) % of VOUT setting 1.3 %
VIN(PGD_VALID) Input voltage for proper PGOOD function 1.0 V
VPGD(LOW) Low level PGOOD function output voltage 46 µA pullup to PGOOD pin, VIN = 1.0 V, EN = 0 V 0.4 V
1 mA pullup to PGOOD pin, VIN = 13.5 V, EN = 0 V 0.4
2 mA pullup to PGOOD pin, VIN = 13.5 V, EN = 3.3 V 0.4
RPGD RDS(ON) of PGOOD output 1 mA pullup to PGOOD pin, EN = 0 V 17 40 Ω
1 mA pullup to PGOOD, EN = 3.3 V 40 90 Ω
IOV Pull down current at the SW node under over voltage condition 0.5 mA
THERMAL SHUTDOWN
TSD_R Thermal shutdown rising threshold(2) 158 168 180 ℃
TSD_HYST Thermal shutdown hysteresis(2) 10 ℃
(1) High side current limit is function of duty factor. High side current limit is highest at small duty factor and less at higher duty factors.
(2) Parameter specified by design, statistical analysis and production testing of correlated parameters.
(3) IQ_VIN = IQ + IBIAS × (VOUT / VIN)