SNVSB99C October   2019  – November 2020 LMR33640

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 System 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 Power-Good Flag Output
      2. 8.3.2 Enable and Start-up
      3. 8.3.3 Current Limit and Short Circuit
      4. 8.3.4 Undervoltage Lockout and Thermal Shutdown
    4. 8.4 Device Functional Modes
      1. 8.4.1 Auto Mode
      2. 8.4.2 Dropout
      3. 8.4.3 Minimum Switch On-Time
  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  Custom Design With WEBENCH® Tools
        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  CBOOT
        7. 9.2.2.7  VCC
        8. 9.2.2.8  CFF Selection
        9. 9.2.2.9  External UVLO
        10. 9.2.2.10 Maximum Ambient Temperature
      3. 9.2.3 Application Curves
    3. 9.3 What to Do and What Not to Do
  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 Device Support
      1. 12.1.1 Development Support
        1. 12.1.1.1 Custom Design With WEBENCH® Tools
    2. 12.2 Documentation Support
      1. 12.2.1 Related Documentation
    3. 12.3 Receiving Notification of Documentation Updates
    4. 12.4 Support Resources
    5. 12.5 Trademarks
    6. 12.6 Electrostatic Discharge Caution
    7. 12.7 Glossary
  13. 13Mechanical, Packaging, and Orderable Information

Package Options

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

7.7 System Characteristics

The following specifications apply to a typical applications circuit, with nominal component values. Specifications in the typical (TYP) column apply to TJ = 25°C only. Specifications in the minimum (MIN) and maximum (MAX) columns apply to the case of typical components over the temperature range of TJ = –40°C to 125°C. These specifications are not ensured by production testing. 
PARAMETERTEST CONDITIONSMINTYPMAXUNIT
VINOperating input voltage rangeVOUT = 3.3 V, IOUT= 0 A3.836V
VOUTOutput voltage regulation for VOUT = 5 V(1)VOUT = 5 V, VIN = 7 V to 36 V, IOUT = 0 A to 4 A–1.6%2.5%
VOUT = 5 V, VIN = 7 V to 36 V, IOUT = 1 A to 4 A–1.6%1.5%
Output voltage regulation for VOUT = 3.3 V(1)VOUT = 3.3 V, VIN = 3.8 V to 36 V, IOUT = 0 A to 4 A–1.6%2.5%
VOUT = 3.3 V, VIN = 3.8 V to 36 V, IOUT = 1 A to 4 A–1.6%1.5%
ISUPPLYInput supply current when in regulationVIN = 12 V, VOUT = 3.3 V, IOUT = 0 A,
RFBT = 1 MΩ		25µA
VDROPDropout voltage; (VIN – VOUT)VOUT = 5 V, IOUT = 1A
Dropout at –1% of regulation,
ƒSW = 140 kHz		150mV
DMAXMaximum switch duty cycle(2)VIN = VOUT = 12 V, IOUT = 1 A98%
VHCFB pin voltage required to trip short-circuit hiccup mode0.4V
tHCTime between current-limit hiccup burst94ms
tDSwitch voltage dead time2ns
TSDThermal shutdown temperatureShutdown temperature165°C
Recovery temperature148°C
(1) Deviation is with respect to VIN = 12 V, IOUT = 1 A.
(2) In dropout the switching frequency drops to increase the effective duty cycle. The lowest frequency is clamped at approximately: ƒMIN = 1 / (tON-MAX + tOFF-MIN). DMAX = tON-MAX /(tON-MAX + tOFF-MIN).