SNAS714C November   2016  – August 2021 LMS3635-Q1 , LMS3655-Q1

PRODUCTION DATA  

  1. 1 Features
  2. 2 Applications
  3. 3 Description
  4. 4 Revision History
  5. 5 Device Comparison Tables
  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 Thermal Information (for Device Mounted on PCB)
    6. 7.6 Electrical Characteristics
    7. 7.7 System Characteristics
    8. 7.8 Timing Requirements
    9. 7.9 Typical Characteristics
  8. 8 Detailed Description
    1. 8.1 Overview
    2. 8.2 Functional Block Diagram
      1. 8.2.1 Control Scheme
    3. 8.3 Feature Description
      1. 8.3.1 RESET Flag Output
      2. 8.3.2 Enable and Start-Up
      3. 8.3.3 Soft-Start Function
      4. 8.3.4 Current Limit
      5. 8.3.5 Hiccup Mode
      6. 8.3.6 Synchronizing Input
      7. 8.3.7 Undervoltage Lockout (UVLO) and Thermal Shutdown (TSD)
      8. 8.3.8 Input Supply Current
    4. 8.4 Device Functional Modes
      1. 8.4.1 AUTO Mode
      2. 8.4.2 FPWM Mode
      3. 8.4.3 Dropout
      4. 8.4.4 Spread-Spectrum Operation
  9. 9 Application and Implementation
    1. 9.1 Application Information
    2. 9.2 Typical Applications
      1. 9.2.1 General Application
        1. 9.2.1.1 Design Requirements
        2. 9.2.1.2 Detailed Design Procedure
          1. 9.2.1.2.1 Custom Design With WEBENCH® Tools
          2. 9.2.1.2.2 External Components Selection
            1. 9.2.1.2.2.1 Input Capacitors
            2. 9.2.1.2.2.2 Output Inductors and Capacitors
              1. 9.2.1.2.2.2.1 Inductor Selection
              2. 9.2.1.2.2.2.2 Output Capacitor Selection
          3. 9.2.1.2.3 Setting the Output Voltage
          4. 9.2.1.2.4 FB for Adjustable Output
          5. 9.2.1.2.5 VCC
          6. 9.2.1.2.6 BIAS
          7. 9.2.1.2.7 CBOOT
          8. 9.2.1.2.8 Maximum Ambient Temperature
        3. 9.2.1.3 Application Curves
      2. 9.2.2 Fixed 5-V Output for USB-Type Applications
        1. 9.2.2.1 Design Requirements
        2. 9.2.2.2 Detailed Design Procedure
        3. 9.2.2.3 Application Curves
      3. 9.2.3 Fixed 3.3-V Output
        1. 9.2.3.1 Design Requirements
        2. 9.2.3.2 Detailed Design Procedure
        3. 9.2.3.3 Application Curves
      4. 9.2.4 6-V Adjustable Output
        1. 9.2.4.1 Design Requirements
        2. 9.2.4.2 Detailed Design Procedure
        3. 9.2.4.3 Application Curves
    3. 9.3 Do's and Don't's
  10. 10Power Supply Recommendations
  11. 11Layout
    1. 11.1 Layout Guidelines
    2. 11.2 Layout Example
  12. 12Device and Documentation Support
    1. 12.1 Device Support
      1. 12.1.1 Third-Party Products Disclaimer
      2. 12.1.2 Development Support
        1. 12.1.2.1 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

7.6 Electrical Characteristics

Limits apply over the recommended operating junction temperature range of –40°C to +150°C, unless otherwise noted. 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.
PARAMETERTEST CONDITIONSMINTYPMAXUNIT
VFBInitial reference voltage for 5-V and 3.3-V optionsVIN = 3.8 V to 36 V, TJ = 25°C–1%1%
VIN = 3.8 V to 36 V–1.5%1.5%
IQOperating quiescent current; measured at VIN pin when enabled and not switching(1)VIN = 13.5 V, VBIAS = 5 V7.516µA
IB_NSWBias current into BIAS pin, enabled, not switchingVIN = 13.5 V, VBIAS = 5 V, FPWM = 0 V5362µA
VIN = 13.5 V, VBIAS = 3.3 V, FPWM = 0 V5362
ISDShutdown quiescent current; measured at VIN pinEN ≤ 0.4 V23µA
VIN-OPERATEMinimum input voltage to operateRising3.23.553.90V
Falling2.953.253.55
Hysteresis0.280.30.4
VRESETRESET upper threshold voltageRising, % of VOUT105%107%110%
RESET lower threshold voltageFalling, % VOUT92%94%96.5%
Magnitude of RESET lower threshold from steady state output voltageSteady-state output voltage and RESET falling threshold read at the same TJ and VIN96%
VRESET_HYSTRESET hysteresis as a percent of output voltage setpoint±1%
VRESET_VALIDMinimum input voltage for proper RESET function50-µA pullup to RESET pin,
EN = 0 V, TJ= 25°C		1.5V
VOLLow level RESET function output voltage50-µA pullup to RESET pin,
VIN = 1.5 V, EN = 0 V		0.4V
0.5-mA pullup to RESET pin,
VIN = 13.5 V, EN = 0 V		0.4
1-mA pullup to RESET pin,
VIN = 13.5 V, EN = 3.3 V		0.4
FSWSwitching frequencyVIN = 13.5 V, center frequency with spread spectrum, PWM operation360400440kHz
VIN = 13.5 V, without spread spectrum, PWM operation360400440
FSYNCSync frequency range250400500kHz
DSYNCSync input duty cycle rangeHigh state input < 5.5 V and > 2.3 V25%75%
VFPWMFPWM input threshold voltageFPWM input high (MODE = FPWM)1.5V
FPWM input low (MODE = AUTO with diode emulation)0.4
FPWM input hysteresis0.151
FSSSFrequency span of spread spectrum operation±3%
FPSSSpread-spectrum pattern frequency(2)1.2Hz
IFPWMFPWM leakage currentVIN = 13.5 V, VFPWM = 3.3 V1µA
VIN = VFPWM = 13.5 V1
ISYNCSYNC leakage currentVIN = 13.5 V, VSYNC = 3.3 V1µA
VIN = VSYNC = 13.5 V1
IL-HSHigh-side switch current limitLMS3635-Q14.567.5A
LMS3655-Q16.78.59.5
IL-LSLow-side switch current limitLMS3635-Q144.56.5A
LMS3655-Q1677.5
IL-ZCZero-cross current limit FPWM = low–0.02A
IL-NEGNegative current limit FPWM = high–1.5
RDSONPower switch on-resistanceHigh-side MOSFET RDSON,
VIN = 13 V, IL = 1 A		60130mΩ
Low-side MOSFET RDSON,
VIN = 13 V, IL = 1 A		4080
VENEnable input threshold voltage - risingEnable rising1.72V
VEN_HYSTEnable threshold hysteresis0.450.55V
VEN_WAKEEnable wake-up threshold0.4V
IENEN pin input currentVIN = VEN = 13.5 V23µA
VCCInternal VCC voltageVIN = 13.5 V, VBIAS = 0 V3.05V
VIN = 13.5 V, VBIAS = 3.3 V3.15
VCC_UVLOInternal VCC input undervoltage lockoutVIN rising2.7V
Hysteresis below VCC-UVLO185mV
IFBInput current from FB to AGNDAdjustable LMS36x5-Q1, FB = 1 V20nA
VREFReference voltage for adjustable option onlyTJ = 25°C0.99311.007V
TJ = –40°C to 125°C0.9911.01
RRESETRDSON of RESEToutputPull FB pin low. Sink 1-mA at RESET pin50120Ω
VSYNCVIH1.5V
VIL0.4
VHYST0.151
TSDThermal shutdown thresholds(2)Rising160185°C
Hysteresis15
DMAXMaximum switch duty cycleFsw = 400 kHz96%
While in dropout(2)98%
(1) This is the current used by the device while not switching, open loop on the ATE. It does not represent the total input current from the regulator system.
(2) Ensured by Design, Not tested at production.