SNVSBV5B December   2020  – December 2021 LM25149

PRODUCTION DATA  

  1. 1 Features
  2. 2 Applications
  3. 3 Description
  4. 4 Revision History
  5. 5 Description (continued)
  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 ACTIVE EMI  Filter
    7. 7.7 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  Input Voltage Range (VIN)
      2. 8.3.2  High-Voltage Bias Supply Regulator (VCC, VCCX, VDDA)
      3. 8.3.3  Precision Enable (EN)
      4. 8.3.4  Power-Good Monitor (PG)
      5. 8.3.5  Switching Frequency (RT)
      6. 8.3.6  Active EMI Filter
      7. 8.3.7  Dual Random Spread Spectrum (DRSS)
      8. 8.3.8  Soft Start
      9. 8.3.9  Output Voltage Setpoint (FB)
      10. 8.3.10 Minimum Controllable On Time
      11. 8.3.11 Error Amplifier and PWM Comparator (FB, EXTCOMP)
      12. 8.3.12 Slope Compensation
      13. 8.3.13 Inductor Current Sense (ISNS+, VOUT)
        1. 8.3.13.1 Shunt Current Sensing
        2. 8.3.13.2 Inductor DCR Current Sensing
      14. 8.3.14 Hiccup Mode Current Limiting
      15. 8.3.15 High-Side and Low-Side Gate Drivers (HO, LO)
      16. 8.3.16 Output Configurations (CNFG)
      17. 8.3.17 Single-Output Dual-Phase Operation
    4. 8.4 Device Functional Modes
      1. 8.4.1 Sleep Mode
      2. 8.4.2 Pulse Frequency Modulation and Synchronization (PFM/SYNC)
      3. 8.4.3 Thermal Shutdown
  9. 9 Application and Implementation
    1. 9.1 Application Information
      1. 9.1.1 Power Train Components
        1. 9.1.1.1 Buck Inductor
        2. 9.1.1.2 Output Capacitors
        3. 9.1.1.3 Input Capacitors
        4. 9.1.1.4 Power MOSFETs
        5. 9.1.1.5 EMI Filter
        6. 9.1.1.6 Active EMI Filter
      2. 9.1.2 Error Amplifier and Compensation
    2. 9.2 Typical Applications
      1. 9.2.1 Design 1 – High Efficiency 2.1-MHz Synchronous Buck Regulator
        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  Custom Design With Excel Quickstart Tool
          3. 9.2.1.2.3  Buck Inductor
          4. 9.2.1.2.4  Current-Sense Resistance
          5. 9.2.1.2.5  Output Capacitors
          6. 9.2.1.2.6  Input Capacitors
          7. 9.2.1.2.7  Frequency Set Resistor
          8. 9.2.1.2.8  Feedback Resistors
          9. 9.2.1.2.9  Compensation Components
          10. 9.2.1.2.10 Active EMI Components
        3. 9.2.1.3 Application Curves
      2. 9.2.2 Design 2 – High Efficiency 440-kHz Synchronous Buck Regulator
        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 Design 3 – Dual-Phase 400-kHz 20-A Synchronous Buck Regulator
        1. 9.2.3.1 Design Requirements
        2. 9.2.3.2 Detailed Design Procedure
        3. 9.2.3.3 Application Curves
  10. 10Power Supply Recommendations
  11. 11Layout
    1. 11.1 Layout Guidelines
      1. 11.1.1 Power Stage Layout
      2. 11.1.2 Gate-Drive Layout
      3. 11.1.3 PWM Controller Layout
      4. 11.1.4 Active EMI Layout
      5. 11.1.5 Thermal Design and Layout
      6. 11.1.6 Ground Plane Design
    2. 11.2 Layout Example
  12. 12Device and Documentation Support
    1. 12.1 Device Support
      1. 12.1.1 Development Support
      2. 12.1.2 Custom Design With WEBENCH® Tools
    2. 12.2 Documentation Support
      1. 12.2.1 Related Documentation
        1. 12.2.1.1 PCB Layout Resources
        2. 12.2.1.2 Thermal Design Resources
    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

7.5 Electrical Characteristics

TJ = –40°C to 150°C. Typical values are at TJ = 25°C and VIN = 12 V (unless otherwise noted).
PARAMETER TEST CONDITIONS MIN TYP MAX UNIT
SUPPLY (VIN)
IQ-VIN1 VIN shutdown current VEN = 0 V 2.3 3.8 µA
IQ-VIN2 VIN standby current Non-switching, 0.5 ≥ VEN ≤ 1 V 124 µA
ISLEEP1 Sleep current, 3.3 V 1.03 V ≤ VEN ≤  42 V, VVOUT = 3.3 V, in regulation, no-load, not switching,  VPFM/SYNC = 0 V  9.5 19.7 µA
ISLEEP2 Sleep current, 5.0 V VEN = 5 V, VVOUT = 5.0 V, in regulation, no-load, not switching,  VPFM/SYNC = 0 V  9.9 19.9 µA
ENABLE (EN)
VSDN Shutdown to standby threshold VEN rising 0.5 V
VEN-HIGH Enable voltage rising threshold VEN rising, enable switching 0.95 1.0 1.05 V
IEN-HYS Enable hysteresis VEN = 1.1 V –12 –10 –8 µA
INTERNAL LDO (VCC)
VVCC-REG VCC regulation voltage IVCC = 0 mA to 100 mA 4.7 5 5.3 V
VVCC-UVLO VCC UVLO rising threshold 3.3 3.4 3.5 V
VVCC-HYST VCC UVLO hysteresis 148 mV
IVCC-REG Internal LDO short-circuit current limit 115 170 mA
INTERNAL LDO (VDDA)
VVDDA-REG VDDA regulation voltage 4.75 5 5.25 V
VVDDA-UVLO VDDA UVLO rising VVCC rising, VVCCX = 0 V 3 3.2 3.3 V
VVDDA-HYST VDDA UVLO hysteresis  VVCCX = 0 V 120 mV
RVDDA VDDA resistance VVCCX = 0 V 5.5 Ω
EXTERNAL BIAS (VCCX)
VVCCX-ON VCCX(ON) rising threshold 4.1 4.3 4.4 V
VVCCX-HYST VCCX hysteresis voltage VVCCX = 5 V 130 mV
RVCCX VCCX resistance VVCCX = 5 V 2 Ω
REFERENCE VOLTAGE
VREF Regulated FB voltage 795 800 808 mV
OUTPUT VOLTAGE (VOUT)
VOUT-3.3V-INT 3.3-V output voltage setpoint RFB = 0 Ω, VIN = 3.8 V to 42 V , internal COMP 3.267 3.3 3.333 V
VOUT-3.3V-EXT 3.3-V output voltage setpoint RFB = 0 Ω, VIN = 3.8 V to 42 V, external COMP 3.267 3.3 3.33 V
VOUT-5V-INT 5-V output voltage setpoint
 		 RFB = 24.9 kΩ, VIN = 5.5 V to 42 V, internal COMP 4.95 5.0 5.05 V
VOUT-5VEXT 5-V output voltage setpoint
 		 RFB = 24.9 kΩ, VIN = 5.5 V to 42 V, external COMP 4.95 5.0 5.05 V
VOUT-12V-INT 12-V output setpoint RFB = 48.7 kΩ, VIN = 24 V to 42 V, internal COMP  11.88 12 12.12 V
VOUT-12V-EXT 12-V output setpoint RFB = 48.7 kΩ, VIN = 24 V to 42 V, external COMP 11.88 12 12.12 V
RFB-OPT1 5-V output select 23 25 27 kΩ
RFB-OPT2 12-V output select 47 50 53 kΩ
ERROR AMPLIFIER (COMP)
gm-EXTERNAL EA transconductance, external compensation FB to EXTCOMP 1020 1200 µS
gm-INTERNAL EA transconductance, internal compensation FB to EXTCOMP, EXTCOMP 100 kΩ to VDDA 30 µS
IFB Error amplifier input bias current 75 nA
VCOMP-CLAMP COMP clamp voltage VFB = 0 V 2.1 V
ICOMP-SRC EA source current VEXTCOMP = 1 V, VFB = 0.6 V 180 µA
ICOMP-SINK EA sink current VEXTCOMP = 1 V, VFB = 1 V 180 µA
RCOMP Internal compensation EXTCOMP 100 kΩ  to VDDA 400 kΩ
CCOMP Internal compensation EXTCOMP 100 kΩ  to VDDA 50 pF
CCOMP-HF Internal compensation EXTCOMP 100 kΩ  to VDDA 1 pF
PULSE FREQUENCY MODULATION (PFM/SYNC)
VPFM-LO PFM detection threshold low 0.8 V
VPFM-HI PFM decection threshold high 2.0 V
VZC-SW Zero-cross threshold –5.5 mV
VZC-DIS Zero-cross threshold disable PFM=VDDA, 1000 SW cycles after first HO pulse 100 mV
FSYNCIN3 Frequency sync range RRT = 10 kΩ, ±20 % of the nominal oscillator frequency 1.74 2.70 MHz
tSYNC-MIN3 Minimum pulse-width of external synchronization signal 20 250 ns
tSYNCIN-HO Delay from PFM faling edge to HO rising edge 45 ns
tPFM-FILTER SYNCIN to PFM mode 13 45 µs
DUAL RANDOM SPREAD SPECTRUM (DRSS)
ΔfC Modulation frequency percentage change 7 %
fm Modulation frequency 8.2 16.2 kHz
SWITCHING FREQUENCY
VRT RT pin regulation voltage 10 kΩ < RRT < 100 kΩ 0.5 V
FSW1 Switching frequency 1  RRT = 97.6 kΩ to GND  0.220 MHz
FSW2 Switching frequency 2 VIN = 12 V, RRT = 9.09 kΩ to GND  1.98 2.2 2.42 MHz
FSW3 Switching frequency 3 RRT = 220 kΩ to GND  100 kHz
SLOPE1 Internal slope compensation 1 RRT = 9.09 kΩ 600 mV/µs
SLOPE2 Internal slope compensation 2 RRT = 97.6 kΩ 50 mV/µs
tON(min) Minimum on-time 50 ns
tOFF(min) Minimum off-time 90 ns
POWER GOOD (PG)
VPG-UV Power Good UV trip level Falling with respect to the regulated voltage 90% 92%  94%
VPG-OV Power Good OV trip level  Rising with respect to the regulation voltage 108% 110% 112%
VPG-UV-HYST Power Good UV hysteresis  Fallinge with respect to the regulated output 3.6%
VPG-OV-HYST Power Good OV hysteresis Rising with respect to the regulation voltage 3.4%
t-PG-RISING-DLY OV filter time VOUT rising 25 µs
t-PG-FALL-DLY UV filter time VOUT falling 25 µs
VPG-OL PG/SYNC voltage Open collector, IPG/SYNC = 2 mA 0.8 V
SYNCHRONIZATION OUTPUT (PG/SYNCOUT)
VSYNCOUT-LO SYNCO-LO low-state voltage RCONFIG = 54.9 kΩ or 71.5 kΩ to VDDA (primary), IPG/SYNCOUT = 2 mA 0.8 V
VSYNCOUT-HO SYNCO-HO high-state voltage RCONFIG = 54.9 kΩ or 71.5 kΩ to VDDA (primary),  IPG/SYNCOUT = 2 mA. 2.0 V
tSYNCOUT Delay from HO rising edge to SYNCOUT (PGOOD pin in primary mode) VPFM = VDDA, FSW set by RRT =  100 kΩ 2.1 µs
STARTUP (Soft Start)
tSS-INT Internal fixed soft-start time 1.9 3 4.6 ms
BOOT CIRCUIT
VBOOT-DROP Internal diode forward drop ICBOOT = 20 mA, VCC to CBOOT 0.63 0.8 V
IBOOT CBOOT to SW quiescent current, not swwitching VEN = 5 V, VCBOOT-SW = 5 V 3.0 4.2 µA
VBOOT-SW-UV-R CBOOT to SW UVLO rising threshold VCBOOT-SW rising 2.83 V
VBOOT-SW-UV-F CBOOT to SW UVLO falling threshold VCBOOT-SW falling 2.5 V
VBOOT-SW-UV-HYS CBOOT to SW UVLO hysteresis 0.05 V
VHO-LOW HO low-state output voltage IHO = 100 mA 38 mV
HIGH-SIDE GATE DRIVER (HO)
VHO-HIGH HO high-state output voltage IHO = –100 mA, , VHO-HIGH = VCBOOT – VHO 106 mV
VHO-LOW HO low-state output voltage IHO = 100 mA 50 mV
tHO-RISE HO rise time (10% to 90%) CLOAD = 2.7 nF 7 ns
tHO-FALL HO fall time (90% to 10%) CLOAD = 2.7 nF 7 ns
IHO-SRC HO peak source current VHO = VSW = 0 V, VCBOOT = VVCCX = 5 V 2.2 A
IHO-SINK HO peak sink current VVCCX = 5 V 3.2 A
LOW-SIDE GATE DRIVER (LO)
VLO-LOW LO low-state output voltage ILO = 100 mA 50 mV
VLO-HIGH LO high-state output voltage ILO = –100 mA 130 mV
tLO-RISE LO rise time (10% to 90%) CLOAD = 2.7 nF 7 ns
tLO-FALL LO fall time (90% to 10%) CLOAD = 2.7 nF 7 ns
ILO-SRC LO peak source current VHO = VSW = 0 V, VCBOOT = VVCCX = 5 V 2.2 A
ILO-SINK LO peak sink current VVCCX = 5 V 3.2 A
ADAPTIVE DEADTIME CONTROL
tDEAD1 HO off to LO on deadtime 20 ns
tDEAD2 LO off to HO on deadtime 20 ns
INTERNAL HICCUP MODE
HICDLY Hiccup mode activation delay VISNS+ – VVOUT > 60 mV 512 cycles
HICCYCLES HICCUP mode fault VISNS+ –VVOUT > 60 mV 16384 cycles
OVERCURRENT PROTECTION
VCS-TH Current limit threshold Measured from ISNS+ to VOUT 49 60 73 mV
tDELAY-ISNS+ ISNS+ delay to output 65 ns
GCS CS amplifier gain  9.0 10 10.8 V/V
IBIAS-ISNS+ CS amplifier input bias current  15 nA
CONFIGURATION
RCNFG-OPT1 Primary, no spread spectrum 28.7 29.4 31 kΩ
RCNFG-OPT2 Primary, with spread spectrum 40.2 41.2 43.2 kΩ
RCNGF-OPT3 Primary, interleaved, no spread spectrum 53.6 54.9 57.6 kΩ
RCNFG-OPT4 Primary, interleaved, with spread spectrum 69.8 71.5 73.2 kΩ
RCNFG-OPT5 Secondary 87 90.9 93.1 kΩ
THERMAL SHUTDOWN
TJ-SD Thermal shutdown threshold (1) Temperature rising 175 °C
TJ-HYS Thermal shutdown hysteresis (1) 15 °C
(1) Specified by design. Not production tested.