SNVSA83C April   2015  – October 2017 LM43602-Q1

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 Timing Requirements
    7. 6.7 Switching Characteristics
    8. 6.8 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  Fixed Frequency Peak Current Mode Controlled Step-Down Regulator
      2. 7.3.2  Light Load Operation
      3. 7.3.3  Adjustable Output Voltage
      4. 7.3.4  Enable (EN)
      5. 7.3.5  VCC, UVLO, and BIAS
      6. 7.3.6  Soft Start and Voltage Tracking (SS/TRK)
      7. 7.3.7  Switching Frequency (RT) and Synchronization (SYNC)
      8. 7.3.8  Minimum ON Time, Minimum OFF Time and Frequency Foldback at Dropout Conditions
      9. 7.3.9  Internal Compensation and CFF
      10. 7.3.10 Bootstrap Voltage (BOOT)
      11. 7.3.11 Power Good (PGOOD)
      12. 7.3.12 Overcurrent and Short Circuit Protection
      13. 7.3.13 Thermal Shutdown
    4. 7.4 Device Functional Modes
      1. 7.4.1 Shutdown Mode
      2. 7.4.2 Standby Mode
      3. 7.4.3 Active Mode
      4. 7.4.4 CCM Mode
      5. 7.4.5 Light Load Operation
      6. 7.4.6 Self-Bias Mode
  8. 8 Applications and Implementation
    1. 8.1 Application Information
    2. 8.2 Typical Applications
      1. 8.2.1 Design Requirements
      2. 8.2.2 Detailed Design Procedure
        1. 8.2.2.1  Custom Design With WEBENCH® Tools
        2. 8.2.2.2  Output Voltage Set-Point
        3. 8.2.2.3  Switching Frequency
        4. 8.2.2.4  Input Capacitors
        5. 8.2.2.5  Inductor Selection
        6. 8.2.2.6  Output Capacitor Selection
        7. 8.2.2.7  Feed-Forward Capacitor
        8. 8.2.2.8  Bootstrap Capacitors
        9. 8.2.2.9  VCC Capacitor
        10. 8.2.2.10 BIAS Capacitors
        11. 8.2.2.11 Soft-Start Capacitors
        12. 8.2.2.12 Undervoltage Lockout Setpoint
        13. 8.2.2.13 PGOOD
      3. 8.2.3 Application Performance Curves
  9. 9 Power Supply Recommendations
  10. 10Layout
    1. 10.1 Layout Guidelines
      1. 10.1.1 Compact Layout for EMI Reduction
      2. 10.1.2 Ground Plane and Thermal Considerations
      3. 10.1.3 Feedback Resistors
    2. 10.2 Layout Example
  11. 11Device and Documentation Support
    1. 11.1 Device Support
      1. 11.1.1 Third-Party Products Disclaimer
    2. 11.2 Development Support
      1. 11.2.1 Custom Design With WEBENCH® Tools
    3. 11.3 Receiving Notification of Documentation Updates
    4. 11.4 Community Resources
    5. 11.5 Trademarks
    6. 11.6 Electrostatic Discharge Caution
    7. 11.7 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

over the recommended operating junction temperature (TJ) range of –40°C to +125°C (unless otherwise noted)(1)
PARAMETER MIN MAX UNIT
Input voltages VIN to PGND –0.3 42(2) V
EN to PGND –0.3 VIN + 0.3
FB, RT, SS/TRK to AGND –0.3 3.6
PGOOD to AGND –0.3 15
SYNC to AGND –0.3 5.5
BIAS to AGND –0.3 30 or VIN(3)
AGND to PGND –0.3 0.3
Output voltages SW to PGND –0.3 VIN + 0.3 V
SW to PGND less than 10-ns transients –3.5 42
CBOOT to SW –0.3 5.5
VCC to AGND –0.3 3.6
Storage temperature, Tstg –65 150 °C
Operating junction temperature –40 150 °C
(1) Stresses beyond those listed under Absolute Maximum Ratings may cause permanent damage to the device. These are stress ratings only, and functional operation of the device at these or any other conditions beyond those indicated under Recommended Operating Conditions is not implied. Exposure to absolute-maximum-rated conditions for extended periods may affect device reliability.
(2) At max duty cycle 0.01% of 10000 hours.
(3) Whichever is lower.

6.2 ESD Ratings

VALUE UNIT
V(ESD) Electrostatic discharge Human-body model (HBM), per AEC Q100-002(1) ±2000 V
Charged-device model (CDM), per AEC Q100-011 ±750
(1) AEC Q100-002 indicates that HBM stressing shall be in accordance with the ANSI/ESDA/JEDEC JS-001 specification.

6.3 Recommended Operating Conditions

over the recommended operating junction temperature (TJ) range of –40°C to +125°C (unless otherwise noted)(1)
MIN MAX UNIT
Input voltages VIN to PGND 3.5 36 V
EN –0.3 VIN
FB –0.3 1.1
PGOOD –0.3 12
BIAS input not used –0.3 0.3
BIAS input used 3.3 28 or VIN(2)
AGND to PGND –0.1 0.1
Output voltage VOUT 1 28 V
Output current IOUT 0 2 A
Temperature Operating junction temperature, TJ –40 125 °C
(1) Recommended Operation Conditions indicate conditions for which the device is intended to be functional, but do not ensure specific performance limits. For specified specifications, see Electrical Characteristics.
(2) Whichever is lower.

6.4 Thermal Information

THERMAL METRIC(1)(2)(3) LM43602-Q1 UNIT
PWP (HTSSOP )
16 PINS
RθJA Junction-to-ambient thermal resistance 38.9(4) °C/W
RθJC(top) Junction-to-case (top) thermal resistance 24.3 °C/W
RθJB Junction-to-board thermal resistance 19.9 °C/W
ψJT Junction-to-top characterization parameter 0.7 °C/W
ψJB Junction-to-board characterization parameter 19.7 °C/W
RθJC(bot) Junction-to-case (bottom) thermal resistance 1.7 °C/W
(1) For more information about traditional and new thermal metrics, see the Semiconductor and IC Package Thermal Metrics application report.
(2) The package thermal impedance is calculated in accordance with JESD 51-7;
(3) Thermal resistances were simulated on a 4 layer, JEDEC board.
(4) See Figure 64 for RθJA vs Copper Area curve.

6.5 Electrical Characteristics

Limits apply over the recommended operating junction temperature (TJ) range of –40°C to +125°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 = 12 V, VOUT = 3.3 V, FS = 500 kHz.
PARAMETER CONDITIONS MIN TYP MAX UNIT
SUPPLY VOLTAGE (VIN PIN)
VIN-MIN-ST Minimum input voltage for startup 3.8 V
ISHDN Shutdown quiescent current VEN = 0 V 1.2 3.1 µA
IQ-NONSW Operating quiescent current (non-switching) from VIN VEN = 3.3 V
VFB = 1.5 V
VBIAS = 3.4 V external		 5 10 µA
IBIAS-NONSW Operating quiescent current (non-switching) from external VBIAS VEN = 3.3 V
VFB = 1.5 V
VBIAS = 3.4 V external		 85 130 µA
IQ-SW Operating quiescent current (switching) VEN = 3.3 V
IOUT = 0 A
RT = open
VBIAS = VOUT = 3.3 V
RFBT = 1 Meg		 27 µA
ENABLE (EN PIN)
VEN-VCC-H Voltage level to enable the internal LDO output VCC VENABLE high level 1.2 V
VEN-VCC-L Voltage level to disable the internal LDO output VCC VENABLE low level 0.525 V
VEN-VOUT-H Precision enable level for switching and regulator output: VOUT VENABLE high level 2 2.2 2.42 V
VEN-VOUT-HYS Hysteresis voltage between VOUT precision enable and disable thresholds VENABLE hysteresis –290 mV
ILKG-EN Enable input leakage current VEN = 3.3 V 0.85 1.75 µA
INTERNAL LDO (VCC and BIAS PINS)
VCC Internal LDO output voltage VCC VIN ≥ 3.8 V 3.28 V
VCC-UVLO Undervoltage lock out (UVLO) thresholds for VCC VCC rising threshold 3.1 V
Hysteresis voltage between rising and falling thresholds –520 mV
VBIAS-ON Internal LDO input change over threshold to BIAS VBIAS rising threshold 2.94 3.18 V
Hysteresis voltage between rising and falling thresholds –75 mV
VOLTAGE REFERENCE (FB PIN)
VFB Feedback voltage TJ = 25ºC 1.012 1.015 1.019 V
TJ = –40ºC to 125 ºC 0.999 1.015 1.032
ILKG-FB Input leakage current at FB pin FB = 1.015 V 0.2 65 nA
THERMAL SHUTDOWN
TSD (1) Thermal shutdown Shutdown threshold 160 ºC
Recovery threshold 150 ºC
CURRENT LIMIT AND HICCUP
IHS-LIMIT Peak inductor current limit 3.65 4.5 5.15 A
ILS-LIMIT Inductor current valley limit 1.75 2 2.25 A
SOFT START (SS/TRK PIN)
ISSC Soft-start charge current 1.25 2 2.75 µA
RSSD Soft-start discharge resistance UVLO, TSD, OCP, or EN = 0 V 18 kΩ
POWER GOOD (PGOOD PIN)
VPGOOD-HIGH Power-good flag over voltage tripping threshold % of FB voltage 110% 113%
VPGOOD-LOW Power-good flag under voltage tripping threshold % of FB voltage 77% 88%
VPGOOD-HYS Power-good flag recovery hysteresis % of FB voltage 6%
RPGOOD PGOOD pin pulldown resistance when power bad VEN = 3.3 V 69 150 Ω
VEN = 0 V 150 350
MOSFETS(2)
RDS-ON-HS High-side MOSFET ON resistance IOUT = 1 A
VBIAS = VOUT = 3.3 V		 120 mΩ
RDS-ON-LS Low-side MOSFET ON resistance IOUT = 1 A
VBIAS = VOUT = 3.3 V		 65 mΩ
(1) Ensured by design.
(2) Measured at the pins.

6.6 Timing Requirements

MIN NOM MAX UNIT
CURRENT LIMIT AND HICCUP
NOC Hiccup wait cycles when LS current limit tripped 32 Cycles
TOC Hiccup retry delay time 5.5 ms
SOFT START (SS/TRK PIN)
TSS Internal soft-start time when SS pin open circuit 4.1 ms
POWER GOOD (PGOOD PIN)
TPGOOD-RISE Power-good flag rising transition deglitch delay 220 µs
TPGOOD-FALL Power-good flag falling transition deglitch delay 220 µs

6.7 Switching Characteristics

over operating free-air temperature range (unless otherwise noted)
PARAMETER TEST CONDITIONS MIN TYP MAX UNIT
SW (SW PIN)
tON-MIN(1) Minimum high side MOSFET ON time 125 165 ns
tOFF-MIN(1) Minimum high side MOSFET OFF time 200 250 ns
OSCILLATOR (SW and SYNC PINS)
FOSC-DEFAULT Oscillator default frequency RT pin open circuit 425 500 580 kHz
FADJ Minimum adjustable frequency With 1% resistors at RT pin 200 kHz
Maximum adjustable frequency 2200 kHz
Frequency adjust accuracy 10%
VSYNC-HIGH Sync clock high level threshold 2 V
VSYNC-LOW Sync clock low level threshold 0.4 V
DSYNC-MAX Sync clock maximum duty cycle 90%
DSYNC-MIN Sync clock minimum duty cycle 10%
TSYNC-MIN Mininum sync clock ON and OFF time 80 ns
(1) Ensured by design.

6.8 Typical Characteristics

Unless otherwise specified, VIN = 12 V, VOUT = 3.3 V, FS = 500 kHz, L = 6.8 µH and room temperature. Refer to Application Performance Curves for bill of materials for other VOUT and FS combinations.
LM43602-Q1 3p3V_500k_Eff_Gr.png
VOUT = 3.3 V FS = 500 kHz
Figure 1. Efficiency at Room Temperature
LM43602-Q1 3p3V_500k_Eff85_Gr.png
VOUT = 3.3 V FS = 500 kHz
Figure 3. Efficiency at 85°C
LM43602-Q1 5V_500k_EffLin_Gr.png
VOUT = 5 V FS = 500 kHz
Figure 5. Efficiency at Room Temperature
LM43602-Q1 3p3_500k_Reg_Gr.png
VOUT = 3.3 V FS = 500 kHz
Figure 7. VOUT Regulation
LM43602-Q1 3p3V_500k_Drop_Gr.png
VOUT = 3.3 V FS = 500 kHz
Figure 9. Dropout Curve
LM43602-Q1 3p3V_500k_FreqDrop_Gr.png
VOUT = 3.3 V FS = 500 kHz
Figure 11. Frequency vs VIN
LM43602-Q1 EN_DOWN.png Figure 13. EN Falling Threshold vs Junction Temperature
LM43602-Q1 EN_Hyst.png Figure 15. EN Hysteresis vs Junction Temperature
LM43602-Q1 HSILIM.png Figure 17. HS Current Limit vs Junction Temperature
LM43602-Q1 HSRDSON.png Figure 19. High Side FET On Resistance vs Junction Temperature
LM43602-Q1 PGOVPUP.png Figure 21. PGOOD OVP Falling Threshold vs Junction Temperature
LM43602-Q1 PGUVPDWN.png Figure 23. PGOOD UVP Falling Threshold vs Junction Temperature
LM43602-Q1 3p3V_500k_EffLin_Gr.png
VOUT = 3.3 V FS = 500 kHz
Figure 2. Efficiency at Room Temperature
LM43602-Q1 5V_500k_Eff_Gr.png
VOUT = 5 V FS = 500 kHz
Figure 4. Efficiency at Room Temperature
LM43602-Q1 5V_500k_Eff85_Gr.png
VOUT = 5 V FS = 500 kHz
Figure 6. Efficiency at 85°C
LM43602-Q1 5V_500k_Reg_Gr.png
VOUT = 5 V FS = 500 kHz
Figure 8. VOUT Regulation
LM43602-Q1 5V_500k_Drop_Gr.png
VOUT = 5 V FS = 500 kHz
Figure 10. Dropout Curve
LM43602-Q1 5V_500k_FreqDrop_Gr.png
VOUT = 5 V FS = 500 kHz
Figure 12. Frequency vs VIN
LM43602-Q1 EN_UP.png Figure 14. EN Rising Threshold vs Junction Temperature
LM43602-Q1 VFB.png Figure 16. FB Voltage vs Junction Temperature
LM43602-Q1 LSILIM.png Figure 18. LS Current Limit vs Junction Temperature
LM43602-Q1 LSRDSON.png Figure 20. Low Side FET On Resistance vs Junction Temperature
LM43602-Q1 PGOVPDOWN.png Figure 22. PGOOD OVP Rising Threshold vs Junction Temperature
LM43602-Q1 PGUVPUP.png Figure 24. PGOOD UVP Rising Threshold vs Junction Temperature