SNOSDL1 December   2024 LMG3650R035

ADVANCE INFORMATION  

  1.   1
  2. 1 Features
  3. 2 Applications
  4. 3 Description
  5. 4 Device Comparison
  6. 5 Pin Configuration and Functions
  7. 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 Switching Characteristics
  8. 7 Parameter Measurement Information
    1. 7.1 Switching Parameters
      1. 7.1.1 Turn-On Times
      2. 7.1.2 Turn-Off Times
      3. 7.1.3 Drain-Source Turn-On and Turn-off Slew Rate
      4. 7.1.4 Zero-Voltage Detection Times (LMG3656R035 only)
  9. 8 Detailed Description
    1. 8.1 Overview
    2. 8.2 Functional Block Diagram
      1. 8.2.1 LMG3650R035 Functional Block Diagram
      2. 8.2.2 LMG3651R035 Functional Block Diagram
      3. 8.2.3 LMG3656R035 Functional Block Diagram
      4. 8.2.4 LMG3657R035 Functional Block Diagram
    3. 8.3 Feature Description
      1. 8.3.1 Drive Strength Adjustment
      2. 8.3.2 VDD Supply
      3. 8.3.3 Overcurrent and Short-Circuit Protection
      4. 8.3.4 Overtemperature Protection
      5. 8.3.5 UVLO Protection
      6. 8.3.6 Fault Reporting
      7. 8.3.7 Auxiliary LDO (LMG3651R035 Only)
      8. 8.3.8 Zero-Voltage Detection (ZVD) (LMG3656R035 Only)
      9. 8.3.9 Zero-Current Detection (ZCD) (LMG3657R035 Only)
    4. 8.4 Device Functional Modes
  10. 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 Slew Rate Selection
        2. 9.2.2.2 Signal Level-Shifting
    3. 9.3 Power Supply Recommendations
      1. 9.3.1 Using an Isolated Power Supply
      2. 9.3.2 Using a Bootstrap Diode
        1. 9.3.2.1 Diode Selection
        2. 9.3.2.2 Managing the Bootstrap Voltage
    4. 9.4 Layout
      1. 9.4.1 Layout Guidelines
  11. 10Device and Documentation Support
    1. 10.1 Receiving Notification of Documentation Updates
    2. 10.2 Support Resources
    3. 10.3 Trademarks
    4. 10.4 Electrostatic Discharge Caution
    5. 10.5 Glossary
  12. 11Revision History
  13. 12Mechanical, Packaging, and Orderable Information
    1. 12.1 Tape and Reel Information

Package Options

Mechanical Data (Package|Pins)
  • KLA|9
Thermal pad, mechanical data (Package|Pins)
Orderable Information

8.3.1 Drive Strength Adjustment

The LMG365xR035 allows users to adjust the drive strength of the device and obtain a desired slew rate, which provides flexibility when optimizing switching losses and minimizing EMI. The typical value of turn-on slew rate and the maximum value of turn-off slew rate can be independently controlled by connecting the resistors and capacitor as shown in the Figure 8-1. The resistance and capacitance on FLT/RDRV pin is sensed once at power-up. To do so, the device forces a step-function from 0V to 1.2V on the external R1-R2-C2 network and measures the resulting current waveform. The DC measurement determines the turn-on slew rate setting, which is programmed by the resistance R1. The AC measurement dependent on R1-R2-C2 determines the turn-off slew rate setting, which is dependent on the magnitude of the drain-to-source current charging the output capacitance but can be limited to a maximum value programmed by the resistance R2 and capacitance C2, connected in parallel to R1. Table 8-1 shows the recommended typical resistances and capacitance programming values at each slew rate setting.

The slew rate settings are determined one time at power up, then the FLT/RDRV pin is used as a push-pull 5V digital output for fault monitoring, as described in Fault Reporting. If R2 and C2 are not used, the device turns-off at full-speed and the turn-off slew rate is strictly determined by the Coss and the load current. If R1 is not used, the device defaults to the 100V/ns slew rate setting. Using slower turn-on settings results in higher Eon losses, and slower turn-off settings results in higher Eoff losses.

LMG3650R035 LMG3651R035 LMG3656R035 LMG3657R035 Drive Strength Adjustment Circuit Figure 8-1 Drive Strength Adjustment Circuit
Table 8-1 Recommended Typical Programming Resistance (kΩ) and Capacitance (pF) for Adjusting Slew Rates
TYPICAL TURN-ON SLEW RATE (V/ns) MAXIMUM TURN-OFF SLEW RATE (V/ns)
10 20 40 No limit (1)
R1 R2 C2 R2 C2 R2 C2 R2 C2
10 29.4 2 680 4.87 270 9.09 150 high impedance(2)
20 35.7 2 680 4.75 270 8.66 150
40 43.2 2 680 4.64 270 8.25 150
60 53.6 2 680 4.64 270 8.06 150
80 69.8 2 680 4.53 270 7.68 150
100 > 400(2) 2 680 4.22 270 6.98 180
(1) Fully dependent on the magnitude of the drain-to-source current charging the output capacitance
(2) Open-circuit connection for programming resistances is acceptable

For example, setting R1 = 53.6kΩ, R2 = 4.64kΩ and C2 = 270pF results in turn-on slew rate of 60V/ns and turn-off slew rate is limited to a maximum of 20V/ns.