SNVSB11B June   2018  – May 2019 LMZM33606

PRODUCTION DATA.  

  1. 1 Features
  2. 2 Applications
    1.     Simplified Schematic
  3. 3 Description
    1.     Minimum Solution Size
    2.     Typical Efficiency (Auto Mode)
  4. 4 Revision History
  5. 5 Pin Configuration and Functions
    1.     Pin 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 Switching Characteristics
    7. 6.7 Typical Characteristics (VIN = 12 V)
    8. 6.8 Typical Characteristics (VIN = 24 V)
    9. 6.9 Typical Characteristics (VIN = 36 V)
  7. 7 Detailed Description
    1. 7.1 Overview
    2. 7.2 Functional Block Diagram
    3. 7.3 Feature Description
      1. 7.3.1  Adjusting the Output Voltage
      2. 7.3.2  Input Capacitor Selection
      3. 7.3.3  Output Capacitor Selection
      4. 7.3.4  Transient Response
      5. 7.3.5  Feed-Forward Capacitor
      6. 7.3.6  Switching Frequency (RT)
      7. 7.3.7  Synchronization (SYNC/MODE)
      8. 7.3.8  Output Enable (EN)
      9. 7.3.9  Programmable System UVLO (EN)
      10. 7.3.10 Internal LDO and BIAS_SEL
      11. 7.3.11 Power Good (PGOOD) and Power Good Pull-Up (PGOOD_PU)
      12. 7.3.12 Mode Select (Auto or FPWM)
      13. 7.3.13 Soft Start and Voltage Tracking
      14. 7.3.14 Voltage Dropout
      15. 7.3.15 Overcurrent Protection (OCP)
      16. 7.3.16 Thermal Shutdown
    4. 7.4 Device Functional Modes
      1. 7.4.1 Active Mode
      2. 7.4.2 Auto Mode
      3. 7.4.3 FPWM Mode
      4. 7.4.4 Shutdown Mode
  8. 8 Application and Implementation
    1. 8.1 Application Information
    2. 8.2 Typical Application
      1. 8.2.1 Design Requirements
      2. 8.2.2 Detailed Design Procedure
        1. 8.2.2.1 Output Voltage Setpoint
        2. 8.2.2.2 Setting the Switching Frequency
        3. 8.2.2.3 Input Capacitors
        4. 8.2.2.4 Output Capacitor Selection
        5. 8.2.2.5 Feed-Forward Capacitor (CFF)
        6. 8.2.2.6 Application Curves
  9. 9 Power Supply Recommendations
  10. 10Layout
    1. 10.1 Layout Guidelines
    2. 10.2 Layout Example
    3. 10.3 Theta JA vs PCB Area
    4. 10.4 Package Specifications
    5. 10.5 EMI
      1. 10.5.1 EMI Plots
  11. 11Device and Documentation Support
    1. 11.1 Device Support
      1. 11.1.1 Third-Party Products Disclaimer
    2. 11.2 Receiving Notification of Documentation Updates
    3. 11.3 Community Resources
    4. 11.4 Trademarks
    5. 11.5 Electrostatic Discharge Caution
    6. 11.6 Glossary
  12. 12Mechanical, Packaging, and Orderable Information
    1. 12.1 Tape and Reel Information

Package Options

Refer to the PDF data sheet for device specific package drawings

Mechanical Data (Package|Pins)
  • RLX|41
Thermal pad, mechanical data (Package|Pins)
Orderable Information

7.3.6 Switching Frequency (RT)

The recommended switching frequency range of the LMZM33606 is 350 kHz to 1.2 MHz. Table 6 shows the allowable output voltage range for several switching frequency settings for three common input voltages. Under some operating conditions, the device can operate at higher switching frequencies (up to 2.2 MHz), however, this will reduce efficiency and thermal performance. The switching frequency can easily be set by connecting a resistor (RRT) between the RT pin and AGND. Additionally, the RT pin can be left floating, and the LMZM33606 operates at 500 kHz default switching frequency. Use Equation 3 to calculate the RRT value for a desired frequency or simply select from Table 6.

The switching frequency must be selected based on the output voltage setting of the device. See Table 6 for RRT values and the allowable output voltage range at a given switching frequency for several common input voltages. For the most efficient solution, always select the lowest allowable frequency.

Equation 3. LMZM33606 RTeq-01-snvsb11.gif

Table 6. Switching Frequency vs Output Voltage

SWITCHING FREQUENCY (kHz) RRT RESISTOR (kΩ) VIN = 5 V (±10%) VIN = 12 V (±10%) VIN = 24 V (±10%)
VOUT RANGE (V) VOUT RANGE (V) VOUT RANGE (V)
MIN MAX MIN MAX MIN MAX
350 115 1 4 1 8.2 1 8.4
400 100 1 4 1 8.8 1 9.9
500 78.7 or open 1 4 1 9.9 1.1 13.9
600 64.9 1 4 1 9.9 1.3 15.6
700 54.9 1 3.5 1 9.7 1.5 16.9
800 47.5 1 3.4 1 9.6 1.7 18
1000 38.3 1 3.4 1.1 9.3 2.1 20
1200 31.6 1 3.3 1.3 9.1 2.5 19.1
1500 25.5 1 2.9 1.8 8.1 3.2 18.1
1800 21.0 1.1 2.7 2.1 7.7 3.9 17.2
2000 19.1 1.2 2.5 2.5 7.5 4.4 16.5
2200 17.4 1.3 2.4 2.7 7.2 4.8 15.9