ZHCS803E June   2013  – February 2020 LMZ31704

PRODUCTION DATA.  

  1. 1 特性
  2. 2 应用
  3. 3 说明
    1.     简化应用
  4. 4 修订历史记录
  5. 5 Specifications
    1. 5.1 Absolute Maximum Ratings
    2. 5.2 ESD Ratings
    3. 5.3 Recommended Operating Conditions
    4. 5.4 Package Specifications
    5. 5.5 Thermal Information
    6. 5.6 Electrical Characteristics
  6. 6 Device Information
    1. 6.1 Functional Block Diagram
    2.     Pin Functions
  7. 7 Typical Characteristics (PVIN = VIN = 12 V)
  8. 8 Typical Characteristics (PVIN = VIN = 5 V)
  9. 9 Typical Characteristics (PVIN = 3.3 V, VIN = 5 V)
  10. 10Application Information
    1. 10.1  Adjusting the Output Voltage
    2. 10.2  Capacitor Recommendations for the LMZ31704 Power Supply
      1. 10.2.1 Capacitor Technologies
        1. 10.2.1.1 Electrolytic, Polymer-Electrolytic Capacitors
        2. 10.2.1.2 Ceramic Capacitors
        3. 10.2.1.3 Tantalum, Polymer-Tantalum Capacitors
      2. 10.2.2 Input Capacitor
      3. 10.2.3 Output Capacitor
    3. 10.3  Transient Response
    4. 10.4  Transient Waveforms
    5. 10.5  Application Schematics
    6. 10.6  Custom Design With WEBENCH® Tools
    7. 10.7  VIN and PVIN Input Voltage
    8. 10.8  3.3 V PVIN Operation
    9. 10.9  Power Good (PWRGD)
    10. 10.10 SYNC_OUT
    11. 10.11 Parallel Operation
    12. 10.12 Light Load Efficiency (LLE)
    13. 10.13 Power-Up Characteristics
    14. 10.14 Pre-Biased Start-up
    15. 10.15 Remote Sense
    16. 10.16 Thermal Shutdown
    17. 10.17 Output On/Off Inhibit (INH)
    18. 10.18 Slow Start (SS/TR)
    19. 10.19 Overcurrent Protection
    20. 10.20 Synchronization (CLK)
    21. 10.21 Sequencing (SS/TR)
    22. 10.22 Programmable Undervoltage Lockout (UVLO)
    23. 10.23 Layout Considerations
    24. 10.24 EMI
  11. 11器件和文档支持
    1. 11.1 器件支持
      1. 11.1.1 开发支持
        1. 11.1.1.1 使用 WEBENCH® 工具创建定制设计
    2. 11.2 文档支持
      1. 11.2.1 相关文档
    3. 11.3 接收文档更新通知
    4. 11.4 支持资源
    5. 11.5 商标
    6. 11.6 静电放电警告
    7. 11.7 Glossary
  12. 12机械、封装和可订购信息
    1. 12.1 Tape and Reel Information

封装选项

机械数据 (封装 | 引脚)
散热焊盘机械数据 (封装 | 引脚)
订购信息

10.1 Adjusting the Output Voltage

The VADJ control sets the output voltage of the LMZ31704. The output voltage adjustment range is from 0.6 V to 5.5 V. The adjustment method requires the addition of RSET, which sets the output voltage, the connection of SENSE+ to VOUT, and in some cases, RRT which sets the switching frequency. The RSET resistor must be connected directly between the VADJ (pin 26) and AGND (pin 23). The SENSE+ pin (pin 27) must be connected to VOUT either at the load for improved regulation or at VOUT of the device. The RRT resistor must be connected directly between the RT/CLK (pin 22) and AGND (pin 23). Table 1 gives the standard external RSET resistor for a number of common bus voltages, along with the recommended RRT resistor for that output voltage.

Table 1. Standard RSET Resistor Values for Common Output Voltages

RESISTORS OUTPUT VOLTAGE VOUT (V)
0.9 1.0 1.2 1.8 2.5 3.3 5.0
RSET (kΩ) 2.87 2.15 1.43 0.715 0.453 0.316 0.196
RRT (kΩ) 1000 1000 487 169 90.9 90.9 63.4

For other output voltages, the value of the required resistor can either be calculated using the following formula, or simply selected from the range of values given in Table 2.

Equation 1. LMZ31704 q_rset01_lvsaw7.gif

Table 2. Standard RSET Resistor Values

VOUT (V) RSET (kΩ) RRT(kΩ) fSW(kHz) VOUT (V) RSET (kΩ) RRT(kΩ) fSW(kHz)
0.6 open OPEN 200 3.1 0.348 90.9 750
0.7 8.66 OPEN 200 3.2 0.332 90.9 750
0.8 4.32 OPEN 200 3.3 0.316 90.9 750
0.9 2.87 1000 250 3.4 0.309 90.9 750
1.0 2.15 1000 250 3.5 0.294 90.9 750
1.1 1.74 1000 250 3.6 0.287 90.9 750
1.2 1.43 487 300 3.7 0.280 90.9 750
1.3 1.24 487 300 3.8 0.267 90.9 750
1.4 1.07 487 300 3.9 0.261 90.9 750
1.5 0.953 487 300 4.0 0.255 90.9 750
1.6 0.866 487 300 4.1 0.243 63.4 1000
1.7 0.787 487 300 4.2 0.237 63.4 1000
1.8 0.715 169 500 4.3 0.232 63.4 1000
1.9 0.665 169 500 4.4 0.226 63.4 1000
2.0 0.619 169 500 4.5 0.221 63.4 1000
2.1 0.576 169 500 4.6 0.215 63.4 1000
2.2 0.536 169 500 4.7 0.210 63.4 1000
2.3 0.511 169 500 4.8 0.205 63.4 1000
2.4 0.475 169 500 4.9 0.200 63.4 1000
2.5 0.453 90.9 750 5.0 0.196 63.4 1000
2.6 0.432 90.9 750 5.1 0.191 63.4 1000
2.7 0.412 90.9 750 5.2 0.187 63.4 1000
2.8 0.392 90.9 750 5.3 0.182 63.4 1000
2.9 0.374 90.9 750 5.4 0.178 63.4 1000
3.0 0.357 90.9 750 5.5 0.174 63.4 1000