SLVSBR0C October   2014  – June 2015 TPS8268090 , TPS8268105 , TPS8268120 , TPS8268150 , TPS8268180

PRODUCTION DATA.  

  1. Features
  2. Applications
  3. Description
  4. Revision History
  5. Device Comparison Table
  6. Pin Configuration and Functions
  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 Timing Requirements
    7. 7.7 Typical Characteristics
  8. Detailed Description
    1. 8.1 Overview
    2. 8.2 Functional Block Diagram
    3. 8.3 Feature Description
      1. 8.3.1 Soft Start
      2. 8.3.2 Undervoltage Lockout
      3. 8.3.3 Short-Circuit Protection
      4. 8.3.4 Thermal Shutdown
      5. 8.3.5 Enable
      6. 8.3.6 MODE Pin
    4. 8.4 Device Functional Modes
      1. 8.4.1 Spread Spectrum, PWM Frequency Dithering
  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 Input Capacitor Selection
        2. 9.2.2.2 Output Capacitor Selection
      3. 9.2.3 Application Curves
  10. 10Power Supply Recommendations
  11. 11Layout
    1. 11.1 Layout Guidelines
    2. 11.2 Layout Example
    3. 11.3 Surface Mount Information
    4. 11.4 Thermal and Reliability Information
  12. 12Device and Documentation Support
    1. 12.1 Documentation Support
      1. 12.1.1 References
    2. 12.2 Related Links
    3. 12.3 Trademarks
    4. 12.4 Electrostatic Discharge Caution
    5. 12.5 Glossary
  13. 13Mechanical, Packaging, and Orderable Information
    1. 13.1 Package Summary
    2. 13.2 MicroSiP™ DC/DC Module Package Dimensions

パッケージ・オプション

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メカニカル・データ(パッケージ|ピン)
  • SIP|9
サーマルパッド・メカニカル・データ
発注情報

9 Application and Implementation

NOTE

Information in the following applications sections is not part of the TI component specification, and TI does not warrant its accuracy or completeness. TI’s customers are responsible for determining suitability of components for their purposes. Customers should validate and test their design implementation to confirm system functionality.

9.1 Application Information

The TPS8268x device is a complete DC/DC step-down power supply optimized for small solution size. Included in the package are the switching regulator, inductor and input/output capacitors. Integration of passive components enables a tiny solution size of only 6.7mm2.

9.2 Typical Application

TPS8268180 TPS8268150 TPS8268120 TPS8268105 TPS8268090 PM_sch_TPS8268105.gifFigure 23. Typical Application Schematic

9.2.1 Design Requirements

Figure 23 shows the schematic of the typical application. The following design guidelines provide all information to operate the device within the recommended operating conditions. An external input capacitor may be required depending on the source impedance of the battery or pre-regulator used to power TPS8268x. See also Power Supply Recommendations.

Reference Description Manufacturer
IC1 MicroSIP Module TPS8268xSIP Texas Instruments
C1 Tantalum Capacitor; T520B157M006ATE025; 150uF/6.3V Kemet

9.2.2 Detailed Design Procedure

The TPS8268x allows the design of a complete power supply with no additional external components. The input capacitance can be increased in case the source impedance is large or if there are high load transients expected at the output. The dc bias effect of the input and output capacitors must be taken into account and the total capacitance on the output must not exceed the value given in the recommended operating conditions.

9.2.2.1 Input Capacitor Selection

Because the nature of the buck converter has a pulsating input current, a low ESR input capacitor is required.

For most applications, the input capacitor that is integrated into the TPS8268x is sufficient. If the application exhibits a noisy or erratic switching frequency, experiment with additional input ceramic capacitance to find a remedy.

The TPS8268x uses a tiny ceramic input capacitor. When a ceramic capacitor is combined with trace or cable inductance, such as from a wall adapter, a load step at the output can induce ringing at the VIN pin. This ringing can couple to the output and be mistaken as loop instability or can even damage the part. In this circumstance, additional "bulk" capacitance, such as electrolytic or tantalum, should be placed between the input of the converter and the power source lead to reduce ringing that can occur between the inductance of the power source leads and CI.

9.2.2.2 Output Capacitor Selection

The advanced fast-response voltage mode control scheme of the TPS8268x allows the use of tiny ceramic output capacitors. Ceramic capacitors with low ESR values have the lowest output voltage ripple and are recommended. For most applications, the output capacitor integrated in the TPS8268x is sufficient. An additional output capacitor may be used for the purpose of improving AC voltage accuracy during large load transients.

To further reduce the voltage drop during load transients, additional external output capacitance up to 30µF can be added. A low ESR multilayer ceramic capacitor (MLCC) is suitable for most applications. The total effective output capacitance must remain below 30µF.

As the device operates in PWM mode, the overall output voltage ripple is the sum of the voltage step that is caused by the output capacitor´s ESL and the ripple current that flows through the output capacitor´s impedance.

Because the damping factor in the output path is directly related to several resistive parameters (e.g. inductor DCR, power-stage rDS(on), PCB DC resistance, load switches rDS(on) …) that are temperature dependant, the converter´s small and large signal behavior should be checked over the input voltage range, load current range and temperature range.

The easiest test is to evaluate, directly at the converter’s output, the following items:

  • efficiency
  • load transient response
  • output voltage ripple

During the recovery time from a load transient, the output voltage can be monitored for settling time, overshoot or ringing that helps judge the converter’s stability. Without any ringing, the loop typically has more than 45° of phase margin.

9.2.3 Application Curves

TPS8268180 TPS8268150 TPS8268120 TPS8268105 TPS8268090 TPS8268x_Load_Tran_VIN_5p0V_VOUT_1p8V.gifFigure 24. Load Transient Response for TPS8268180
(Vout = 1.80V, Iout = 170mA to 1.47A to 170mA, Vin = 5V)
TPS8268180 TPS8268150 TPS8268120 TPS8268105 TPS8268090 TPS8268x_Line_Tran_IOUT_800mA_VOUT_1p8V.gifFigure 25. Line Transient Response for TPS8268180
(Vout = 1.80V; Iout = 800mA, Vin = 4V to 5V to 4V)
TPS8268180 TPS8268150 TPS8268120 TPS8268105 TPS8268090 TPS8268x_scope6_Vin5_Vout_1p8_SLVSBR0.gif
Figure 26. Startup for TPS8268180
(Vin = 5V, Vout = 1.80V)
TPS8268180 TPS8268150 TPS8268120 TPS8268105 TPS8268090 TPS82683_load_transient_5V0_1V5_1p6A_SLVSBR0.gifFigure 28. Load Transient Response for TPS8268150
(Vout = 1.5V, Iout = 160mA to 1.44A to 160mA, Vin = 5V)
TPS8268180 TPS8268150 TPS8268120 TPS8268105 TPS8268090 TPS82683_startup_SLVSBR0.gif
Figure 30. Startup for TPS8268150
(Vin = 5V, Vout = 1.5V)
TPS8268180 TPS8268150 TPS8268120 TPS8268105 TPS8268090 TPS8268x_Load_Tran_VIN_5p0V_VOUT_1p2V.gifFigure 32. Load Transient Response for TPS8268120
(Vout = 1.20V, Iout = 170mA to 1.47A to 170mA, Vin = 5V)
TPS8268180 TPS8268150 TPS8268120 TPS8268105 TPS8268090 TPS8268x_scope4_Vin5_Vout_1p2_SLVSBR0.gif
Figure 34. Startup for TPS8268120
(Vin = 5V, Vout = 1.20V)
TPS8268180 TPS8268150 TPS8268120 TPS8268105 TPS8268090 TPS8268105_Load_Transient_5V0_1V05_1p6A_SLVSBR0.gifFigure 36. Load Transient Response for TPS8268105
(Vout = 1.05V, Iout = 160mA to 1.44A to 160mA, Vin = 5V)
TPS8268180 TPS8268150 TPS8268120 TPS8268105 TPS8268090 TPS8268105_Start_up_scope_plot_SLVSBR0.gifFigure 38. Startup for TPS8268105
(Vin = 5V, Vout = 1.05V)
TPS8268180 TPS8268150 TPS8268120 TPS8268105 TPS8268090 TPS8268x_Load_Tran_VIN_5p0V_VOUT_0p9V.gifFigure 40. Load Transient Response for TPS8268090
(Vout = 0.9V, Iout = 170mA to 1.47A to 170mA, Vin = 5V)
TPS8268180 TPS8268150 TPS8268120 TPS8268105 TPS8268090 TPS82685_startup_SLVSBR0.gifFigure 42. Startup for TPS8268090
(Vin = 5V, Vout = 0.9V)
TPS8268180 TPS8268150 TPS8268120 TPS8268105 TPS8268090 TPS8268180_Voripple_SLVSBR0.gifFigure 27. Output Voltage Ripple for TPS8268180
(Vin = 5V, Vout = 1.80V, Iout = 900mA)
TPS8268180 TPS8268150 TPS8268120 TPS8268105 TPS8268090 TPS82683_LINE_transient_response_SLVSBR0.gifFigure 29. Line Transient Response for TPS8268150
(Vout = 1.5V, Iout = 800mA, Vin = 4V to 5V to 4V)
TPS8268180 TPS8268150 TPS8268120 TPS8268105 TPS8268090 TPS82683_vout_ripple_SLVSBR0.gifFigure 31. Output Voltage Ripple for TPS8268150
(Vin = 5V, Vout = 1.5V, Iout = 900mA)
TPS8268180 TPS8268150 TPS8268120 TPS8268105 TPS8268090 TPS8268x_Line_Tran_IOUT_800mA_VOUT_1p2V.gifFigure 33. Line Transient Response for TPS8268120
(Vout = 1.20V; Iout = 800mA, Vin = 4V to 5V to 4V)
TPS8268180 TPS8268150 TPS8268120 TPS8268105 TPS8268090 TPS8268120_Voripple_SLVSBR0.gifFigure 35. Output Voltage Ripple for TPS8268120
(Vin = 5V, Vout = 1.20V, Iout = 900mA)
TPS8268180 TPS8268150 TPS8268120 TPS8268105 TPS8268090 TPS8268105_LINE_transient_response_SLVSBR0.gifFigure 37. Line Transient Response for TPS8268105
(Vout = 1.05V; Iout = 900mA, Vin = 4V to 5V to 4V)
TPS8268180 TPS8268150 TPS8268120 TPS8268105 TPS8268090 TPS8268105_vout_ripple_SLVSBR0.gifFigure 39. Output Voltage Ripple for TPS8268105
(Vin = 5V, Vout = 1.05V, Iout = 900mA)
TPS8268180 TPS8268150 TPS8268120 TPS8268105 TPS8268090 TPS8268x_Line_Tran_IOUT_800mA_VOUT_0p9V.gifFigure 41. Line Transient Response for TPS8268090
(Vout = 0.90V; Iout = 900mA, Vin = 4V to 5V to 4V)
TPS8268180 TPS8268150 TPS8268120 TPS8268105 TPS8268090 TPS82685_vout_ripple_SLVSBR0.gifFigure 43. Output Voltage Ripple for TPS8268090
(Vin = 5V, Vout = 0.9V, Iout = 900mA)