SLVS294F September   2000  – August 2015 TPS62000 , TPS62002 , TPS62003 , TPS62004 , TPS62005 , TPS62006 , TPS62007 , TPS62008

PRODUCTION DATA.  

  1. 1 Features
  2. 2 Applications
  3. 3 Description
  4. 4 Revision History
  5. 5 Device Comparison Table
  6. 6 Pin Configuration and Functions
  7. 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 Typical Characteristics
  8. 8 Detailed Description
    1. 8.1 Overview
    2. 8.2 Functional Block Diagram
    3. 8.3 Feature Description
      1. 8.3.1 Low Noise Antiringing Switch
      2. 8.3.2 Enable
      3. 8.3.3 Undervoltage Lockout
      4. 8.3.4 Power Good Comparator
    4. 8.4 Device Functional Modes
      1. 8.4.1 Soft Start
      2. 8.4.2 Synchronization, Power Save Mode, and Forced PWM Mode
      3. 8.4.3 100% Duty Cycle Operation
      4. 8.4.4 No Load Operation
  9. 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 Inductor Selection
        2. 9.2.2.2 Output Capacitor Selection
        3. 9.2.2.3 Input Capacitor Selection
      3. 9.2.3 Application Curves
    3. 9.3 System Examples
      1. 9.3.1 Standard 5-V to 3.3-V/600-mA Conversion; High Efficiency
      2. 9.3.2 Single Li-ion to 2.5-V/600-mA Using Ceramic Capacitors Only
      3. 9.3.3 Single Li-ion to 1.8 V/300 mA; Smallest Solution Size
      4. 9.3.4 Dual Cell NiMH or NiCd to 1.2 V/200 mA; Smallest Solution Size
      5. 9.3.5 Dynamic Output Voltage Programming As Used in Low Power DSP Applications
  10. 10Power Supply Recommendations
  11. 11Layout
    1. 11.1 Layout Guidelines
    2. 11.2 Layout Example
  12. 12Device and Documentation Support
    1. 12.1 Device Support
      1. 12.1.1 Third-Party Products Disclaimer
    2. 12.2 Community Resources
    3. 12.3 Related Links
    4. 12.4 Trademarks
    5. 12.5 Electrostatic Discharge Caution
    6. 12.6 Glossary
  13. 13Mechanical, Packaging, and Orderable Information

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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 TPS6200x device family are highly efficient synchronous step down DC/DC converters providing adjustable output voltages from 0.9 V to VIN and fixed output voltages.

9.2 Typical Application

TPS62000 TPS62001 TPS62002 TPS62003 TPS62004 TPS62005 TPS62006 TPS62007 TPS62008 app_cir_lvs294.gifFigure 5. Typical Application Circuit for Adjustable Output Voltage Option

9.2.1 Design Requirements

When the adjustable output voltage version (TPS62000DGS) is used, the output voltage is set by the external resistor divider (see Figure 5).

The output voltage is calculated as:

Equation 1. TPS62000 TPS62001 TPS62002 TPS62003 TPS62004 TPS62005 TPS62006 TPS62007 TPS62008 eq_1_lvs294.gif

with R1 + R2 ≤ 1 MΩ

R1 + R2 should not be greater than 1 MW because of stability reasons.

For stability reasons, a small bypass capacitor (C(ff)) is required in parallel to the upper feedback resistor, refer to Figure 5. The bypass capacitor value can be calculated as:

Equation 2. TPS62000 TPS62001 TPS62002 TPS62003 TPS62004 TPS62005 TPS62006 TPS62007 TPS62008 eq_2_lvs294.gif
Equation 3. TPS62000 TPS62001 TPS62002 TPS62003 TPS62004 TPS62005 TPS62006 TPS62007 TPS62008 eq_3_lvs294.gif

R1 is the upper resistor of the voltage divider. For C(ff), choose a value which comes closest to the computed result.

9.2.2 Detailed Design Procedure

9.2.2.1 Inductor Selection

A 10 μH minimum output inductor is used with the TPS6200x. Values larger than 22 μH or smaller than 10 μH may cause stability problems because of the internal compensation of the regulator.

For output voltages greater than 1.8 V, a 22 μH inductance might be used in order to improve the efficiency of the converter.

After choosing the inductor value of typically 10 μH, two additional inductor parameters should be considered: first the current rating of the inductor and second the DC resistance.

The DC resistance of the inductance influences directly the efficiency of the converter. Therefore, an inductor with lowest DC resistance should be selected for highest efficiency.

In order to avoid saturation of the inductor, the inductor should be rated at least for the maximum output current plus the inductor ripple current which is calculated as:

Equation 4. TPS62000 TPS62001 TPS62002 TPS62003 TPS62004 TPS62005 TPS62006 TPS62007 TPS62008 eq_4_lvs294.gif

where

  • ƒ = Switching frequency (750 kHz typical)
  • L = Inductor value
  • ΔIL = Peak-to-peak inductor ripple current
  • IL(max) = Maximum inductor current

The highest inductor current occurs at maximum VIN.

A more conservative approach is to select the inductor current rating just for the maximum switch current of the TPS6200x which is 1.6 A with ILIM = VIN and 900 mA with ILIM = GND. See Table 1 for recommended inductors.

Table 1. Tested Inductors

OUTPUT CURRENT INDUCTOR VALUE COMPONENT SUPPLIER COMMENTS
0 mA to 600 mA 10 μH Coilcraft DO3316P-103
Coilcraft DT3316P-103
Sumida CDR63B-100
Sumida CDRH5D28-100		 High efficiency
Coilcraft DO1608C-103
Sumida CDRH4D28-100		 Smallest solution
0 mA to 300 mA 10 μH Coilcraft DO1608C-103 High efficiency
Murata LQH4C100K04 Smallest solution

9.2.2.2 Output Capacitor Selection

For best performance, a low ESR output capacitor is needed. At output voltages greater than 1.8 V, ceramic output capacitors can be used to show the best performance. Output voltages below 1.8 V require a larger output capacitor and ESR value to improve the performance and stability of the converter.

Table 2. Capacitor Selection

OUTPUT VOLTAGE RANGE OUTPUT CAPACITOR OUTPUT CAPACITOR ESR
1.8 V ≤ VIN ≤ 5.5 V Co ≥ 10 μF ESR ≤ 120 mΩ
0.8 V ≤ VIN < 1.8 V Co ≥ 47 μF ESR > 50 mΩ

See Table 3 for recommended capacitors.

If an output capacitor is selected with an ESR value ≤ 120 mΩ, its RMS ripple current rating always meets the application requirements. Just for completeness, the RMS ripple current is calculated as:

Equation 5. TPS62000 TPS62001 TPS62002 TPS62003 TPS62004 TPS62005 TPS62006 TPS62007 TPS62008 eq_5_lvs294.gif

The overall output ripple voltage is the sum of the voltage spike caused by the output capacitor ESR plus the voltage ripple caused by charging and discharging the output capacitor:

Equation 6. TPS62000 TPS62001 TPS62002 TPS62003 TPS62004 TPS62005 TPS62006 TPS62007 TPS62008 eq_6_lvs294.gif

Where the highest output voltage ripple occurs at the highest input voltage VI.

Table 3. Tested Capacitors

CAPACITOR VALUE ESR/mΩ COMPONENT SUPPLIER COMMENTS
10 μF 50 Taiyo Yuden JMK316BJ106KL Ceramic
47 μF 100 Sanyo 6TPA47M POSCAP
68 μF 100 Spraque 594D686X0010C2T Tantalum

9.2.2.3 Input Capacitor Selection

Because of the nature of the buck converter having a pulsating input current, a low ESR input capacitor is required for best input voltage filtering and minimizing the interference with other circuits caused by high input voltage spikes.

The input capacitor should have a minimum value of 10 μF and can be increased without any limit for better input voltage filtering.

The input capacitor should be rated for the maximum input ripple current calculated as:

Equation 7. TPS62000 TPS62001 TPS62002 TPS62003 TPS62004 TPS62005 TPS62006 TPS62007 TPS62008 eq_7_lvs294.gif

The worst case RMS ripple current occurs at D = 0.5 and is calculated as: TPS62000 TPS62001 TPS62002 TPS62003 TPS62004 TPS62005 TPS62006 TPS62007 TPS62008 inline_lvs294.gif

Ceramic capacitor show a good performance because of their low ESR value, and they are less sensitive against voltage transients compared to tantalum capacitors.

Place the input capacitor as close as possible to the input pin of the IC for best performance.

9.2.3 Application Curves

TPS62000 TPS62001 TPS62002 TPS62003 TPS62004 TPS62005 TPS62006 TPS62007 TPS62008 eff2_io_lvs294.gifFigure 6. Efficiency vs Load Current
TPS62000 TPS62001 TPS62002 TPS62003 TPS62004 TPS62005 TPS62006 TPS62007 TPS62008 eff4_io_lvs294.gifFigure 8. Efficiency vs Load Current
TPS62000 TPS62001 TPS62002 TPS62003 TPS62004 TPS62005 TPS62006 TPS62007 TPS62008 line_trns_lvs294.gifFigure 10. Line Transient Response
TPS62000 TPS62001 TPS62002 TPS62003 TPS62004 TPS62005 TPS62006 TPS62007 TPS62008 startup_lvs294.gifFigure 12. Start-Up vs Time
TPS62000 TPS62001 TPS62002 TPS62003 TPS62004 TPS62005 TPS62006 TPS62007 TPS62008 eff3_io_lvs294.gifFigure 7. Efficiency vs Load Current
TPS62000 TPS62001 TPS62002 TPS62003 TPS62004 TPS62005 TPS62006 TPS62007 TPS62008 load_trns_lvs294.gifFigure 9. Load Transient Response
TPS62000 TPS62001 TPS62002 TPS62003 TPS62004 TPS62005 TPS62006 TPS62007 TPS62008 pwr_sav_lvs294.gifFigure 11. Power Save Mode Operation
TPS62000 TPS62001 TPS62002 TPS62003 TPS62004 TPS62005 TPS62006 TPS62007 TPS62008 vo_io_lvs294.gifFigure 13. Output Voltage vs Load Current

9.3 System Examples

9.3.1 Standard 5-V to 3.3-V/600-mA Conversion; High Efficiency

TPS62000 TPS62001 TPS62002 TPS62003 TPS62004 TPS62005 TPS62006 TPS62007 TPS62008 standard_lvs294.gifFigure 14. Standard 5-V to 3.3-V/600-mA Conversion; High Efficiency

9.3.2 Single Li-ion to 2.5-V/600-mA Using Ceramic Capacitors Only

TPS62000 TPS62001 TPS62002 TPS62003 TPS62004 TPS62005 TPS62006 TPS62007 TPS62008 cir_caps_lvs294.gifFigure 15. Single Li-ion to 2.5-V/600-mA Using Ceramic Capacitors Only

9.3.3 Single Li-ion to 1.8 V/300 mA; Smallest Solution Size

TPS62000 TPS62001 TPS62002 TPS62003 TPS62004 TPS62005 TPS62006 TPS62007 TPS62008 small_lvs294.gif

NOTE:

For low noise operation connect SYNC to VIN
Figure 16. Single Li-ion to 1.8 V/300 mA; Smallest Solution Size

9.3.4 Dual Cell NiMH or NiCd to 1.2 V/200 mA; Smallest Solution Size

TPS62000 TPS62001 TPS62002 TPS62003 TPS62004 TPS62005 TPS62006 TPS62007 TPS62008 dual_cell_lvs294.gifFigure 17. Dual Cell NiMH or NiCd to 1.2 V/200 mA; Smallest Solution Size

9.3.5 Dynamic Output Voltage Programming As Used in Low Power DSP Applications

TPS62000 TPS62001 TPS62002 TPS62003 TPS62004 TPS62005 TPS62006 TPS62007 TPS62008 dsp_app_lvs294.gif
1. Use a small R-C filter to filter wrong reset signals during output voltage transitions.
2. A large value is used for C(ff) to compensate for the parasitic capacitance introduced into the regulation loop by Q1.
Figure 18. Dynamic Output Voltage Programming As Used in Low Power DSP Applications