SLVSAT8E November   2011  – May 2017 TPS62170 , TPS62171 , TPS62172 , TPS62173


  1. Features
  2. Applications
  3. Description
  4. Revision History
  5. Device Voltage Options
  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 Typical Characteristics
  8. Detailed Description
    1. 8.1 Overview
    2. 8.2 Functional Block Diagram
    3. 8.3 Feature Description
      1. 8.3.1 Enable and Shutdown (EN)
      2. 8.3.2 Current Limit and Short Circuit Protection
      3. 8.3.3 Power Good (PG)
      4. 8.3.4 Undervoltage Lockout (UVLO)
      5. 8.3.5 Thermal Shutdown
    4. 8.4 Device Functional Modes
      1. 8.4.1 Soft Start
      2. 8.4.2 Pulse Width Modulation (PWM) Operation
      3. 8.4.3 Power Save Mode Operation
      4. 8.4.4 100% Duty-Cycle Operation
  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. Custom Design with WEBENCH® Tools
        2. Programming the Output Voltage
        3. External Component Selection
          1. Inductor Selection
        4. Capacitor Selection
          1. Output Capacitor
          2. Input Capacitor
        5. Output Filter and Loop Stability
        6. TPS6216x Components List
      3. 9.2.3 Application Curves
    3. 9.3 System Examples
      1. 9.3.1 Inverting Power Supply
  10. 10Power Supply Recommendations
  11. 11Layout
    1. 11.1 Layout Guidelines
    2. 11.2 Layout Example
    3. 11.3 Thermal Considerations
  12. 12Device and Documentation Support
    1. 12.1 Device Support
      1. 12.1.1 Third-Party Products Disclaimer
      2. 12.1.2 Development Support
        1. Custom Design With WEBENCH® Tools
    2. 12.2 Documentation Support
      1. 12.2.1 Related Documentation
    3. 12.3 Related Links
    4. 12.4 Community Resources
    5. 12.5 Trademarks
    6. 12.6 Electrostatic Discharge Caution
    7. 12.7 Glossary
  13. 13Mechanical, Packaging, and Orderable Information

Package Options

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

Application and Implementation


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.

Application Information

The TPS6217x device family are easy to use synchronous step-down DC-DC converters optimized for applications with high power density. A high switching frequency of typically 2.25 MHz allows the use of small inductors and provides fast transient response as well as high output voltage accuracy by utilization of the DCS-Control™ topology. With its wide operating input voltage range of 3 V to 17 V, the devices are ideally suited for systems powered from either a Li-Ion or other battery as well as from 12-V intermediate power rails. It supports up to 0.5-A continuous output current at output voltages between 0.9 V and 6 V (with 100% duty cycle mode).

Typical Application


TPS62170 TPS62171 TPS62172 TPS62173 SLVSAT8_measinfo.gif Figure 7. TPS62170 Adjustable Power Supply


Design Requirements

The design guideline provides a component selection to operate the device within the Recommended Operating Conditions.

Detailed Design Procedure

Custom Design with WEBENCH® Tools

Click here to create a custom design using the TPS62170 device with the WEBENCH® Power Designer.

  1. Start by entering your VIN, VOUT, and IOUT requirements.
  2. Optimize your design for key parameters like efficiency, footprint and cost using the optimizer dial and compare this design with other possible solutions from Texas Instruments.
  3. The WEBENCH Power Designer provides you with a customized schematic along with a list of materials with real time pricing and component availability.
  4. In most cases, you will also be able to:
    • Run electrical simulations to see important waveforms and circuit performance
    • Run thermal simulations to understand the thermal performance of your board
    • Export your customized schematic and layout into popular CAD formats
    • Print PDF reports for the design, and share your design with colleagues
  5. Get more information about WEBENCH tools at

Programming the Output Voltage

While the output voltage of the TPS62170 is adjustable, the TPS62171/TPS62172/TPS62173 are programmed to fixed output voltages. For fixed output versions, the FB pin is pulled down internally and may be left floating. it is recommended to connect it to AGND to improve thermal resistance. The adjustable version can be programmed for output voltages from 0.9 V to 6 V by using a resistive divider from VOUT to AGND. The voltage at the FB pin is regulated to 800 mV. The value of the output voltage is set by the selection of the resistive divider from Equation 6. It is recommended to choose resistor values which allow a current of at least 2 uA, meaning the value of R2 should not exceed 400 kΩ. Lower resistor values are recommended for highest accuracy and most robust design. For applications requiring lowest current consumption, the use of fixed output voltage versions is recommended.


Equation 6. TPS62170 TPS62171 TPS62172 TPS62173 SLVSAG7_eqvout.gif


In case the FB pin gets opened, the device clamps the output voltage at the VOS pin to about 7.4 V.

External Component Selection

The external components have to fulfill the needs of the application, but also the stability criteria of the devices control loop. The TPS6217x is optimized to work within a range of external components. The LC output filter's inductance and capacitance have to be considered together, creating a double pole, responsible for the corner frequency of the converter (see Output Filter and Loop Stability). Table 2 can be used to simplify the output filter component selection. Checked cells represent combinations that are proven for stability by simulation and lab test. Further combinations should be checked for each individual application.


Table 2. Recommended LC Output Filter Combinations(1)

4.7µF 10µF 22µF 47µF 100µF 200µF 400µF
2.2µH (2)
The values in the table are nominal values. Variations of typically ±20% due to tolerance, saturation and DC bias are assumed.
This LC combination is the standard value and recommended for most applications.


More detailed information on further LC combinations can be found in SLVA463.

Inductor Selection

The inductor selection is affected by several effects like inductor ripple current, output ripple voltage, PWM-to-PSM transition point and efficiency. In addition, the inductor selected has to be rated for appropriate saturation current and DC resistance (DCR). Equation 7 and Equation 8 calculate the maximum inductor current under static load conditions.


Equation 7. TPS62170 TPS62171 TPS62172 TPS62173 SLVSAM2_eqilmax.gif



Equation 8. TPS62170 TPS62171 TPS62172 TPS62173 SLVSAG7_eqiripple.gif


  • IL(max) is the maximum inductor current
  • ΔIL is the peak-to-peak inductor ripple current
  • L(min) is the minimum effective inductor value
  • fSW is the actual PWM switching frequency


Calculating the maximum inductor current using the actual operating conditions gives the minimum saturation current of the inductor needed. A margin of about 20% is recommended to add. A larger inductor value is also useful to get lower ripple current, but increases the transient response time and size as well. Table 3 lists inductors that are recommended for use with the TPS6217x.

Table 3. List of Inductors

Type Inductance [µH] Current [A](1) Dimensions [L x B x H] mm MANUFACTURER
VLF3012ST-2R2M1R4 2.2 µH, ±20% 1.9 A 3.0 x 2.8 x 1.2 TDK
VLF302512MT-2R2M 2.2 µH, ±20% 1.9 A 3.0 x 2.5 x 1.2 TDK
VLS252012-2R2 2.2 µH, ±20% 1.3 A 2.5 x 2.0 x 1.2 TDK
XFL3012-222MEC 2.2 µH, ±20% 1.9 A 3.0 x 3.0 x 1.2 Coilcraft
XFL3012-332MEC 3.3 µH, ±20% 1.6 A 3.0 x 3.0 x 1.2 Coilcraft
XPL2010-222MLC 2.2 µH, ±20% 1.3 A 1.9 x 2.0 x 1.0 Coilcraft
XPL2010-332MLC 3.3 µH, ±20% 1.1 A 1.9 x 2.0 x 1.0 Coilcraft
LPS3015-332ML 3.3 µH, ±20% 1.4 A 3.0 x 3.0 x 1.4 Coilcraft
PFL2512-222ME 2.2 µH, ±20% 1.0 A 2.8 x 2.3 x 1.2 Coilcraft
PFL2512-333ME 3.3 µH, ±20% 0.78 A 2.8 x 2.3 x 1.2 Coilcraft
744028003 3.3 µH, ±30% 1.0 A 2.8 x 2.8 x 1.1 Wuerth
PSI25201B-2R2MS 2.2 uH, ±20% 1.3 A 2.0 x 2.5 x 1.2 Cyntec
NR3015T-2R2M 2.2 uH, ±20% 1.5 A 3.0 x 3.0 x 1.5 Taiyo Yuden
BRC2012T2R2MD 2.2 µH, ±20% 1.0 A 2.0 x 1.25 x 1.4 Taiyo Yuden
BRC2012T3R3MD 3.3 µH, ±20% 0.87 A 2.0 x 1.25 x 1.4 Taiyo Yuden
IRMS at 40°C rise or ISAT at 30% drop.

TPS6217x can operate with an inductor as low as 2.2 µH. However, for applications running with low input voltages, 3.3 µH is recommended, to allow the full output current. The inductor value also determines the load current at which power save mode is entered:

Equation 9. TPS62170 TPS62171 TPS62172 TPS62173 SLVSAG7_eqipsm.gif

Using Equation 8, this current level is adjusted by changing the inductor value.

Capacitor Selection

Output Capacitor

The recommended value for the output capacitor is 22 µF. The architecture of the TPS6217x allows the use of tiny ceramic output capacitors with low equivalent series resistance (ESR). These capacitors provide low output voltage ripple and are recommended. To keep its low resistance up to high frequencies and to get narrow capacitance variation with temperature, it is recommended to use an X7R or X5R dielectric. Using a higher value can have some advantages like smaller voltage ripple and a tighter DC output accuracy in power save mode (see SLVA463).

Note: In power save mode, the output voltage ripple depends on the output capacitance, its ESR and the peak inductor current. Using ceramic capacitors provides small ESR and low ripple.

Input Capacitor

For most applications, 10 µF is sufficient and is recommended, though a larger value reduces input current ripple further. The input capacitor buffers the input voltage for transient events and also decouples the converter from the supply. A low ESR multilayer ceramic capacitor is recommended for best filtering and should be placed between VIN and PGND as close as possible to those pins.



DC bias effect: High capacitance ceramic capacitors have a DC bias effect, which has a strong influence on the final effective capacitance. Therefore the right capacitor value has to be chosen carefully. Package size and voltage rating in combination with dielectric material are responsible for differences between the rated capacitor value and the effective capacitance.


Output Filter and Loop Stability

The devices of the TPS6217x family are internally compensated to be stable with L-C filter combinations corresponding to a corner frequency calculated with Equation 10:


Equation 10. TPS62170 TPS62171 TPS62172 TPS62173 SLVSAG7_eqLCfilt.gif


Proven nominal values for inductance and ceramic capacitance are given in Table 2 and are recommended for use. Different values may work, but care has to be taken on the loop stability which is affected. More information including a detailed L-C stability matrix is found in SLVA463.

The TPS6217x devices, both fixed and adjustable versions, include an internal 25 pF feed forward capacitor, connected between the VOS and FB pins. This capacitor impacts the frequency behavior and sets a pole and zero in the control loop with the resistors of the feedback divider, per Equation 11 and Equation 12:


Equation 11. TPS62170 TPS62171 TPS62172 TPS62173 SLVSAG7_eqCffzero.gif


Equation 12. TPS62170 TPS62171 TPS62172 TPS62173 SLVSAG7_eqCffpole.gif


Though the TPS6217x devices are stable without the pole and zero being in a particular location, adjusting their location to the specific needs of the application can provide better performance in power save mode and/or improved transient response. An external feed-forward capacitor can also be added. A more detailed discussion on the optimization for stability vs. transient response can be found in SLVA289 and SLVA466.

If using ceramic capacitors, the DC bias effect has to be considered. The DC bias effect results in a drop in effective capacitance as the voltage across the capacitor increases (see NOTE in Capacitor selection section).

TPS6216x Components List

Table 4 shows the list of components for the Application Curves.

Table 4. List of Components

IC 17 V, 0.5A Step-Down Converter, WSON TPS62170DSG, Texas Instruments
L1 2.2 uH, 1.4 A, 3 mm x 2.8 mm x 1.2 mm VLF3012ST-2R2M1R4, TDK
C1 10 µF, 25 V, Ceramic, 0805 Standard
C2 22 µF, 6.3 V, Ceramic, 0805 Standard
R1 depending on VOUT
R2 depending on VOUT
R3 100 kΩ, Chip, 0603, 1/16 W, 1% Standard

Application Curves

VIN = 12V, VOUT = 3.3V, TA=25°C, (unless otherwise noted)
TPS62170 TPS62171 TPS62172 TPS62173 SLVSAT8_eff60iout.png Figure 8. Efficiency vs Output Current, VOUT = 6 V
TPS62170 TPS62171 TPS62172 TPS62173 SLVSAT8_eff50iout.png Figure 10. Efficiency vs Output Current, VOUT = 5 V
TPS62170 TPS62171 TPS62172 TPS62173 SLVSAT8_eff33iout.png Figure 12. Efficiency vs Output Current, VOUT = 3.3 V
TPS62170 TPS62171 TPS62172 TPS62173 SLVSAT8_eff18iout.png Figure 14. Efficiency vs Output Current, VOUT = 1.8 V
TPS62170 TPS62171 TPS62172 TPS62173 SLVSAT8_eff09iout.png Figure 16. Efficiency vs Output Current, VOUT = 0.9 V
TPS62170 TPS62171 TPS62172 TPS62173 SLVSAT8_loadreg.png Figure 18. Output Voltage Accuracy (Load Regulation)
TPS62170 TPS62171 TPS62172 TPS62173 SLVSAT8_fswiout.png Figure 20. Switching Frequency vs Output Current
TPS62170 TPS62171 TPS62172 TPS62173 SLVSAT8_voutripple.png Figure 22. Output Voltage Ripple
TPS62170 TPS62171 TPS62172 TPS62173 SLVSAT8_mode01.gif Figure 24. PWM to PSM Mode Transition
TPS62170 TPS62171 TPS62172 TPS62173 SLVSAT8_loadtranfull.gif Figure 26. Load Transient Response in PWM Mode
(200 mA to 500 mA)
TPS62170 TPS62171 TPS62172 TPS62173 SLVSAT8_loadtranrise.gif Figure 28. Load Transient Response in PWM Mode
(200 mA to 500 mA), Rising Edge
TPS62170 TPS62171 TPS62172 TPS62173 SLVSAT8_stuplow.gif Figure 30. Startup with IOUT = 500 mA, VOUT = 3.3 V
TPS62170 TPS62171 TPS62172 TPS62173 SLVSAT8_PSMtyp.gif Figure 32. Typical Operation in Power Save Mode
(IOUT = 66 mA)
TPS62170 TPS62171 TPS62172 TPS62173 SLVSAT8_eff60vin.png Figure 9. Efficiency vs Input Voltage, VOUT = 6 V
TPS62170 TPS62171 TPS62172 TPS62173 SLVSAT8_eff50vin.png Figure 11. Efficiency vs Input Voltage, VOUT = 5 V
TPS62170 TPS62171 TPS62172 TPS62173 SLVSAT8_eff33vin.png Figure 13. Efficiency vs Input Voltage, VOUT = 3.3 V
TPS62170 TPS62171 TPS62172 TPS62173 SLVSAT8_eff18vin.png Figure 15. Efficiency vs Input Voltage, VOUT = 1.8 V
TPS62170 TPS62171 TPS62172 TPS62173 SLVSAT8_eff09vin.png Figure 17. Efficiency vs Input Voltage, VOUT = 0.9 V
TPS62170 TPS62171 TPS62172 TPS62173 SLVSAT8_linereg.png Figure 19. Output Voltage Accuracy (Line Regulation)
TPS62170 TPS62171 TPS62172 TPS62173 SLVSAT8_fswvin.png Figure 21. Switching Frequency vs Input Voltage
TPS62170 TPS62171 TPS62172 TPS62173 SLVSAT8_ioutmax.png Figure 23. Maximum Output Current
TPS62170 TPS62171 TPS62172 TPS62173 SLVSAT8_mode02.gif Figure 25. PSM to PWM Mode Transition
TPS62170 TPS62171 TPS62172 TPS62173 SLVSAT8_loadtranlight.gif Figure 27. Load Transient Response from
Power Save Mode (100 mA to 500 mA)
TPS62170 TPS62171 TPS62172 TPS62173 SLVSAT8_loadtranfall.gif Figure 29. Load Transient Response in PWM Mode
(200 mA to 500 mA), Falling Edge
TPS62170 TPS62171 TPS62172 TPS62173 SLVSAT8_stuphigh.gif Figure 31. Startup with IOUT = 500 mA, VOUT = 3.3 V
TPS62170 TPS62171 TPS62172 TPS62173 SLVSAT8_PWMtyp.gif Figure 33. Typical Operation in PWM mode (IOUT = 500 mA)

System Examples

Figure 34 through Figure 40 show various TPS6217x devices and input voltages that provide a 0.5-A power supply with output voltage options.

TPS62170 TPS62171 TPS62172 TPS62173 SLVSAT8_app5V.gif Figure 34. 5-V and 0.5-A Power Supply
TPS62170 TPS62171 TPS62172 TPS62173 SLVSAT8_app3.3V.gif Figure 35. 3.3-V and 0.5-A Power Supply
TPS62170 TPS62171 TPS62172 TPS62173 SLVSAT8_app2.5V.gif Figure 36. 2.5-V and 0.5-A Power Supply
TPS62170 TPS62171 TPS62172 TPS62173 SLVSAT8_app1.8V.gif Figure 37. 1.8-V and 0.5-A Power Supply
TPS62170 TPS62171 TPS62172 TPS62173 SLVSAT8_app1.5V.gif Figure 38. 1.5-V and 0.5-A Power Supply
TPS62170 TPS62171 TPS62172 TPS62173 SLVSAT8_app1.2V.gif Figure 39. 1.2-V and 0.5-A Power Supply
TPS62170 TPS62171 TPS62172 TPS62173 SLVSAT8_app1V.gif Figure 40. 1-V and 0.5-A Power Supply

Inverting Power Supply

The TPS6217x can be used as inverting power supply by rearranging external circuitry as shown in Figure 41. As the former GND node now represents a voltage level below system ground, the voltage difference between VIN and VOUT has to be limited for operation to the maximum supply voltage of 17 V (see Equation 13).


Equation 13. TPS62170 TPS62171 TPS62172 TPS62173 SLVSAT8_eqinv.gif


TPS62170 TPS62171 TPS62172 TPS62173 SLVSAT8_inverter.gif Figure 41. –5-V Inverting Power Supply

The transfer function of the inverting power supply configuration differs from the buck mode transfer function, incorporating a right half plane zero additionally. The loop stability has to be adapted and an output capacitance of at least 22 µF is recommended. A detailed design example is given in SLVA469.