SLVSAE8F September   2011  – November 2016 TPS62080 , TPS62080A , TPS62081 , TPS62082

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 Diagrams
    3. 8.3 Feature Description
      1. 8.3.1 Power Good
      2. 8.3.2 100% Duty Cycle Low Dropout Operation
      3. 8.3.3 Output Discharge
      4. 8.3.4 Soft-Start
      5. 8.3.5 Undervoltage Lockout
      6. 8.3.6 Thermal Shutdown
      7. 8.3.7 Inductor Current Limit
    4. 8.4 Device Functional Modes
      1. 8.4.1 Enabling and Disabling the Device
      2. 8.4.2 Power Save Mode
      3. 8.4.3 Snooze Mode
  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 Setting the Output Voltage
          1. 9.2.2.1.1 Adjustable Output Voltage Version
        2. 9.2.2.2 Output Filter Design
        3. 9.2.2.3 Inductor Selection
        4. 9.2.2.4 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 Thermal Considerations
  12. 12Device and Documentation Support
    1. 12.1 Device Support
      1. 12.1.1 Third-Party Products Disclaimer
    2. 12.2 Documentation Support
      1. 12.2.1 Related Documentation
    3. 12.3 Related Links
    4. 12.4 Receiving Notification of Documentation Updates
    5. 12.5 Community Resources
    6. 12.6 Trademarks
    7. 12.7 Electrostatic Discharge Caution
    8. 12.8 Glossary
  13. 13Mechanical, Packaging, and Orderable Information

Package Options

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

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 TPS62080 and TPS62080A are synchronous step-down converter whose output voltage is adjusted by component selection. The following section discusses the design of the external components to complete the power supply design for several input and output voltage options by using typical applications as a reference. The TPS62081 and TPS62082 provide a fixed output volage which do not need an external resistor divider.

9.2 Typical Application

TPS62080 TPS62080A TPS62081 TPS62082 TPS62080_adj_typ_app.gif Figure 7. Typical Application Schematic

9.2.1 Design Requirements

For this design example, use Table 2 as the input parameters.

Table 2. Design Parameters

DESIGN PARAMETER EXAMPLE VALUE
Input voltage 2.3 V to 6 V
Output voltage 1.2 V
Output ripple voltage < 20 mV
Maximum output current 1.2 A

9.2.2 Detailed Design Procedure

Table 3 lists the components used for the example.

Table 3. List of Components

REFERENCE DESCRIPTION MANUFACTURER
C1 10 uF, Ceramic Capacitor, 6.3 V, X5R, size 0603 Std
C2 22 uF, Ceramic Capacitor, 6.3 V, X5R, size 0805, GRM21BR60J226ME39L Murata
L1 1.0 µH, Power Inductor, 2.2 A, size 3 × 3 × 1.2 mm, XFL3012-102MEB Coilcraft
R1 Depending on the output voltage of TPS62080, 1%; Not populated for TPS62081, TPS62082; Std
R2 39.2k, Chip Resistor, 1/16W, 1%, size 0603 Std
R3 178k, Chip Resistor, 1/16W, 1%, size 0603 Std

9.2.2.1 Setting the Output Voltage

The TPS608x devices are available as fixed and adjustable output voltage versions. The fixed voltage versions are internally programmed to a fixed output voltage, whereas the adjustable output voltage version needs to be programmed via an external voltage divider to set the desired output voltage.

9.2.2.1.1 Adjustable Output Voltage Version

For the adjustable output voltage version, an external resistor divider is used. By selecting R1 and R2, the output voltage is programmed to the desired value.

When the output voltage is regulated, the typical voltage at the FB pin is VFB for the adjustable devices. The following equation can be used to calculate R1 and R2.

Equation 2. TPS62080 TPS62080A TPS62081 TPS62082 EQ1_VS_lvsae8.gif

For best accuracy, R2 should be kept smaller than 40kΩ to ensure that the current flowing through R2 is at least 100 times larger than IFB. Changing towards a lower value increases the robustness against noise injection. Changing towards higher values reduces the input current. For lowest input current during Snooze Mode, it is recommended to use a fixed output voltage version such as TPS62081 and TPS62082.

9.2.2.2 Output Filter Design

The inductor and the output capacitor together provide a low pass filter. To simplify this process, Table 4 outlines possible inductor and capacitor value combinations for most applications. Checked cells represent combinations that are proven for stability by simulation and lab test. Further combinations should be checked for each individual application.

Table 4. Matrix of Output Capacitor and Inductor Combinations

L [µH](3) COUT [µF](3)
10 22 47 100 150
0.47
1 + +(1)(2) + +
2.2 + + + +
4.7
(1) Plus mark indicates recommended filter combinations.
(2) Filter combination in typical application.
(3) Capacitance tolerance and bias voltage de-rating is anticipated. The effective capacitance can vary by +20% and –50%. Inductor tolerance and current de-rating is anticipated. The effective inductance can vary by +20% and –30%.

9.2.2.3 Inductor Selection

The main parameters for the inductor selection are the inductor value and then the saturation current of the inductor. To calculate the maximum inductor current under static load conditions, Equation 3 is given.

Equation 3. TPS62080 TPS62080A TPS62081 TPS62082 Eq_IL_peak_PWM_lvsae8.gif

where

  • IOUT,MAX = Maximum output current
  • ΔIL = Inductor current ripple
  • fSW = Switching frequency
  • L = Inductor value

TI recommends to choose the saturation current for the inductor 20%~30% higher than the IL,MAX, out of Equation 3. A higher inductor value is also useful to lower ripple current, but increases the transient response time as well. The following inductors are recommended for use.

Table 5. List of Recommended Inductors

INDUCTANCE
[µH]		 CURRENT RATING
[mA]		 DIMENSIONS
L x W x H [mm3]		 DC RESISTANCE
[mΩ typ]		 TYPE MANUFACTURER
1.0 2500 3 x 3 x 1.2 35 XFL3012-102ME Coilcraft
1.0 1650 3 x 3 x 1.2 40 LQH3NPN1R0NJ0 Murata
2.2 2500 4 x 3.7 x 1.65 49 LQH44PN2R2MP0 Murata
2.2 1600 3 x 3 x 1.2 81 XFL3012-222ME Coilcraft

9.2.2.4 Capacitor Selection

The input capacitor is the low impedance energy source for the converter which helps to provide stable operation. A low ESR multilayer ceramic capacitor is recommended for best filtering and should be placed between VIN and GND as close as possible to those pins. For most applications 10 μF is sufficient, though a larger value reduces input current ripple.

The architecture of the TPS6208X 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 resistance up to high frequencies and to get narrow capacitance variation with temperature, it's recommended to use X7R or X5R dielectric. The TPS6208x is designed to operate with an output capacitance of 10 µF to 100 µF and beyond, as outlined in Table 4. Load transient testing and measuring the bode plot are good ways to verify stability with larger capacitor values.

Table 6. List of Recommended Capacitors

CAPACITANCE
[µF]		 TYPE DIMENSIONS
L x W x H [mm3]		 MANUFACTURER
10 GRM188R60J106M 0603: 1.6 x 0.8 x 0.8 Murata
22 GRM188R60G226M 0603: 1.6 x 0.8 x 0.8 Murata
22 GRM21BR60J226M 0805: 2.0 x 1.2 x 1.25 Murata

9.2.3 Application Curves

TPS62080 TPS62080A TPS62081 TPS62082 TPS62080_1.png Figure 8. Efficiency vs Load Current
TPS62080 TPS62080A TPS62081 TPS62082 TPS62080_3.png Figure 10. Efficiency vs Load Current
TPS62080 TPS62080A TPS62081 TPS62082 TPS62080_4.png Figure 12. Efficiency vs Load Current
TPS62080 TPS62080A TPS62081 TPS62082 TPS62080_7.png Figure 14. Output Voltage vs Input Voltage
TPS62080 TPS62080A TPS62081 TPS62082 TPS62080_9.png Figure 16. Output Voltage vs Input Voltage
TPS62080 TPS62080A TPS62081 TPS62082 TPS62080_11.png Figure 18. Output Voltage vs Load Current
TPS62080 TPS62080A TPS62081 TPS62082 TPS62080_13.png Figure 20. Output Voltage vs Load Current
TPS62080 TPS62080A TPS62081 TPS62082 TPS62080_15.png
Figure 22. Switching Frequency vs Load Current
TPS62080 TPS62080A TPS62081 TPS62082 G15_TPS62080.gif
VIN = 3.3 V, VOUT = 1.2 V, Load Current = 10 mA
Figure 24. Typical Application (PFM Mode)
TPS62080 TPS62080A TPS62081 TPS62082 G17_TPS62080.gif
VIN = 3.3 V, VOUT = 1.2 V, Load Current = 50 mA to 1 A
Figure 26. Load Transient
TPS62080 TPS62080A TPS62081 TPS62082 G19_TPS62080.gif
VIN = 3.3 V, VOUT = 1.2 V, Load = 2.2 Ω
Figure 28. Start Up
TPS62080 TPS62080A TPS62081 TPS62082 G21_TPS62080.gif
VIN = 3.3 V, VOUT = 1.2 V, No Load
Figure 30. Shutdown
TPS62080 TPS62080A TPS62081 TPS62082 TPS62080_2.png Figure 9. Efficiency vs Load Current
TPS62080 TPS62080A TPS62081 TPS62082 TPS62080_5.png Figure 11. Efficiency vs Load Current
TPS62080 TPS62080A TPS62081 TPS62082 TPS62080_6.png Figure 13. Output Voltage vs Input Voltage
TPS62080 TPS62080A TPS62081 TPS62082 TPS62080_8.png Figure 15. Output Voltage vs Input Voltage
TPS62080 TPS62080A TPS62081 TPS62082 TPS62080_10.png Figure 17. Output Voltage vs Load Current
TPS62080 TPS62080A TPS62081 TPS62082 TPS62080_12.png Figure 19. Output Voltage vs Load Current
TPS62080 TPS62080A TPS62081 TPS62082 TPS62080_14.png Figure 21. Switching Frequency vs Load Current
TPS62080 TPS62080A TPS62081 TPS62082 G14_TPS62080.gif
VIN = 3.3 V, VOUT = 1.2 V, Load Current = 500 mA
Figure 23. Typical Application (PWM Mode)
TPS62080 TPS62080A TPS62081 TPS62082 G16_TPS62080.gif
VIN = 3.3 V, VOUT = 1.2 V, Load Current = 2 mA
Figure 25. Typical Application (Snooze Mode)
TPS62080 TPS62080A TPS62081 TPS62082 G18_TPS62080.gif
VIN = 3.3 V to 4.2 V, VOUT = 1.2 V, Load = 2.2 Ω
Figure 27. Line Transient
TPS62080 TPS62080A TPS62081 TPS62082 G20_TPS62080.gif
VIN = 3.3 V, VOUT = 1.2 V, No Load
Figure 29. Start Up (Without Load)