SBAS221H December   2001  – October  2015 REG71050 , REG71055


  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 Typical Characteristics
  8. Detailed Description
    1. 8.1 Overview
    2. 8.2 Functional Block Diagram
    3. 8.3 Feature Description
      1. 8.3.1 Shutdown Mode
      2. 8.3.2 Protection
    4. 8.4 Device Functional Modes
      1. 8.4.1 Peak Current Reduction
      2. 8.4.2 Efficiency
  9. Application and Implementation
    1. 9.1 Application Information
    2. 9.2 Typical Applications
      1. 9.2.1 Design Requirements
      2. 9.2.2 Detailed Design Procedure
        1. Capacitor Selection
      3. 9.2.3 Application Curves
    3. 9.3 System Examples
      1. 9.3.1 1.8 V to 5.0 V With 10-mA Output Current
      2. 9.3.2 Doubling the Output Current
      3. 9.3.3 Driving LEDs
  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 Related Links
    3. 12.3 Community Resources
    4. 12.4 Trademarks
    5. 12.5 Electrostatic Discharge Caution
    6. 12.6 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


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 REG710 is a switched capacitor voltage converter that produces a regulated, low-ripple output voltage from an unregulated input voltage range from 1.8 V to 5.5 V. The high switching frequency allows the use of small surface-mount capacitors. The following section gives guidance to choose external components to complete the power supply design. Application curves are included for the typical application shown below.

9.2 Typical Applications

REG71050 REG71055 REG710 ai_typ_cir_bas221.gif Figure 7. Typical Operating Circuit

9.2.1 Design Requirements

The REG710 family of switched capacitor voltage converters offers a variety of regulated fixed output voltages. This family supports unregulated input voltages which can have values that are lower or higher than the regulated output voltage. Only input and output capacitors as well as a pump capacitor are required to have a fully functional converter. The following design procedure is adequate for the whole VIN, VOUT and load current range of REG710.

9.2.2 Detailed Design Procedure Capacitor Selection

For minimum output voltage ripple, the output capacitor COUT should be a ceramic, surface-mount type. Tantalum capacitors generally have a higher effective series resistance (ESR) and may contribute to higher output voltage ripple. Leaded capacitors also increase ripple due to the higher inductance of the package itself. To achieve best operation with low input voltage and high load current, the input and pump capacitors (CIN and CPUMP, respectively) should also be surface-mount ceramic types. In all cases, X7R or X5R dielectric are recommended. See the typical operating circuit shown in Figure 7 for component values.

With light loads or higher input voltage, a smaller 0.1-μF pump capacitor (CPUMP) and smaller 1-μF input and output capacitors (CIN and COUT, respectively) can be used. To minimize output voltage ripple, increase the output capacitor, COUT, to 10 μF or larger.

The capacitors listed in Table 2 can be used with the REG710. This table is only a representative list of compatible parts.

Table 2. Suggested Capacitors

Kemet C1206C255K8RAC 2.2 μF ±10% X7R 1206 10 V
C1206C224K8RAC 0.22 μF ±10% X7R 1206 10 V
Panasonic ECJ−2YBOJ225K 2.2 μF ±10% X5R 805 6.3 V
ECJ−2VBIC224K 0.22 μF ±10% X7R 805 16 V
ECJ−2VBIC104 0.1 μF ±10% X7R 805 16 V
Taiyo Yuden EMK316BJ225KL 2.2 μF ±10% X7R 1206 16 V
TKM316BJ224KF 0.22 μF ±10% X7R 1206 25 V

9.2.3 Application Curves

REG71050 REG71055 REG710 tc_eff_vin_bas221.gif
Figure 8. Efficiency vs VIN
REG71050 REG71055 REG710 tc_eff_load-33v_bas221.gif
Figure 10. Efficiency vs Load Current
REG71050 REG71055 REG710 tc_eff_load-27v_bas221.gif
Figure 12. Efficiency vs Load Current
REG71050 REG71055 REG710 tc_load_trans_bas221.gif
Figure 14. Load Transient Response
REG71050 REG71055 REG710 tc_out_rip_bas221.gif
Figure 16. Output Ripple Voltage
REG71050 REG71055 REG710 tc_orv-vin_bas221.gif
REG710-2.5 REG710-5
Figure 18. Output Ripple Voltage vs VIN
REG71050 REG71055 REG710 tc_scope_input_bas221.gif
Figure 20. Input Current at Turn-On
REG71050 REG71055 REG710 tc_eff_load_bas221.gif
REG710-5V, REG71050
Figure 9. Efficiency vs Load Current
REG71050 REG71055 REG710 tc_eff_load-3v_bas221.gif
Figure 11. Efficiency vs Load Current
REG71050 REG71055 REG710 tc_eff_load-25v_bas221.gif
Figure 13. Efficiency vs Load Current
REG71050 REG71055 REG710 tc_line_trans_bas221.gif
Figure 15. Line Transient Response
REG71050 REG71055 REG710 tc_out_rip_vlt_bas221.gif
Figure 17. Output Ripple Voltage vs VIN
REG71050 REG71055 REG710 tc_sc_load_bas221.gif
Figure 19. Short-Circuit Load Current vs VIN

9.3 System Examples

9.3.1 1.8 V to 5.0 V With 10-mA Output Current

The REG710 family of charge pumps can be cascaded to reach higher output voltages, as shown in Figure 21.

REG71050 REG71055 REG710 ai_cir_step-up_bas221.gif Figure 21. REG710 Circuit for Step-Up Operation From 1.8 V to 5 V With 10-mA Output Current

This application circuits operates from 1.8 V input voltage and generates 5 V output voltage supporting 10 mA load current.

Higher output voltages can be achieved when two REG710 devices are connected in cascade. When cascading two devices from the REG710 family, the relationship between output current and input voltage must be taken into account. (see Electrical Characteristics). In this case, REG710 can deliver a maximum of 10 mA. REG710-3.3 or REG710-3 can be used. A second charge pump, REG71050 or REG710-5, steps up the voltage from 3 V or 3.3 V to 5 V. Connect both Enable pins together.

9.3.2 Doubling the Output Current

REG71050 REG71055 REG710 ai_cir_doub_bas221.gif Figure 22. REG710 Circuit for Doubling the Output Current

When higher output currents are required, the REG710 family can be paralleled to double the output current. When paralleling two devices the relationship between output current and input voltage must be taken into account (see Electrical Characteristics).

This particular application can deliver 20 mA for an input voltage from 1.8 V to 5.5 V, or 60-mA output for an input voltage from 2.2 V to 5.5 V. The output voltage is 3.3 V.

9.3.3 Driving LEDs

REG71050 REG71055 REG710 ai_cir_driv_led_bas221.gif Figure 23. REG710 Circuit for Driving LEDs

The REG710 family can be used to drive LEDs. The feed forward voltage of the chosen LED determines the required output voltage. In this application, the charge pump can drive multiple LEDs up to 60 mA in total.

Equation 2. REG71050 REG71055 REG710 eq_SBAS221H.gif