SBVS184A December   2011  – August 2015 TPS7A4201

PRODUCTION DATA.  

  1. 1 Features
  2. 2 Applications
  3. 3 Description
  4. 4 Revision History
  5. 5 Pin Configuration and Functions
  6. 6 Specifications
    1. 6.1 Absolute Maximum Ratings
    2. 6.2 ESD Ratings
    3. 6.3 Recommended Operating Conditions
    4. 6.4 Thermal Information
    5. 6.5 Electrical Characteristics
    6. 6.6 Dissipation Ratings
    7. 6.7 Typical Characteristics
  7. 7 Detailed Description
    1. 7.1 Overview
    2. 7.2 Functional Block Diagram
    3. 7.3 Feature Description
      1. 7.3.1 Enable Pin Operation
      2. 7.3.2 Thermal Protection
    4. 7.4 Device Functional Modes
      1. 7.4.1 Normal Operation
      2. 7.4.2 Dropout Operation
      3. 7.4.3 Disabled
  8. 8 Application and Implementation
    1. 8.1 Application Information
      1. 8.1.1 Adjustable Operation
      2. 8.1.2 Transient Voltage Protection
    2. 8.2 Typical Application
      1. 8.2.1 Design Requirements
      2. 8.2.2 Detailed Design Procedure
        1. 8.2.2.1 Capacitor Recommendations
        2. 8.2.2.2 Input and Output Capacitor Requirements
        3. 8.2.2.3 Bypass Capacitor Requirements
        4. 8.2.2.4 Maximum AC Performance
        5. 8.2.2.5 Transient Response
      3. 8.2.3 Application Curves
  9. 9 Power Supply Recommendations
  10. 10Layout
    1. 10.1 Layout Guidelines
      1. 10.1.1 Board Layout Recommendations to Improve PSRR and Noise Performance
    2. 10.2 Layout Example
    3. 10.3 Thermal Considerations
    4. 10.4 Power Dissipation
  11. 11Device and Documentation Support
    1. 11.1 Community Resources
    2. 11.2 Trademarks
    3. 11.3 Electrostatic Discharge Caution
    4. 11.4 Glossary
  12. 12Mechanical, Packaging, and Orderable Information

Package Options

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

8 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.

8.1 Application Information

8.1.1 Adjustable Operation

The TPS7A4201 has an output voltage range of ~1.175 V to 26 V. The nominal output voltage of the device is set by two external resistors, as shown in Figure 12.

TPS7A4201 ai_adj_oper_bvs184.gifFigure 12. Adjustable Operation for Maximum AC Performance

R1 and R2 can be calculated for any output voltage range using the formula shown in Equation 1. To ensure stability under no-load conditions, this resistive network must provide a current greater than or equal to 10 μA.

Equation 1. TPS7A4201 q_r1_bvs184.gif

If greater voltage accuracy is required, take into account the output voltage offset contributions because of the feedback pin current and use 0.1% tolerance resistors.

8.1.2 Transient Voltage Protection

One of the primary applications of the TPS7A4201 is to provide transient voltage protection to sensitive circuitry that may be damaged in the presence of high-voltage spikes.

This transient voltage protection can be more cost-effective and compact compared to topologies that use a transient voltage suppression (TVS) block.

8.2 Typical Application

TPS7A4201 typ_app_bvs184.gifFigure 13. Example Circuit to Maximize Transient Performance

8.2.1 Design Requirements

For this design example, use the following parameters listed in Table 2.

Table 2. Design Parameters

PARAMETER VALUE
VIN 12 V
VOUT 5 V (ideal), 4.981 V (actual)
IOUT 28 mA
Accuracy 5 %
R1, R2 162 kΩ, 49.9 kΩ

8.2.2 Detailed Design Procedure

The maximum value of total feedback resistance can be calculated to be 500 kΩ. Equation 1 was used to calculate R1 and R2, and standard 1% resistors were selected to keep the accuracy within the 5% allocation. 10-uF ceramic input and output capacitors were selected, along with a 10-nF bypass capacitor for optimal AC performance.

8.2.2.1 Capacitor Recommendations

Low equivalent series resistance (ESR) capacitors should be used for the input, output, and bypass capacitors. Ceramic capacitors with X7R and X5R dielectrics are preferred. These dielectrics offer more stable characteristics. Ceramic X7R capacitors offer improved over-temperature performance, while ceramic X5R capacitors are the most cost-effective and are available in higher values.

Note that high ESR capacitors may degrade PSRR.

8.2.2.2 Input and Output Capacitor Requirements

The TPS7A4101 high voltage linear regulator achieves stability with a minimum output capacitance of 4.7 µF and input capacitance of 1 µF; however, it is highly recommended to use 10-μF output and input capacitors to maximize ac performance.

8.2.2.3 Bypass Capacitor Requirements

Although a bypass capacitor (CBYP) is not needed to achieve stability, it is highly recommended to use a 10-nF bypass capacitor to maximize ac performance (including line transient, noise and PSRR).

8.2.2.4 Maximum AC Performance

In order to maximize line transient, noise, and PSRR performance, it is recommended to include 10-μF (or higher) input and output capacitors, and a 10-nF bypass capacitor; see Figure 12. The solution shown delivers minimum noise levels of 58 μVRMS and power-supply rejection levels above 36 dB from 10 Hz to 10 MHz.

8.2.2.5 Transient Response

As with any regulator, increasing the size of the output capacitor reduces over/undershoot magnitude but increases duration of the transient response.

Note that the presence of the CBYP capacitor may greatly improve the TPS7A4201 line transient response, as noted in Figure 1.

8.2.3 Application Curves

TPS7A4201 tc_load_trans_bvs162.gif
Figure 14. Load Transient Response