SLVUBX0A July   2021  – January 2022 TPSM8A28 , TPSM8A29

 

  1.   Trademarks
  2. 1Introduction
  3. 2Description
  4. 3Getting Started With the TPSM8A29EVM
    1. 3.1 J1 - Input Voltage Supply Connector
    2. 3.2 J4 and J7 - Positive and Negative Output Connectors
    3. 3.3 J2 - Enable Header
    4. 3.4 J5 - Switching Frequency and Operating Mode
    5. 3.5 J6 - Output Voltage Selection Header
  5. 4Test Point Description
    1. 4.1 TP12 - SS/REF_IN
    2. 4.2 TP14 - VCC
  6. 5Test Setup and Results
    1. 5.1 Startup Procedure
    2. 5.2 Efficiency
    3. 5.3 Load Regulation
    4. 5.4 Line Regulation
    5. 5.5 Output Voltage Ripple
    6. 5.6 Startup and Shutdown
    7. 5.7 Load Transient
    8. 5.8 Bode Plot
  7. 6TPSM8A29EVM Schematic
  8. 7TPSM8A29EVM PCB Layers
  9. 8TPSM8A29EVM Bill of Materials
  10. 9Revision History

3.5 J6 - Output Voltage Selection Header

A jumper on the J6 header is used to configure a range of output voltage from 0.8 V to 5 V. Note that while the default maximum output voltage of the EVM is 5 V, the minimum and maximum output voltage can be increased to 0.6 V and 5.5 V, respectively, by changing one of the high-side feedback resistors.

The output voltage is configured with a voltage divider between VOUT and PGND, where the midpoint is connected to the FB pin of the TPSM8A29. On this EVM, the low-side feedback resistor (RFB_LS, R10) is fixed by default at 10 kΩ, and the jumper on J6 changes the high-side feedback resistor (RFB_HS, see Figure 6-1). To calculate the high-side feedback resistor for any valid output voltage (0.6 V to 5.5 V) for this EVM, Equation 3 is used, where RFB_HS is the high-side resistor of the output voltage divider (several options for this EVM, see Figure 6-1), VOUT is the desired output voltage, VINTREF is the internal reference voltage (typical 0.6 V), and RFB_LS is the low-side resistor of the output voltage divider (R10). For high DC accuracy, 1% or better resistors should be used with a temperature coefficient of ±100 ppm/°C or lower.

Equation 3. R F B H S =   V O U T     -     V I N T R E F V I N T R E F     × R F B L S
Equation 4. R F B H S =   V O U T   -   0 . 6   V   0 . 6   V × 10   k Ω