Using the TPS6102x with Ceramic Output Caps
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Transcript of Using the TPS6102x with Ceramic Output Caps
Using the TPS6102x with Ceramic Output Caps
Datasheet Requires ESR above 30 mOhm
Test Results
• TPS61020EVM-025 evaluated with a DC load and with a load transient
• Evaluated with both recommended output capacitors and non-recommend output ceramic capacitors
• Test conditions: 2.5V in, 3.3V out, DC load 500 mA, transient load 200 mA to 500 mA
• Slides 4-7 are the standard EVM circuit with the proper output capacitor, while slides 8-12 use only ceramic
Output Voltage Ripple (DC Coupled)
Output Voltage Ripple (AC Coupled)
Transient Response (DC Coupled)
Transient Response (AC Coupled)
EVM Modified by Replacing C3 with 22uF ceramic
Insert 22uF ceramic
Output Voltage Ripple (DC Coupled)
Output Voltage Ripple (AC Coupled)
Transient Response (DC Coupled)
Transient Response (AC Coupled)
Conclusion
• TPS6102x is unstable with ceramic output capacitors, which have low ESR– Shows low frequency oscillation/ripple– Performance is normal when output capacitors with
sufficient ESR are used• If ceramic output capacitors are required:– Use the newer, smaller TPS61200– Use ceramic output capacitors with a discrete 30
mOhm resistors in series to give them the needed ESR