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Delivering MORE Together
What is SuPA?
SuPA: Supply for Power Amplifier
“SuPA” = DC/DC converter that provides an adaptive, optimized output power supply for the RF PA to extend battery life and improve thermal performance
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Traditional Approach:Fixed Battery Supply to PA
More Efficient Approach:TI SuPA Adaptive Supply to PA
VBATT
RFIN
VCC
RFOUT
VCC
RFOUT
RFIN
SuPA
VBATT
VCTRL
VOUT
VOUT is optimized for given POUT
SuPA Benefit #1:Reduced Battery Current Draw• RF PAs have efficiencies between 4-40% TI SuPA solution can reduce
battery current by 20%-50%– Longer battery life– Smaller battery form factor– More voice/usage time
and coverage
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SuPA Benefit #2:Thermal Dissipation Improvement• TI SuPA solution reduces worst case hot temperature by up to 30ºC
– Reduced thermal constraints– Higher reliability– Thinner, lighter phone design
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With SuPAWithout SuPA
60.1˚C90.5˚C
30˙C Temperature Reduction + 33% Power Savings
SuPA Key Characteristics
Differences vs Standard DC/DC Converter
• Higher Switching Frequencies
• Bypass Mode: ACB (Active Current Bypass)
• ACLR, EVM RF Compliance
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Standard Buck vs. SuPA Buck
Digital core Buck SuPA Buck
No Vcon pin needed for changing output voltage
Vcon pin critical for changing output voltage
Typically operates at low duty cycles<25% to 60%
Operates over wide duty cycles10% to 100%
High efficiency over entire output current range
High efficiency over entire output voltage range
Iq critical since it spends more time in standby
Iq not that critical since PA is a constant load ~30mA to 50mA
Standard Buck vs. SuPA Buck (cont.)
Digital core Buck SuPA Buck
Current Limit designed to support max Iout
Designed for Vcon transients and max Iout
Transient response is optimized for Line/Load Transients
Optimized for Vcon transients (output voltage)
Start-up time not that critical as long as it’s below 700uS
Critical, it must be less than 50uS
Drop-out not critical and no need for a Bypass FET
Designed to provide low output ripple and smooth transition
ti.com/rfpower
SuPA: Supply for Power Amplifier
Benefits– Reduced Battery Current Draw– Thermal Dissipation Improvement
Different from a standard buck converter
Summary
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