SI9161 Datasheet, PDF (11/12 Pages) Vishay Siliconix – Optimized-Efficiency Controller for RF Power Amplifier Boost Converter

Si9161
Vishay Siliconix
FIGURE 6. Efficiency of Si9161 and Si6801 Boost converter
at various fixed frequencies
FIGURE 7. Output noice of the Si9160 demo board
Output Noise
The noise generated by a dc-dc converter is always an issue
within the mobile phone. The Si9161 offers two benefits.
1. The noise spectrum is a constant, i.e. no random noise or
random harmonic generation.
2. The switching fundamental can be synchronized to a
known frequency, e.g. 812.5 kHz which is ¹ ₁₆-th of the
GSM/DCS system clock, or 1.23 MHz which is the channel
spacing frequency for CDMA, etc.
Figures 7 through 9 show the output noise and output
spectrum analysis.
Output Noise Spectrum
Note there is no random noise, only switching frequency
harmonics. This is very good news for the RF stages, where
an unknown, or random noise spectrum will cause problems.
FIGURE 8. Spectrum response for the Si9161 demo board output voltage
FaxBack 408-970-5600, request 70747
www.siliconix.com
S-60752—Rev. B, 05-Apr-99
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