A　high-PSRR　low　dropout　regulator　using　the　first-stage　reference-included　coarse-filtering　technique　is　presented,　for　the　reduced　output　ripple　of　the　low　noise　block　(LNB)　power　supply　in　the　satellite　set-top　box.　Compared　with　the　conventional　system,　the　regulator　with　the　technique　is　characterized　by　the　two　successive　negative　feedback　loops,　so　as　to　alleviate　the　output　ripple　of　the　power　supply　caused　by　the　preceding　DC-DC　converter＇s　modulation　signal.　With　the　technique,　the　ripple　near　to　the　frequency　of　the　LNB　supply　voltage　tuning　signal　(22　kHz)　can　be　significantly　alleviated.　To　further　enhance　the　PSRR　performance　without　the　reference-by-pass　capacitor,　the　bipolar-loop　buffer　amplifier　and　the　reference-included　coarse-filtering　regulator　are　proposed.　The　circuits　are　extracted　from　the　LDO　layout　and　simulated　with　a　0.35　mu　m　BCD　process　in　Cadence.　With　the　typical　16.3V　input　supply　voltage　and　loading　current　100　mA,　the　line　regulation　corresponding　to　the　DC　supply　voltage　is　achieved　at　-72　dB;　the　PSRR　performance　of　the　supply　voltage　ripple　up　to　the　frequency　(100　kHz)　is　better　than　-70　dB;　Moreover,　the　quiescent　current　without　the　loading　impedance　is　less　than　153　mu　A.