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Stave module with External Shunt Regulation. BNL shunts (Dave Lynn/Phil Kuczewsk ). Liverpool Shunts. External shunts provide an alternative source of voltage regulation for a hybrid Hybrids currently come with a distributed shunt scheme ( Mshunt )
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Stave module with External Shunt Regulation BNL shunts (Dave Lynn/Phil Kuczewsk) Liverpool Shunts • External shunts provide an alternative source of voltage regulation for a hybrid • Hybrids currently come with a distributed shunt scheme (Mshunt) • Regulator circuit on board hybrid with 2 off bypass transistors per ABCN-25 • External shunt uses an external regulator circuit with a single bypass transistor (mounted on a plug-in) • Mshunt disabled by connecting control lines to hybrid (local) ground on plug-in • 2 flavours of shunt plug-ins available: • BNL shunt, fixed output voltage (preset to 2.6V) • 2 off provided, used as a first proof of principle on a module • Liverpool shunt, output voltage trimmable over the range 2.6V to 3.0V (set to 2.6V) • 8 off available to complement a stavelet
Stave module with BNL Shunt Regulator - results 3PT Gain Input Noise @1fC 590e 600e 601e 591e Dtnoise scans Dtnoise @1fC Dtnoise @0.75fC 0 662 0 0 AC AC 1 26 1 0 24510 6822 1243 1259 DC DC 1249 23929 7559 1262 • Numbers in black are the sum(hits) for BNL Plug-in • Red is the sum(hits) for the on-board shunt regulator • Noise bands present irrespective of the shunt regulation scheme with no additional decoupling capacitors
Stave module with Liverpool Shunt Regulator - results 3PT Gain Input Noise @1fC 586e 609e 588e 611e Dtnoise scans with decoupling capacitors added (as prescribed by Peter Phillips) Dtnoise@0.5fC 204 131 • Dtnoise is clean down to 0.75fC for both BNL and Liverpool shunts • Once decoupling is added • Dtnoise plot at 0.5fC is shown for Liverpool plug-in • Numbers in black are the sum(hits) for Liverpool shunt • Red is the sum(hits) for the BNL shunt 93 53 122 1641 85 1444
Summary • External shunt regulation for the powering of module has been shown to work • Input noise is as expected at ~600e ENC • The Dtnoise scans show noise bands at 1fC – this is true for both the BNL and Liverpool shunts • As is the case for the onboard Mshunt • Additional capacitive decoupling is required to recover Dtnoise performance • Both external shunts provide clean occupancies down to 0.75fC • Only at low threshold of 0.5fC do we see evidence of the noise bands • Currently have 8 Liverpool shunts tested and (presently being) shipped to RAL for stavelet testing