Jan 12, 2006 #1 J jutek Full Member level 4 Joined Oct 21, 2005 Messages 211 Helped 6 Reputation 12 Reaction score 1 Trophy points 1,298 Activity points 3,140 LDO's opamp hello when i design an opamp for LDO, i should calculate it for the lowest value of supply? and size of PMOS pass device i should also choose for these conditions to ensure max I load? regards
LDO's opamp hello when i design an opamp for LDO, i should calculate it for the lowest value of supply? and size of PMOS pass device i should also choose for these conditions to ensure max I load? regards
Jan 12, 2006 #2 H hoonsk Member level 2 Joined Jan 9, 2006 Messages 44 Helped 10 Reputation 20 Reaction score 0 Trophy points 1,286 Activity points 1,715 Re: LDO's opamp Yes, dropout condition, min VDD and max I to determine your power PMOS.
Jan 13, 2006 #3 S sunking Advanced Member level 3 Joined May 25, 2004 Messages 873 Helped 70 Reputation 140 Reaction score 23 Trophy points 1,298 Activity points 6,283 LDO's opamp of course you should take care of it.
Jan 13, 2006 #4 J jutek Full Member level 4 Joined Oct 21, 2005 Messages 211 Helped 6 Reputation 12 Reaction score 1 Trophy points 1,298 Activity points 3,140 Re: LDO's opamp and how to assure 500mV of drop-out voltage?
Jan 14, 2006 #5 H hoonsk Member level 2 Joined Jan 9, 2006 Messages 44 Helped 10 Reputation 20 Reaction score 0 Trophy points 1,286 Activity points 1,715 Re: LDO's opamp jutek said: and how to assure 500mV of drop-out voltage? Click to expand... A couple of ways : 1.) Make the power transistor W/L big ! 2.) Make sure the gate (CMOS) of power device can have wide swing i.e. the previous stage driving the gate is not limiting the swing.
Re: LDO's opamp jutek said: and how to assure 500mV of drop-out voltage? Click to expand... A couple of ways : 1.) Make the power transistor W/L big ! 2.) Make sure the gate (CMOS) of power device can have wide swing i.e. the previous stage driving the gate is not limiting the swing.
Jan 14, 2006 #6 A allan_guo Junior Member level 3 Joined Jan 6, 2006 Messages 28 Helped 4 Reputation 8 Reaction score 2 Trophy points 1,283 Activity points 1,555 Re: LDO's opamp If you gain is high, the power mos can work in liner region.
Feb 8, 2006 #7 P pillar_chen Member level 3 Joined Nov 2, 2005 Messages 59 Helped 1 Reputation 2 Reaction score 1 Trophy points 1,288 Activity points 1,682 LDO's opamp yes, there is no doubt that we want to get big regulated voltage, so the PMOS is made fat.
LDO's opamp yes, there is no doubt that we want to get big regulated voltage, so the PMOS is made fat.