I think he needs a design for on-chip, rather than an external LDO..
Anyway, an LDO is basically an amplifer and a pass device. Look for the Rincon-Mora thesis on LDO's for a good starter, but I will show you one here.
I used a generic 1um CMOS process, assuming the process could withstand the VIN range up to 5.5v. I made a little 2-stage amp that drives a 250/1 sized PMOS, plenty of PMOS for 10mA.
The amp gets a bandgap as one input, and a resistor divider of the output as the second input. If the output is low, the PMOS is turned on harder, bringing the output into regulation.
My 2-stage amp has pretty good DC gain (83dB), so it is very accurate but needs an external cap to make it stable, probably a good idea to use an external cap anyway since you have switching circuits on board, else you won't be able to get rid of all the VCO noise and it will pollute your analog supply. You can make the resistor divider internal, so all you need is a VOUT pin to connect the cap to. If you make your PMOS a little bigger (and use a bigger cap) you can probably supply external circuitry, always a nice addition.
Anyway, this is just an example. Take a look and let me know if you have any questions. With 80dB gain, the line regulation from 3-5V and the load regulation from 0-10mA is quite awesome, much less than 1mV.
The nice thing about this much gain is that as long as your bandgap is relatively flat over temperature, the amp will drive out almost all temperature effects of the LDO, giving you a nice flat LDO output over temp. One caveat is the pass device, which may add a little tempco, you'll need to draw your own LDO and check it.
I'll be available for questions, and I'd like to see your circuit when you get it working. You can PM if you want, but I'd rather you kept your questions in this thread so others can learn!