Could anyone recommend a low power Power-On-Reset chip?

I am currently using a Mot MC33064P-5, but this unit draws ~ 400 - 500 uA
quiescent current which seems a bit much when tied to a PIC12C509 which is
in SLEEP mode 99 % of the time.

I don't use the internal MCLR mode since I can't afford any problems with
brownouts and Microchip indicated at their seminar that an external chip
would be helpful for brownout protection

Thanks for any help

Guy Farebrother