Are the XC18V00, XC17S00, and XC1700 PROMs pin-compatible?
Given the same package footprint, the devices are pin-compatible, with the exception of the PC20 package.
For example, you can prototype with an XC18V04 PC44 ISP PROM, then replace this with a one-time-programmable (OTP) XC1704L PC44 PROM during production.
However, the reverse is not true. For example, you cannot replace a 1700 PROM with an 18V00, as the 18V00 has pins that must be driven that the 1700 does not have, such as extra VCC, GND, and VCCO pins. Please see the respective data sheets for details.