Several DIP variants for ICs exist, mostly distinguished by packaging material:
Ceramic Dual In-line Package (CERDIP or CDIP)
Plastic Dual In-line Package (PDIP)
Shrink Plastic Dual In-line Package (SPDIP) – A denser version of the PDIP with a 0.07 in. (1.778 mm) lead pitch.
Skinny Dual In-line Package (SDIP or SPDIP) – Sometimes used to refer to a "narrow" 0.300 in. (or 300 mil) wide DIP, normally when clarification is needed e.g. for DIP with 24 pins or more, which usually come in "wide" 0.600 in. wide DIP package. An example of a typical proper full spec for a "narrow" DIP package would be 300 mil body width, 0.1" pin pitch.
EPROMs were sold in ceramic DIPs manufactured with a circular window of clear quartz over the chip die to allow the part to be erased by ultraviolet light. Often, the same chips were also sold in less expensive windowless PDIP or CERDIP packages as one-time programmable (OTP) versions. Windowed and windowless packages were also used for microcontrollers, and other devices, containing EPROM memory. Windowed CERDIP-packaged EPROMs were used for the BIOS ROM of many early IBM PC clones with an adhesive label covering the window to prevent inadvertent erasure through exposure to ambient light.
Molded plastic DIPs are much lower in cost than ceramic packages; one 1979 study showed that a plastic 14 pin DIP cost around US 63 cents, and a ceramic package cost 82 cents.
A single in-line (pin) package (SIP or SIPP) has one row of connecting pins. It is not as popular as the DIP, but has been used for packaging RAM chips and multiple resistors with a common pin. SIPs group RAM chips together on a small board either by the DIP process or surface mounting SMD process. The board itself has a single row of pin-leads that resembles a comb extending from its bottom edge, which plug into a special socket on a system or system-expansion board. SIPs are commonly found in memory modules. As compared to DIPs with a typical maximum I/O count of 64, SIPs have a typical maximum I/O count of 24 with lower package costs.
One variant of the single in-line package uses part of the lead frame for a heat sink tab. This multi-leaded power package is useful for such applications as audio power amplifiers, for example.