PCB LAYERS IN LAYOUTPrepared by: Anum Mairaj

TYPE OF LAYERS IN PCB LAYOUT

GLOBAL LAYER

1.GLOBAL LAYER “The boundary or outline around a component on PCB, where any other component is not enter, this layer is known as global layer.”

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2. TOP LAYER “In solder mount assembly, the layer which

are at the top of PCB where are mounted,

called TOP layer. This layer is normally

green in colour.”

3. BOT (BOTTOM) LAYER “In through hole, where the components

are soldered, this layer is called BOT

(BOTTOM) layer.”

5. SMT (Solder Mask Top) “On the top of PCB Solder mask is a thin layer of polymer that

is usually applied to the copper traces of a printed circuit

board (PCB) for protection against oxidation.”

6. SMB (Solder Mask Bottom) “The green layer which is on the bottom of PCB, coated with

solder mask, called SMB (Solder Mask Bottom).”

With Solder Mask Without Solder

Mask

7. SPT (Solder Paste Top) “The layer which is on the top of PCB, use to define the area

of solder paste on the pad of any component, this is called

SPT (Solder Paste Top).”

8. SPB (Solder Paste Bottom) “On the bottom of PCB, the layer is use to define the area of

solder paste on pad of any component, called SPB (Solder

Paste Bottom).”

PAD OF COMPONENT

SOLDER PASTE LAYER

9. SST (Silk Screen Top) “Line, art and text may be printed onto the top surface of PCB usually by screen printing epoxy ink, the layer use to represent the area of the text is known as SST (Silk Screen Top).”

10. SSB (Silk Screen Bottom) “Line art and text may be printed onto the bottom surface of PCB usually by screen printing epoxy ink, the layer use to represent the area of the text is known as SSB (Silk Screen Bottom).”

11. AST (ASSEMBLY TOP) “The size or shape of any component is

define on the top of PCB, through layer

called AST (Assembly Top).”

Assembly layer

12. ASB (ASSEMBLY BOTTOM) layer

“The size or shape of any component

is define on the bottom of PCB, through

layer called ASB (Assembly BOTTOM).”

4. INNER LAYER “In multilayer PCB, the central

or mid Layer is present between

top and bottom layer, called

INNER layer of PCB.”

13. DRL (DRILL LAYER) “The layer which is use to define the diameter or size of drill on pad of any component, is known as DRL (DRILL LAYER).” DRILL LAYER

PAD OF COMPONENT