Figure 5-3shows the PC board land pattern for the Rabbit 3000 chip in a 128-pin LQFP package. This land pattern is based on the IPC-SM-782 standard developed by the Surface Mount Land Patterns Committee and specified in Surface Mount Design and Land Pat- tern Standard, IPC, Northbrook, IL, 1999.

16.85mm (max.)

13.75mm (min.)

15.3 mm

12.4 mm

13.75 mm (min.)

16.85 mm (max.)

0.40 mm

 

0.28 mm (max.)

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

1.55 mm

12.4 mm

15.3 mm

TOLERANCE AND SOLDER JOINT ANALYSIS

JT: 0.29–0.55 mm

JH: 0.29–0.604 mm

Lmin

T

Smax

 

Zmax: 16.85 mm

 

Gmin: 13.75 mm

JS: -0.01–0.077 mm

Wmin

X: 0.28 mm

(max.)

Toe Fillet

Heel Fillet

Side Fillet

J:Solder fillet min/max (toe, heel, and side respectively)

L:Toe-to-toe distance across chip

S:Heel-to-heel distance across chip

T:Toe-to-heel distance on pin

W:Width of pin

Figure 5-3. PC Board Land Pattern for Rabbit 3000 128-pin LQFP

58

Rabbit 3000 Microprocessor

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Image 67
Jameco Electronics 2000 manual PC Board Land Pattern for Rabbit 3000 128-pin Lqfp