SMT焊盘设计指南：尺寸、阻焊开窗与间距要点

SMT组件PCB焊垫尺寸设计

1、被动组件PCB焊垫尺寸

(1) 一般RLC组件：置放外框不可重迭，相邻两chip间 (指 pad 至 pad ) 距离最小为10mils，非规格内RLC之 Pad 请依下列原则设计：

(i) B=W1+10 mil(ii) C=10+H(电极宽度)+15 mil(iii) 0201零件PAD四边R2圆角；0402 & 0603零件PAD四边R4圆角;

(i) 电阻及电感类零件尺寸一览表

Package	Body Size (mm)	Pin Lead Size (mm)	Pad Size (mil)	Placement (mil)
0201	0.6X0.3	0.15X0.3	S12X14 -R2	22X51
0402	1.0X0.5	0.25X0.5	S22X22 -R4	40X74
0603	1.6X0.8	0.3X0.8	S34X34 -R4	52X108
0805	2.0X1.25	0.35X1.25	S55X45	76X140
1206	3.1X1.55	0.4X1.55	S65X50	86X182
1210	3.1X2.55	0.4X2.55	S110X55	130X190
2010	5.0X2.5	0.5X2.5	S110X45	136X266
2512	6.3X3.2	0.5X3.2	S138X70	168X320

(ii) 电容类零件尺寸一览表

Package	Body Size (mm)	Pin Lead Size (mm)	Pad Size (mil)	Placement (mil)
0201	0.6X0.3	0.15X0.3	S12X14-R2	22X51
0402	1.0X0.5	0.225X0.5	S24X24-R4	34X75
0603	1.6X0.8	0.4X0.8	S34X34-R4	49X105
0805	2.0X1.25	0.475X1.25	S55X45	76X140
1206	3.2X1.6	0.575X1.55	S65X50	86X182
1210	3.1X2.5	0.65X2.55	S110X55	130X190
1808	4.5X2.0	0.5X2.5	S90X50	120X230
1812	4.5X3.2	0.7X3.2	S136X60	166X237

(2) 钽质电容

Type	Body Size	Pad Size	Silk Screen Outline Size
L1	W1	A	B	C	D	L2	W2
1206	124	66	176	80	50	76	216	91
1411	142	113	240	90	90	60	280	138
2412	232	130	336	105	90	156	376	155
2916	282	173	338	95	90	158	390	200

(3) 筒型零件：二极管

Type	Body Size	Pad Size	Silk Screen Outline Size
L1	W1	A	B	C	D	L2	W2
35 x 14	140	56	200	60	60	80	260	116
参考尺寸: L2 = A + 60 ; W2 = W1 + 60

(4) 晶体管 / 3-PIN 二极管

(5) 4-Pin排阻

Unit:mil

Type	Body Size	Pad Size	Silk Screen Outline Size
L1	W1	A	B	D	F	L2	W2
0404	40	40	26	14	47.6	25.2	120	79
参考尺寸

(6) 8-Pin排阻

Type	Body Size	Pad Size	Silk Screen Outline Size
L1	W1	A	B	C	D	E	F	L2	W2
1206	120	60	40	27	20	32	35	62	170	140
参考尺寸

(7) 10-Pin排阻

Type	Body Size	Pad Size	Silk Screen Outline Size
L1	W1	A	B	C	D	E	F	L2	W2
1206	120	60	46	24	14	25	30	66	175	155
2412	240	120	51	44	34	50	55	117	295	210
参考尺寸

(8) 16-Pin排阻

(9) 功率晶体

(10) 电解电容

•A=I+0.96mm(38mils)

•B=W+0.7mm(28mils)

•C=P-0.5mm(20mils)

注：对于SMT Type之电解质电容和 12 mm x 12 mm 以上的电感(chock)在接地端需以 thermal relief design 隔开大面积铜箔;2、 IC类组件PCB焊垫尺寸

IC类零件之零件脚Pad长度若需小于标准值 (C) 时，则须符合：Tip side pad size 至少15mil；heel side pad size 至少10mil。

(1) SSOP

Unit : mil

Pitch	Body Size	Pad Size	Silk Screen Outline Size
b	W1	L1	a	c	d	W2	L2
19.485 (0.5mm)		12	60	W1+30	d+30	L1+20
25.59 (0.65mm)	16	60	W1+30	d+30	L1+20
31.496 (0.8mm)	18	60	W1+30	d+30	L1+20

(2) SOP & SOJ

Unit :mil

Pitch

Body Size

Pad Size

Silk Screen

Outline Size

W1+30

L1+20

d+100

(3) PLCC

Unit :mil

Pitch

Body Size

Pad Size

Silk Screen

Outline Size

W1+30

L1+30

d1+100

d2+100

(4) PQFP

Unit : mil

Pitch	Body Size	Pad Size	Silk Screen Outline Size
b	W1	L1	a	c	d1	d2	W2	L2
19.485 (0.5mm)		12	60	W1+40	L1+40	d1+20	d2+20
25.59 (0.65mm)	16	90	W1+50	L1+50	d1+20	d2+20
31.496 (0.8mm)	18	90	W1+50	L1+50	d1+20	d2+20

(5) QFN

Unit :mil

Pitch	Body Size	Pad Size
b	D	E	a	c	d1	d2	d3
19.485 (0.5mm)		12	60	E+40 (两边各20)	D+40 (两边各20)	F-20 (两边各10)
25.59 (0.65mm)	14	60	E+40 (两边各20)	D+40 (两边各20)	F-20 (两边各10)

(6) LFCSP

•a = follow recommended pattern or reference normal QFN

•b = B

•c = C + 0.1mm

•silkscreen = D x E

•c － 0.4mm ≧ F

3、BGA pad size and Geometry Design for LF Process

(1)一般设计：Pitch ≧ 0.8mm 的 BGA 零件四个角落的各9个PAD必须加大2 mil

(2) SMD (Solder Mask Design) 设计，适用于客户要求、零件厂商建议或设计需求

A = 零件厂商所建议之设计值(直径)	Finish Pad	Copper Pad
SMD (Solder Mask Design)针对BGA每个角落的 8 个pad	A	A+4
NSMD (Non Solder Mask Design)	A	A