ETA1188

www.etasolution.com

13

Powering Minds of the Smart

PCB RECOMMENDATION

Please always put PMID capacitor closet to the PMID pins and PGND pins, with wires directly connected to the PMID

and PGND pins. DONOT connect the negative terminal of PMID capacitor to the ground plane, while the PGND pins

are also connected to the ground pin. As such PMID capacitor serves as the input capacitor of switching charger, and

if the capacitor is connected to the PGND pins thru ground plane, 2 serial vias (capacitor to ground plane and ground

plane to PGND pins) are introduced, which means a serial parasitic inductor is placed between the input capacitor and

the real input pins. And thus, the decoupling function of such input capacitor is compromised, a lot of switching noise

may no longer be filtered by the input capacitor and leads to instability of the switching charger. Please also draw wide

enough metal for VIN, VOUT and GND because current through each wire will be huge. Otherwise, it will affect to load

regulation or input supply dropping. And just next to the PMID capacitor, VOUT capacitors must be placed, should not

be far from PMID capacitors.

Following illustration shows the correct way to place the PMID, and VOUT capacitor.

1

2

3

4

5

15

14

13

12

11

20

19

18

17

16

6

7

8

9

10

VOUT

PMID

SW

SW

SCL

BOOT

VOUT

PMID

SW

VIN

ISET

VOUT

PMID

SW

22 uF

10 uF

22 uF

22 uF

ETA1188

10uF

22 uF

22 uF

Top Layer

Bottom Layer

Via

VOUT

GND

VIN

GND

GND

Figure 3: ETA1188 PCB Recommendation

PACKAGE OUTLINE

FCQFN3x3-20

SYMBOL MIN TYP MAX

TOTAL THICKNESS

A

0.5 0.55 0.6

STAND OFF

A1

0 0.02 0.05

MOLD THICKNESS

A2

--- 0.4 ---

L/F THICKNESS

A3

0.152 REF

LEAD WIDTH

b

0.15 0.2 0.25

BODY SIZE

X

D

3 BSC

Y

E

3 BSC

LEAD PITCH

e

0.4 BSC

EP SIZE

X

D1

0.2 0.3 0.4

D2

0.2 0.3 0.4

D3

1.17 1.27 1.37

Y

E1

0.02 0.12 0.22

LEAD LENGTH

L1

0.3 0.4 0.5

LEAD TIP TO EXPOSED

PAD EDGE

K

0.63 REF

K1

0.71 REF

EXPOSED PAD TO

EXPOSED PAD EDGE

K2

0.3 REF

K3

0.3 REF

PACKAGE EDGE

TOLERANCE

aaa

0.1

MOLD FLATNESS

ccc

0.1

COPLANARITY

eee

0.08

LEAD OFFSET

bbb

0.1

D

Pin 1

Coner

E

B

C

TOP VIEW

C

aaa

BOTTOM VIEW

5

6

1

20

1

20

15

16

11

C

fff

A B

C

fff

A B

20 x L

10

K1

K2

K3

4 x E1

EXPOSED DIE

ATTACH PAD

PIN 1 I.D.

K

C

bbb

A B

M

D1

D2

20 x b

A2

A

A3

A1

SIDE VIEW

SEATING PLANE

C

aaa

2 x D3

C

fff

A B

C

eee

A

C

fff

A B

e