Bluegiga Technologies Oy

Page 17 of 31

5 Design Guidelines

5.1 General Design Guidelines

BLE112 can be used directly with a coin cell battery. Due to relatively high internal resistance of a coin cell

battery it is recommended to place a 100uF capacitor in parallel with the battery. The internal resistance of a

coin cell battery is initially in the range of 10 ohms but the resistance increases rapidly as the capacity is used.

Basically the higher the value of the capacitor the higher is the effective capacity of the battery and thus the

longer the life time for the application. The minimum value for the capacitor depends on the end application

and the maximum transmit power used. The leakage current of a 100uF capacitor is in the range of 0.5 uA to

3 uA and generally ceramic capacitors have lower leakage current than tantalum or aluminum electrolytic

capacitors.

Optio

nally TI’s TPS62730 can be used to reduce the current consumption during TX/RX and data processing

stages. TPS62730 is an ultra low power DC/DC converter with by-pass mode and will reduce the current

consumption during transmission nominally by ~20% when using 3V coin cell battery.

A ferrite bead is recommended to be used to filter any excessive noise in the power supply lines to guarantee

the radio performance.

-

PR A

BLE112 Evaluation Board

-

1 2 .0 4 .2 0 1 1

-

-C1.0

1 3

REV:

SIZE:

CODE:

DRAWN:DATED:

DATED:

CHECKED:

QUAL ITY CONTROL :DATED:

DATED:

REL EASED:

COM PANY:

TITL E:

DRAWING NO:

SHEET:

OF

SCAL E:

REVISION RECORD

APPROVED:

ECO NO:

L TR

DATE:

1

2

3

4

5

6

D

C

B

A

C

D

B

A

OPTIONAL DC/DC

PROGRAMMING INTERFACE

1

2

U4

BATTERYHOLDER_SMD_CR2032

C1 5

1 0 0 u F/6 .3 V/X5 R

1

STAT

2

SW

3

VIN

5

ON/BYP

6

VOUT

U5

TPS62730

C1 0

2 .2 u F/1 0 V/X5 R

C1 1

2 .2 u F/1 0 V/X5 R

L 1

2 .2

µH±20%, 130m A, 0.43ohm

1

GND

2

AVDD

3

AVDD

4

P2_2

5

P2_1

6

P2_0

7

P1_7

8

P1_6

9

DVDD_USB

10

GND

11

USB+

12

USB-

13

P1_5

22

P0_6

23

P0_5

24

P0_4

25

P0_3

26

P0_2

27

P0_1

28

P0_0

29

RESET

30

GND

M OD2

BLE112-A

1

3

5

2

4

6

7 8

9 1 0

J 1

HEADER_ 2 X5 _ SM D_ 1 .2 7 M M

C3

1 u F/1 6 V/X5 R

C5

1 u F/1 6 V/X5 R

C6

1 u F/1 6 V/X5 R

P1 _ 7 /DCDC

VBAT

P2 _ 2

2 V...3 V3 _ SW

P2 _ 1

RESET_ N

RESET_ N

P2 _ 2

P2 _ 1

P1 _ 7 /DCDC

Figure 12: Example schematic for BLE112 with a coin cell battery

12.04.2011

--

-

BLE112 Evaluation Board

P R A

C-1.0

23

REV:

SI ZE:

CO DE:

DRAWN: DATED:

DATED:

CHECKED:

Q UALI TY CO NTRO L: DATED:

DATED:

RELEASED:

CO MPANY:

TI TLE:

DRAWI NG NO :

SHEET:

O F

SCALE:

REVI SI O N RECO RD

APPRO VED:

ECO NO :

LTR

DATE:

1

2

3

4

5

6

D

C

B

A

C

D

B

A

1

VBUS

2

D-

3

D+

4

NC

5

G ND

J10

CO N- MI NI USB- SO CKET- SMD

3

VI N

2

VO UT

P1

MCP1700T- 3302E/ T

L4

FB 1kohm

1

2

R13

33R, 50V, 0. 063W

1

2

R14

33R, 50V, 0. 063W

R15

1. 5K, 50V, 0. 063W

C127

47pF/ 50V/ C0G

C128

47pF/ 50V/ C0G

1

G ND

2

AVDD

3

AVDD

4

P2_2

5

P2_1

6

P2_0

7

P1_7

8

P1_6

9

DVDD_USB

10

G ND

11

USB+

12

USB-

13

P1_5

22

P0_6

23

P0_5

24

P0_4

25

P0_3

26

P0_2

27

P0_1

28

P0_0

29

RESET

30

G ND

MO D3

BLE112- A

C7

1uF/ 16V/ X5R

C8

1uF/ 16V/ X5R

C9

1uF/ 16V/ X5R

RESET

Figure 13: Example schematic for BLE112 with USB