ADP3604

REV. 0

–7–

POWER DISSIPATION

The power dissipation of the ADP3604 circuit must be limited

such that the junction temperature of the device does not ex-

ceed the maximum junction temperature rating.

Power is dissipated in two components, power loss due to volt-

age drops in the switches, and the power loss due to MOSFET

drive current losses. Total power dissipation is calculated:

P

≈ (V

ADP3604.

tion is:

P

≈ (5.5 V–|–2.8 V|)(0.12) + (5.5 V)(0.003 A) = 341 mW

This is far below the power dissipation capability of the

ADP3604 package which is 660 mW.

LAYOUT AND GROUNDING TIPS

The ADP3604 switches turn on and off very fast. Good PC

board layout practices will ensure the proper operation of the

device. Important layout considerations include:

Use adequate ground and power traces or planes.

Keep components as close as possible to the device.

Use short trace lengths from the input and output capacitors to

the input and output pins respectively.

Use single point ground for the device ground pins and the in-

put and output capacitors.

Improper layouts will result in poor load regulation, especially

with heavy loads.

APPLICATIONS

ADP3604 EVALUATION BOARD LAYOUT

The ADP3604 evaluation board is a general purpose circuit

board. Its flexible design allows the user to optimize the circuit

performance by external components selection and circuit con-

figuration. The circuit board can be configured as a basic charge

pump voltage inverter with one pump capacitor and two bypass

capacitors or as a more complex circuit with input and output

LC filters.

PC layout is designed for surface mount components and can

be easily configured for through hole components as well.

ADP3604

8

7

3

C3

4.7µF

1

4

C4

4.7µF

2

5

SENSE

INPUT

L2

10µH

C5

4.7µF

C2

4.7µF

L1

1µH

C1

4.7µF

Figure 21. Evaluation Board Circuit Diagram

C2

C1

C4

C5

L1

C3

L2

Figure 23. Eight-Pin SOIC-Layout, Component Placement

Diagram (1

× Scale)

Figure 24. Eight-Pin-SOIC Layout, Component Side

(1

× Layout)

Table V. Recommended Components for Circuit in Figure 21

Component

Manufacturer/Type

C3

Sprague, 293D475X0035D2W

C1, C2, C4, C5

TOKIN, 1E475ZY5UC205F

L1

Coiltronics, CTX32CT-1R0

L2

Coiltronics, CTX32CT-100

FILTERED INPUT

INPUT

OUTPUT

FILTERED OUTPUT

SHDN

OUTPUT GND

Figure 22. Eight-Pin SOIC Layout, Wiring Connection