Data Sheet

ADP1606/ADP1607

CHOOSING THE INPUT CAPACITOR

The ADP1606/ADP1607 require a 10 µF or greater input bypass

currents while maintaining a constant input voltage. The value

of the input capacitor can be increased without any limit for

smaller input voltage ripple and improved input voltage filtering.

The capacitor must have a 4 V or higher voltage rating to support

the maximum input operating voltage. It is recommended that

Different types of capacitors can be considered, but for battery-

powered applications, the best choice is the multilayer ceramic

capacitor, due to its small size, low equivalent series resistance

(ESR), and low equivalent series inductance (ESL). X5R or X7R

dielectrics are recommended. Do not use Y5V capacitors due to

their variation in capacitance over temperature. Alternatively,

use a high value, medium ESR capacitor in parallel with a 0.1 µF

low ESR capacitor.

CHOOSING THE OUTPUT CAPACITOR

The ADP1606/ADP1607 require a 10 µF output capacitor

load. The output capacitor supplies the current to the load when

When choosing the output capacitor, it is also important to account

for the loss of capacitance due to output voltage dc bias. The

loss of capacitance due to output voltage dc bias may necessitate

the use of a capacitor with a higher rated voltage to achieve the

desired capacitance value. See Figure 29 for an example of how

the capacitance of a 10 µF ceramic capacitor changes with the

dc bias voltage.

0

2

4

6

8

10

12

0

1

2

3

4

5

6

DC BIAS VOLTAGE (V)

Figure 29. Typical Ceramic Capacitor Performance

The value and characteristics of the output capacitor greatly

affect the output voltage ripple, transient performance, and

continuous operation is calculated as follows:

OUT

ON

OUT

OUT

C

OUT

C

t

I

C

Q

V

×

=

=

∆

(4)

where:

SW

ON

f

D

t

=

(5)

and,

OUT

IN

OUT

V

V

V

D

−

=

(6)

As shown in the duty cycle and output ripple voltage equations,

the output voltage ripple increases with the load current.

Rev. D | Page 13 of 16