Data Sheet

ADP7183

Rev. 0 | Page 15 of 19

APPLICATIONS INFORMATION

ADIsimPOWER DESIGN TOOL

The ADIsimPower™ design tool set supports the ADP7183.

ADIsimPower is a collection of tools that produce complete

power designs optimized for a specific design goal. The tools

enable the user to generate a full schematic, bill of materials,

and calculate performance in minutes. ADIsimPower can

optimize designs for cost, area, efficiency, and parts count,

taking into consideration the operating conditions and

limitations of the IC and all external components. For more

information about, and to obtain ADIsimPower design tools,

visit www.analog.com/ADIsimPower.

CAPACITOR SELECTION

Output Capacitor

The ADP7183 operates with small, space-saving ceramic

capacitors; however, it functions with general-purpose

capacitors as long as care is taken with regard to the ESR value.

The ESR of the output capacitor affects the stability of the LDO

regulator control loop. A minimum of 4.7 μF capacitance with

an ESR of 0.05 Ω or less is recommended to ensure the stability of

the ADP7183. Output capacitance affects the transient response

to changes in load currents. Using a larger value for the output

capacitance improves the transient response of the ADP7183 to

large changes in load current. Figure 46 shows the transient

response for an output capacitance value of 4.7 μF.

CH1 200mA CH2 2.00mV

M10.00µs

A CH1

–222mA

1

2

T

21.4µs

T

Input Bypass Capacitor

Connecting a 4.7 μF or greater capacitor from VIN to GND

reduces the circuit sensitivity to the PCB layout, especially when

long input traces or high source impedance are encountered.

When more than 4.7 μF of output capacitance is required,

increase the input capacitance to match it.

The ultralow output noise of the ADP7183 is achieved by

keeping the LDO error amplifier in unity gain and setting the

reference voltage equal to the output voltage. In this architecture,

LDO error amplifier for improved PSRR. However, the LDO

function of the output voltage. To minimize the output voltage

be connected between the VA and VAFB pins to keep the ac

REFERENCE

VA

VAFB

GND

R2

R1

Input and Output Capacitor Properties

Any good quality ceramic capacitors can be used with the

ADP7183 if they meet the minimum capacitance and maximum

ESR requirements. Ceramic capacitors are manufactured with a

variety of dielectrics, each with different behavior over temperature

and applied voltage. Capacitors must have a dielectric adequate to

ensure the minimum capacitance over the necessary temperature

range and dc bias conditions. X5R and X7R dielectrics with a

voltage rating from 6.3 V to 10 V are recommended. Due to their

poor temperature and dc bias characteristics, Y5V and Z5U

dielectrics are not recommended.