MIC5201 datasheet(12/22 Pages) MICROCHIP

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MIC5201

DS20005718D-page 12



2017 - 2022 Microchip Technology Inc. and its subsidiaries

4.0

APPLICATIONS INFORMATION

Figure 4-1 shows a basic fixed-voltage application with

the unused enable input connected to VIN.

FIGURE 4-1:

Fixed Application.

Adjustable regulators require two resistors to set the

output voltage. See Figure 4-2.

FIGURE 4-2:

Adjustable Application.

Resistor values are not critical because ADJ (adjust)

has a high impedance, but for best results use resistors

of 470 kΩ or less.

4.1

Output Capacitors

A 1 μF capacitor is recommended between the

MIC5201 output and ground to prevent oscillations due

to instability. Larger values serve to improve the

regulator’s transient response. Most types of tantalum

or aluminum electrolytics will be adequate; film types

will work, but are costly and therefore not

recommended. Many aluminum electrolytics have

electrolytes that freeze at about –30°C, so solid

tantalums are recommended for operation below

–25°C. The important parameters of the capacitor are

an effective series resistance of about 5Ω or less and a

resonant frequency above 500 kHz. The value of this

capacitor may be increased without limit.

At lower values of output current, less output

capacitance is required for output stability. The

capacitor can be reduced to 0.47 μF for current below

10 mA or 0.33 μF for currents below 1 mA.

4.2

Input Capacitors

A 1 μF capacitor should be placed from the MIC5201

input to ground if there is more than 10 inches of wire

between the input and the AC filter capacitor or if a

battery is used as the input.

4.3

Noise Reduction Capacitors

On adjustable devices, a capacitor from ADJ to GND

will decrease high-frequency noise on the output. See

Figure 4-3.

FIGURE 4-3:

Decreasing Output Noise.

4.4

Minimum Load

The MIC5201 will remain stable and in regulation with

no load unlike many other voltage regulators. This is

especially important in CMOS RAM keep-alive

applications.

4.5

Dual-Supply Systems

When used in dual supply systems where the regulator

load is returned to a negative supply, the output voltage

must be diode clamped to ground.

4.6

Thermal Considerations Layout

The MIC5201-x.xYM (8-pin surface mount package)

has the following thermal characteristics when

mounted on a single layer copper-clad printed circuit

board.

Multilayer boards having a ground plane, wide traces

near the pads, and large supply bus lines provide better

thermal conductivity.

The “worst case” value of 160°C/W assumes no ground

plane, minimum trace widths, and a FR4 material

board.

MIC5201-x.xYM

MIC5201-x.xYS

OUT

GND

1μF

VIN

VOUT

MIC5201YM

OUT

GND

VIN

ADJ

3.3μF

VOUT

OUT = 1.242V x (1+

)

TABLE 4-1:

THERMAL

CHARACTERISTICS

PCB Dielectric

θJA

FR4

160ºC/W

Ceramic

120ºC/W

MIC5201YM

OUT

GND

VIN

ADJ

3.3μF

VOUT

CADJ

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