MP2002 – LOW INPUT VOLTAGE, 500mA LINEAR REGULATOR

MP2002 Rev. 1.11

www.MonolithicPower.com

8

10/10/2011

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© 2011 MPS. All Rights Reserved.

APPLICATION INFORMATION

Setting the Output Voltage

The MP2002 has an adjustable output voltage,

set via an external resistor divider (R1 and R2

in Figure 2).

⎟⎟

⎠

⎞

⎜⎜

⎝

⎛

−

×

=

FB

FB

OUT

V

V

V

2

R

1

R

voltage.)

Example: For 2.5V Output and R2=10kΩ

2.5 0.5

R1 10k

40k

0.5

−

⎛⎞

=×

=

Ω

⎜⎟

⎝⎠

A standard 40kΩ (

±1%) resistor can be selected

for R1.

Table 1 lists the selected R1 values for some

typical output voltages (assuming R2 = 10kΩ).

Power Good

The power good pin is an open collector output

completed with a pull up resistor (10kΩ

recommended). The pull up resistor can be tied

to a supply within the voltage range of the pin

(0V to 5.5V). For example, the pull up resistor

can be tied to the input voltage when it is being

monitored by an IC powered from this input

voltage. It monitors the output voltage, and if

the output voltage is 10% below its regulation

point, the PG pin becomes low.

Table 1—Adjustable Output Voltage R1 Values

(R2=10kΩ)

R1 (Ω)

1.25

15k

1.5

20k

1.8

26k

2

30k

2.5

40k

2.8

46k

3

50k

3.3

56k

4

70k

5

90k

Bypass Capacitors

For lower noise, the reference voltage can be

bypassed by an external capacitor. A low ESR

capacitor, such as the ceramic type, will provide

the best performance.