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SQ2131

CMOS Positive

Voltage Regulator

Elektronische Bauelemente

Any changing of specification will not be informed individual

1

Pin Number

Pin Name

Pin Function

2

3

4

5

SQ2131-12

Gnd

EN

PG

1.2V

Supply Input

Ground

Enable/Shutdown (Input): CMOS Compatible Input

Logic High= Enable; Logic Low= Shutdown. Do Not Leave Open

Regulator Output

Power Good Output

1C122

XXXX

Ordering Information(contd.)

Part Number

Marking

Output Voltage

Part Number

Marking

Output Voltage

Pin Description

01-Jun-2002 Rev. A

Page

2 of 5

Detailed Description

The SQ2131 of COMS regulators contain a PMOS pass transistor,voltage reference, error amplifier,over-current protection and

thermal shutdown and Power Good function.The P-channel pass transistor receives data from the error amplifier,over-current shutdown,

and thermal protection circuits. During normal operation, the error amplifier compares the output voltage to a precision reference.

Over-current and Thermal shutdown

circuits become active when the junction temperature exceeds150 C,or the current exceeds 300mA.

During thermal shutdown,the output voltage remains low. Normal operation is restored when the junction temperature drops below 120 C.

The SQ2131 switches from voltage mode to current mode when the load exceeds the rated output current.This prevents over-stress.

The SQ2131 also incorporates

o

o

current fold-back to reduce power dissipation when the output is short circuited.This feature becomes active

when the output drops below 0.8 volts, and reduces the current flow by 65%. Full current is restored when the voltage exceeds 0.8 volts.

External Capacitors

The SQ2131 is stable with an output capacitance to ground of 2.2uF or greater. Ceramic capacitors have the lowest ESR, and will offer

the best AC performance. Conversely, Aluminum Elertrolytic capacitors exhibit the highest ESR, resulting in the poorest AC response.

Unfortunately, large value ceramic capacitors are comparatively expensive. One option is to parallel a 0.1 uF ceramic capacitor with a

10 uF Aluminum Electrolytic. The benefit is low ESR, high capacitance, and low overall cost. A second capacitor is recommended

between the input and ground to stabilize Vin. The input capacitor should be at least 0.1uF to have a beneficial effect. All capacitors

should be placed in close proximity to the pins. A "Quiet" ground termination is desirable . The can be achieved with a "Star" connection.

Enable

The Enable pin normally floats high. When actively, pulled low, the PMOS pass transistor shuts off, and all internal circuits are powered

down. In this state, the quiescent current is less than 1uA. This pin behaves much like an electronic switch.

Fig 1. Typical Application Schematic

Fig 2. Typical Application For Processor

VID Code Power Sequencing Schematic

SQ2131

SQ2131