3/5

ISSUED DATE :2006/04/10

REVISED DATE :

Ordering Information ( contd. )

Part Number

Marking

Output Voltage

Part Number

Marking

Output Voltage

GSC2146-15

6D152

XXXX

1.5V

GSC2146-18

6D182

XXXX

1.8V

GSC2146-25

6D252

XXXX

2.5V

GSC2146-27

6D272

XXXX

2.7V

GSC2146-28

6D282

XXXX

2.8V

GSC2146-2H

6D2H2

XXXX

2.85V

GSC2146-29

6D292

XXXX

2.9V

GSC2146-30

6D302

XXXX

3.0V

GSC2146-31

6D312

XXXX

3.1V

GSC2146-33

6D332

XXXX

3.3V

GSC2146-34

6D342

XXXX

3.4V

GSC2146-35

6D352

XXXX

3.5V

GSC2146-36

6D362

XXXX

3.6V

GSC2146-37

6D372

XXXX

3.7V

GSC2146-38

6D382

XXXX

3.8V

Detailed Description

The GSC2146 series of COMS regulators contain a PMOS pass transistor, voltage reference, error amplifier,

over-current protection, and thermal shutdown.

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 exceeds

150 : , or the current exceeds 600mA. During thermal shutdown, the output voltage remains low. Normal

operation is restored when the junction temperature drops below 120 : .

The GSC2146 switches from voltage mode to current mode when the load exceeds the rated output current.

This prevents over-stress. The GSC2146 also incorporates 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 GSC2146 is stable with an output capacitance to ground of 2.2 F or greater. Ceramic capacitors have the

lowest ESR, and will offer the best AC performance. Conversely, Aluminum Electrolytic 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 F ceramic capacitor with a 10 F Aluminum Electrolytic.

The benefit is low ESR, high capacitance, and low overall cost.

be at least 0.1 F to have a beneficial effect.

A third capacitor can be connected between the BY-PASS pin and GND. This capacitor can be a low cost

Polyester Film variety between the value of 0.001~0.01 F. A large capacitor improves the AC ripple rejection,

but also makes the output come up slowly. This “Soft” turn-on is desirable in some applications to limit turn-on

surges.

All capacitors should be placed in close proximity to the pins. A “Quiet” ground termination is desirable. This

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 1 A. This pin behaves much

like an electronic switch.