GS2231PSF datasheet(6/8 Pages) GLOBALTECH

6 / 8 page

www.gs-power.com

Application Information

The GS2231 is a high performance linear regulator

specifically designed to deliver up to 3A output current

with very low input voltage and ultra low dropout voltage.

With dual-supply configuration. The GS2231 operates

with a wide input voltage VIN range from 1.2V to 5.5V

Power-On-Reset

A Power-On-Reset (POR) circuit monitors both of supply

voltages on VCNTL and VIN pins to prevent wrong logic

controls. The POR function initiates a soft-start process

after both of the supply voltages exceed their rising POR

voltage thresholds during powering on. The POR function

also pulls low the PGOOD voltage regardless of the

output status when one of the supply voltages falls below

its falling POR voltage threshold.

Soft-Start

An internal soft-start function controls rise rate of the

output voltage to limit the current surge during start-up.

The typical soft-start interval is about 0.6ms.

Current-Limit Protection

The GS2231 monitors the current flowing through the

output NMOS and limits the maximum current to prevent

load and GS2231 from damages during current overload

conditions.

Short Circuit Current-limit Protection

The short current-limit function reduces the current-limit

level down to 0.8A (typical) when the voltage on FB pin

falls below 0.2V (typical) during current overload or short

circuit conditions.

The short current-limit function is disabled for successful

start-up during soft-start.

Thermal Shutdown

A thermal shutdown circuit limits the junction temperature

of GS2231. When the junction temperature exceeds

+170ºC, a thermal sensor turns off the output NMOS,

allowing the device to cool down. The regulator regulates

the output again through initiation of a new soft-start

process after the junction temperature cools by 50ºC,

resulting in a pulsed output during continuous thermal

overload conditions. The thermal shutdown is designed

with a 50ºC hysteresis to lower the average junction

temperature

during

continuous

thermal

overload

conditions, extending lifetime of the device.

For normal operation, the device power dissipation

should be externally limited so that junction temperatures

will not exceed +125ºC.

Enable Control

A logic low signal applied to this pin shuts down the

output. Following a shutdown, a logic high signal

re-enables the output through initiation of a new soft-start

cycle. When left open, this pin is pulled up by an internal

current source (5uA typical) to turn off operation.

Power Sequencing

The power sequencing of VIN and VCNTL is not necessary

to be concerned. However, do not apply a voltage to VOUT

for a long time when the main voltage applied at VIN is not

present. The reason is the internal parasitic diode from

VOUT to VIN conducts and dissipates power without

protections due to the forward-voltage.

Output Voltage Regulation

An error amplifier working with a temperature

compensated 0.8V reference and an output NMOS

regulates output to the preset voltage. The error

amplifier is designed with high bandwidth and DC gain

provides very fast transient response and less load

regulation.

Power-OK and Delay

The GS2231 indicates the status of the output voltage

by monitoring the feedback voltage (VFB) on FB pin. As

the VFB rises and reaches the rising Power-OK voltage

threshold (VTH_POK), an internal delay function starts to

work. At the end of the delay time, the IC turns off the

internal NMOS of the POK to indicate the output is ok.

As the VFB falls and reaches the falling Power-OK

voltage threshold, the IC turns on the NMOS of the

POK (after a de bounce time of 10ms typical).

Output Capacitor

The GS2231 requires a proper output capacitor to

maintain stability and improve transient response. The

output capacitor selection is dependent upon ESR

(equivalent series resistance) and capacitance of the

output capacitor over the operating temperature.

Ultra-low-ESR capacitors (such as ceramic chip

capacitors) and low-ESR bulk capacitors (such as solid

tantalum,

POSCap,

and

Aluminum

electrolytic

capacitors) can all be used as output capacitors.

During load transients, the output capacitors which is

depending on the stepping amplitude and slew rate of

load current, are used to reduce the slew rate of the

current seen by the GS2231 and help the device to

minimize the variations of output voltage for good

transient response. For the applications with large

stepping load current, the low-ESR bulk capacitors are

normally recommended.

Decoupling ceramic capacitors must be placed at the

load and ground pins as close as possible and the

impedance of the layout must be minimized.

Input Capacitor

Ultra-low-ESR capacitors (such as ceramic chip

capacitors) and low-ESR bulk capacitors (such as solid

tantalum,

POSCap,

and

Aluminum

electrolytic

capacitors) can all be used as input capacitor. For

most

applications,

the

recommended

input

capacitance is at least 10µF.

More capacitance reduces the variations of the supply

voltage on the VIN pin.

Setting Output Voltage

The output voltage is programmed by the resistor

divider connected to the FB pin. The preset output

voltage is calculated by the following equation :

Where R1 is the resistor connected from VOUT to FB

with Kelvin sensing connection and R2 is the resistor

connected from FB to GND. A bypass capacitor (C1)

may be connected in parallel with R1 to improve load

transient response and stability.

GS2231PSF bảng dữ liệu(PDF) 6 Page - Globaltech Semiconductor Co.,Ltd

GS2231PSF bảng dữ liệu(HTML) 6 Page - Globaltech Semiconductor Co.,Ltd

Html Pages

1 2 3 4 5 6 7 8

bảng dữ liệu tải về

Link URL