Datasheet

1.25V

R4 =

300μA

TLV62090

SLVSBB9B –MARCH 2012–REVISED APRIL 2012

www.ti.com

(6)

In the calculation of R4, 300 µA current is used to achieve sufficient accuracy by taking into account the typical

7.5 µA soft-start current. After determining R4, R3 can be calculated using Equation 5.

Short Circuit Protection (Hiccup-Mode)

The device is protected against hard short circuits to GND and over-current events. This is implemented by a two

level short circuit protection. During start-up and when the output is shorted to GND the switch current limit is

reduced to 1/3 of its typical current limit of 4.6 A. Once the output voltage exceeds typically 0.6 V the current limit

is released to its nominal value. The full current limit is implemented as a hiccup current limit. Once the internal

current limits is triggered 32 times the device stops switching and starts a new start-up sequence after a typical

delay time of 66 µS passed by. The device will go through these cycles until the high current condition is

released.

Output Discharge Function

To make sure the device starts up under defined conditions, the output gets discharged via the VOS pin with a

typical discharge resistor of 200 Ω whenever the device shuts down. This happens when the device is disabled

or if thermal shutdown, undervoltage lockout or short circuit hiccup-mode is triggered.

Power Good Output (PG)

The power good output is low when the output voltage is below its nominal value. The power good will become

high impedance once the output is within 5% of regulation. The PG pin is an open drain output and is specified to

typically sink up to 1 mA. This output requires a pull-up resistor to be monitored properly. The pull-up resistor

cannot be connected to any voltage higher than the input voltage of the device.

Undervoltage Lockout (UVLO)

To avoid mis-operation of the device at low input voltages, an undervoltage lockout is included. UVLO shuts

down the device at input voltages lower than typically 2.2 V with a 200 mV hysteresis.

Thermal Shutdown

The device goes into thermal shutdown once the junction temperature exceeds typically 150°C with a 20°C

hysteresis.

Product Folder Link(s): TLV62090