TS33000

Final Datasheet

Rev 1.9

May 1, 2015

www.semtech.com

8 of 17

Semtech

Internal Protection Details

Internal Current Limit

Current limit is always active when the regulator is enabled.

High side current limit will shorten the high side on time and

tri-state the high side. Additionally, low side current limit will

protect the low side FET and turn off the switch if current limit

is sensed on the low side switch. Since the output is fully

synchronous, the current limit is protected on the low side in

both the positive and negative direction.

Soft Start

Soft start ensures current limit does not prevent regulator

startup and minimize overshoot at startup. The typical startup

time is 925us. These values do not change with output

voltage, current limit settings, or adjustable/fixed mode. The

soft start is re-triggered with the any rising edge that enables

the regulator, including the EN input pins, thermal shutdown,

VCC Undervoltage, or a VCC Power cycle.

Thermal Shutdown

If the temperature of the die exceeds 170C, the VSW outputs

will tri-state to protect the device from damage. The PG and all

other protection circuitry will stay active to inform the system

of the failure mode. Once the device cools to 160C, the device

will attempt to start up again, following the normal soft start

sequence with 10ms delay on PG. If the device reaches 170C,

the shutdown/restart sequence will repeat.

Output Overvoltage

If the output of the regulator exceeds 106% of the regulation

voltage, the VSW outputs will tri-state to protect the device

from damage. This check occurs at the start of each switching

cycle. If it occurs during the middle of a cycle, the switching

for that cycle will complete, and the VSW outputs will tri-state

at the beginning of the next cycle.

VCC Under-Voltage Lockout

The device is held in the off state until VCC reaches 1.9V. There

is a 100mV hysteresis on this input, which requires the input to

fall below 1.8V before the device will disable.