TPS51116-EP

SLUSB52A – OCTOBER 2012 – REVISED NOVEMBER 2012

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Overvoltage and Undervoltage Protection for VDDQ

TPS51116 monitors a resistor divided feedback voltage to detect overvoltage and undervoltage. If VDDQSET is

connected to V5IN or GND, the feedback voltage is made by an internal resistor divider inside VDDQSNS pin. If

an external resistor divider is connected to VDDQSET pin, the feedback voltage is VDDQSET voltage itself.

When the feedback voltage becomes higher than 115% of the target voltage, the OVP comparator output goes

high and the circuit latches as the high-side MOSFET driver OFF and the low-side MOSFET driver ON.

Also, TPS51116 monitors VDDQSNS voltage directly and if it becomes greater than 4 V TPS51116 turns off the

high-side MOSFET driver. When the feedback voltage becomes lower than 70% of the target voltage, the UVP

comparator output goes high and an internal UVP delay counter begins counting. After 32 cycles, TPS51116

latches OFF both top and low-side MOSFETs. This function is enabled after 1007 cycles of SMPS operation to

ensure startup.

V5IN Undervoltage Lockout (UVLO) Protection

TPS51116 has 5-V supply undervoltage lockout protection (UVLO). When the V5IN voltage is lower than UVLO

threshold voltage, SMPS, VTTLDO and VTTREF are shut off. This is a non-latch protection.

V5IN Input Capacitor

Add a ceramic capacitor with a value between 1.0

μF and 4.7 μF placed close to the V5IN pin to stabilize 5 V

from any parasitic impedance from the supply.

Thermal Shutdown

TPS51116 monitors the temperature of itself. If the temperature exceeds the threshold value, 160°C (typ),

SMPS, VTTLDO and VTTREF are shut off. This is a non-latch protection and the operation is resumed when the

device is cooled down by about 10°C.

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