DIA7976

Version 1.9, Apr 2025

www.dioo.com

© 2025 Dioo Microcircuits Co., Ltd. Jiangsu

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protection circuit may turn on and off repeatedly. This cycling helps to limit regulator dissipation and protect the

regulator from overheating damage. Activating the thermal shutdown feature usually indicates excessive power

dissipation as a result of the product of the (VIN - VOUT) voltage and the load current. For reliable operation, limit

junction temperature to 150°C maximum. To estimate the margin of safety in a complete design, increase the

ambient temperature until the thermal protection is triggered, use worst-case loads and signal conditions.

The DIA7976 has a built-in protection circuit that guards against overload conditions. However, it's not meant to

be triggered during regular operation. Running the device continuously into thermal shutdown can harm the

device's reliability.

9.7.Device functional modes

The Device functional modes table shows the conditions that lead to the different modes of operation.

Table 1. Device functional modes

Operating Mode

VIN

VEN

IOUT

TJ

Normal operation

VIN > VOUT(nom) + VDO

and VIN > VIN(min)

VEN > VEN(HI)

IOUT < IOUT(max)

TJ < TSD(shutdown)

Dropout operation

VIN(min) < VIN < VOUT(nom) + VDO

VEN > VEN(HI)

IOUT < IOUT(max)

TJ < TSD(shutdown)

Disabled (any true condition

disables the device)

VIN < VUVLO

VEN < VEN(LOW)

Not applicable

TJ > TSD(shutdown)

Note:

(1) See the Electrical Characteristics table for parameter values.

9.8.Dropout operation

If all conditions are met for normal operation but the input voltage is lower than the nominal output voltage plus

the specified dropout voltage, the device operates in dropout mode. During dropout mode, the output voltage

tracks the input voltage and the transient performance of the device becomes significantly degraded and acts as

a switch Line or load transients in dropout can result in large output-voltage deviations.

When the device is in dropout, VIN < VOUT(NOM) + VDO, directly after being in a normal regulation state, but not

during startup, the pass transistor is driven into the ohmic or triode region. The output voltage can overshoot for

a short period while the device pulls the pass transistor back into the linear region when the input voltage returns

to a value greater than or equal to the nominal output voltage plus the dropout voltage (VOUT(NOM) + VDO).

9.9.Disabled

Shutting down the output of the device will require forcing the voltage of the enable pin to less than the maximum

EN pin low-level input voltage. The pass transistor is turned off internal circuits are shutdown, and the output

voltage is actively discharged to the ground by an internal discharge circuit from the output to the ground, when

the device is disabled.