PM6641 datasheet(34/47 Pages) STMICROELECTRONICS

34 / 47 page

Device description

PM6641

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7.11.3

Thermal shutdown

If the device temperature exceeds 150 ºC, a thermal protection is triggered. As a

consequence, the Output Soft End takes place for all the outputs of the PM6641 (VDDQ rail

(1.8 V), VTT, VTTREF, 1.5 V, 1.05 V) by closing the output discharge MOSFET (see

Chapter 7.7: Outputs Soft-End on page 29

section for details) .

The thermal protection condition is not latched: the device leaves this condition and

reactivates itself automatically when its temperature falls below 135 ºC (i.e. there is a 15 ºC

of hysteresis).

7.11.4

Input under voltage lock-out

The PM6641 AVCC pin is the device power supply input. This pin must be fed with 5 V,

±10 % in order to allow the device to work properly. If this rail falls under 3.9 V typical

threshold, the input under voltage is detected and the device performs the Under Voltage

Lock-Out (UVLO) protection. When this event occurs, each regulator stops switching and

the following actions are performed:

●

The memory supply rails (VDDQ, VTT and VTTREF) are discharged by closing the

output discharge MOSFET (see Chapter 7.7: Outputs Soft-End on page 29 section for

details);

●

Chipset power supply output rails (1V5 and 1V05 rails) are discharged through the low

side power MOSFETs;

●

The device is turned OFF.

The PM6641 is turned on again when the AVCC pin voltage reaches the UVLO on threshold

(about 4.1 V).

PM6641 数据表(PDF) 34 Page - STMicroelectronics