PM6641 STMicroelectronics, PM6641 Datasheet - Page 34

• Manufacturer Part Number: PM6641
• Description: IC MONO VR DDR2/3 PC VFQFPN-48
• Manufacturer: STMicroelectronics

Specifications of PM6641

• Applications: Converter, DDR2, DDR3
• Voltage - Input: 2.7 ~ 5.5 V
• Number Of Outputs: 3
• Voltage - Output: 0.8 ~ 5.5 V
• Operating Temperature: 0°C ~ 85°C
• Mounting Type: Surface Mount
• Package / Case: 48-VFQFN
• Output Voltage: 0.9 V
• Output Current: 3 A
• Input Voltage: 2.7 V to 5.5 V
• Switching Frequency: 1000 KHz
• Operating Temperature Range: - 40 C to + 125 C
• Mounting Style: SMD/SMT
• For Use With: 497-8425 - KIT EVAL PM6641 CHIPSET/DDR2/3
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

Device description
7.11.3
7.11.4
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Thermal shutdown
If the device temperature exceeds 150 °C, 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
The thermal protection condition is not latched: the device leaves this condition and
reactivates itself automatically when its temperature falls below 135 °C (i.e. there is a 15 °C
of hysteresis).
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 PM6641 is turned on again when the AVCC pin voltage reaches the UVLO on threshold
(about 4.1 V).
The memory supply rails (VDDQ, VTT and VTTREF) are discharged by closing the
output discharge MOSFET (see
details);
Chipset power supply output rails (1V5 and 1V05 rails) are discharged through the low
side power MOSFETs;
The device is turned OFF.
Doc ID 13510 Rev 3
Chapter 7.7: Outputs soft-end on page 29
section for details).
section for
PM6641