PM6670S STMicroelectronics, PM6670S Datasheet - Page 36

• Manufacturer Part Number: PM6670S
• Description: IC CTLR DDR2/3 MEM PS VFQFPN-24
• Manufacturer: STMicroelectronics

Specifications of PM6670S

• Applications: Memory, DDR2/DDR3 Regulator
• Current - Supply: 800µA
• Voltage - Supply: 4.5 V ~ 36 V
• Operating Temperature: -40°C ~ 85°C
• Mounting Type: Surface Mount
• Package / Case: 24-VFQFN, 24-VFQFPN
• For Use With: 497-8411 - BOARD EVAL PM6670S DDR2/3
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

Device description
7.1.11
7.1.12
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Over voltage and under voltage protections
When the switching output voltage is about 115 % of its nominal value, a latched over-
voltage protection (OVP) occurs. In this case the synchronous rectifier immediately turns on
while the high-side MOSFET turns OFF. The output capacitor is rapidly discharged and the
load is preserved from being damaged. The OVP is also active during the soft start. Once
an OVP has occurred, a toggle on S5 pin or a power-on-reset is necessary to exit from the
latched state.
When the switching output voltage is below 70 % of its nominal value, a latched under-
voltage protection occurs. This event causes the switching section to be immediately
disabled and both switches to be opened. The controller enters in soft-end mode and the
output is eventually kept to ground, turning the low side MOSFET on when the voltage is
lower than 400 mV. If S3 and S5 are forced low, the low-side MOSFET is released and only
the 22 Ω switch is active.
The under-voltage protection circuit is enabled only at the end of the soft-start. Once an
UVP has occurred, a toggle on S5 pin or a power-on-reset is necessary to clear the fault
state and restart the device.
Device thermal protection
The internal control circuitry of the PM6670S self-monitors the junction temperature and
turns all outputs off when the 150 °C limit has been overrun. This event causes the switching
section to be immediately disabled and both switches to be opened. The controller enters in
Soft-End Mode and the output is eventually kept to ground, turning the low side MOSFET on
when the voltage is lower than 400 mV. If S3 and S5 are forced low, the low-side switch is
released and only the 22 Ω discharge MOSFET is active.
The thermal fault is a latched protection and normal operating condition is restored by a
Power-on reset or toggling S5.
Table 10.
VDDQ under voltage
VDDQ over voltage
Junction over
temperature
Fault
OV, UV and OT faults management
VDDQ > 115 % of the
VDDQ < 70 % of the
nominal value
nominal value
T
Conditions
J
> +150 °C
Doc ID 14432 Rev 4
LGATE pin is forced high and the device latches off.
Exit by a power-on reset or toggling S5
LGATE pin is forced high after the soft-end, then the
device latches off. Exit by a power-on reset or
toggling S5.
LGATE pin is forced high after the soft-end, then the
device latches off. Exit by a power-on reset or
toggling S5 after 15 °C temperature drop.
Action
PM6670S