ADP3422
Pin No.
13
Mnemonic
DPRSLP
Function
Deeper Sleep Mode (active high). This is a digital input pin coming from a system signal corresponding to
Deeper Sleep mode of the CPU operation in its active high state. It is used to initiate a blanking period
for the PWRGD signal (to disable its response to a pending dynamic core voltage change according to the
VID code) whenever a signal transition occurs.
Power Good (active high). This is an open drain output pin which, via the assistance of an external
pull-up resistor, indicates that the core voltage is within the specified tolerance of the VID programmed
value or else in a VID transition state as indicated by a recent state transition of either the
BOM
or
DPRSLP pins. PWRGD is deactivated (pulled low) when the IC is disabled or in UVLO mode or
soft-start. The open drain output allows external ORing with other open drain/collector power-
good indicators.
Shutdown (active low). This is a digital input pin coming from a system signal which, in its active
state, shuts down the IC operation, placing the IC in its lowest quiescent current state for maximum
power savings.
Clamp (active high). This is an open drain output pin which, via the assistance of an external pull-up
resistor, indicates that the core voltage should be clamped for its protection. To allow the highest
level of protection, the CLAMP signal is developed using both a redundant reference and a re-
dundant feedback path with respect to those of the main regulation loop. It is also latched. In a
preferred and more conservative configuration, the core voltage is clamped by an external FET.
The initial protection function is served when it is activated by detection of either an overvoltage or a
reverse-voltage condition on the COREFB pin. A backup protection function due to loss of the
latched signal at IC power-off is served by connecting the pull-up resistor to a system 鈥淎LWAYS鈥?/div>
regulator output (e.g., V5_ALWAYS). If the external FET is used, this implementation will keep the
core voltage clamped until the ADP3422 has power reapplied, thus keeping protection for the
CPU even after a hard-failure power-down and restart (e.g., a shorted top FET).
Drive-Low Shutdown (active low). This is a digital output pin which, in its active state, indicates that
the lower FET of the core VR should be disabled. In the suggested application schematic this pin is
directly connected to the pin of the same name on the ADP3415 or other driver IC. The pin is normally
asserted in the light load condition, but its assertion will be deactivated by the consideration of a
number of dynamic conditions where operation of the lower FET may be needed.
Switched Node Feedback. This is a high-impedance analog input pin that is used to allow the
ON-time noise blanking function to terminate earlier than its internally preset time by its indication
that the turn-ON of the upper FET has occurred. A resistor must be inserted between the pin and the
switched node of the core VR so that the input can be clamped (at ~7V) and is not exposed to
high voltage. This pin can also be shorted to ground if the need for this speed enhancement is
deemed unnecessary.
Soft Start. This is an analog I/O pin whose output is a controlled current source used to charge or
discharge an external grounded capacitor and whose input is the detected voltage that is indicative of
elapsed time. The pin controls the soft start time of the IC as well as the hiccup cycle time during
short circuit. Hiccup operation is a feature that was added to reduce short circuit power dissipation by
more than an order of magnitude, while still allowing an automatic restart when the short is removed.
Core Feedback. This is a high-impedance analog input pin that is used to monitor the output voltage
for setting the proper state of the PWRGD and CLAMP pins. It is generally recommended to
RC-filter the noise from the monitored core voltage, as suggested by the application schematic.
VID-Programmed Digital-to-Analog Converter Output. This voltage is the reference voltage for output
voltage regulation.
Ground
Driver Command Output Signal. This is a digital output pin which is used to command the state of the
switched node via the driver. It should be connected to the IN pin of the ADP3415 or similar driver.
Power Supply
14
PWRGD
15
SD
16
CLAMP
17
DRVLSD
18
SWFB
19
SS
20
COREFB
21
22
23
24
DACOUT
GND
OUT
VCC
REV. 0
鈥?鈥?/div>
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