REV. 0

ADP3422

–8–

ADOPT is a trademark of Analog Devices, Inc.

Pin No.

Mnemonic

Function

25

RAMP

Regulation Ramp Feedback Input. This is a high-impedance analog input pin which is used for providing

negative feedback of the hysteretically-controlled output. Several switched current sources also

appear at this input, most notably the cycle-by-cycle hysteresis-setting switched current programmed by

the HYSSET pin. The external resistive termination at this pin sets the magnitude of the hysteresis

applied to the regulation loop.

26

REG

Regulation Voltage Summing Input. This is a high-impedance analog input pin into which the voltage

reference of the feedback loop allows the summing of both the DACOUT voltage and the core voltage for

programming the output resistance of the core voltage regulator. This is also the pin at which an optimized

transient response can be tailored using Analog Devices’ patented ADOPT™ design technique.

27

CS+

Current Limit Positive Sense. This is a high-impedance analog input pin that is normally connected to the

positive node of the current sense resistor.

28

CS–

Current Limit Negative Sense. This is a high-impedance analog input pin that is normally connected via

a current-limit programming resistor to the negative node of the current sense resistor. A hysteretically-

controlled current—three times the current programmed at the HYSSET pin—flows out of this pin

and develops a current-limit-setting voltage across that resistor. This voltage must be exceeded by the

inductor current generated current sense voltage in order to trigger the current limit function. When it is

triggered, the current flowing out of this pin is reduced—to two-thirds of its previous value—producing

hysteresis in the current limit operation.