ADP5075

Data Sheet

Rev. B | Page 12 of 19

SOFT START

The regulator in the ADP5075 includes soft start circuitry that

ramps the output voltage in a controlled manner during startup,

thereby limiting the inrush current. The soft start time is internally

set to the fastest rate when the SS pin is open.

Connecting a resistor between SS and ground allows the

adjustment of the soft start delay.

SLEW RATE CONTROL

The ADP5075 uses programmable output driver slew rate control

circuitry. This circuitry reduces the slew rate of the switching

node as shown in Figure 24, resulting in reduced ringing and

lower EMI. To program the slew rate, connect the SLEW pin to

the VREG pin for normal mode, to the GND pin for slow mode,

or leave it open for fast mode. This configuration allows the use of

an open-drain output from a noise sensitive device to switch the

slew rate from fast to slow, for example, during ADC sampling.

Note that slew rate control causes a trade-off between efficiency

and low EMI.

FASTEST

SLOWEST

Figure 24. Switching Node at Various Slew Rate Settings

CURRENT-LIMIT PROTECTION

The inverting regulator in the ADP5075 includes current-limit

protection circuitry to limit the amount of forward current

through the MOSFET switch.

When the peak inductor current exceeds the overcurrent limit

threshold for a number of clock cycles during an overload or

short-circuit condition, the regulator enters hiccup mode. The

regulator stops switching and then restarts with a new soft start

removed.

OVERVOLTAGE PROTECTION

An overvoltage protection mechanism is present on the FB pin

for the inverting regulator.

the switching stops until the voltage rises above the threshold.

This functionality is enabled after the soft start period has elapsed.

THERMAL SHUTDOWN

In the event that the ADP5075 junction temperature rises above

junction temperatures can be the result of prolonged high current

operation, poor circuit board design, and/or high ambient

temperature. Hysteresis is included so that when thermal shutdown

occurs, the ADP5075 does not return to operation until the on-

from thermal shutdown, a soft start is performed.