L6911C

6/20

Note that forcing a 50

µA current into this pin, the device stops switching because no current is delivered to the

oscillator.

Figure 1.

Digital to Analog Converter

The built-in digital to analog converter allows the adjustment of the output voltage from 1.30V to 2.05V with

50mV binary steps and from 2.10V to 3.50V with 100mV binary steps as shown in the previous table 1. The

internal reference is trimmed to ensure the precision of 1%.

The internal reference voltage for the regulation is programmed by the voltage identification (VID) pins. These

are TTL compatible inputs of an internal DAC that is realized by means of a series of resistors providing a par-

tition of the internal voltage reference. The VID code drives a multiplexer that selects a voltage on a precise

set-point of the error amplifier). Internal pull-ups are provided (realized with a 5

µA current generator); in this

way, to program a logic "1" it is enough to leave the pin floating, while to program a logic "0" it is enough to short

the pin to GND.

The voltage identification (VID) pin configuration also sets the power-good thresholds (PGOOD) and the over-

voltage protection (OVP) thresholds.

The VID code "11111" disable the device (as a short on the SS pin) and no output voltage is regulated.

Soft Start and Inhibit

shown in figure 1.

f

S

200kH z

4.306 10

7

⋅

R

()

-----------------------------

+

=

f

S

200kH z

15 10

7

⋅

R

()

--------------------

+

=

10

100

1000

F re quency [kH z]

10

10 0

1000

10000

R T to G N D

R T to V C C =1 2 V

R T to V C C =5 V