E-L6911C STMicroelectronics, E-L6911C Datasheet - Page 6

• Manufacturer Part Number: E-L6911C
• Description: IC CTRLR 5BIT PROGR STPDN 20SOIC
• Manufacturer: STMicroelectronics
• Type: Step-Down (Buck)r

Specifications of E-L6911C

• Internal Switch(s): No
• Synchronous Rectifier: Yes
• Number Of Outputs: 1
• Voltage - Output: 1.3 ~ 3.5 V
• Current - Output: 1.3A
• Frequency - Switching: 200kHz
• Voltage - Input: 5 ~ 12 V
• Operating Temperature: -40°C ~ 150°C
• Mounting Type: Surface Mount
• Package / Case: 20-SOIC (7.5mm Width)
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Power - Output: -
• Lead Free Status / Rohs Status: Lead free / RoHS Compliant

L6911C
Switching frequency variations vs. R
Note that forcing a 50 A 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
point of the divider. The DAC output is delivered to an amplifier obtaining the V
set-point of the error amplifier). Internal pull-ups are provided (realized with a 5 A 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
At start-up a ramp is generated charging the external capacitor C
shown in figure 1.
When the voltage across the soft start capacitor (V
6/20
f
S
1 0 00 0
f
1 00 0
S
=
10 0
1 0
T
=
200kH z
1 0
are reported in Fig.1.
200kH z
+
4.306 10
---------------------------- -
+
R
15 10
--------------------
R
SS
F re q u e n cy [kH z]
R T to G N D
R T to V C C =1 2 V
R T to V C C =5 V
T
T
) reaches 0.5V the lower power MOS is turned on to dis-
k
k
1 0 0
7
7
SS
V
V
CC
by means of a 10µA constant current, as
CC
= 5V
= 12V
1 0 0 0
PROG
voltage reference (i.e. the