L6728DTR STMicroelectronics, L6728DTR Datasheet - Page 15

• Manufacturer Part Number: L6728DTR
• Description: IC PWM CTLR 1PH POWERGOOD 10DFN
• Manufacturer: STMicroelectronics

Specifications of L6728DTR

• Pwm Type: Voltage Mode
• Number Of Outputs: 1
• Frequency - Max: 330kHz
• Duty Cycle: 80%
• Voltage - Supply: 5 V ~ 12 V
• Buck: Yes
• Boost: No
• Flyback: No
• Inverting: No
• Doubler: No
• Divider: No
• Cuk: No
• Isolated: No
• Operating Temperature: -40°C ~ 125°C
• Package / Case: 10-DFN
• Frequency-max: 330kHz
• Duty Cycle (max): 80 %
• Mounting Style: SMD/SMT
• Switching Frequency: 300 KHz
• Operating Supply Voltage: 5 V to 12 V
• Supply Current: 6 mA
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Other names: 497-10432-2

L6728D
9
Output voltage setting and protections
The L6728D is capable of precisely regulating an output voltage as low as 0.8 V. In fact, the
device is equipped with a fixed 0.8 V internal reference that guarantees the output regulated
voltage remains within a ±0.8% tolerance over line and temperature variations (excluding
output resistor divider tolerance, when present).
Output voltages higher than 0.8 V can be easily achieved by adding a resistor R
the FB pin and ground. Referring to
where V
The L6728D monitors the voltage at the VSEN pin and compares it to the internal reference
voltage in order to provide undervoltage and overvoltage protection as well as a PGOOD
signal. Depending on the level of VSEN, different actions are performed by the controller:
●
●
●
●
PGOOD: If the voltage monitored through VSEN goes outside the PGOOD window
limits, the device de-asserts the PGOOD signal while still continuing to switch and
regulate. PGOOD is asserted at the end of the soft-start phase.
Undervoltage protection: If the voltage at VSEN pin drops below the UV threshold,
the device turns off both the HS and LS MOSFETs, latching the condition. Cycle the
VCC to recover.
Overvoltage protection: If the voltage at VSEN pin rises over OV threshold (1 V typ),
overvoltage protection turns off the HS MOSFET and turns on the LS MOSFET. The LS
MOSFET is turned off as soon as VSEN goes below Vref/2 (0.4 V). The condition is
latched. Cycle the VCC to recover. Note that even if the device is latched, the device
still controls the LS MOSFET and can switch it on whenever VSEN rises above the OV
threshold.
Feedback disconnection protection: In order to provide load protection even if the
VSEN pin is not connected, a 100 nA bias current is always sourced from this pin. If
VSEN pin is not connected, this current permanently pulls it up, causing the device to
detect an OV. Thus, LS is latched on, preventing the output voltage from rising out of
control.
REF
is 0.8 V.
V
Doc ID 16498 Rev 1
OUT
Figure
=
V
REF
1, the steady-state DC output voltage is:
⋅
⎛
⎝
Output voltage setting and protections
1
+
---------- -
R
R
OS
FB
⎞
⎠
OS
between
15/33