Datasheet

LM5574, LM5574-Q1
www.ti.com SNVS478F –JANUARY 2007–REVISED APRIL 2013
PIN DESCRIPTIONS (continued)
Pin(s) Name Description Application Information
15 PRE Pre-charge assist for the bootstrap This open drain output can be connected to SW pin to aid
capacitor charging the bootstrap capacitor during very light load conditions
or in applications where the output may be pre-charged before
the LM5574 is enabled. An internal pre-charge MOSFET is
turned on for 250ns each cycle just prior to the on-time interval
of the buck switch.
16 BST Boost input for bootstrap capacitor An external capacitor is required between the BST and the SW
pins. A 0.022µF ceramic capacitor is recommended. The
capacitor is charged from Vcc via an internal diode during the
off-time of the buck switch.
These devices have limited built-in ESD protection. The leads should be shorted together or the device placed in conductive foam
during storage or handling to prevent electrostatic damage to the MOS gates.
Absolute Maximum Ratings
(1)(2)
V
IN
to GND 76V
BST to GND 90V
PRE to GND 76V
SW to GND (Steady State) -1.5V
BST to V
CC
76V
SD, V
CC
to GND 14V
BST to SW 14V
OUT to GND Limited to Vin
SYNC, SS, FB, RAMP to GND 7V
ESD Rating
(3)
Human Body Model 2kV
Storage Temperature Range -65°C to +150°C
(1) Absolute Maximum Ratings are limits beyond which damage to the device may occur. Operating Ratings are conditions under which
operation of the device is intended to be functional. For ensured specifications and test conditions, see the Electrical Characteristics.
(2) If Military/Aerospace specified devices are required, please contact the Texas Instruments Sales Office/Distributors for availability and
specifications.
(3) The human body model is a 100pF capacitor discharged through a 1.5kΩ resistor into each pin.
Operating Ratings
(1)
V
IN
6V to 75V
Operation Junction Temperature −40°C to + 125°C
(1) Absolute Maximum Ratings are limits beyond which damage to the device may occur. Operating Ratings are conditions under which
operation of the device is intended to be functional. For ensured specifications and test conditions, see the Electrical Characteristics.
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