LM34922 Datasheet, PDF (3/17 Pages) Texas Instruments – 28V, 2A Constant On-Time Switching Regulator with Adjustable Current Limit

Pin Descriptions
Pin No.
1
2
3
4
5
6
7
8
9
10
Name
VIN
RT
PGD
SS
SGND
FB
CSG
CS
SW
BST
Description
Application Information
Input supply voltage
Operating input range is 6V to 28V. Transient capability is 30V. A low ESR
capacitor must be placed as close as possible to the VIN and SGND pins.
On-time Control
An external resistor from VIN to this pin sets the buck switch on-time, and
the switching frequency.
Power Good
Logic output indicates when the voltage at the FB pin has increased to
above 95% of the internal reference voltage. Hysteresis is provided. An
external pull-up resistor to a voltage less than 7V is required.
Soft-Start
An internal current source charges an external capacitor to provide the soft-
start function.
Signal Ground
Ground for all internal circuitry other than the current limit sense circuit.
Feedback
Internally connected to the regulation comparator. The regulation level is
2.51V.
Current Sense Ground
Ground connection for the current limit sensing circuit. Connect to ground
and to the current sense resistor.
Current sense
Connect to the current sense resistor and the anode of the free-wheeling
diode.
Switching Node
Internally connected to the buck switch source. Connect to the external
inductor, cathode of the free-wheeling diode, and bootstrap capacitor.
Bootstrap capacitor connection of the Connect a 0.1µF capacitor from SW to this pin. The capacitor is charged
buck switch gate driver.
during the buck switch off-time via an internal diode.
3
www.ti.com