LM34919C-Q1 Datasheet, PDF (6/29 Pages) Texas Instruments – LM34919C-Q1 Ultra Small 50V, 600 mA Constant On-Time Buck Switching Regulator

LM34919C-Q1
SNVS831A – SEPTEMBER 2013 – REVISED DECEMBER 2013
www.ti.com
PIN
NUMBER
B2
PIN NUMBER
(WSON-12)
9
B3
8
C1
2
C2
3
C3
10
D1
1
D2
12
D3
11
EP (WSON Only)
NAME
PGD
SS
ISEN
EN
VCC
VIN
SW
BST
Pin Descriptions (continued)
DESCRIPTION
APPLICATION INFORMATION
Power Good
Soft-start
Current sense
Enable Pin
Output from the startup regulator
Input supply voltage
Switching Node
Boost pin for bootstrap capacitor
Open drain. Logic output indicates when the voltage
at the FB pin has increased above 92% of the
internal reference. The falling threshold for PGD is
90% of the internal reference. An external pull-up
resistor connecting PGD pin to a voltage less than
14 V is required.
An internal current source charges an external
capacitor to 2.52 V, providing the soft-start function.
The re-circulating current flows through the internal
sense resistor and out of this pin to the free-
wheeling diode. Valley current limit is nominally set
at 0.64 A.
Pull low to disable the part for low shutdown current.
Shutdown threshold is 1.3 V (typ).
Nominally regulated at 7.0 V. An external voltage (7
V - 14 V) can be applied to this pin to reduce
internal dissipation. An internal diode connects V_CC
to VIN.
Nominal input range is 4.5 V to 50 V.
Internally connected to the buck switch source.
Connects to the inductor, free-wheeling diode, and
bootstrap capacitor.
Connect a 0.022 µF capacitor from SW to this pin.
The capacitor is charged from V_CC via an internal
diode during each off-time.
Exposed pad should be connected to RTN pin and
system ground for proper cooling.
6
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