SC411 Datasheet, PDF (5/27 Pages) Semtech Corporation – Synchronous Buck Pseudo-Fixed Frequency Power Supply Controller

SC411
POWER MANAGEMENT
Electrical Characteristics (Cont.)
Parameter
Soft-Start
Soft-Start Ramp Time
Under-Voltage Blank Time
Gate Drivers
Shoot-Through Delay⁽⁴⁾
DL Pull-Down Resistance
DL Sink Current
DL Pull-Up Resistance
DL Source Current
Conditions
25°C
-40°C to 125°C
Units
Min
Typ
Max
Min
Max
EN/PSV High to PGD High
440
EN/PSV High to UV High
440
clks⁽³⁾
clks⁽³⁾
DH or DL Rising
30
DL Low
0.80
DL = 2.5V
3.1
DL High
2
DL = 2.5V
1.3
ns
1.75
Ω
A
4
Ω
A
Notes:
1) When the inductor is in continuous and discontinuous conduction mode, the output voltage will have a DC regulation level higher than the
error-comparator threshold by 50% of the ripple voltage.
2) Using a current sense resistor, this measurement relates to PGND minus the voltage of the source on the low-side MOSFET. These values
guaranteed by the ILIM Source Current and Current Comparator Offset tests.
3) clks = Switching cycles.
4) Guaranteed by design. See Shoot-Through Delay Timing Diagram on Page 8.
5) Semtech’s SmartDriver^TM FET drive first pulls DH high with a pull-up resistance of 10Ω (typ) until LX = 1.5V (typ). At this point, an additional
pull-up device is activated, reducing the resistance to 2Ω (typ). This negates the need for an external gate or boost resistor.
© 2007 Semtech Corp.
5
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