POWER MANAGEMENT
1
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SC1405D
High Speed Synchronous Power
MOSFET Smart Driver
PRELIMINARY
Features
Applications
Revision: June 8, 2005
Typical Application Circuit
Description
The SC1405D is a Dual-MOSFET Driver with an internal
Overlap Protection Circuit to prevent shoot-through. Each
driver is capable of driving a 3000pF load in 15ns rise/
fall time and has ULTRA-LOW propagation delay from in-
put transition to the gate of the power FETs. Adaptive
Overlap Protection circuit ensures that the synchronous
FET does not turn on until the top FET source has reached
a voltage low enough to prevent shoot-through. The de-
lay between the bottom gate going low to the top gate
transitioning high is externally programmable via a ca-
pacitor to minimize dead time. The bottom FET may be
disabled at light loads by keeping S_MOD low to trigger
asynchronous operation, thus saving the bottom FET’s
gate drive current and inductor ripple current.
An internal voltage reference allows threshold adjustment
for an Output Over-Voltage protection circuitry, indepen-
dent of the PWM controller. The device provides over-
voltage protection independent of the PWM feedback
loop with a unique “adaptive OVP” comparator which re-
jects noise but responds quickly to a true OVP situation.
Under-Voltage-Lock-Out circuit is included to guarantee
that both driver outputs are off when Vcc is less than or
equal to 4.4V (typ) at supply ramp up (4.35V at supply
ramp down). A CMOS output provides status indication
of the 5V supply. A low enable input places the IC in stand-
by mode, reducing supply current to less than 10µA.
Fast rise and fall times (15ns with 3000pf load)
14ns max. Propagation delay (BG going with low)
Adaptive and programmable shoot-through
protection
Adaptive overvoltage protection
Wide input voltage range (4.5V - 25V)
Programmable delay between FETs
Power saving asynchronous mode control
Output overvoltage protection/overtemp shutdown
Under-Voltage lock-out and power ready signal
Less than 10µA stand-by current (EN=low)
Power ready output signal
High frequency (to 1.2MHz) operation allows use of
small inductors and low cost caps in place of
electrolytics
TSSOP-14 package
High Density/Fast transient microprocessor power
supplies
Motor Drives/Class-D amps
High efficiency portable computers
