SC1211 Datasheet, PDF (1/11 Pages) Semtech Corporation – High Speed, Combi-SenseTM Synchronous MOSFET Driver

POWER MANAGEMENT
Description
SC1211
High Speed, Combi-Sense^TM
Synchronous MOSFET Driver
Features
The SC1211 is a high speed, Combi-Sense^TM, dual out-
put driver designed to drive high-side and low-side
MOSFETs in a synchronous Buck converter. These
drivers combined with Combi-Sense PWM controllers,
such as Semtech SC2643VX or SC2643, provide a
cost effective multi-phase voltage regulator for advanced
microprocessors
The Combi-Sense^TM is a technique to sense the inductor
current for peak current mode control of voltage regula-
tor without using sensing resistor. It provides the follow-
ing advantages:
- No costly precision sensing resistor
- Lossless current sensing
- High level noise free signal
- Fast response
- Suitable for wide range of duty cycle
- Only two small signal components (third optional)
The detailed explanation of the technique can be found
in the Applications Information section.
u High efficiency
u +12V supply voltage with internal LDO for optimum
gate drive
u High peak drive current
u Adaptive non-overlapping gate drives provide
shoot-through protection
u Support Combi-Sense^TM and VID-on-fly operations
u Fast rise and fall times (15ns typical with 3000pf
load)
u Ultra-low (<30ns) propagation delay (BG going low)
u Floating top gate drive
u Crowbar function for over voltage protection
u High frequency (to 1.5 MHz) operation allows use
of small inductors and low cost ceramic capacitors
u Under-voltage-lockout
u Low quiescent current
A 30ns max propagation delay from input transition to
the gate of the power FET’s guarantees operation at high
switching frequencies. Internal overlap protection circuit
prevents shoot-through from Vin to PGND in the main
and synchronous MOSFETs. The adaptive overlap pro-
tection circuit ensures the bottom FET does not turn on
until the top FET source has reached 1V, to prevent cross-
conduction.
Applications
u Intel Pentium^TM processor power supplies
u AMD Athlon^TM and K8^TM processor power supplies
u High current low voltage DC-DC converters
8.5V gate drive provides optimum enhancement of
MOSFETs at minimum driver and MOSFET switching loss.
High current drive capability allows fast switching, thus
reducing switching losses at high (up to 1.5MHz) frequen-
cies without causing thermal stress on the driver.
Under-voltage-lockout and over-temperature shutdown
features are included for proper and safe operation.
Timed latches and improved robustness are built into
the housekeeping functions such as the Under Voltage
Lockout and adaptive Shoot-through protection circuitry
to prevent false triggering and to assure safe operation.
The SC1211 is offered in a Power SOIC-8L package.
February 24, 2003
1
www.semtech.com