LTC1629-6_15 Datasheet, PDF (8/28 Pages) Linear Technology – PolyPhase, Synchronous Step-Down Switching Regulator

LTC1629-6
PI FU CTIO S
PLLIN (Pin 6): External Synchronization Input to Phase
Detector. This pin is internally terminated to SGND with
50kΩ. The phase-locked loop will force the rising top gate
signal of controller 1 to be synchronized with the rising
edge of the PLLIN signal.
PHASMD (Pin 7): Control Input to Phase Selector which
determines the phase relationships between controller 1,
controller 2 and the CLKOUT signal.
I_TH (Pin 8): Error Amplifier Output and Switching Regula-
tor Compensation Point. Both current comparator’s thresh-
olds increase with this control voltage. The normal voltage
range of this pin is from 0V to 2.4V.
SGND (Pin 9): Signal Ground, common to both control-
lers, must be routed separately from the input switched
current ground path to the common (–) terminal(s) of the
C_OUT capacitor(s).
V_DIFFOUT (Pin 10): Output of a Differential Amplifier that
provides true remote output voltage sensing. This pin
normally drives an external resistive divider that sets the
output voltage.
V_OS–, V_OS+ (Pins 11, 12): Inputs to an Operational Ampli-
fier. Internal precision resistors capable of being elec-
tronically switched in or out can configure it as a differen-
tial amplifier or an uncommitted Op Amp.
PGOOD (Pin 15): Open-Drain Logic Output. PGOOD is
pulled to ground when the voltage on the EAIN pin is not
within ±10% of its set point.
TG2, TG1 (Pins 16, 27): High Current Gate Drives for Top
N-Channel MOSFETS. These are the outputs of floating
drivers with a voltage swing equal to INTV_CC superim-
posed on the switch node voltage SW.
SW2, SW1 (Pins 17, 26): Switch Node Connections to
Inductors. Voltage swing at these pins is from a Schottky
diode (external) voltage drop below ground to V_IN.
BOOST2, BOOST1 (Pins 18, 25): Bootstrapped Supplies
to the Topside Floating Drivers. Capacitors are connected
between the Boost and Switch pins and Schottky diodes
are tied between the Boost and INTV_CC pins. Voltage swing
at the Boost pins is from INTV_CC to (V_IN + INTV_CC).
BG2, BG1 (Pins 19, 23): High Current Gate Drives for
Bottom Synchronous N-Channel MOSFETS. Voltage swing
at these pins is from ground to INTV_CC.
PGND (Pin 20): Driver Power Ground. Connect to sources
of bottom N-channel MOSFETS and the (–) terminals of
C_IN.
INTV_CC (Pin 21): Output of the Internal 5V Linear Low
Dropout Regulator and the EXTV_CC Switch. The driver and
control circuits are powered from this voltage source.
Decouple to power ground with a 1µF ceramic capacitor
placed directly adjacent to the IC and minimum of 4.7µF
additional tantalum or other low ESR capacitor.
EXTV_CC (Pin 22): External Power Input to an Internal
Switch . This switch closes and supplies INTV_CC, bypass-
ing the internal low dropout regulator whenever EXTV_CC is
higher than 4.7V. See EXTV_CC Connection in the Applica-
tions Information section. Do not exceed 7V on this pin
and ensure V_EXTVCC ≤ V_INTVCC.
V_IN (Pin 24): Main Supply Pin. Should be closely decoupled
to the IC’s signal ground pin.
CLKOUT (Pin 28): Output Clock Signal available to
daisychain other controller ICs for additional MOSFET
driver stages/phases.
16296f
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