ISL95808 Datasheet, PDF (1/9 Pages) Intersil Corporation – Three-state PWM input for power stage shutdown

DATASHEET
High Voltage Synchronous Rectified Buck MOSFET Driver
ISL95808
The ISL95808 is a high frequency, dual MOSFET driver with low
shutdown current, optimized to drive two N-Channel power
MOSFETs in a synchronous-rectified buck converter topology. It
is especially suited for mobile computing applications that
require high efficiency and excellent thermal performance. The
driver, combined with an Intersil multiphase Buck PWM
controller, forms a complete single-stage core-voltage
regulator solution for advanced mobile microprocessors.
The ISL95808 features a 4A typical sinking current for the
lower gate driver. This current is capable of holding the lower
MOSFET gate off during the rising edge of the phase node. This
prevents shoot-through power loss caused by the high dv/dt of
phase voltages. The operating voltage matches the 30V
breakdown voltage of the MOSFETs commonly used in mobile
computer power supplies.
The ISL95808 also features a three-state PWM input. This
PWM input, working together with Intersil’s multiphase PWM
controllers, will prevent negative voltage output during CPU
shutdown. This feature eliminates a protective Schottky diode
usually seen in microprocessor power systems.
MOSFET gates can be efficiently switched up to 2MHz using
the ISL95808. Each driver is capable of driving a 3000pF load
with propagation delays of 8ns and transition times under
10ns. Bootstrapping is implemented with an internal Schottky
diode. This reduces system cost and complexity, while allowing
for the use of higher performance MOSFETs. Adaptive
shoot--through protection is integrated to prevent both
MOSFETs from conducting simultaneously.
A diode emulation feature is integrated in the ISL95808 to
enhance converter efficiency at light load conditions. This
feature also allows for monotonic start-up into prebiased
outputs. When diode emulation is enabled, the driver will allow
discontinuous conduction mode by detecting when the
inductor current reaches zero and subsequently turning off the
low-side MOSFET gate.
The ISL95808 also features very low shutdown supply current
(5V, 3µA) to ensure the low power consumption.
Features
• Dual MOSFET drivers for synchronous rectified bridge
• Adaptive shoot-through protection
• 0.5Ω ON-resistance and 4A sink current capability
• Supports high switching frequency up to 2MHz
- Fast output rise and fall time
- Low propagation delay
• Three-state PWM input for power stage shutdown
• Internal bootstrap Schottky diode
• Low shutdown supply current (5V, 3µA)
• Diode emulation for enhanced light-load efficiency and
prebiased start-up applications
• VCC POR (Power-On Reset) feature integrated
• Low three-state shutdown hold-off time (typical 160ns)
• DFN package
• Pb-free (RoHS compliant)
Applications
• Core voltage supplies for Intel® and AMD™ mobile
microprocessors
• High frequency low profile DC/DC converters
• High current low output voltage DC/DC converters
• High input voltage DC/DC converters
Related Literature
• TB389, “PCB Land Pattern Design and Surface Mount
Guidelines for MLFP Packages”
• TB447, “Guidelines for Preventing Boot-to-Phase Stress on
Half-Bridge MOSFET Driver ICs”
May 25, 2016
FN8689.2
VCC
FCCM
PWM
CONTROL
10kΩ ^LOGIC
SHOOT-
THROUGH
PROTECTION
VCC
BOOT
UGATE
PHASE
LGATE
GND
THERMAL PAD
FIGURE 1. BLOCK DIAGRAM
1
CAUTION: These devices are sensitive to electrostatic discharge; follow proper IC Handling Procedures.
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