ISL6625A_14 Datasheet, PDF (1/10 Pages) Intersil Corporation – Synchronous Rectified Buck MOSFET Drivers

Synchronous Rectified Buck MOSFET Drivers
ISL6625A
The ISL6625A is a high frequency MOSFET driver designed to
drive upper and lower power N-Channel MOSFETs in a
synchronous rectified buck converter topology.
In ISL6625A, the upper and lower gates are both driven to an
externally applied voltage. This provides the capability to
optimize applications involving trade-offs between gate charge
and conduction losses.
An advanced adaptive shoot-through protection is integrated to
prevent both the upper and lower MOSFETs from conducting
simultaneously and to minimize dead time. The ISL6625A has
a 10kΩ integrated high-side gate-to-source resistor to prevent
self turn-on due to high input bus dV/dt.
This driver also has an overvoltage protection feature, which is
operational while VCC is below the POR threshold. The PHASE
node is connected to the gate of the low-side MOSFET (LGATE)
via a 30kΩ resistor, limiting the output voltage of the converter
close to the gate threshold of the low-side MOSFET. This is
dependent on the current being shunted, which provides some
protection to the load should the upper MOSFET(s) become
shorted.
Applications
• High light load efficiency voltage regulators
• Core regulators for advanced microprocessors
• High current DC/DC converters
Features
• Dual MOSFET drives for synchronous rectified bridge
• Advanced adaptive zero shoot-through protection
- PHASE detection
- LGATE detection
- Auto-Zero of r_DS(ON) conduction offset effect
• Low standby bias current
• 36V internal bootstrap switcher
• Bootstrap capacitor overcharging prevention
• Integrated high-side gate-to-source resistor to prevent from
self turn-on due to high input bus dV/dt
• Pre-POR overvoltage protection for start-up and shutdown
• Power rails undervoltage protection
• Expandable bottom copper pad for enhanced heat sinking
• Dual flat no-lead (DFN) package
- Near chip-scale package footprint; improves PCB
efficiency and thinner in profile
• Pb-Free (RoHS compliant)
Related Literature
• Technical Brief TB363 “Guidelines for Handling and
Processing Moisture Sensitive Surface Mount Devices
(SMDs)”
• Technical Brief TB417 “Designing Stable Compensation
Networks for Single Phase Voltage Mode Buck Regulators”
VCC
PIN 6
PWM
+5V
30.4k
POR/
CONTROL
LOGIC
32k
SHOOT-
THROUGH
PROTECTION
FIGURE 1. BLOCK DIAGRAM
BOOT
UGATE
10k
PHASE
30k
VCC
PIN 7
PINS 6 AND 7 MUST BE
TIED TOGETHER
LGATE
GND
September 19, 2012
1
FN7978.0
CAUTION: These devices are sensitive to electrostatic discharge; follow proper IC Handling Procedures.
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