ISL8120 Datasheet, PDF (1/35 Pages) Intersil Corporation – Dual/n-Phase Buck PWM Controller with Integrated Drivers

®
Data Sheet
April 7, 2009
ISL8120
FN6641.1
Dual/n-Phase Buck PWM Controller with
Integrated Drivers
The ISL8120 integrates two voltage-mode synchronous
buck PWM controllers to control a dual independent voltage
regulator or a 2-phase single output regulator. It has PLL
circuits and can output a phase-shift-programmable clock
signal for the system to be expanded to 3-, 4-, 6-, 12- phases
with desired interleaving phase shift. It also integrates
current sharing control for the power module to operate in
parallel, which offers high system flexibility.
It has voltage feed forward compensation to maintain a
constant loop gain for optimal transient response, especially
for applications with a wide input voltage range. Its
integrated high speed MOSFET drivers and multi-feature
functions provide complete control and protection for a
2/n-phase synchronous buck converter, dual independent
regulators, or DDR tracking applications (VDDQ and VTT
outputs).
The output voltage of a ISL8120-based converter can be
precisely regulated to as low as the internal reference
voltage 0.6V, with a system accuracy of ±0.6% over
commercial temperature and line load variations. Channel 2
can track an external ramp signal for DDR/tracking
applications.
The ISL8120 integrates an internal linear regulator, which
generates VCC from input rail for applications with only one
single supply rail. The internal oscillator is adjustable from
150kHz to 1.5MHz, and is able to track an external clock
signal for frequency synchronization and phase paralleling
applications. The integrated Pre-Biased Digital Soft-Start,
Differential Remote Sensing Amplifier, and Programmable
Input Voltage POR features enhance the value of ISL8120.
The ISL8120 protects against overcurrent conditions by
inhibiting the PWM operation while monitoring the current
with r_DS(ON) of the lower MOSFET, DCR of the output
inductor, or a precision resistor. It also has a PRE-POR
Overvoltage Protection option, which provides some
protection to the load device if the upper MOSFET(s) is
shorted. See “PRE-POR Overvoltage Protection (PRE-POR-
OVP)” on page 25 for details.
The ISL8120’s Fault Hand Shake feature protects any
channel from overloading/stressing due to system faults or
phase failure. The undervoltage fault protection features are
also designed to prevent a negative transient on the output
voltage during falling down. This eliminates the Schottky
diode that is used in some systems for protecting the load
device from reversed output voltage damage.
Features
• Wide VIN Range Operation: 3V to 22V
- VCC Operation from 3V to 5.60V
• Fast Transient Response
- 80MHz Bandwidth Error Amplifier
- Voltage-Mode PWM Leading-edge Modulation Control
- Voltage Feed-forward
• Dual Channel 5V High Speed 4A MOSFET Gate Drivers
- Internal Bootstrap Diodes
• Internal Linear Regulator Provides a 5.4V Bias from VIN
• External Soft-Start Ramp Reference Input for
DDR/Tracking Applications
• Excellent Output Voltage Regulation
- 0.6V ±0.6%/±0.9% Internal Reference Over
Commercial/Industrial Temperature
- True Differential Remote Voltage Sensing
• Oscillator Programmable from 150kHz to 1.5MHz
• Frequency Synchronization
• Scale for 1-, 2-, 3-, 4-, 6-, up to 12- Phase with Single
Output
- Excellent Phase Current Balancing
- Programmable Phase Shift Between the 2 Phases
Controlled by the ISL8120 and Programmable Phase
Shift for Clockout Signal
- Interleaving Operation Results in Minimum Input RMS
Current and Minimum Output Ripple Current
• Fault Hand Shake Capability for High System Reliability
• Overcurrent Protection
- DCR, r_DS(ON), or Precision Resistor Current Sensing
- Independent and Average Phase Current OCP
• Output Overvoltage and Undervoltage Protections
• Programmable Phase Shift in Dual Mode Operation
• Digital Soft-Start with Pre-Charged Output Start-up
Capability
• Power-Good Indication
• Dual Independent Channel Enable Inputs with Precision
Voltage Monitor and Voltage Feed-forward Capability
- Programmable Input Voltage POR and its Hysteresis
with a Resistor Divider at EN Input
• Over-Temperature Protection
• Pre-Power-On-Reset Overvoltage Protection Option
• 32 Ld 5x5 QFN Package - Near Chip-Scale Footprint
- Enhanced Thermal Performance for MHz Applications
• Pb-free (RoHS compliant)
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CAUTION: These devices are sensitive to electrostatic discharge; follow proper IC Handling Procedures.
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