ISL8105B Datasheet, PDF (1/16 Pages) Intersil Corporation – +5V or +12V Single-Phase Synchronous Buck Converter PWM Controller with Integrated MOSFET Gate Drivers, Extended Soft-Start Time

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Data Sheet
April 15, 2010
ISL8105B
FN6447.2
+5V or +12V Single-Phase Synchronous
Buck Converter PWM Controller with
Integrated MOSFET Gate Drivers,
Extended Soft-Start Time
The ISL8105B is a simple single-phase PWM controller for a
synchronous buck converter. It operates from +5V or +12V bias
supply voltage. With integrated linear regulator, boot diode, and
N-Channel MOSFET gate drivers, the ISL8105B reduces
external component count and board space requirements.
These make the IC suitable for a wide range of applications.
Utilizing voltage-mode control, the output voltage can be
precisely regulated to as low as 0.6V. The 0.6V internal
reference features a maximum tolerance of ±1.0% over the
commercial temperature range, and ±1.5% over the
industrial temperature range. The controller operates with a
fixed switching frequency of 300kHz.
The ISL8105B features the capability of safe start-up with
pre-biased load. It also provides overcurrent protection by
monitoring the ON-resistance of the bottom-side MOSFET to
inhibit PWM operation appropriately. During start-up interval,
the resistor connected to BGATE/BSOC pin is employed to
program overcurrent protection condition. This approach
simplifies the implementation and does not deteriorate
converter efficiency.
Pinouts
ISL8105B
(10 LD 3X3 DFN)
TOP VIEW
BOOT 1
TGATE 2
N/C 3
GND 4
BGATE/BSOC 5
GND
10 LX
9 COMP/EN
8 FB
7 N/C
6 VBIAS
ISL8105B
(8 LD SOIC)
TOP VIEW
BOOT 1
TGATE 2
GND ³
BGATE/BSOC 4
8 LX
7 COMP/EN
6 FB
5 VBIAS
Features
• Operates from +5V or +12V Bias Supply Voltage
- 1.0V to 12V Input Voltage Range (up to 20V possible
with restrictions; see Input Voltage Considerations)
- 0.6V to V_IN Output Voltage Range
• 0.6V Internal Reference Voltage
- ±1.0% Tolerance Over the Commercial Temperature
Range (0°C to +70°C)
- ±1.5% Tolerance Over the Industrial Temperature
Range (-40°C to +85°C).
• Integrated MOSFET Gate Drivers that Operate from
V_BIAS (+5V to +12V)
- Bootstrapped High-side Gate Driver with Integrated
Boot Diode
- Drives N-Channel MOSFETs
• Simple Voltage-Mode PWM Control
- Traditional Dual Edge Modulation
• Fast Transient Response
- High-Bandwidth Error Amplifier
- Full 0% to 100% Duty Cycle
• Fixed 300kHz Operating Frequency
• Fixed Internal Soft-Start with Pre-biased Load Capability
• Lossless, Programmable Overcurrent Protection
- Uses Bottom-side MOSFET’s r_DS(ON)
• Enable/Disable Function Using COMP/EN Pin
• Output Current Sourcing and Sinking Currents
• Pb-Free (RoHS Compliant)
Applications
• 5V or 12V DC/DC Regulators
• Industrial Power Systems
• Telecom and Datacom Applications
• Test and Measurement Instruments
• Distributed DC/DC Power Architecture
• Point of Load Modules
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CAUTION: These devices are sensitive to electrostatic discharge; follow proper IC Handling Procedures.
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