ISL8023_12 Datasheet, PDF (1/20 Pages) Intersil Corporation – Compact Synchronous Buck Regulator

Compact Synchronous Buck Regulator
ISL8023, ISL8024
The ISL8023, ISL8024 are highly efficient, monolithic,
synchronous step-down DC/DC converters that can deliver 3A
(ISL8023) or 4A (ISL8024) of continuous output current from a
2.7V to 5.5V input supply. The devices use current mode control
architecture to deliver very low duty cycle operation at high
frequency with fast transient response and excellent loop stability.
The ISL8023 and ISL8024 integrate a very low On-resistance
P-Channel (45mΩ) high side FET and N-Channel (19mΩ) low
side FET to maximize efficiency and minimize external
component count. The 100% duty-cycle operation allows less
than 200mV dropout voltage at 4A output current. The
operation frequency of the pulse-width modulator (PWM) is
adjustable from 500kHz to 4MHz. The default switching
frequency of 1MHz is set by connecting the FS pin high, which
allows for the use of small external components.
The ISL8023, ISL8024 can be configured for discontinuous or
forced continuous operation at light load. Forced continuous
operation reduces noise and RF interference while
discontinuous mode provides higher efficiency by reducing
switching losses at light loads.
Fault protection is provided by internal hiccup mode current
limiting during short circuit and overcurrent conditions. Other
protection, such as overvoltage and over-temperature are also
integrated into the device. A power-good output voltage
monitor indicates when the output is in regulation.
The ISL8023, ISL8024 offer a 1ms Power-Good (PG) timer at
power-up. When in shutdown, ISL8023, ISL8024 discharges
the output capacitor through an internal soft-stop switch. Other
features include internal fixed or adjustable soft-start and
internal/external compensation.
The ISL8023 and ISL8024 are offered in a space saving 16 Ld
3x3 Pb-free QFN package with an exposed pad for improved
thermal performance and 1mm maximum height. The
complete converter occupies less than 0.22 in² area.
Various fixed output voltages are available upon request. See
the “Ordering Information” on page 4 for more details.
Features
• 2.7V to 5.5V Input Voltage Range
• Very Low On-Resistance FET’s - P-Channel 45mΩ and
N-channel 19mΩ Typical Values
• High Efficiency Synchronous Buck Regulator with up to 95%
Efficiency
• 0.8% Reference Accuracy Over-temperature/Load/Line
• Complete BOM with as Few as 3 External Parts
• Start-up with Pre-Biased Output
• Internal Soft-Start - 1ms or Adjustable
• Soft-Stop Output Discharge During Disabled
• Adjustable Frequency from 500kHz to 4MHz - Default at
1MHz (8023/24), 2MHz (8023A/24A)
• External Synchronization up to 4MHz
• Over-temperature, Overcurrent, Overvoltage and Negative
Overcurrent Protection
• Tiny 3x3 QFN Package
Applications
• DC/DC POL Modules
• μC/µP, FPGA and DSP Power
• Plug-in DC/DC Modules for Routers and Switchers
• Portable Instruments
• Test and Measurement Systems
• Li-ion Battery Powered Devices
Related Literature
• See AN1759, “3A/4A Low Quiescent Current High Efficiency
Synchronous Buck Regulator”
100
90
3.3V_OUT PFM
80
70
3.3V_OUT PWM
60
50
40
0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0
I_OUT (A)
FIGURE 1. EFFICIENCY T = +25°C V_IN = 5V
May 17, 2012
1
FN7812.2
CAUTION: These devices are sensitive to electrostatic discharge; follow proper IC Handling Procedures.
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