ISL78322 Datasheet, PDF (1/18 Pages) Intersil Corporation – Dual 2A/1.7A Low Quiescent Current 2.25MHz High Efficiency Synchronous Buck Regulator

DATASHEET
Dual 2A/1.7A Low Quiescent Current 2.25MHz High
Efficiency Synchronous Buck Regulator
ISL78322
The ISL78322 is a high efficiency, dual synchronous step-down
DC/DC regulator that can deliver up to 2A/1.7A continuous
output current per channel. The channels are 180° out-of-phase
for input RMS current and EMI reduction. The supply voltage
range of 2.8V to 5.5V allows for the use of a single Li+ cell, three
NiMH cells or a regulated 5V input. The current mode control
architecture enables very low duty cycle operation at high
frequency with fast transient response and excellent loop
stability. The ISL78322 operates at 2.25MHz switching frequency
which allows for the use of small, low cost inductors and
capacitors. Each channel is optimized for generating an output
voltage as low as 0.6V.
The ISL78322 has a user configurable mode of operation-forced
PWM mode and PFM/PWM mode. The forced PWM mode
reduces noise and RF interference while the PFM mode provides
highest efficiency by reducing switching losses at light loads. In
PFM mode of operation, both channels draw a total quiescent
current of only 40µA, hence enabling high light load efficiency
and maximizing battery life.
The ISL78322 offers a 1ms Power-Good (PG) signal to monitor
both outputs at power-up. When shut down, ISL78322
discharges the output capacitors. Other features include internal
digital soft-start, enable for power sequence, overcurrent
protection, and thermal shutdown. The ISL78322 is offered in a
4mmx3mm, 12 Lead DFN package with 1mm maximum height.
The complete converter occupies less than 1.8cm² area.
The ISL78322 is qualified to AEC-Q100 and specified for
operation across the -40°C to +105°C (grade 2) ambient
temperature range.
Features
• Dual 2A/1.7A high efficiency synchronous buck regulator with
up to 97% efficiency, low I_Q (40µA)
• 180° out-of-phase outputs reduce ripple current and EMI
• Start-up with prebiased output prevents negative current flow
in output stage
• Selectable forced PWM mode and PFM mode
• External synchronization up to 8MHz
• Negative current detection and protection
• 100% maximum duty cycle for lowest dropout
• Internal current mode compensation
• Peak current limiting, hiccup mode short circuit protection and
over-temperature protection
• Pb-free (RoHs compliant)
• AEC-Q100 qualified component
Applications
• DC/DC POL modules
• µC/µP, FPGA and DSP power
• Automotive embedded processor power supply systems
100
90
80
2.5V_OUT1 PFM
2.5V_OUT1 PWM
70
3.3V_OUT2 PFM
60
50 _{3.3VOUT2 PWM}
2.25MHz 5V_IN AT +25°C
400.0 _{0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6 1.8 2.0}
OUTPUT LOAD (A)
FIGURE 1. CHARACTERISTIC CURVE
August 26, 2014
1
FN7908.2
CAUTION: These devices are sensitive to electrostatic discharge; follow proper IC Handling Procedures.
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