DATASHEET
ISL78233, ISL78234
3A and 4A Compact Synchronous Buck Regulators
FN8359
Rev.9.00
Feb 21, 2019
The ISL78233 and ISL78234 are highly efficient, monolithic,
synchronous step-down DC/DC converters that can deliver 3A
(ISL78233), or 4A (ISL78234) of continuous output current from
a 2.7V to 5.5V input supply. The devices use current mode control
architecture to deliver a very low duty cycle operation at high
frequency with fast transient response and excellent loop stability.
Features
• 2.7V to 5.5V input voltage range
• Very low ON-resistance FETs - P-channel 35mΩ and
N-channel 11mΩ typical values
• High efficiency synchronous buck regulator with up to 95%
efficiency
The ISL78233 and ISL78234 integrate a very low
ON-resistance P-channel (35mΩ) high-side FET and N-channel
(11mΩ) 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 2MHz is set by connecting the FS pin high.
• -1.2%/1% reference accuracy over temperature/load/line
• Complete BOM with as few as 3 external parts
• Internal soft-start - 1ms or adjustable
• Soft-stop output discharge during disable
• Adjustable frequency from 500kHz to 4MHz - default at
2MHz
The ISL78233 and ISL78234 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.
• External synchronization up to 4MHz
• Over-temperature, overcurrent, overvoltage, and negative
overcurrent protection
• Shared common device pinout allows simplified output
power upgrades over time
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.
• Tiny 3mmx3mm TQFN package
• AEC-Q100 qualified
Applications
• DC/DC POL modules
The ISL78233 and ISL78234 offer a 1ms Power-Good (PG)
timer at power-up. When in shutdown, the ISL78233 and
ISL78234 discharge the output capacitor through an internal
soft-stop switch. Other features include internal fixed or
adjustable soft-start and internal/external compensation.
• μC/µP, FPGA, and DSP power
• Video processor/SOC power
• Li-ion battery powered devices
• Automotive infotainment power
The ISL78233 and ISL78234 are available in a 3mmx3mm 16
Ld Thin Quad Flat (TQFN) Pb-free package and in a 5mmx5mm
16 Ld Wettable Flank Quad Flat No-Lead (WFQFN) package
with an exposed pad for improved thermal performance. The
ISL78233 and ISL78234 are rated to operate across the
temperature range of -40°C to +125°C.
Related Literature
For a full list of related documents, visit our website:
• ISL78233, ISL78234 device pages
100
90
3.3V
OUT
1.5V
80
OUT
1.2V
OUT
1.8V
OUT
70
60
50
40
2.5V
OUT
0.0
0.5
1.0
1.5
2.0
2.5
3.0
3.5
4.0
OUTPUT LOAD (A)
FIGURE 1. EFFICIENCY vs LOAD (2MHz 5V PFM, T = +25°C)
IN
A
FN8359 Rev.9.00
Feb 21, 2019
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