ISL78268 Datasheet, PDF (1/33 Pages) Intersil Corporation – Integrated 2A sourcing

DATASHEET
55V Synchronous Buck Controller with Integrated 3A
Driver
ISL78268
The ISL78268 is a grade 1, automotive, synchronous buck
controller with integrated high/low side MOSFET drivers. It
supports a wide operating input voltage range of 5V to 55V
and up to 60V at V_IN when not switching. The integrated driver
offers adaptive dead-time control and is capable of supplying
up to 2A sourcing and 3A sinking current, allowing the
ISL78268 to support power stages designed for a wide range
of loads, from under 1A to over 25A.
ISL78268’s fully synchronous architecture enables power
conversion with very high efficiency and improved thermal
performance over standard buck converters. The ISL78268 also
offers diode emulation mode for improved light load efficiency.
While ISL78268 is a peak current mode PWM controller, it
also includes a dedicated average output current modulation
loop, which achieves constant output current limiting for
applications such as battery charging, super-cap charging, and
temperature control systems where a constant current must
be provided.
The ISL78268 supports switching frequencies from 50kHz to
1.1MHz allowing the user the flexibility to trade-off switching
frequency and efficiency against the size of external
components.
The ISL78268 offers comprehensive protection features. It
includes robust current protection with cycle-by-cycle peak
current limiting, average current limiting, and a selectable
hiccup or latch-off fault responses. In addition, it offers
protection against over-temperature, as well as input and
output overvoltages.
Features
• Wide input range 5V to 55V (switching); withstand 60V
(non-switching)
• Integrated 2A sourcing, 3A sinking MOSFET drivers
• Constant current regulation/limiting - dedicated average
current control loop
• Adjustable switching frequency or external synchronization
from 50kHz up to 1.1MHz
• Low shutdown current, I_Q <1µA
• Peak current mode control with adjustable slope
compensation
• Selectable diode emulation mode for high efficiency at light
load
• Input and output OVP, cycle-by-cycle current limiting,
average current OCP, OTP
• Selectable hiccup or latch-off fault responses
• Pb-free 24 Ld 4x4 QFN package (RoHS compliant)
• AEC-Q100 qualified
Applications
• Automotive power
• Telecom and industrial power supplies
• General purpose power
• Supercap charging
Related Literature
• AN1946, “ISL78268EVAL1Z Evaluation Board User Guide”
VIN
EN_IC
PVCC
EN
VCC
VIN
ISEN1P
ISEN1N
IMON/DE
PVCC
BOOT
FSYNC
UG
PLL_COMP ISL78268
PH
LG
SLOPE
COMP
SS
ISEN2P
ISEN2N
FB
HIC/LATCH
SGND PGND
CLKOUT
PGOOD
PVCC
VOUT
VCC
POWER GOOD
FIGURE 1. SIMPLIFIED TYPICAL APPLICATION SCHEMATIC
100
95
90
85
V_IN = 24V
V_IN = 15V
80
V_IN = 36V
75
70
V_IN = 55V
65
60
55
V_OUT = 12V, T_A = +25°C
50
0
1
2
3
4
5
I_OUT (A)
FIGURE 2. EFFICIENCY CURVES (ISL78268EVAL1Z/DE MODE)
December 12, 2014
1
FN8657.3
CAUTION: These devices are sensitive to electrostatic discharge; follow proper IC Handling Procedures.
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