XR76203 Datasheet, PDF (1/20 Pages) Exar Corporation – 3A/5A/8A Synchronous Step Down COT Regulator

XR76203/5/8
40V PowerBlox^TM
3A/5A/8A Synchronous Step Down COT Regulator
General Description
The XR76203, XR76205 and XR76208 are synchronous step-down regu-
lators combining the controller, drivers, bootstrap diode and MOSFETs in
a single package for point-of-load supplies. The XR76203, XR76205 and
XR76208 have load current ratings of 3A, 5A and 8A respectively. A wide
5V to 40V input voltage range allows for single supply operation from
industry standard 24V ±10%, 18V-36V, and rectified 18VAC and 24VAC
rails.
With a proprietary emulated current mode Constant On-Time (COT) con-
trol scheme, the XR76203, XR76205 and XR76208 provide extremely
fast line and load transient response using ceramic output capacitors.
They require no loop compensation, simplifying circuit implementation
and reducing overall component count. The control loop also provides
0.07% load and 0.15% line regulation and maintains constant operating
frequency. A selectable power saving mode allows the user to operate in
discontinuous conduction mode (DCM) at light current loads thereby sig-
nificantly increasing the converter efficiency.
A host of protection features, including over-current, over-temperature,
short-circuit and UVLO, helps achieve safe operation under abnormal
operating conditions.
The XR76203/5/8 are available in a RoHS-compliant, green/halogen-free
space-saving QFN 5x5mm package.
FEATURES
 Controller, drivers, bootstrap diode and
MOSFETs integrated in one package
 3A, 5A and 8A Step Down Regulators
 Wide 5V to 40V Input Voltage Range
 >0.6V Adjustable Output Voltage
 Proprietary Constant On-Time Control
 No Loop Compensation Required
 Stable Ceramic Output Capacitor Operation
 Programmable 200ns to 2μs On-Time
 Constant 100kHz to 800kHz Frequency
 Selectable CCM or CCM/DCM
 CCM/DCM for high efficiency at light-load
 CCM for constant frequency at light-load
 Programmable Hiccup Current Limit with
Thermal Compensation
 Precision Enable and Power Good flag
 Programmable Soft-start
 30-pin 5x5mm QFN package
APPLICATIONS
 Distributed Power Architecture
 Point-of-Load Converters
 Power Supply Modules
 FPGA, DSP, and Processor Supplies
 Base Stations, Switches/Routers, and Servers
Ordering Information – back page
Typical Application
VIN
Enable/Mode
Power Good
CIN
R
VIN
PVIN
EN/MODE
BST
PGOOD
SW
XR76208
VCC _XR76205
SS ^XR76203 ILIM
CVCC
CSS
TON
RON
AGND
FB
PGND
CBST
RLIM
L1
VOUT
CFF
R1
R2
COUT
Line Regulation
3.340
3.330
3.320
3.310
3.300
3.290
3.280
3.270
3.260
5
10 15 20 25 30 35 40
V_IN (V)
© 2015 Exar Corporation
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exar.com/XR76203/5/8
Rev 1A