XR76117 Datasheet, PDF (1/18 Pages) Exar Corporation – PowerBloxTM 15A Synchronous

XR76117
PowerBlox^TM 15A Synchronous
Step-Down COT Regulator
Description
The XR76117 is a synchronous step-down regulator combining the
controller, drivers, bootstrap diode and MOSFETs in a single package
for point-of-load supplies. The XR76117 has a load current rating
of 15A. A wide 5V to 22V input voltage range allows for single supply
operation from industry standard 5V, 12V and 19.6V rails.
With a proprietary emulated current mode constant on-time (COT)
control scheme, the XR76117 provides extremely fast line and
load transient response using ceramic output capacitors. It require
sno loop compensation, simplifying circuit implementation and
reducing overall component count. The control loop also provides
0.1% load and 0.1% line regulation and maintains constant
operating frequency. A selectable power saving mode, allows the user
to operate in discontinuous mode (DCM) at light current loads thereby
significantly increasing the converter efficiency.
A host of protection features, including overcurrent, over temperature,
overvoltage, short-circuit, open feedback detect and UVLO, helps
achieve safe operation under abnormal operating conditions.
The XR76117 is available in a RoHS compliant, green/halogen-free
space-saving 5mm x 6mm QFN package.
Typical Application
ENABLE
VIN
POWER GOOD
CIN
R
CBST
EN
BST
VIN
SW
RLIM
PVIN
ILIM
PGOOD
XR76117
VCC
FB
SS
FCCM
CVCC CSS
TON
RON
AGND
VSNS
PGND
L1
CFF
RFF
VOUT
R1
R2
VOUT
R1
COUT
R2
Figure 1. Typical Application
FEATURES
■■ 15A step-down regulator
4.5V to 5.5V low V_IN operation
5V to 22V wide single input voltage
3V to 22V operation with external
5V bias
≥0.6V adjustable output voltage
■■ Proprietary constant on-time control
No loop compensation required
Ceramic output capacitor stable
operation
Programmable 70ns-1µs on-time
Constant 200kHz-1MHz frequency
Selectable CCM or CCM/DCM
operation
■■ Power-good flag with low impedance when
power removed
■■ Precision enable
■■ Programmable soft-start
■■ 5mm x 6mm QFN package
APPLICATIONS
■■ Servers
■■ Distributed power architecture
■■ Point-of-load converters
■■ FPGA, DSP and processor supplies
■■ Base stations, switches/routers
100
98
96
94
92
90
88
86
84
82
80
78
76
74
72
70
0.0
600kHz
800kHz
5.0V
3.3V
2.5V
1.8V
1.5V
1.2V
1.0V
5.0
10.0
15.0
IOUT (A)
Figure 2. Efficiency
REV1A
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