XR76116 Datasheet, PDF (1/19 Pages) Exar Corporation – PowerBloxTM 15A and 20A Synchronous

XR76116/20
PowerBlox^TM 15A and 20A Synchronous
Step-Down COT Regulators
Description
The XR76116 and XR76120 are synchronous step-down regulators
combining the controller, drivers, bootstrap diode and MOSFETs
in a single package for point-of-load supplies. The XR76116 has a
load current rating of 15A and the XR76120 has a load current rating
of 20A. 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 XR76116/20 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 0.1% 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 XR76116/20 are available in a RoHS-compliant, green/halogen-
free space-saving 5mm x 6mm QFN package.
FEATURES
■ 15A and 20A step-down regulators
■ 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
Typical Application
ENABLE
VIN
POWER GOOD
CIN
R
CBST
EN
BST
VIN
SW
RLIM
PVIN
ILIM
PGOOD
XR76116/20
VCC
FB
SS
FCCM
CVCC CSS
TON
RON
AGND
VSNS
PGND
L1
CFF
RFF
VOUT
R1
R2
VOUT
R1
COUT
R2
Figure 1. XR76116/20 Typical Application
100
98
96
94
92
90
88
86
84
82
80
78
76
74
72
70
0.1
600kHz
800kHz
5.0V
3.3V
2.5V
1.8V
1.5V
1.2V
1.0V
5.1
10.1
15.1
20.1
IOUT (A)
Figure 2. XR76120 Efficiency
REV1A
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