XR79120
22V, 20A Synchronous Step Down COT Power Module
FEATURES
General Description
Controller, drivers, bootstrap diode and capaci-
tor, MOSFETs, Inductor, CIN and COUT integrated
The XR79120 is a 20A synchronous step-down Power Module for point-of
load supplies. A wide 4.5V to 22V input voltage range allows for single
supply operation from industry standard 5V, 12V, and 19.6V rails.
in one package
20A Step Down Module
Wide 4.5V to 22V 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 400kHz to 600kHz 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 Ther-
mal Compensation
With a proprietary emulated current mode Constant On-Time (COT) con-
trol scheme, the XR79120 provides extremely fast line and load transient
response using ceramic output capacitors. It requires no loop compensa-
tion hence simplifying circuit implementation and reducing overall compo-
nent count. The control loop also provides 0.12% load and 0.17% 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. With a 93% peak efficiency and 84% for loads as low as
100mA, the XR79120 is suitable for applications where low power losses
are important.
A host of protection features, including over-current, over-temperature,
short-circuit and UVLO, help achieve safe operation under abnormal
operating conditions.
Precision Enable and Power Good flag
Programmable Soft-start
74-pin 12x14x4mm QFN package
The XR79120 is available in a RoHS compliant, green/halogen free
space-saving 74-pin 12x14x4mm QFN package. With integrated control-
ler, drivers, bootstrap diode and capacitor, MOSFETs, inductor, CIN and
COUT, this solution allows the smallest possible 20A POL design.
APPLICATIONS
Networking and Communications
Fast Transient Point-of-Loads
Industrial and Medical Equipment
Embedded High Power FPGA
Ordering Information – back page
Typical Application
Line Regulation
VIN
1.820
1.815
VIN
PVIN
Enable/Mode
EN/MODE
PGOOD
1.810
1.805
1.800
1.795
1.790
1.785
1.780
VOUT
Power Good
R
VOUT
SW
CIN
VCC
SS
XR79120
RLIM
CFF
R1
R2
ILIM
FB
COUT
TON
CVCC
CSS
RON
AGND
PGND
4
6
8
10 12 14 16 18 20 22
VIN (V)
1 / 19
exar.com/XR79120
Rev 1A
© 2014 Exar Corporation