XR76108 Datasheet, PDF (1/17 Pages) Exar Corporation – 8A and 12A Synchronous Step Down COT Regulator

XR76108 and XR76112
PowerBlox™
8A and 12A Synchronous Step Down COT Regulator
General Description
The XR76108 and XR76112 are synchronous step-down
regulators combining the controller, drivers, bootstrap
diode and MOSFETs in a single package for point-of-load
supplies. The XR76108 has a load current rating of 8A and
the XR76112 has a load current rating of 12A. A wide 4.5V
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 XR76108 and XR76112
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 0.25% 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 over-current,
over-temperature, short-circuit and UVLO, help achieve
safe operation under abnormal operating conditions.
The XR76108/12 are available in a RoHS-compliant,
green/halogen-free space-saving QFN 5x5mm package.
Typical Application
VIN
Enable/Mode
Power Good
CIN
R3
VIN
PVIN
EN/MODE
BST
PGOOD
SW
VCC XR76108
XR76112
SS
ILIM
CVCC
CSS
TON
RON
AGND
FB
PGND
CBST
RLIM
L1
VOUT
CFF
R1
R2
COUT
Figure 1: XR76108/12 Application Diagram
FEATURES
 8A and 12A Capable Step Down
Regulators
 4.5V to 5.5V Low VIN Operation
 4.5V to 22V Wide Single Input
Voltage
 ≥0.6V Adjustable Output Voltage
 Controller, drivers, bootstrap diode and
MOSFETs integrated in one package
 Proprietary Constant On-Time Control
 No Loop Compensation Required
 Ceramic Output Cap. Stable operation
 Programmable 200ns-2µs On-Time
 Constant 200kHz-800kHz Freq.
 Selectable CCM or CCM/DCM
Operation
 Precision Enable and Power-Good Flag
 Programmable Soft-start
 5x5mm 30-pin QFN Package
APPLICATIONS
 Distributed Power Architecture
 Point-of-Load Converters
 Power Supply Modules
 FPGA, DSP, and Processor Supplies
 Base Stations, Switches/Routers, and
Servers
1.220
1.215
1.210
1.205
1.200
1.195
1.190
1.185
1.180
5
10
15
20
V_IN (V)
Figure 2: XR76112 Line Regulation
©2013-2014 Exar Corporation
www.exar.com
Rev. 2A