Document
XR76203 / XR76205 / XR76208
May 17, 2023
40V 3A/5A/8A Synchronous Step Down COT Regulators
General Description
The XR76203, XR76205 and XR76208 are synchronous step-down regulators 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 4.5V 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) control 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 significantly 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, XR76205, and XR76208 are all available in a RoHScompliant, 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 4.5V 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
CFF
R1
R2
VOUT COUT
Efficiency %
XR76208 Efficiency, VIN = 24V
100 98 96 94 92 90 88 86 84 82 80 78 76 74 72 70 0.1
200kHz, 8.2uH 3.3uH
2.2uH 1.5uH
12V DCM 5.0V DCM 3.3V DCM 1.8V DCM
1.0
IOUT (A)
12V CCM 5.0V CCM 3.3V CCM 1.8V CCM
10.0
1
XR76203 / XR76205 / XR76208
Absolute Maximum Ratings
Stresses beyond the limits listed below may cause permanent damage to the device. Exposure to any Absolute Maximum Rating condition for extended periods may affect device reliability and lifetime. PVIN, VIN....