MAX8792 Datasheet, PDF (1/29 Pages) Maxim Integrated Products – Single Quick-PWM Step-Down Controller with Dynamic REFIN

19-0739; Rev 0; 1/07
EVAALVUAAILTAIOBNLEKIT
Single Quick-PWM Step-Down
Controller with Dynamic REFIN
General Description
The MAX8792 pulse-width modulation (PWM) controller
provides high efficiency, excellent transient response,
and high DC-output accuracy needed for stepping
down high-voltage batteries to generate low-voltage
core or chipset/RAM bias supplies in notebook comput-
ers. The output voltage can be dynamically controlled
using the dynamic REFIN, which supports input volt-
ages between 0 to 2V. The REFIN adjustability com-
bined with a resistive voltage-divider on the feedback
input allows the MAX8792 to be configured for any out-
put voltage between 0 to 0.9 V_IN.
Maxim’s proprietary Quick-PWM™ quick-response, con-
stant-on-time PWM control scheme handles wide
input/output voltage ratios (low-duty-cycle applications)
with ease and provides 100ns “instant-on” response to
load transients while maintaining a relatively constant
switching frequency. Strong drivers allow the MAX8792
to efficiently drive large synchronous-rectifier MOSFETs.
The controller senses the current across the synchro-
nous rectifier to achieve a low-cost and highly efficient
valley current-limit protection. The adjustable current-
limit threshold provides a high degree of flexibility,
allowing thermally compensated protection using an
NTC or foldback current-limit protection using a volt-
age-divider derived from the output.
The MAX8792 includes a voltage-controlled soft-start
and soft-shutdown in order to limit the input surge cur-
rent, provide a monotonic power-up (even into a
precharged output), and provide a predictable power-
up time. The controller also includes output fault protec-
tion—undervoltage and overvoltage protection—as well
as thermal-fault protection.
The MAX8792 is available in a tiny 14-pin, 3mm x 3mm
TDFN package. For space-constrained applications,
refer to the MAX17016 single step-down with 10A, 26V
internal MOSFETs available in a small 40-pin, 6mm x
6mm TQFN package.
.
Applications
Notebook Computers
I/O and Chipset Supplies
GPU Core Supply
DDR Memory—VDDQ or VTT
Point-of-Load Applications
Step-Down Power Supply
Features
o Quick-PWM with Fast Transient Response
o Supports Any Output Capacitor
No Compensation Required with
Polymers/Tantalum
Stable with Ceramic Output Capacitors Using
External Compensation
o Precision 2V ±10mV Reference
o Dynamically Adjustable Output Voltage
(0 to 0.9 V_IN Range)
Feedback Input Regulates to 0 to 2V REFIN
Voltage
0.5% V_OUT Accuracy Over Line and Load
o 26V Maximum Input Voltage Rating
o Adjustable Valley Current-Limit Protection
Thermal Compensation with NTC
Supports Foldback Current Limit
o Resistively Programmable Switching Frequency
o Overvoltage Protection
o Undervoltage/Thermal Protection
o Voltage Soft-Start and Soft-Shutdown
o Monotonic Power-Up with Precharged Output
o Power-Good Window Comparator
Ordering Information
PART
PIN-PACKAGE
PKG TOP
CODE MARK
MAX8792ETD+T 14 TDFN-EP* 3mm x 3mm T1433-1 ADC
Note: This device is specified over the -40°C to +80°C operating
temperature range.
+Denotes a lead-free package.
Pin Configuration
TOP VIEW
14 13 12 11 10 9 8
MAX8792
GND
1234567
Quick-PWM is a trademark of Maxim Integrated Products, Inc.
TDFN
(3mm x 3mm)
________________________________________________________________ Maxim Integrated Products 1
For pricing, delivery, and ordering information, please contact Maxim/Dallas Direct! at
1-888-629-4642, or visit Maxim’s website at www.maxim-ic.com.