Document
19-3569; Rev 2; 4/07 EVAALVUAAILTAIOBNLEKIT
Interleaved High-Efficiency, Dual Power-Supply Controllers for Notebook Computers
MAX8716/MAX8717/MAX8756/MAX8757
General Description
The MAX8716/MAX8717/MAX8756/MAX8757 are dual, step-down, interleaved, fixed-frequency, switch-mode power-supply (SMPS) controllers with synchronous rectification. The MAX8716/MAX8717/MAX8756/MAX8757 are intended for main (5V/3.3V) power generation, while the MAX8756 is optimized for I/O power rails in batterypowered systems.
Fixed-frequency operation with optimal interleaving minimizes input ripple current from the lowest input voltages up to the 26V maximum input. Optimal 40/60 interleaving allows the input voltage to go down to 8.3V before duty-cycle overlap occurs in 5V/3.3V applications, compared to 180° out-of-phase regulators where the dutycycle overlap occurs when the input drops below 10V.
Accurate output current limit is achieved using a sense resistor. Alternatively, power dissipation can be reduced using lossless inductor current sensing. Independent ON/OFF controls and power-good signals allow flexible power sequencing. Soft-start reduces inrush current, while soft-stop gradually ramps the output voltage down preventing negative voltage dips.
A low-noise mode maintains high light-load efficiency while keeping the switching frequency out of the audible range.
The MAX8716 is available in a 24-pin thin QFN package, and the MAX8717/MAX8756/MAX8757 are available in a 28-pin thin QFN package.
Applications
2 to 4 Li+ Cell Battery-Powered Devices
Notebook and Subnotebook Computers
PDAs and Mobile Communicators
Main or I/O Power Supplies
Dual Mode is a trademark of Maxim Integrated Products, Inc.
Features
o Fixed Switching Frequency 200kHz, 300kHz, or 500kHz 250kHz, 300kHz, or 400kHz (MAX8756 Only)
o No Current-Sense Resistor Required
o 40/60 Optimal Interleaving
o Reduced Input-Capacitor Requirement
o Output Voltage Fixed or Adjustable Outputs (Dual Mode™) 3.3V/5V Fixed or 1V to 5.5V Adjustable 1.5V/1.8V Fixed or 1V to 2.3V Adjustable (MAX8756 Only)
o 4V to 26V Input Range
o Independently Selectable PWM, Skip, and LowNoise Mode Operation
o Soft-Start and Soft-Stop
o 2V Precision Reference with 0.75% Accuracy
o Independent Power-Good Outputs
Ordering Information
PART
TEMP RANGE PINPACKAGE
PKG CODE
MAX8716ETG
-40°C to +85°C
24 Thin QFN 4mm x 4mm
T2444-4
MAX8716ETG+
-40°C to +85°C
24 Thin QFN 4mm x 4mm
T2444-4
MAX8717ETI
-40°C to +85°C 28 Thin QFN 5mm x 5mm
T2855-6
+Denotes a lead-free package.
Ordering Information continued at end of data sheet.
Pin Configurations
TOP VIEW
LX2
DL2
VDD
GND
DL1
LX1
18 17 16 15 14 13
DH1 19 BST1 20 CSH1 21 CSL1 22 FB1 23 PGOOD1 24
+
MAX8716ETG 123 4 56
12 DH2 11 BST2 10 CSH2 9 CSL2 8 FB2 7 PGOOD2
ON2
ON1
SKIP2
REF
SKIP1
VCC
TQFN A "+" SIGN WILL REPLACE THE FIRST PIN INDICATOR ON LEAD-FREE PACKAGES.
TOP VIEW
LX1 DL1 AGND PGND VDD DL2 LX2
21 20 19 18 17 16 15
DH1 22
14 DH2
BST1 23
13 BST2
CSH1 2.