19-2286; Rev 1; 9/03
Low-Cost Voltage-Mode PWM
Step-Down Controllers
General Description
The MAX1966/MAX1967 are voltage-mode pulse-width-
modulated (PWM), step-down DC-DC controllers that
are ideal for a variety of cost-sensitive applications.
They drive low-cost N-MOSFETs for both the high-side
switch and synchronous rectifier and require no external
Schottky power diode or current-sense resistor. Short-
circuit and current-limit protection is provided by sens-
ing the drain-to-source voltage on the low-side FET.
Both devices can supply outputs as low as 0.8V and are
well suited for DSP cores and other low-voltage logic.
The MAX1966 has an input range of 2.7V to 5.5V while
the MAX1967 has an input range of 2.7V to 28V. In
ultra-low-cost designs, the MAX1966/MAX1967 can
provide efficiency exceeding 90% and can achieve
95% efficiency with optimized component selection.
The MAX1966/MAX1967 operate at 100kHz and ac-
commodate aluminum electrolytic capacitors and pow-
dered-iron core magnetics in minimum-cost designs.
They also provide excellent performance with high-per-
formance surface-mount components. The MAX1966 is
available in a low-cost 8-pin SO package. The MAX1967
is available in a 10-pin µMAX package.
o
Cost-Optimized Design
o
No Schottky Diode or Current-Sense Resistor
Required
o
>95% Efficiency
o
Low-Cost External Components
o
All N-Channel FET Design
o
2.7V to 5.5V Input Range (MAX1966)
o
2.7V to 28V Input Range (MAX1967)
o
0.8V Feedback for Low-Voltage Outputs
o
100kHz Switching Frequency Accommodates
Low-Cost Components
o
Thermal Shutdown
o
Output Current-Limit and Short-Circuit Protection
Features
MAX1966/MAX1967
Ordering Information
PART
MAX1966ESA
MAX1967EUB
TEMP RANGE
-40°C to +85°C
-40°C to +85°C
PIN-PACKAGE
8 SO
10 µMAX
Applications
Set-Top Boxes
Graphic Card Supplies
xDSL Modems and
Routers
Cable Modems and
Routers
Telecom Power Supplies
Networking Power
Supplies
Termination Supplies
Typical Operating Circuit
2.7V TO
5.5V INPUT
Pin Configurations
VIN
BST
DH
V
OUT
LX
COMP/EN
DL
TOP VIEW
MAX1966
BST
COMP/EN
FB
1
2
8
7
DH
LX
GND
DL
GND
MAX1966
3
6
5
VIN 4
FB
SO
Pin Configurations continued at end of data sheet.
________________________________________________________________
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.