19-0182; Rev 3; 9/95
5 V/3 .3 V/3 V 5 A S t e p -Do w n , P WM,
S w it c h -Mo d e DC-DC Re g u la t o rs
/MAX789
_______________Ge n e ra l De s c rip t io n
___________________________Fe a t u re s
♦ Input Range: Up to 40V
The MAX787/MAX788/MAX789 are monolithic, bipolar,
pulse-width modulation (PWM), switch-mode, step-down
DC-DC regulators. Each is rated at 5A. Very few external
components are needed for standard operation because
the power switch, oscillator, feedback, and control circuitry
are all on-chip. Employing a classic buck topology, these
regulators perform high-current step-down functions.
♦ 5A On-Chip Power Switch
♦ Fixed Outputs: 5V (MAX787)
3.3V (MAX788)
3V (MAX789)
♦ 100kHz Switching Frequency
♦ Excellent Dynamic Characteristics
♦ Few External Components
♦ 8.5mA Quiescent Current
♦ TO-220 Package
The MAX787/MAX788/MAX789 have excellent dynamic
and transient response characteristics, while featuring
cycle-by-cycle current limiting to protect against overcurrent
faults and short-circuit output faults. They also have a wide
8V to 40V input range.
______________Ord e rin g In fo rm a t io n
Each regulator is available in a 5-pin TO-220 package.
These devices have a preset 100kHz oscillator frequency
and a preset current limit of 6.5A. See the MAX724/
MAX726 data sheet for more applications information.
PART
TEMP. RANGE
0°C to +70°C
PIN-PACKAGE
5 TO-220
MAX787CCK
MAX787ECK
MAX788CCK
MAX788ECK
MAX789CCK
MAX789ECK
-40°C to +85°C
0°C to +70°C
5 TO-220
5 TO-220
_______________________Ap p lic a t io n s
-40°C to +85°C
0°C to +70°C
5 TO-220
Distributed Power from High-Voltage Buses
High-Current, High-Voltage Step-Down
Multiple-Output Buck Converter
5 TO-220
-40°C to +85°C
5 TO-220
___________P ro d u c t S e le c t io n Gu id e
PART
V
OUT
(V)
I
MAX (A)
OUT
MAX724
MAX726
MAX727
MAX728
MAX729
MAX787
MAX788
MAX789
Adjustable
5
2
2
2
2
5
5
5
Adjustable
5
3.3
3
__________Typ ic a l Op e ra t in g Circ u it
5
3.3
3
INPUT
8V TO 40V
OUTPUT
5V AT 5A
50µH
V
IN
V
SW
__________________P in Co n fig u ra t io n
220µF
MAX787
MBR745
FRONT VIEW
V
C
SENSE
470µF
V
IN
5
4
MAX787
MAX788
MAX789
2.7k
V
SW
GND
GND
3
2
0.01µF
V
C
1
SENSE
5-PIN TO-220
STEP-DOWN CONVERTER
CASE IS CONNECTED TO GROUND. STANDARD PACKAGE HAS STAGGERED LEADS.
CONTACT FACTORY FOR STRAIGHT LEADS.
________________________________________________________________ Maxim Integrated Products
1
Ca ll t o ll fre e 1 -8 0 0 -9 9 8 -8 8 0 0 fo r fre e s a m p le s o r lit e ra t u re .