19-2988; Rev 0; 9/03
1A, 76V, High-Efficiency MAXPower
Step-Down DC-DC Converter
General Description
Features
The MAX5035 easy-to-use, high-efficiency, high-volt-
age, step-down DC-DC converter operates from an
input voltage up to 76V and consumes only 350µA qui-
escent current at no load. This pulse-width modulated
(PWM) converter operates at a fixed 125kHz switching
frequency at heavy loads, and automatically switches
to pulse-skipping mode to provide low quiescent cur-
rent and high efficiency at light loads. The MAX5035
includes internal frequency compensation simplifying
circuit implementation. The device uses an internal low-
on-resistance, high-voltage, DMOS transistor to obtain
high efficiency and reduce overall system cost. This
device includes undervoltage lockout, cycle-by-cycle
current limit, hiccup mode output short-circuit protec-
tion, and thermal shutdown.
ꢀ Wide 7.5V to 76V Input Voltage Range
ꢀ Fixed (3.3V, 5V, 12V) and Adjustable
(1.25V to 13.2V) Versions
ꢀ 1A Output Current
ꢀ Efficiency Up to 94%
ꢀ Internal 0.4Ω High-Side DMOS FET
ꢀ 350µA Quiescent Current at No Load, 10µA
Shutdown Current
ꢀ Internal Frequency Compensation
ꢀ Fixed 125kHz Switching Frequency
ꢀ Thermal Shutdown and Short-Circuit Current
The MAX5035 delivers up to 1A output current. External
shutdown is included, featuring 10µA (typ) shutdown
current. The MAX5035A/B/C versions have fixed output
voltages of 3.3V, 5V, and 12V, respectively, while the
MAX5035D features an adjustable output voltage from
1.25V to 13.2V.
Limit
ꢀ 8-Pin SO and PDIP Packages
Ordering Information
The MAX5035 is available in space-saving 8-pin SO
and 8-pin plastic DIP packages and operates over the
industrial (0°C to +85°C) temperature range.
OUTPUT
VOLTAGE
(V)
PIN-
PACKAGE
PART
TEMP RANGE
MAX5035AUSA
MAX5035AUPA
MAX5035BUSA
MAX5035BUPA
MAX5035CUSA
MAX5035CUPA
MAX5035DUSA
MAX5035DUPA
0°C to +85°C
0°C to +85°C
0°C to +85°C
0°C to +85°C
0°C to +85°C
0°C to +85°C
0°C to +85°C
0°C to +85°C
8 SO
3.3
5.0
12
8 PDIP
8 SO
Applications
Consumer Electronics
Industrial
8 PDIP
8 SO
8 PDIP
8 SO
Distributed Power
ADJ
8 PDIP
Typical Operating Circuit
V
IN
Pin Configuration
7.5V TO 76V
V
IN
68µF
BST
LX
0.1µF
100µH
TOP VIEW
MAX5035
V
OUT
5V
R1
R2
D1
BST
VD
1
2
3
4
8
7
6
5
LX
50SQ100
ON/OFF
V
IN
68µF
MAX5035
ON
FB
SGND
FB
GND
VD
OFF
SGND
GND
ON/OFF
0.1µF
SO/PDIP
________________________________________________________________ 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.