MAX5025_09 Datasheet, PDF (1/13 Pages) Maxim Integrated Products – 500kHz, 36V Output, SOT23, PWM Step-Up DC-DC Converters

19-2239; Rev 2; 3/09
EVAALVUAAILTAIOBNLEKIT
500kHz, 36V Output, SOT23,
PWM Step-Up DC-DC Converters
General Description
The MAX5025–MAX5028 constant-frequency, pulse-
width modulating (PWM), low-noise boost converters
are intended for low-voltage systems that often need a
locally generated high voltage. These devices are
capable of generating low-noise, high output voltages
required for varactor diode biasing in TV tuners, set-top
boxes, and PCI cable modems. The MAX5025–
MAX5028 operate from as low as 3V and switch at
500kHz.
The constant-frequency, current-mode PWM architec-
ture provides for low output noise that is easy to filter. A
40V lateral DMOS device is used as the internal power
switch, making the devices ideal for boost converters
up to 36V. The MAX5025/MAX5026 adjustable versions
require the use of external feedback resistors to set the
output voltage. The MAX5027/MAX5028 offer a fixed
30V output. These devices are available in a small, 6-
pin SOT23 package.
Applications
TV Tuner Power Supply
Low-Noise Varactor Diode Biasing
Set-Top Box Tuner Power Supply
PCI Cable Modem
Voice-Over-Cable
LCD Power Supply
Avalanche Photodiode Biasing
Features
♦ Input Voltage Range:
3V to 11V (MAX5026/MAX5028)
4.5V to 11V (MAX5025/MAX5027)
♦ Wide Output Voltage Range: V_CC to 36V
♦ Output Power: 120mW (max)
♦ User-Adjustable Output Voltage with
MAX5025/MAX5026 Using External Feedback
Resistors
♦ Fixed 30V Output Voltage: MAX5027/MAX5028
♦ Internal 1.3Ω (typ), 40V Switch
♦ Constant PWM Frequency Provides Easy Filtering
in Low-Noise Applications
♦ 500kHz (typ) Switching Frequency
♦ 1μA (max) Shutdown Current
♦ Small, 6-Pin SOT23 Package
PA RT
MAX5025EUT-T
MAX5026EUT-T
MAX5027EUT-T
MAX5028EUT-T
Ordering Information
TEMP RANGE
-40°C to +85°C
-40°C to +85°C
-40°C to +85°C
-40°C to +85°C
PIN-PACKAGE
6 SOT23-6
6 SOT23-6
6 SOT23-6
6 SOT23-6
Typical Operating Circuit
V_CC = 4.5V TO 11V
(MAX5027)
V_CC = 3V TO 11V
(MAX5028)
L1
D1
V_CC
LX
MAX5027
MAX5028
SHDN
FB
C1
PGND
GND
V_OUT
30V
C2
Selector Guide appears at end of data sheet.
Pin Configuration
TOP VIEW
PGND 1
6 LX
MAX5025–
GND 2 _MAX5028 5 V_CC
FB 3
4 SHDN
SOT23-6
________________________________________________________________ Maxim Integrated Products 1
For pricing, delivery, and ordering information, please contact Maxim Direct at 1-888-629-4642,
or visit Maxim’s website at www.maxim-ic.com.