General Description

The MAX5025–MAX5028 constant-frequency, pulsewidth 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.

Features

♦ Input Voltage Range:
3V to 11V (MAX5026/MAX5028)
4.5V to 11V (MAX5025/MAX5027)
♦ Wide Output Voltage Range: VCC 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

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