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.

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