Boost converter with current monitor targets APD-biasing

APRIL 1, 2009 -- Maxim Integrated Products (search Lightwave for Maxim) has introduced the MAX15031, a constant-frequency, pulse-width modulated (PWM) step-up converter that is designed for low-voltage systems that require a locally generated high voltage.

Operating from a 2.7- to 11-V supply, the device delivers a low-noise output voltage up to 76 V (300 mW of power) without an external voltage doubler. Additionally, Maxim says its BiCMOS process technology enables the MAX15031 to integrate a high-side current monitor with fast (1-microsec) current limiting to save space and cost in diode-biasing applications. This device is designed for applications such as avalanche photodiode (APD) biasing, PIN biasing, and varacter biasing in fiber modules.

The MAX15031 uses a peak current-mode PWM architecture with a fixed switching frequency of 400 kHz to produce a low-noise output. The onboard current monitor offers three decades of dynamic range, and monitors current from 500 nA to 4 mA with high accuracy. Resistor-adjustable current limiting protects the APD from optical power transients. Internal soft-start circuitry limits the input inrush current during power up, while a clamp diode protects the monitor's output from over-voltage conditions.

The MAX15031 is available in a 4x4-mm, 16-pin TQFN package, and is fully specified over the -40 degrees Celsius to +125 degrees Celsius temperature range. Prices start at $1.65 (1000 up, FOB USA).

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