4.5V-60V, 1.7A step-down DC-DC converter with internal compensation

April 14, 2014 // By Graham Prophet
Maxim Integrated has posted information on a device that it believes to be the only available 60V, 1.7A, internal FET, synchronous buck converter in its class.

MAX17505 is a high-efficiency, high-voltage, synchronously rectified step-down converter with dual integrated MOSFETs that operates over a 4.5V to 60V input. It delivers up to 1.7A and 0.9V to 90% V IN output voltage.

Built-in compensation across the output voltage range eliminates the need for external components. The feedback (FB) regulation accuracy over -40°C to +125°C is ±1.1%. The device is available in a compact (4 x 4mm) TQFN lead(Pb)-free package with an exposed pad. Simulation models are available.

The device features a peak-current-mode control architecture with a MODE feature that can be used to operate the device in pulse-width modulation (PWM), pulse-frequency modulation (PFM), or discontinuous-conduction mode (DCM) control schemes. PWM operation provides constant frequency operation at all loads, and is useful in applications sensitive to switching frequency. PFM operation disables negative inductor current and additionally skips pulses at light loads for high efficiency. DCM features constant frequency operation down to lighter loads than PFM mode, by not skipping pulses but only disabling negative inductor current at light loads. DCM operation offers efficiency performance that lies between PWM and PFM modes. The low-resistance, on-chip MOSFETs ensure high efficiency at full load and simplify the layout.

A programmable soft-start feature allows users to reduce input inrush current. The device also incorporates an output enable/undervoltage lockout pin (EN/UVLO) that allows the user to turn on the part at the desired input-voltage level. An open-drain active-low RESET pin provides a delayed power-good signal to the system upon achieving successful regulation of the output voltage.

Features include; reduced external component count; no-Schottky synchronous operation; internal compensation for stable operation at any output voltage; all-ceramic capacitor solutionwith as few as eight external components. Its frequency is adjustable over 100 kHz to 2.2 MHz, with external synchronisation, and its shut-down current is 2.8 µA (typ).

Maxim Integrated; http://www.maximintegrated.com/datasheet/index.mvp/id/8360