Analog Devices UG-204

Description

This document describes the design, operation, and test results of the ADP1850SP-EVALZ. The input range for this evaluation board is 10 V to 20 V, and the two regulated output voltages are set to 3.3 V (VOUT1) and 1.8 V (VOUT2) with a maximum 14 A output current. A switching frequency (fSW) of 600 kHz is chosen to achieve a good balance between efficiency and the sizes of the power components.

The ADP1850 is a dual-channel, step-down switching controller with integrated drivers for external N-channel synchronouspower MOSFETs. The two PWM outputs are phase shifted 180°, which reduces the input RMS ripple current, thus minimizing required input capacitance. The two outputs can be combined for dual-phase PWM operation that can deliver more than 50 A output current. The internal parameters of the two channels are optimized for current sharing.

In addition, boost diodes are integrated into the ADP1850, thus lowering the overall system cost and component count. The ADP1850 can be set to operate in pulse skip, high efficiency mode under light load or in PWM continuous conduction mode.

The ADP1850 includes externally adjustable soft start, output overvoltage protection, externally adjustable current limit, power good, tracking function, and a programmable oscillator frequency that ranges from 200 kHz to 1.5 MHz. The ADP1850 provides an output voltage accuracy of ±0.85% from −40°C to +85°C and ±1.5% from −40°C to +125°C junction temperature. This controller can be powered from a 2.75 V to 20 V supply and is available in a 32-lead 5 mm × 5 mm LFCSP package.

Features

• Input range: 10 V to 20 V
• Two output voltages: 3.3 V and 1.8 V
• Output current: 14 A per channel
• Switching frequency: 600 kHz
• Operates in PWM or PSM
• Compact, low cost, and efficient design

More information

• Datasheet
• IC product information