MAXREFDES7#: Isolated ±12V @ 90mA, 3.3V in

Summary

This document details the Lakewood (MAXREFDES7#) subsystem reference design, a 3.3V input, ±12V (±15V) output, isolated power supply. The Lakewood reference design includes a 3W primary-side transformer Hbridge driver for isolated supplies, and two wide input range and adjustable output low dropout (LDO) linear regulators. Test results and hardware files are included.

The Lakewood design (MAXREFDES7#) uses an H-bridge transformer driver (MAX256) and a pair of low dropout (LDO) linear regulators (MAX1659 x2) to create a ±12V (±15V) output isolated power supply from a 3.3V voltage input (Figure 1).

This general-purpose power solution can be used in many different types of isolated power applications, but is mainly targeted for industrial sensors, industrial automation, process control, and medical applications.

Specifications

Manufacturer	Analog Devices Inc./Maxim Integrated
Category	AC/DC and DC/DC Conversion
Sub-Category	DC/DC SMPS - Multi Output
Eval Board Part Number	MAXREFDES7#-ND
Eval Board Supplier	Analog Devices Inc./Maxim Integrated
Eval Board	Normally In Stock
Topology	Step Up
Outputs and Type	2 Isolated
Voltage Out: Highest Current First	±12V
Current Out	90mA per Channel
Voltage In	3.3 V
Efficiency @ Conditions	>65%, 3.3V in, 12V @ 25 ~ 90 mA
Voltage Out Range	1.25 ~ 16 V
Features	Current Limit (Adj. or Fixed) Reverse Polarity Protection Short Circuit Protection Shutdown, Enable, Standby Thermal Protection
Switching Frequency	1 MHz
Standby Current [Typical]	100 nA
Quiescent Current [Typical]	30 µA
Component Count + Extras	27 + 14
Internal Switch	Yes
Design Author	Maxim Integrated Products
Application / Target Market	Factory Automation Medical Point of Load (PoL) Smart Building Controls
Standby Current [Maximum]	1 µA
Quiescent Current [Maximum]	60 µA
Main I.C. Base Part	MAX1659 MAX256
Date Created By Author	2012-11
Date Added To Library	2014-01